机械毕业设计英文外文翻译144发动机工作原理 - 副本

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发动机类毕业设计外文翻译

1 SummarizeOutline uses a more compact design along with the engine and has in a big way, the engine produces the waste heat density also obviously increases along with it. Some essential regions, if around a row of tyre valve radiates the question to have first to consider, the cooling system even if appears the small breakdown also possibly to create the disaster in such region consequence. The engine cooling system radiation ability generally should satisfy when the engine full load radiation demand, because this time engine produces the quantity of heat is biggest. However, when partial loads, the current capacity which the cooling system can have the power loss, which the water pumping station provides the refrigerant current capacity surpasses needs. We hoped starts the starting time to be as far as possible short. Because engine time discharges pollutant more, the oil consumption is also big. The cooling system structure has a more tremendous influence to the engine cold starting time.2 Characteristics of modern engine cooling systemModern engines series characteristic tradition cooling system function reliably protects the engine, but also should have the function which the improvement fuel economy and reduces discharges. Therefore, the modern cooling system must synthesize under the consideration the factor: Engine interior friction loss; Cooling system water pump power; Burning boundary condition, like combustion chamber temperature, complete density, complete temperature. The advanced cooling system uses systematized, the modular design method, the overall plan considered each influence factor, causes the cooling system both to guarantee the engine normal work, and enhances the engine efficiency and the reduction discharges.2.1 The temperatures set point Temperatures hypotheses firing in bursts motive operating temperature limit value are decided by a row oftire valve the peripheral region maximum temperature. The most ideal situation is according to the metal temperature but is not the refrigerant temperature control cooling system, like this can protect the engine well. Because the cooling system hypothesis cooling temperature is by the full load time most is big is the foundation, therefore, engine and cooling system in partial loads time is at not too the perfect condition, when urban district travel and low speed travel, can have the high oil consumption and discharge. Supposes the fixed point through the change refrigerant temperature to be possible to improve the engine and the cooling system in partial loads time performance. According to a row of tyre valve the peripheral region temperature limit value, may elevate either reduce the refrigerant or the metal temperature supposes the fixed point. Elevates or reduced temperature all respectively has the characteristic, this is decided the goal which achieved to the hope.2.2 Enhances the temperature Enhances the temperature to suppose the fixed-point enhancement operating temperature to suppose the fixed point is one kind of comparison the method which welcome. Enhances the temperature to have many merits, it directly affects the engine loss and the cooling system effect as well as the engine discharging formation. Will enhance the operating temperature to enhance the engine Mac reduce the engine to rub wears, reduces the engine fuel oil consumption. The research indicated that, the engine operating temperature to rubs the loss to have the very tremendous influence. Discharges the temperature the refrigerant to enhance to 150 ℃, causes the cylinder temperature to elevate to 195 ℃, the oil consumption drops 4%-6%. Maintains the refrigerant temperature in 90-115 ℃ scope, causes the engine machine oil the maximum temperature is 140 ℃, then oil consumption in partial loads time drops 10%. Enhances the operating temperature also obvious influence cooling system the potency. Enhances the refrigerant or the metaltemperature can improve the engine and disperse the steam heat transfer transmission the effect, reduces the refrigerant the speed of flow, reduces the water pump the rated power, thus reduces the engine the power dissipation. In addition, may select the different method, further reduces the refrigerant the speed of flow.2.3 Reduce the temperatures set point Reduced temperatures suppose the fixed point to reduce the cooling system the operating temperature to be possible to enhance the engine charge efficiency, reduces the inlet temperature. This to the combustion process, the fuel oil efficiency and discharges advantageously. The reduced temperature supposes the fixed point to be allowed to save the engine movement cost, enhances the part service life. The research indicated, if the cylinder head temperature reduces to 50 ℃, the ignition angle of advance may 3 ℃ A but not have the engine knock ahead of time, the charge efficiency enhances 2%, the engine operational factor improvement, is helpful to the optimized compression ratio and the parameter choice, obtains the better fuel oil efficiency and discharges the performance.2.4 Precise cooling system Precise cooling systems precise cooling system mainly manifests in the cooling jacket structural design and in the refrigerant speed of flow design. In precise cooling system, hot essential area, if around a row of tyre valve, the refrigerant has an greater speed of flow, the heat transfer efficiency is high, the refrigerant gradient of temperature changes slightly. Such effect comes from to reduce these place refrigerant channels the lateral section, enhances the speed of flow, reduces the current capacity. The precise cooling system design key lies in the determination cooling jacket the size, the choice match cooling water pump, guaranteed the system the radiation ability can satisfy when the low speed big load essential region operating temperature demand. The engine refrigerant speed of flow rangeof variation is quite big, from time 1 m/s to maximum work rate time 5 m/s. Therefore should considered the cooling jacket and the cooling system whole that, mutually supplemented, display biggest potential. The research indicated that, uses the precise cooling system, in the engine entire work rotational speed scope, the refrigerant current capacity may drop 40%. Covers the cooling jacket to the air cylinder the precise design, may make the ordinary speed of flow to enhance from 1.4m/s to 4 m/s, greatly enhances the cylinder cover or cap thermal conductivity, cylinder cover or cap metal temperature drop to 60 ℃.2.5 Divergences types cooling system Divergences types cooling system divergence type cooling system for other one kind of cooling system. In this kind of cooling system, the hine oil temperature, will cylinder cover or cap friendly cylinder body cools by respective return route, the cylinder cover or cap friendly cylinder body has the different temperature. The divergence -like cooling system has the unique superiority, may cause engine each part to suppose the fixed-point work at the most superior temperature. The cooling system overall efficiency achieves in a big way. Each cooling return route will suppose under the fixed point or the speed of flow in the different cooling temperature works, will create the ideal engine temperature distribution. The ideal engine hot active status is the cylinder head temperature lower but the air cylinder body temperature relative is higher. The cylinder head temperature is lower may enhance the charge efficiency, increases. The temperature is low also greatly may promote completely to burn, reduces CO, HC and the NOx formation, also enhances the output. The higher air cylinder body temperature can reduce the friction to lose, directly improves the fuel oil efficiency, indirectly reduces in the cylinder the peak value pressure and the temperature. The divergence type cooling system may cause the cylinder cover and the cylinder body temperaturediffers 100 ℃. The cylinder temperature may reach as high as 150 ℃, but the cylinder cover temperature may reduce 50 ℃, reduces the cylinder body to rub loses, reduces the oil consumption. The higher cylinder body temperature causes the oil consumption to reduce 4%-6%, when partial loads HC reduces 20%-35%. When the damper all opens, the cylinder cover and the cylinder body temperature supposes the definite value to be possible to move to 50 ℃ and 90 ℃, improves the fuel oil consumption, the power output from the whole and discharges.2.6 Controllable cooling system Controllable engine cooling system tradition engine cooling system belongs to the passive form, the structure simple or the cost is low. The controllable cooling system may make up at present cooling system the insufficiency. Now the cooling system design standard solves time the full load radiation problem, thus partially shoulders time the oversized radiation ability will cause the engine power waste. This to the light vehicle said especially obvious, these vehicles majority time all under the partial loads go in the urban district, only uses the partial engine power, causes a cooling system higher loss. In order to solve the engine to get down the hot question in the peculiar circumstance, the present cooling system volume was bigger, causes the evaporation efficiency to reduce, has increased the cooling system power demand, lengthened the engine during warm machine-hour. The controllable engine cooling system generally includes the sensor, the execution and the electrically controlled module. The controllable cooling system can act according to the engine working condition adjustment cooling quantity, reduces the engine power loss. In the controllable cooling system, the execution for the cooling water pump and the thermostat, generally and the control valve is composed by the electrically operated water pump, may act according to requests to adjust the cooling quantity. Temperature sensor for a system part, but rapidly bequeaths the engine hot conditionthe controller. Controllable installment, if the electrically operated water pump, may suppose the temperature the fixed point from 90 ℃ to enhance to 110 ℃, saves 2%-5% fuel oil, CO reduces 20%, HC reduces 10%. When steady state, the metal temperature ratio tradition cooling system is high 10 ℃, the controllable cooling system has the quicker response ability, may cool the temperature to maintain is supposing the fixed point ±2 ℃ the scope. From 110 ℃ drops to 100 ℃ only needs 2 s. The engine during warm machine-hour reduces 200s, the cooling system operating region draws close to the work limit region, can reduce the engine cooling temperature and the metal temperature undulation scope, reduces circulates the fatigue of metal which the hot load creates, lengthens the component life.3 ConclusionIn front of 3 conclusions introduced several kind of advanced cooling systems have the improvement cooling system performance the potential, can enhance the fuel oil efficiency and discharge the performance. The cooling system can control the nature is improves the cooling system the key, can the controlling expression to the engine structure protection essential parameter, like the metal temperature, the refrigerant temperature and the machine oil temperature and so on can control, guarantees the engine to work in the safety margin scope. The cooling system can make the rapid reaction to the different operating mode, the most earth saves the fuel, reduces discharges, but does not affect the engine overall performance. Looked from the design and the operational performance angle that, divergence type cooling and precise cooling unifies has the very good prospects for development, both can provide the ideal engine protection, and can enhance the fuel oil efficiency and discharge the nature. This kind of structure is advantageous to forming the engine ideal temperature distribution. Directly to a cylinder coveror cap row of tyre valve around the supplies refrigerant, reduced the cylinder head temperature change, causes the cylinder cover temperature distribution to be evener, also can maintains the machine oil and the cylinder body temperature at the design operating region, has a lower friction to damage the pollution withdrawal. method as follows: 1st, the cooling system function, is part of quantity of heats which absorbs the engine part carries off, guaranteed the diesel engine various components maintain in the normal temperature range. cooling system function and maintenance maintenance2nd, the cooling water should be does not contain dissolves the Xie salt the soft water, like clean river water, rain water and so on. Do not use hard water and so on the well water, water seepage or sea water, guards against produces, causes the engine to radiate not good, question occurrence and so on air cylinder heat.3rd, with the funnel when joins the cooling water the water tank, must prevent the water splashes to on the engine and the radiator, prevented on the radiator fin and the organism accumulates the dust, smears, affects the cooling effect.4th, if when the engine lacks the water causes the hyperpyrexia, cannot immediately add water, should cause the engine idling speed to revolve 10 □15 minutes, after the uniform temperature slightly reduces, slowly does not join the cooling water in the engine situation.5th, the winter, the water tank planted agent adds the hot water. After the start should surpass 40 degree-hour the slow revolution to the water temperature to be able to work. After the work had ended, must put the completely cooling water.6th, must regularly eliminate in the water tank, must frequently scour the sludge to the forced-air cooling engine radiator fin, dirty is filthy. The radiator fin cannot damage, after if damages must promptlyreplace, in order to avoid influence radiation effect.4 LathesLathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool.The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod.The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed.The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuouslyvariable speed range through electrical or mechanical drives.Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle.The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw.The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers.Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances,but swings up to 1270 mm(50 inches) and center distances up to 3658mm(12 feet) are not uncommon. Most have chip pans and a built-in coolant circulating system. Smaller engine lathes-with swings usually not over 330 mm (13 inches ) –also are available in bench type, designed for the bed to be mounted on a bench on a bench or cabinet.Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the work piece, thy are not suitable for quantity production. Often the actual chip-production tine is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations, and such persons are costly and often in short supply. However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highly developed and are widely used in manufacturing.5 Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For examples part might be made 6 in. long with a variation allowed of 0.003 (three-thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are knownas the limits. The difference between upper and lower limits is called the tolerance.1 概述随着发动机采用更加紧凑的设计和具有更大的比功率，发动机产生的废热密度也随之明显增大。

毕业设计论文外文文献翻译汽车专业发动机概述中英文对照[管理资料]

General comments of automobile engineEngine is the source of far, automotive engines are all powered by heat except for a few of automotives drived by automotive engines are called internal combustion engines because fuel burns inside the engine .The engine converts the burning fuel’s thermal energy to mechanical energy.By Cooling Systems Liquid-cooled engines and air-cooled engines are being used .Liquid-cooled engines are the most common in the diesel industry .By Fuel System Gasoline diesel and propane fuel systems are currently used in a wide variety of engines .By Ignition Method Gas engines use the spark (electrical)ignition diesel engines use the heat fro BDC to TDC ;it varies with cylinder bore size ,length of piston stroke ,and numb system injection .The calory of diesel engine come from the fuel emblazed by the compressed diesel engine’compression ration is much bigger than the gas sufficient calory is from the fuel burned by the pressed air.By valve Arrangement Four types of valve arrangements have been used in gasoline and diesel engines .Of the four types (L, T ,F ,and I heads ),the I head is commonly used on diesel engines .By Cylinder Arrangement Engine block configuration or cylinder arrangement depends on cylinder block design .Cylinders may be arranged in a straight line one behind the other .The most common in-line designs are the four-and six-cylinder engines .The V type of cylinder arrangement uses two banks of cylinders arranged in a 60°to 90°V design .The most common examples are those with two banks of three to eight cylinders each .The opposed engine uses two banks of cylinders opposite each other with the crankshaft in between .Engine’classificationAccording to the differences of the piston’movement, the piston intenal combusition engine will be classified reciprocating intenal combusition engine and rotary piston intenal combusition we will introduce working principle diagram of reciprocating internal combustion engine.Except for the wankel rotary ,engine ,all production automotive engines are the reciprocating ,or piston ,design . Reciprocating means “up and down “ or “back and forth“ .It is this up-and-down action of a piston in a cylinder that gives the reciprocating engine its name .Almost all engines of this type are built upon a cylinder block ,or engine block .The block is an iron or aluminum casting that contains the engine cylinders .The top of the block is covered with the cylinder head ,which forms the combustion chambers .The bottom of the block is covered with an oil pan ,or oil sump .A major exception to this type of engine on struction is the air-cooled V olkwagen engine .It is representative of the horizontally opposed air-cooled engines used by Porsche ,Chevrolet (Corvair ) ,and some other automobile manufacturers in years past .Power is produced by the inline motion of a piston in a cylinder .However ,this linear motion must be changed to rotating motion to turn the wheels of a car or truck .The piston is attached to the top of a connecting rod by a pin ,,called a piston pin or connecting rod transmits the up-and –down motion of the piston to the crankshaft ,which changes it to rotating motion .The connecting rod is mounted on the crankshaft with large bearings called rod bearings .Similar bearings , called main bearings ,are used to mount the crankshaft in the block.The crankshaft changes the reciprocating motion of the pistons to rotating motion .The combustible mixture of gasoline and air enters the cylinders through valves .Automotive engines use poppet valves .The valves can be in the cylinder head or in the block .The opening and closing of the valves is controlled by a camshaft .Lobes on the camshaft push the valves open as the camshaft rotates .A spring closes each valve when the lobe is not holding it open .The most common arrangements of engine cylinders and valves are discussed later .The basic single-cylinder engine consists of a cylinder (engine block ),a movable piston inside this cylinder ,a connecting rod attached at the top end to the piston and at the bottom to the offset portion of a crankshaft ,a camshaft to operate the two valves (intake and exhaust ), and a cylinder head .A flywheel is attached to one end of the crankshaft .The other end of the crankshaft has a gear to drive the camshaft gear .The camshaft gear is twice as large as the crankshaft gear .This drives the camshaft at half the speed of the crankshaft on four-stroke-cycle engines ,the crankshaft and camshaft run at the same speed .Energy ConversionThe internal combustion diesel engine is a device used to convert the chemical energy of the fuel into heat energy and then convert this heat energy into usable mechanical energy .This is achieved by combining the appropriate amounts of air andfuel and burning them in an enclosed cylinder at a controlled rate .A movable piston in the cylinder is forced down by the expanding gases of combustion .The movable piston in cylinder is connected to the top of a connecting rod .The bottom of the connected rod is attached to the offset portion is transferred to the crankshaft ,As the piston is forced down ,this offset portion of a crankshaft ,to rotate .The reciprocating (back and forth or up and down )movement of the piston is converted to rotary (turning )motion of the crankshaft ,which supplies the power to drive the vehicle .In general an average air-fuel ratio for good combustion is about 15parts of air to 1 part of fuel by weight .However ,the diesel engine always takes in a full charge of air (since there is no throttle plate in most systems ) ,but only a small part of this air is used at low or idle engine speeds .Air consists of about 20 percent oxygen while the remaining 80 percent is mostly nitrogen .This means that ,for every gallon of fuel burned ,the oxygen in 9,000 to 10,000gallons of air is required .Four-Stroke CycleGasoline by itself will not burn ,it must be mixed with oxygen (air ) .This burning is called combustion and is a way of releasing the energy stored in the air-fuel mixture .To do any useful work in an engine ,the air-fuel mixture must be compressed and burned in a sealed chamber .Here the combustion energy can work on the movable piston to produce mechanical energy .The combustion chamber must be sealed as tightly as possible for efficient engine operation .Any leakage from the combustion chamber allows part of the combustion energy to dissipate without adding to the mechanical energy developed by the piston movement .The 4-stroke engine is also called the Otto cycle engine ,in honor of the German engineer ,Dr. Nikolaus Otto ,who first applied the principle in 1876 .In the 4-stroke engine ,four strokes of the piston in the cylinder are required to complete one full operating cycle :two strokes up and two strokes down .Each stroke is named after the action it performs-intake ,compression ,power ,and exhaust :1、Intake Stroke As the piston moves down ,the vaporized ,mixture of fuel ;and air enters the cylinder past the open intake valve .2、Compression Stroke The piston returns up ,the intake valve closes ,the mixture is compressed within the combustion chamber ,and ignited by a spark .3、Power Stroke The expanding gases of combustion force the piston down in the cylinder .The exhaust valve opens near the bottom of the stroke .4、Exhaust Stroke The piston moves back up with the exhaust valve open ,and the burned gases are pushed out to prepare for the next intake stroke .The intake valve usually opens just before the top of the exhaust stroke .This 4-stroke cycle is continuously repeated in every cylinder as long as the engine remains running .Two-Stroke-CycleThe two-stroke-cycle diesel engine completes all four events:intake,compression, power ,and exhaust. in one revolution of the crankshaft or two strokes of the piston .A series of ports or openings is arranged around the cylinder in such a position that the ports are open when the piston is at the bottom of its stroke .A blower forces air into the cylinder through the open ports .expelling all remaining exhaust gases past the open exhaust valves and filling the cylinder with air .This is called scavenging .As the piston moves up ,the exhaust valves close and the piston covers the ports .The air trapped above the piston is compressed ton covers the ports .The air trapped above the piston is compressed since the exhaust valve is closed .Just before the piston reaches top dead center ,the required amount of fuel is injected into the cylinder .The heat generated by compressing the air ignites the fuel almost immediately .Combustion continues until the fuel injected has been burned .The pressure resulting from combustion forces the piston downward on the power stroke .When the piston is approximately falfway down ,the exhaust valves are opened ,allowing the exhaust gases to escape .Further downward movement uncovers the inlet ports ,causing fresh air to enter the cylinder and expel the exhaust gases .The entire procedure is then repeated ,as the engine continues to run .The differences of the two intenal combustion engineIt could be assumed that a two-cycle engine with the same number of cylinders ,the same displacement ,compression ratio ,and speed as a four-cycle engine would have twice the power since it has twice as many power .However ,this is not the case ,since both the power and compression strokes are shortened to allow scavenging to take place .Thetwo-cycle engine also requires a blower ,which takes engine power to drive .About 160 degrees out of each 360 degrees of crankshaft rotation are required for exhaust gas expulsion and fresh air intake (scavenging )in a two-cycle engine .About 415 degrees of each 720 degrees of crankshaft rotation in a four-cycle engine are required forintake and exhaust .These figures indicate that about % of crank rotation is used for the power producing events in the two-cycle engine ,while about 59% of crank rotation is used for these purposes in the four-cycle engine .Friction losses are consequently greater in the four-cycle engine .Heat losses ,however ,are greater in the two-cycle engine though both the exhaust and the cooling systems .In spite of these differences ,both engine types enjoy prominent use worldwide .Engine constructionCylinder Block:The cylinder block is cast in one piece. Usually, this is the largest and the most complicated single piece of metal in the automobile.The cylinder block is a complicated casting made of gray iron (cast iron ) or aluminum. It contains the cylinders and the water jackets that surround them. To make the cylinder block, a sand form called a mold is made. Then molten metal is poured into the mold. When the metal has cooled the sand mold is broken up and removed. This leaves the tough cylinder-block casting. The casting. The casting is then cleaned and machined to make the finished block.Cylinder blocks for diesel engines are very similar to those for spark-ignition engines. The basic difference is that the diesel-engine cylinder block is heavier and stronger. This is because of the higher pressures developed in the diesel-engine cylinders.Several engines have aluminum cylinder blocks. Aluminum is relatively light metal, weighing much less than cast iron. also ,aluminum conducts heat more rapidly than cast soft to use as cylinder wall material. It wears too rapidly. Therefore, aluminum cylinder blocks must have cast-iron cylinder liners or be cast from an aluminum alloy that has silicon particles in it.Some manufactures make an aluminum cylinder block that does not have cylinder liners, or sleeves. Instead ,the aluminum is loaded with silicon particles. Silicon is a very hard material. After the cylinder block is cast, the cylinders are honed. Then they are treated with a chemical that etches eats away, the surface aluminum. This leaves only the silicon particles exposed. the piston and rings slide on the silicon with minimum wear. Piston:The piston converts the potential energy of the fuel into the kinetic energy that turns the crankshaft. The piston is a cylindrical shaped hollow part that moves up and down inside the engine’s cylinder. It has grooves around its perimeter near the top where thering are placed. The piston fits snugly in the cylinder. It has grooves around its perimeter near the top where the rings are placed. The piston fits snugly in the cylinder. The pistons ate used to ensure a snug “air tight” fit.The piston in your engine’s cylinder are similar to your legs when you ride a bicycle. Think of your legs as pistons; they go up and down on the pedals, providing power. Pedals are like the connecting rods; they are “attached”to your legs. The pedals are attached to the bicycle crank which is like the crank shaft, because it turns the wheels.To reverse this, the pistons (legs) are attached to the connecting rods ( pedals ) which are attached to the crankshaft (the bicycle rank). The power from the combustion in the cylinders powers the from the combustion rods to turn the crankshaft. Connecting rod：The connecting rod shown in is made of forged high strength steel. It transmits force and motion from the piston to the crank pin on the crankshaft. A steel piston pin, or “wrist pin”, connects the small end of the connecting rod. Some rods have a lock bolt in the small end. As the piston moves up and down in the cylinder, the pin rocks back and forth in the hole, or bore, in the piston. The big end of the connecting rod is attached to a crank pin by a rod bearing cap.Connecting rod and rod-bearing caps are assembled during manufacture. Then the hold for the bearing is bored with the cap in place. This is called line-bring. It make each rod and its cap a matched set. Usually, the same number is stamped on the rod and cap. This prevents the caps setting mixed during engine service. If the caps are mixed, the bearing bore will not be round. An engine assembled with the rod bearing caps switched will probably lock the crankshaft. If the crankshaft turns, the bearing will probably have improper clearance and early bearing failure will result.Another reason for keeping the cap and rod matched is to prevent engine unbalance and unwanted vibration. All connecting rods in an engine must be as light as possible. But they must all weigh the same. If one rod is heavier than the other, the engine will vibrate. This could damage the engine.Crankshaft：The crankshaft then main rotating member, or shaft, in the engine. It has crank-pins, to which the connecting rod from the pistons are attached. During the power strokes, the connecting rods force the crank-pins and therefore the crankshaft to rotate. The reciprocating motion of the pistons is changed to rotary motion as the crankshaft spins. This rotary motion is transmitted through the power train to the car wheels.The crankshaft is a strong, one-piece casting, or forging, or heat-treated alloy steel. It must be strong to take the downward force of power strokes without excessive bending. It must be balanced so the engine will run without excessive vibration.Engine DisplacementThe frequently used engine specifications are engine displacement and compression ratio .Displacement and compression ration are related to each other ,as we will learn in the following paragraphs .By Displacement Engine displacement is the amount of air displaced by the piston when it moves fro .The electrical ignition system causes a spark across the spark plug electrodes in the cylinder at the end of the compression stroke ,which ignites the vaporized fuel and air mixture .m compressing the air to ignite the fuel when it is injected into the cylinder at the end of the compression ratios are much higher than gasoline engine compression ratios ,sufficient heat is generated by compressing the air to ignite the fuer of cylinders .engines are classified as low ,medium ,high ,and super high speed .Commonly used to indicate engine size ,this specification is really a measurement of cylinder volume ..The number of cylinders is a factor in determining displacement ,but the arrangement of the cylinders or valves is not .Engine displacement is calculated by multiplying the number of cylinders in the engine by the total engine displacement is the volume displaced by all the pistons .The displacement of one cylinder is the space through which the piston’s top surfa ce moves as it travels from the bottom of its stroke (bottom dead center )to the top of its stroke (top dead center ).It is the volume displaced by the cylinder by one piston stroke .Piston displacement can be calculated as follows :the bore (cylinder Diameter )by gives you the radius of the bore .the radius (multiply it by itself ).the square of the radius by (pi orπ)to find the area of the cylinder cross section .the area of the cylinder cross section by the length of the stroke .You now know the piston displacement for one cylinder .Multiply this by the number of cylinders to determine the total engine displaceme`nt .The formula for the complete procedure reads :R2*π*stroke* cylinders =displacementCompression RatioThis specification compares the total cylinder volume to the volume of only the combustion cylinder volume may seem to be the same as piston displacement ,but it is not .Total cylinder volume .The combustion chamber volume with the piston at top dead center is often called the clearance volume .Compression ratio is the total volume of a cylinder divided by its clearance volume .If the clearance volume is one-eighth of the total cylinder volume ,the compression ratio is 8 (8to1).The formula is as follows :olumeClearancev e Totalvolum =Compression ratio. In theory ,the higher the compression ratio ,the greater the efficiency of the engine ,and the more power an engine will develop from a given quantity of fuel .The reason for this is that combustion takes place faster because the fuel molecules are more tightly packed and the flame of combustion travels more rapidly .But there are practical limits to how high a compression ratio can be .Because of the unavailability of high octane fuel ,most gasolineburning engines are restricted to a compression ratio no greater than to this high ,however ,create high combustion chamber temperatures .This in turn creates oxides of nitrogen (NOx) ,a primary air pollutant .In the early 1970s ,compression ratios were lowered to around 8 to permit the use of lower octane low-lead or unleaded fuel ,and to reduce NOx formation .Advances in electronic engine control in the 1980s have allowed engineers to raise compression ratios to the 9and 10 to 1 range for optimum performance and economy发动机概述发动机是汽车的动力源。

机械设计制造及其自动化毕业设计外文翻译

英文原文名Automatic production line PLC control中文译文：自动化生产线自动上料站的PLC控制自动生产线是由工件传送系统和控制系统，将一组自动机床和辅助设备按照工艺顺序联结起来，自动完成产品全部或部分制造过程的生产系统，简称自动线。

二十世纪20年代，随着汽车、滚动轴承、小电机和缝纫机和其他工业发展,机械制造业开始出现在自动生产线,第一个是组合机床自动线。

在20世纪20年代,第一次出现在汽车工业流水生产线和半自动生产线,然后发展成自动生产线。

第二次世界大战后,在机械制造工业发达国家,自动生产线的数量急剧增加。

采用自动生产线生产的产品应该足够大,产品设计和技术应该是先进的、稳定的和可靠的,基本上保持了很长一段时间维持不变。

自动线用于大,大规模生产可以提高劳动生产率,稳定和提高产品质量,改善劳动条件,降低生产区域,降低生产成本,缩短生产周期,保证生产平衡、显著的经济效益。

自动生产线的一个干预指定的程序或命令自动操作或控制的过程,我们的目标是稳定、准确、快速。

自动化技术广泛用于工业、农业、军事、科学研究、交通运输、商业、医疗、服务和家庭,等自动化生产线不仅可以使人们从繁重的体力劳动、部分脑力劳动以及恶劣、危险的工作环境,能扩大人的器官功能,极大地提高劳动生产率,提高人们认识世界的能力,可以改变世界。

下面我说下它的应用范围：机械制造业中有铸造、锻造、冲压、热处理、焊接、切削加工和机械装配等自动线，也有包括不同性质的工序，如毛坯制造、加工、装配、检验和包装等的综合自动线。

加工自动线发展最快,应用最广泛的机械制造。

主要包括:用于处理盒、外壳、各种各样的部件,如组合机床自动线;用于加工轴、盘部分,由通用、专业化、或自动机器自动专线;转子加工自动线;转子自动线加工过程简单、小零件等。

1.确保节拍时间:无论什么样的产品,都必须完成的时间生产。

2.单元过程:只有一个产品,单位部分处理、组装、加工和材料。

现代包装机械设备毕业课程设计外文文献翻译、中英文翻译

1 英文文献翻译1.1 Modern PackagingAuthor：Abstract1. Changing Needs and New RolesLooking back, historical changes are understandable and obvious. That all of them have had an impact on the way products are brought, consumed and packaged is also obvious. What is not so obvious is what tomorrow will bring. Yet, it is to the needs, markets, and conditions of tomorrow that packaging professionals must always turn their attention.The forces that drove packaging during the Industry Revolution continue to operate today. The consumer society continues to grow and is possibly best described by a 1988s bumper sticker, “Born to Shop”. We consume goods today at a rate 4 to 5 times greater than we did as recently as 1935. Most of these goods are not essential to survival; they constitute what we may call “the good life”.In the second half of the 20th century， the proliferation of goods was so high that packaging was forced into an entirely new role, that of providing the motivation rather than presenting the goods itself. On a shelf of 10 competing products, all of them similar in performance and quality, the only method of differentiating became the package itself. Marketer aimed at lifestyles, emotional values, subliminal images, features, and advantages beyond the basic product rather than the competitor’s. In some in instances, the package has become the product, and occasionally packaging has become entertainment.A brand product to carry the product manufacturer or product sales of theretailer’s label, usually by the buyer as a quality assessment guidance. In some cases, competing brands of product quality is almost no difference, a difference is the sale of its packaging. An interesting visually attractive packaging can give a key marketing advantage and convince impulse spending. However, the packaging should accurately reflect the quality of products/brand value in order to avoid the disappointment of consumers, encourage repeat purchases and build brand loyalty. Ideally, the product should exceed customer expectations.2. Packaging and the Modern Industrial SocietyThe importance of packaging to a modern industrial society is most evident when we examine the food-packaging sector. Food is organic in nature, having an animal or plant source. One characteristic of such organic matter is that, by and large, it has a limited natural biological life.A cut of meat, left to itself, might be unfit for human consumption by the next day. Some animal protein products, such as seafood, can deteriorate within hours.The natural shelf life of plant-based food depends on the species and plant involved. Pulpy fruit portions tend to have a short life span, while seed parts, which in nature have to survive at least separated from the living plant are usually short-lived.In addition to having a limited natural shelf life, most food is geographically and season-ally specific. Thus, potatoes and apples are grown in a few North American geographical regions and harvest during a short maturation period. In a world without packaging，we would need to live at the point of harvest to enjoy these products, and our enjoyment of them would be restricted to the natural biological life span of each. It is by proper storage, packaging and transport techniques that we are able to deliver fresh potatoes and apples, or the products derived from them, throughout the year and throughout the country. Potato-whole,canned, powdered, flaked, chipped, frozen, and instant is available, anytime, anywhere. This ability gives a society great freedom and mobility. Unlike less-developed societies, we are no longer restricted in our choice of where to live, since we are no longer tied to the food-producing ability of an area. Food production becomes more specialized and efficient with the growth of packaging. Crops and animal husbandry are moved to where their production is most economical, without regard to the proximity of a market. Most important, we are free of the natural cycles of feast and famine that are typical of societies dependent on natural regional food-producing cycles.Central processing allows value recovery from what would normally be waste by products of the processed food industry from the basis of other sub-industries. Chicken feathers are high in protein and, properly mill and treated, can be fed back to the next generation of chickens. Vegetable waste is fed to cattle or pigs. Bagasse, the waste cane from sugar pressing, is a source of fiber for papermaking. Fish scales are refined to make additives for paints and nail polish.The economical manufacture of durable goods also depends on good packaging.A product's cost is directly related to production volume. The business drive to reduce costs in the supply chain must be carefully balanced against the fundamental technical requirements for food safety and product integrity, as well as the need to ensure an. efficient logistics service. In addition, there is a requirement to meet the aims of marketing to protect and project brand image through value-added pack design. The latter may involve design inputs that communicate distinctive, aesthetically pleasing, ergonomic, functional and/or environmentally aware attributes. But for a national or international bicycle producer to succeed, it must be a way of getting the product to a market, which may be half a world away. Again, sound packaging, in this case distributionpackaging, is a key part of the system.Some industries could not exist without an international market. For example, Canada is a manufacturer of irradiation equipment, but the Canadian market (which would account for perhaps one unit every several years) could not possibly support such a manufacturing capability. However, by selling to the world, a manufacturing facility becomes viable. In addition to needing packaging for the irradiation machinery and instrumentation, the sale of irradiation equipment requires the sale packaging and transport of radioactive isotopes, a separate challenge in itself. In response to changing consumer lifestyles, the large retail groups and the food service industry development. Their success has been involved in a competition fierce hybrid logistics, trade, marketing and customer service expertise, all of which is dependent on the quality of packaging. They have in part led to the expansion of the dramatic range of products offered, technology innovation, including those in the packaging. Supply retail, food processing and packaging industry will continue to expand its international operations. Sourcing products around the world more and more to assist in reducing trade barriers. The impact of the decline has been increased competition and price pressure. Increased competition led to the rationalization of industrial structure, often in the form of mergers and acquisitions. Packaging, it means that new materials and shapes, increased automation, packaging, size range extension of lower unit cost. Another manufacturer and mergers and acquisitions, the Group's brand of retail packaging and packaging design re-evaluation of the growing development of market segmentation and global food supply chain to promote the use of advanced logistics and packaging systems packaging logistics system is an integral part of, and played an important role in prevention in the food supply or reduce waste generation.3. World Packaging.This discussion has referred to primitive packaging and the evolution of packaging functions. However, humankind's global progress is such that virtually every stage in the development of society and packaging is present somewhere in the world today. Thus, a packager in a highly developed country will agonize over choice of package type, hire expensive marketing groups to develop images to entice the targeted buyer and spend lavishly on graphics. In less-developed countries, consumers are happy to have food, regardless of the package. At the extreme, consumers will bring their own packages or will consume food on the spot, just as they did 2000 years ago.Packagers from the more developed countries sometimes have difficulty working with less-developed nations, for the simple reason that they fail to understand that their respective packaging priorities are completely different. Similarly, developing nations trying to sell goods to North American markets cannot understand our preoccupation with package and graphics.The significant difference is that packaging plays a different role in a market where rice will sell solely because it is available. In the North American market, the consumer may be confronted by five different companies offering rice in 30 or so variations. If all the rice is good and none is inferior, how does a seller create a preference for his particular rice? How does he differentiate? The package plays a large role in this process.The package-intensive developed countries are sometimes criticized for over packaging, and certainly over-packaging does exist. However, North Americans also enjoy the world's cheapest food, requiring only about 11 to 14% of our disposable income. European food costs are about 20% of disposable income, and in the less-developed countries food can take 95%of family income.4. The status and development trend of domestic and international packaging machineryWorldwide, the history of the development of the packaging machinery industry is relatively short, science and technology developed in Europe and America in general started in the 20th century until the 1950s the pace greatly accelerated.From the early 20th century, before the end of World War II World War II，medicine，food, cigarettes，matches，household chemicals and other industrial sectors, the mechanization of the packaging operations; the 1950s, the packaging machine widely used common electric switches and tube for the main components of the control system to achieve the primary automation; 1960s, Electrical and optical liquid-gas technology is significantly increased in the packaging machine, machines to further expand on this basis a dedicated automated packaging line; the 1970s, the micro- electronic technology into the automation of packaging machines and packaging lines, computer control packing production process; from the 1980s to the early 1990s, in some field of packaging, computer, robot application for service, testing and management, in preparation for the over-flexible automatic packaging lines and "no" automatic packaging workshop.Actively promoted and strong co-ordination of all aspects of society, and gradually establish a packaging material, packaging, printing, packaging machinery and other production sectors, and corresponding to the research, design, education, academic, management and organization, and thus the formation of independent and complete. The packaging of light industrial system, and occupies an important place in the national economy as a whole.Based on recent years data that members of the World Packaging Alliance output value of the packaging industry accounts for about 2% of the total output value of the national economy; in which the proportion of packaging machinery, though not large, but the rapid development of an annual average of almost growing at a rate of about 10%. Put into use at the packaging machine is now more than thousand species of packaging joint machines and automated equipment has been stand-alone equate. According to the new technological revolution in the world development trend is expected to packaging materials and packaging process and packaging machinery will be closely related to obtain the breakthrough of a new step, and bring more sectors into the packaging industry.China Packaging Technology Association was established in 1980. Soon, the China National Packaging Corporation have been born. Since then, one after another in the country organized a national and international packaging machinery exhibition, seminars, also published I had the first ever "China Packaging Yearbook and other packaging technology books. All this indicates that China is creating a new packaging historical perio d.1.2中文翻译现代包装1、不断变化的需求和新的角色,回顾以往,包装所带来明显的历史性变化是可以理解的, 一个产品包装方式的给他们的销量带来的影响也是显而易见的。

外文翻译-引擎机械概述

本科毕业设计（论文）中英文对照翻译院（系部）专业名称年级班级学生姓名指导老师2012年5月ENGINE MECHANICALOperation Main Components and Classification of the Engine The automotive engine is essentially a heat mobiles are internal combustion engines.Princiole of OperationThe spark-ignition engine is an internal-combustion engine with externally supplied in ignition .The gasoline engine is a kind of spark-ignition engines.The four-stroke-cycle gasoline engine cycle is spread over four pistion strokes.The first stroke in your engine is called the intake stroke. Instead of opening the intake valve after you have drawn the poston down . you will find it better to open the intake valve as the piston starts down . This allows the air to draw fuel in the entire time the piston is moving down.Remember , the intake stroke starts with the piston at the top of the cylinder(intake valve open and exhaust valve closed)and stops with the piston at the bottom of its travel . This requires one half turn of the crankshaft.As the crankshaft continues to move , the piston is forced up through the cylinder . If you keep both valves closed , the fuel mixture will be squeezed , or compressed , as the piston reaches the top .This is called the compression stroke . It , too , requires a half turn of the crankshaft .The compression stroke serves to break up the fule into even smaller particles . This happens due to the the sudden swelling and churning of the mixture as it is compressed .When the air fule mixture is subjected to a sudden sharp compression force . its temperature rises .This increase in temperature makes the mixture easier to ignite and causes it to explode with greater force , As the piston reaches the top of its travel on the compression sroke , it has returned to the pro[er position to be pushed back down by the explosion.Remember , the compression stroke starts with the piston at the bottom of the cylinder(both valves closed)and the stops with the piston at the top of the cylinder . This requires an additional half turn of crankshaft .As the piston reaches the top the compression stroke ,the mixture is broken into tiny particles and heated up . when ignited , it will explode with great force . This is the right time to explode the mixture . A spark plug provides a spark inside the combustion chamber ,The spark produced at the plug is formed by the ignition system.Just imagine that a hot spark has been provided in the fuel mixture .The mixture will explode and , in turn , force the piston down into the cylinder . This gives the crankshaft a quick and forceful push . This is the power stroke , Both valves must be kept closed during the power stroke or the pressure of the burning fuel will squirt out through the valve ports . Remenber , the power storke starts with the piston at the top of ylinder(both valves closed) and stops with the piston at the botton of the cylinder , T his requires another half turn of the crankshaft .When the piston reaches the bottom of the power stroke .the exhaust valve opens . The spinning crankshaft forces the piston up through the cylinder , pushing burned gases out . This is the exhaust stroke .Remenber , the exhaust stroke starts with the piston at the bottom of the cylinder (exhaust valve open and intake valve closed) . It stops with the piston at the top of the cylinder . This requires one more half turn of the crankshaft .If you count the number of half turns in the intake , compression , power , and exhaust storkes , You will find you have a total of four , This gives you two complete turns , or revolutions ,of the crankshaft . When the crankshaft is turning around twice ,it is receiving power only during one half turn , or one fourth of the time .As soon as the piston reaches the top of the exhaust stroke , it starts down on another intake , compression , power ,and exhaust cycle , this cycle is repeated over and over ,Each complete cycle consists of four strokes of the piston , hence the name four-storke cycle.Main Engine ComponenntsEngine BlockThe engine block serves as a rigid metal foundation for all parts of engine . It contains the cylinders and supports the crankshaft and camshaft . In older engines ,the valve seats , ports ,and guides are built into the block ,Accessry unis and the clutch housing are boled to it .Blocks are made of either cast iron or aluninum ,The lighter the block(providing it has sufficient strength), the better ,The modern thin-wall casting proces controls core size and placement much more accuratcely than the older casting process .This permits casting the block walls much thinner , reducing the weight of the block .Since the bolck wall thickness is more uniform , block distortion during service less severe .CylindersThe cylinder is a aroud hole formed in the block .It forms a guide guide for the piston and acts as a containner for taking in , compressing ,firing , and the exhausting the air-fuel chareg , Cylinder have been made of both steel and cast iron .Cast iron is by far the most popular.When steel cylinders are desired in an aluminum block, they are installed in the form of cylinder sleeves(round , pipe-like liners ), These sleeves may be eiher cast or pressed into the block ,Some engines use removable cylinder sleeves . When the cylinde becomes won The old sleeves can be pulled out and new sleeves can be pressed in . The sleeves are pressed into oversize cylinder holes ,Cylinder sleeves are widely used in heavy-duty truck and industrial engines ,Sleeves can also be used to be repair a won or cracked cylinder in a cast iron block .PistonsThe piston must move down through the cylinder to the cylinder to produce a vacuum to draw a fuel charge into the cylinder . It then travels up in the cylinder and compresses the mixture ,When the mixture is fired , the pressure of the expanding gas is transmitted to the top of piston . This drives the piston back down through the cylinder with great force , transmitting the expanding gas to the crankshaft ,The piston then then travels up through the cylinder and exhaust the burned fuel charge.Pistons are usually made of aluminum . Often ,aluminum piston are tin-plated to allow proper break-in when the engine is stared ,Aluminum pistons can be forged ,but they are more commonly cast .Cast iron is a good material for pistons used m a slow-speed engine .It has excellent wear characteristics and will provide good performance .Connecting RodsAs the name implies , connecting rods are used to connect protons to the crankshaft .The upper end of the rod oscillates(swings back and forth), while the lower ,or big end ,bearing rotates(turns).Because there is very little bearing movement in the upper end , the bearing area can be reasonably small . The lower end rotates very fast , and the crankshaft bearing journal turns inside the connecting rod . This rotational speed tends to produce heat and wear .To make the rod wear well, a larger bearing area is required.The upper end of the rod has a hole through it for the piston pin ,The botton of the large end of the connecting red must be removed SO the rod can be installed on the crankshaft journal .The section that is removed is called the connecting rod cap.Connecting rods are normally made of alloy steel .They are drop-forged shape and then machined .CrankshaftThe engine crankshaft provides a constant turning force to the wheels ,it has through to which connecting rods are attached ,and its function to change the reciprocating motion of the piston to a rotary motion to drivethe wheels . Crankshaft are made of alloy steel or cast iron.The crankshaft is held in position by a series of main bearings ,The maximum mumber of main bearings for a crankshaft is one more than the munber of cylinders. It may have fewer main bearings than cylinder .Most engines use pressman insert bearings that are constructed like the connecting rod bearings, But are somewhat larger .In addition to supporting the crankshaft , one of the main bearings must control the forward and backward movement.FlywheelA heavy flywheel is attached to the rear of the crankshaft with bolts ,The function of the flywheel is to smooth out engine speed and keep the crankshaft spinning between power strokes . in some engines , the flywheel also serves as a mounting ,surface for the clutch . The outer rim of the flywheel has a large ring attached with gear teeth cut into it , The teeth of the starter motor engine these teeth and spin the flywheel to crank the engine . When all automatic transmission is used ,the torque converter assembly works with the flywheel.CamshaftThe camshaft is used to open and close the valves . There is one cam on the camshaft for each valve in the engine ,Generally only one camshaft is used in most engines . Newer engines are increasingly equipped with two or more camshaft.ValvesEach engine cylinder ordinarily has two valves . However , modern engines often use four valves per cylinder(two intake and two exhaust), A few engines used in smaller vehicles have three intake valves per cylinder : two intake valves and one exhaust valves or three intake valves and two exhaust valves .Because the head of an exhaust valve operates at temperatures up to 1300C(704C) ,valves are made of heat-resistant metal . In order to prevent burning ,the valve must give off heat to the valve seat and to the valve guide . The valve must be make good contact with seat and must run with minimum clearance in the guide .Valve LiftersMechanical valve lifters are usually made of cast iron , The bottom Dart that contacts the camshaft is hardened .Some lifters are hollow to reduce weight .Most valve trains that contain mechanical lifters have some provision for adjusting clearance . Mechanical valve lifters were used in older engines .Hydraulic valve lifters perform the same job as mechanical lifters , However ,hydraulic lifters are self-adjusting , operate with no lifte-to –rockerarm clearance . and uses engine oil under pressure to operate ,Hydraulic lifters are quite in operration .Engine ClassificationCycle ClassificationEngines are often classified according to cycle . Most internal combustion piston engines use a two-or four –stroke cycle .All modern automobile engines use the four stroke cycle engine .The two-stroke cycle engine performs the intake , compression , firing , and exhaust sequence in one revolution of the crankshaft.Cylinder ClassificationThe inline engine has its cylinders arranged one after the other in a straight line , They are in a vertical , or near vertical position . Most modern inline engines are four cylinders .A V-type engine places two banks or rows of cylinders at an angle to each other-genre-ally at 60or 90 ,The V-type engine has several advantages: short length , extra block rigidity , a short , heavy crankshaft , and low profile that is conducive to low hood lines , The shorter block permits a reduction in vehicle length with riot sacrifice in passenger room .The horizontal opposed engine is like a V-type engine , except that both banks lie in a horizontal plane . The advantage here is all extrmely low overall height .Which makes this engine ideally suited installations where space is limited .Cooling ClassificationAs you have learned ,engines are either liquid-collde or air-colled . Most vehicles use liquid-colled engines .Air-colled engines are used in limited numbers modern vehicles .Fuel ClassificationAutomobile engines can use gasoline , diesel fule , gasohol(mixture of gasoline and alcohol), alcohol , LNG(liquefied natural gas) ,CNG(compressed natural gas) ,or LPG(liquefied propane gas ) .Gasoline powers the majority of vehicles , but diesel fule is used in some vehicles .Gosohol ,LNG ,CNG ,and LPG are beginning to see wider use .One of the principle differences in these engines is in method of fuel delivery and carburction .Gasoline ,LNG ,CNG ,and LPG utilize the same basic type of engine , but LNG ,CNG ,and LPG utilize a slightly different fule delivery setup .Diesel engines do not use a carburetor or all ignition system .Valve SystemOperation of Valve systemYou have seen that the intake valve stroke .Both valves must remain closed during the compression and power stroke ,and the eshaust valve opens during the exhaust stroke , The designer must design a device to open and close the valves at the proper times .The shaft will have an egg-shaped bump called a cam lobe .The cam lobe is machined as an integral part of the shaft .This shaft is called a camshaft .The distance the valve will be raised , how long it will stay open , and how fast it opens and closes can all be controlled by the height and shape of the hole .As you will see later , it is impractical to have the cam lobe contact the end of valve stem .When the camshaft is turn ,the lobes will not even touch the valve stem ,The lifter is installed between the cam lobe and the valve stem . The upper end rides on the lobe and the lower and almost touches the valve stem . The lifter slides up and down in a a hole bored in the head metal that separates the valve stem from the camshaft .You have developed a method of opening and closing the valves .The next problem is how and at what speed to turn the camshafts , Each valve must be open for one storke .The intake valve is open during the intake storke and remains closed during the compression ,power ,and exhaust stroke .This would indicate that the cam lobe must be turn fast enough to raise the valve erery fourth stroke .You can see that it takes one complete revolution of the cam lobe four strokes of the piston .Remember that four srokes of the piston require two revolutions of the crankshaft , the cam shaft must be once , If you are speaking of the speed of the camshaft ,you can say that the camshaft must turn at one-half crankshaft speed .If the crankshaft is turning and the camshaft must turn at one-half crankshaft speed , it seems logical to use the spinning crankshaft to turn the camshaft ,One very simple way to drive the camshaft would be by means of gears and a belt . One gear is fastened on the end of the crankshaft ,and the other is fastened on the end of the camshaft .The large camshaft gear drives the smaller crankshaft gear through the belt .If ,for instance ,the small gear Oil the crankshaft has 10 teeth and the large gear on the camshaft has 20 teeth ,the crankshaft will truth the camshaft at exactly one-half crankshaft speed .VVT-Toyota`s Continuously Variable Valve TimingThe most significant and satisfying changes to the Lexus GS line are inthe area power train . In the case of GS300 , Lexus breathes new life into last year`s 3.0Lin-line six by introducing VVT-continuously variable valve timing syestem .On the dyne ,VVT shows up as only five additional horsepower and 10 lb-ft of torque . But in the car it meansfuel economy improvements of 1.6 mpg .smoother idle ,California TLEV (transitional tow-emissions vehicle )certification and zero-to 60 mph a half second quicker .Toyota eliminates the compromise of conventional valve timig with the introduction of VVT , By continuously varying intake valve timing (up to 60 crank angle degrees) , Toyota optimizes low-to mid-speed torque , improves fule economy and lowers emissions without having a negative impact on idle .In essence ,the system controls valve overlap ,which means it can climinate it completyly for a glass smooth idle . or maximize it to boost volumetric efficiency ang reduce pumping losses this translates into power ,economy and cleaner running at all engine speeds.The heart of the system is the intake cam pulley , which consists of an inner and outer section ,The inner portion is fixed to the camshaft and nests inside the belt-driven outer pulley via helical spline gears . An electronically controlled hydraulic piston moves the pully halves relative to one another ,causing the cam portion to rotate within the outer pulley.This rotation davances or retarda intake valve timing .A spool valve reacting to signals from the ECU controls hydraulic pressure .VTEC-Honda Variable Valve Timing and Lift Electronic Control By desiging a higher valve lift ,wider valve-timing ,and large valve valve diameter ,it is possible to obtain a higher volumetric efficienvy to copy with higer output engine speeds ,The VTEC is used to improve volumetric effiency from low engine speed to high engine speed .With VTEC, the valve timing and lift can be dajusted at low engine rotation to increase troque and prevent air from being forced back through the intake .VTEC OperationFig.2-4 shows the VTEC mechanism while operating at low engine speeds . In the low-speed mode the 3 rocker arms are separated and use cams A&B only . At this time the mid rocker arm is in contact with the high speed cam due to the spring force in the lost motion mechanism .It is separated from the primary and secondary rocker arm and thus is not actuating the valve .Fig.2-5shows the VTEC mechanism while operating in the high speed mode . During high speed engine operation the 3 rocker arms are connected and move together due to the 2 hydraulic pistons which have moved over due to increased hydraulic presure.MIVEC-Mitsubishi Innovative Valve timing Elecctronnic Control systemThe MIVEC dual-intake valve canshaft enables changing betweeen low-speed and high-speed moders(Fig.2-6), resulting in easy operation from low to high rams ,improving the driving experience when staring from a stop light , merging on to the freeway ,or accelerating to overtake another car .In the pursuit of pure driving enjoyment,potentially incompatible goals like fuel economy ,environment-friendiness,and clean driving have all been achieved . Low-speed ModeThe difference in the dual-intake valve lift(low lift and medium lift)and enhanced in-cylinder streaming further stabilize combustion without compromising fuel econmy ,emissions ,and torque .High-speed ModeExtending the injection valve opening time and expanding the valve lift range in ,creases intake air mass and achieves output close to best in class .The Grandis is equipped with the 2.4L MIVEC and the Colt is equipped with the 1.3 and 1.5L MIVEC .Electronic Valve Control SystemAn electronic valve control (EVC) system replace the mechanical camshaft ,controling each valve with actuators for inpendent valve with actuators for independent valve timing .The EVC system control the opening and closing time and lift amout of each intake and exhaust valve with independent actuators on each valve .Changing from a mechanical camshaft driven valve into dependently controled actuator valves provide a huge amount of flexibility in engine control strategy .Vehicles utilizing EVC can realize several benefits including :1)increase engine power and fuel economy.2)Allows centralized and distributed EVC system to perform at their full potential.3)Adapts to engines of varied cylinder counts .With all of improved efficiencies and consumer benefits , auto manufacturers are eager to get their first EVC systems on the road ,The EVC system is targeted to operate in temperatures up to 125C ,while the actuator can be controlled in a centralized syetem with a high-speed multiplex bus (up to 10Mbps)or in a distributed system with a nominal speed bus .EVC systems must be compact in size ,specifically the actuators that must be small enough to fit in the engine space .A vchicle that use a 42V system is ideal for EVC because it requires high voltage to control the valveactuators , and EVC is targeted for V8 and V12 engines.Smart ValvesValco is actively developing technology for reducing fuel consumption and emissions with an engine cylinder-head design that uses its smart valve. Actuation(SV A)in place of conventional operation of engine valves by the cam belt ,camshaft,and hydraulic cam followers .SV A is the first of many innovations that Valco intends to actively develop and market to meet increasing demand for better fuel economy and reduced pollution following its acquisition of Johnson Control`s Engine Electronics Division .In a camless engine ,each engine valve is operated by an actuator mounted above the Valve guides.Each actuator is linked to an engine-mounted valve control units that ensures optimal of all valves and performs the power drive function .By controlling residual gases ,minimizing pumping losses ,and deactivating cylinders and valves ,this technology can reduce consumption and pollutant emissions by 20%. Consumers will benfit from enhanced performance from increases in low-end engine torque .The SV A development program is supposed by several car manufactures and is scheduled for volume production in 2009.Piston and Rod RepairThis repair procedure requires removal of the cylinder head and oil pan .It is much easier to perform this work with the engine removed from the vehicle and mounted on a stand .These procedures requires certain hand tools .A cylinder ridge reamer, a numbered punch set ,piston ring expander ,snapring tools and piston intallation tool ring compressor are all necessary for correct piston and rod repair .Cleaning&InspectionIf the piston is out of specification or otherwise unusable ,it must be replaced,If the cylinder is worm or damaged ,the engine block must be bored and oversize pistons installed.1.Remove the piston rings from the piston .The compression rings (top and middle rings) must be removed using a piston ring expander ,to prevent breakage and /or scratching the piston.2.If there is no obvious damage to the piston and the intent is to reuse the piston ,clean the ring grooves with a ring groove cleaner , being careful not to cut into the piston metal .Heavy carbon deposits can be cleaned from the top of the piston with a scraper or Wire brush .Do not ,however ,use a wire wheel on the ring grooves or lands .Clean the he oil drain holes in the ring grooves .Clean all remaining dirt ,carbon and varmish from the piston with a suitable solvate and abrush ,Do not use a caustic solution on alumnum parts .3.After cleaning ,inspect the piston for scuffing , scoring ,cracks ,pitting or excessive ring groove wear . Replace the piston if obviusly worm .4.If the piston appears servicable , measure the piston diameter usinga micrometer . Measure the Piston diameter in the thrust direction ,90 degrees to the piston pin axis ,1-1/4 inch below the top of the piston .5.Inspect the cylinder bores for taper and out-of-round .The cylinder bores must be measured at 3 levels top to bottom in directions of East-to-West and North-to-South .Measure the cylinder using a bore gauge, or with a telescope gauge and micrometer .The measurement shoud be made in the piston thrust direction at the top ,middle and bottom of the cylinder . Note: Piston diameter and cylinder measurements shoud be made with the parts at room temperature ,70F(21C).6.Subtract the piston diameter measurement from the cylinder measurement .This I the piston-to-cylinder wall claerance .If the clearance is excesive or if the cylinder wall is badly scored or scuffied ,the cylinder may have to be bored and an oversize piston installed .7.Verify that the cylinder has a proper cross-hatch pattern .These tiny marks are the result of the honing operation dating engine manufacture .They retain engine oil to keep the piston tings from scuffing during engine break-in after overhaul .If little or no cross ,hatch is evident ,the cyliunder may require re-honing if the cylinder is in otherwise good condition or reborn if the cylinder is worn or damaged .8.If the piston-to-cylinder wall clearance is within specifications ,check the ring groove clearance .Roll the piston ring around the ring groove in which it is to be installed and check the clearance with a feeker gauge .Compare the measurement with permeation .High points in the ring groove that may cause the ring to bind may be cleaned up carefully with a small flat file .Replace the piston if the ring groove clearance is not within specification.9.Check the connecting rod for damager or obvious wear .Check for signs of over heating(blue appearance)or fractures and check the bearing bore for out-of-round and taper ,A shiny surface on the pin boss side of the piston usually indicates that the connecting rod is bent or the wrist pin hole is not in proper relation to the piston skirt and ring grooves .Abnormal connecting rob beating wear can be caused by either abent connecting rob . An improperly machined journal or a tapered connecting rob bore .Twisted connecting robs will not create an easily identifiable wear pattern ,but badly twisted robs will disturb the action of the entire piston ,rings ,and connectingrob assembly and may be the cause of excessive oil consumption .10.If the piston must be removed from the connectong rob ,mark the side of the connecting rob that corrresponds with the side of the piston that faces the front of the engine ,so the new piston will be installed facing the same direction ,Most pistons have an zrrow or notch on the top of the piston ,indicating that this side should face the front of the engine .If the original piston is to be reinstalled , use paint or a marker to indicate the cylinder number on the piston , so it can reinstalled on the same connecting rob .11.The piston pin is a press fit in the connecting rob .If the piston and /or connecting rob must be replaced ,the pin must be pressed into the connecting rob using a fixture that will not damage or distort the piston and /or connecting rob .The piston must move freely on the pin after installation . Ridge Removal& HoningRidge RemovalThis particular procedure applies to all vehicles .Inspect the upper portions of cylinder (near the head )for a didge formed by ring wear .If there is ridge , it must be removed by forst shifting the piston down in the cylinder and then covering the piston top completely with a clean rag .Use a ridge reamer to remove metal at the lip until the cylinder , If this is not done , the rings will be damaged during removal of the piston .HoningBefore honing the cylindersa ,stuff plently of clean shop towels under the bores and over the crankshaft (if still in the engine (to keep the abrasive materials from entering the crankshaft area.1. The cylinder bore resizing hone equipped with 220 grit or equivalent is the best tool for this job .In addition to deglazing , it will reduce taper and out-of-round as well a removing light scuffing ,scoring or scratches .Usualy a few strokes will clean up a bore and maintain required limits .2.Deglazing of the cylinder walls may be done using a cylinder surfacing hone (or equivalent ) .Use a tool equipped with 280 grit stones if the cylinder is already straight and round .Usually 20-60strokes ,depending on the bore condition will be sufficient to provide a satisfactory surface .Inspect the cylinder walls each 20 strokes ,using a light hotdog on available from an automotive part store .3.Honing should be done by moving the hone up and down fast enough to get a cross-hatch pattern .When hone marks intersect at 50~60 , the cross-hatch angle is most satisfactory for proper seating of the rings /4. A controlled hone motor speed between 200~300rpm is neccssary to obtain the proper cross-hatch angle .The number of up and down strokes perminute can be regulated to get the desired 50-60angle .Faster up and down strokes increase the crosshatch angle .5.After honing , it will be neccssary to clean the block to remove all traces of abrasive .Rod Bearing ReplacementThe engine crankshaft and connecting rod bearing clearances can be determined by the use of plastigage or a similar product . The follwing is the recommended procedure for the use of of plastigage .1.Rotate the crankshaft until the connecting rod boss to be checked is at the bottom of its stroke /2.With the connecting rod and the connectong and the connecting rod bearing cap removed from the crankshaft ,remove the oil film from the surface to be checked .Plastigage is soluble in oil3.Place a piece of plastigage across the entire width of the bearing shell in the bearing cap approximately 1/4 inch (6.3ram) off center and away from the oil hole .In daaition ,suspect areas can be checked by placing plastigage in the suspect area .4.Before assembling the rod bearing cap with the plaetigage in place , the rankshaft must be rotated until the connecting rod being checked starts moving toward the top of the engine .Only then should the cap be assembled and tightened to specifications .Do not rotate the crankshaft while assembling the cap or the plastigage may be smeared ,giving inaccurate results .5.Remove the bearing cap and compare the width of the flattened plastigage with the metric scale provided on the packaged .Locate the band closest to the same width .This hand shows the amount of clearance in thousandths of a millimeter .Differnces in readings between the ends indicate the amount of taper present . Record all readings taken ,Plastigage generally is accompainied by to scales . Oneself is in inches , the other is a metric scale ,plasigage is available in a variety of clearance ranges .。

机械毕业设计英文外文翻译76齿轮泵的工作原理 - 副本

附录AThe working principle of gear pumpBy into the internal gear pump a pair of gear, gear of two side have cover, shell, cover and gear of each tooth formed many seal groove between work cavity. When gear as shown on the right direction rotates, oil absorption cavity due to mesh with each other in engagement gradually withdraw, seal volume increase gradually, vacuum forming part of the oil in the tank, so outside the atmospheric pressure, the function of the oil absorption, oil absorption into the cavity, the gear, and as full of slot between gear rotating, put the oil to the left pressure oil lumen. In one side, because gear oil pressure here into meshing, seal gradually working chamber volume will decrease, the oil will be out, from pressure oil chamber pressure is sent to the in pipeline. In the working process of the gear pump, as long as two gear direction of rotation unchanged, its to absorb the soot, the position of the cavity is sure the same. Here the meshing point tooth contact line has been space high and low voltage cavity with two plays a role in the gear pump oil, so do not need set up special assignment institutions, this is it and other types of volumetric hydraulic pump differences. The concept of thegear pump is very simple, that is, it is the most basic form of two dimensions of the same gear in a closely in the shell, the shell rotating mesh with each other the internal similar "8" glyph, two gear, gear inside the outer diameter and shell on both sides and closely. From the extruder materials in the suction into two gear, and full of the middle space, with the rotation of the teeth, and the last in the shell movement along the two teeth mesh eduction.I n terms of speaking, the gear pump also called positive displacement device, that is like a cylinder piston, when in a tooth into another tooth fluid, liquid space by mechanical discharged. To squeeze Because liquids as incompressible, so the liquid and tooth can occupy the same space at the same time, such, liquid was ruled out. Because of the constant mesh, this phenomenon is in continuous occur, thus also in the pump export provides a continuous removal amount, pump every around, the amount of discharge are the same. Along with the drive shaft rotation incessantly, the pump is also not a break from fluid. The flow rate of the pump and the speed of the pump directly about.In fact, there were a small amount of the pump fluid loss, which make the pump efficiency can't reach 100%, because these fluid is used to lubricating bearings and gear, and on both sides of the pumpbody can't without clearance fit, so can't make fluid from export 100% from a small amount of fluid loss, so is inevitable. However pump can still operating well, for most extrusion material, it can still reach 93% ~ 98% of efficiency. For viscosity or density in the process of change, this pump is not fluid too much influence. If there is a damper, such as in the row export side put a screen or a limitationfor the device, the pump will promote the fluid through them. If the damper in work, that is, if the mesh changes become dirty, blocked,or the limit of back pressure increased, the pump will remain constant flow, until it reaches the weakest part of the device of mechanical limit (usually equipped with a torque limit device).For a pump rotation speed, in fact, there is a limit, it mainly depends on process flow, if the transfer of oil, it can pump is at high speed rotating, but when the fluid is a kind of high viscositypolymer melt, the restrictions will be significantly reduced. Promote high sticky fluid into the suction side of the two tooth space is very important, if the space did not fill, it can't pump discharge accurate flow, so the PV value (pressure x velocity is also a) a limiting factor, and it's a process variables. Because these restrictions, the gearpump manufacturers will provide a series of products, i.e., different specifications and displacement (every turn a week does quantity).The pump will and the concrete application process, in order to make the system combined capacity and price to achieve optimal.附录B齿轮泵的工作原理轮泵由装在壳体内的一对齿轮所组成，齿轮两侧有端盖，壳体、端盖和齿轮的各个齿间槽组成了许多密封工作腔。

机械专业毕业设计外文翻译1

本科毕业设计（本科毕业论文）外文文献及译文文献、资料题目：High-rise Tower Crane designed文献、资料来源：期刊（著作、网络等）文献、资料发表（出版）日期：2000.3.25院（部）：机电工程学院专业：机电工程及自动化High-rise Tower Crane designed under Turbulent Winds At present, construction of tower cranes is an important transport operations lifting equipment, tower crane accident the people's livelihood, major hazards, and is currently a large number of tower crane drivers although there are job permits, due to the lack of means to monitor and review the actual work of a serious violation . Strengthen the inspection and assessment is very important. Tower crane tipping the cause of the accident can be divided into two aspects: on the one hand, as a result of the management of tower cranes in place, illegal operation, illegal overloading inclined cable-stayed suspended widespread phenomenon; Second, because of the tower crane safety can not be found in time For example,Took place in the tower crane foundation tilt, micro-cracks appear critical weld, bolts loosening the case of failure to make timely inspection, maintenance, resulting in the continued use of tower cranes in the process of further deterioration of the potential defect, eventually leading to the tower crane tipping. The current limit of tower crane and the black box and can not be found to connect slewing tower and high-strength bolts loosening tightened after the phenomenon is not timely, not tower verticality of the axis line of the lateral-line real-time measurement, do not have to fight the anti-rotation vehicles, lifting bodies plummeted Meng Fang, hook hoists inclined cable is a timely reminder and record of the function, the wind can not be contained in the state of suspended operation to prevent tipping on the necessary tips on site there is a general phenomenon of the overloaded overturning of the whole security risks can not be accurately given a reminder and so on, all of which the lease on the tower crane, use, management problems,Through the use of tower crane anti-tipping monitor to be resolved. Tower crane anti-tipping Monitor is a new high-tech security monitoring equipment, and its principle for the use of machine vision technology and image processing technology to achieve the measurement of the tilt tower, tower crane on the work of state or non-working state of a variety of reasons angle of the tower caused by the critical state to achieve the alarm, prompt drivers to stop illegal operation, a computer chip at the same time on the work of the state of tower crane be recorded. Tower crane at least 1 day overload condition occurs, a maximum number of days to reach 23 overloading, the driver to operate the process of playing the anti-car, stop hanging urgency, such as cable-stayed suspended oblique phenomenon often, after verification and education, to avoid the possible occurrence of fatal accidents. Wind conditions in the anti-tipping is particularly important, tower cranes sometimes connected with the pin hole and pin do not meet design requirements, to connect high-strength bolts are not loose in time after the tightening of the phenomenon, through timely maintenance in time after the tightening of the phenomenon, through timely maintenance and remedial measures to ensure that the safe and reliable construction progress. Reduced lateral line tower vertical axis measuring the number of degrees,Observation tower angle driver to go to work and organize the data once a month to ensure that the lateral body axis vertical line to meet the requirements, do not have to every time and professionals must be completed by Theodolite tower vertical axismeasuring the lateral line, simplified the management link. Data logging function to ensure that responsibility for the accident that the scientific nature to improve the management of data records for the tower crane tower crane life prediction and diagnosis of steel structures intact state data provides a basis for scientific management and proactive prevention of possible accidents, the most important thing is, if the joint use of the black box can be easily and realistically meet the current provisions of the country's related industries. Tower crane safety management at the scene of great importance occurred in the construction process should be to repair damaged steel, usually have to do a good job in the steel tower crane maintenance work and found that damage to steel structures, we must rule out potential causes of accidents, to ensure safety in production carried out smoothly. Tower crane in the building construction has become essential to the construction of mechanical equipment, tower crane at the construction site in the management of safety in production is extremely important. A long time, people in the maintenance of tower crane, only to drive attention to the conservation and electrical equipment at the expense of inspection and repair of steel structures, to bring all kinds of construction accidents.Conclusion: The tower crane anti-tipping trial monitor to eliminate potential causes of accidents to provide accurate and timely information, the tower crane to ensure the smooth development of the leasing business, the decision is correct, and should further strengthen and standardize the use of the environment (including new staff training and development of data processing system, etc.).The first construction cranes were probably invented by the Ancient Greeks and were powered by men or beasts of burden, such as donkeys. These cranes were used for the construction of tall buildings. Larger cranes were later developed, employing the use of human treadwheels, permitting the lifting of heavier weights. In the High Middle Ages, harbour cranes were introduced to load and unload ships and assist with their construction – some were built into stone towers for extra strength and stability. The earliest cranes were constructed from wood, but cast iron and steel took over with the coming of the Industrial Revolution.For many centuries, power was supplied by the physical exertion of men or animals, although hoists in watermills and windmills could be driven by the harnessed natural power. The first 'mechanical' power was provided by steam engines, the earliest steam crane being introduced in the 18th or 19th century, with many remaining in use well into the late 20th century. Modern cranes usually use internal combustion engines or electric motors and hydraulic systems to provide a much greater lifting capability than was previously possible, although manual cranes are still utilised where the provision of power would be uneconomic.Cranes exist in an enormous variety of forms – each tailored to a specific use. Sizes range from the smallest jib cranes, used inside workshops, to the tallest tower cranes,used for constructing high buildings, and the largest floating cranes, used to build oil rigs and salvage sunken ships.This article also covers lifting machines that do not strictly fit the above definition of a crane, but are generally known as cranes, such as stacker cranes and loader cranes.The crane for lifting heavy loads was invented by the Ancient Greeks in the late 6th century BC. The archaeological record shows that no later than c.515 BC distinctive cuttings for both lifting tongs and lewis irons begin to appear on stone blocks of Greek temples. Since these holes point at the use of a lifting device, and since they are to be found either above the center of gravity of the block, or in pairs equidistant from a point over the center of gravity, they are regarded by archaeologists as the positive evidence required for the existence of the crane.The introduction of the winch and pulley hoist soon lead to a widespread replacement of ramps as the main means of vertical motion. For the next two hundred years, Greek building sites witnessed a sharp drop in the weights handled, as the new lifting technique made the use of several smaller stones more practical than of fewer larger ones. In contrast to the archaic period with its tendency to ever-increasing block sizes, Greek temples of the classical age like the Parthenon invariably featured stone blocks weighing less than 15-20 tons. Also, the practice of erecting large monolithic columns was practically abandoned in favour of using several column drums.Although the exact circumstances of the shift from the ramp to the crane technology remain unclear, it has been argued that the volatile social and political conditions of Greece were more suitable to the employment of small, professional construction teams than of large bodies of unskilled labour, making the crane more preferable to the Greek polis than the more labour-intensive ramp which had been the norm in the autocratic societies of Egypt or Assyria.The first unequivocal literary evidence for the existence of the compound pulley system appears in the Mechanical Problems (Mech. 18, 853a32-853b13) attributed to Aristotle (384-322 BC), but perhaps composed at a slightly later date. Around the same time, block sizes at Greek temples began to match their archaic predecessors again, indicating that the more sophisticated compound pulley must have found its way to Greek construction sites by then.During the High Middle Ages, the treadwheel crane was reintroduced on a large scale after the technology had fallen into disuse in western Europe with the demise of the Western Roman Empire. The earliest reference to a treadwheel (magna rota) reappears in archival literature in France about 1225, followed by an illuminated depiction in a manuscript of probably also French origin dating to 1240. In navigation, the earliest uses of harbor cranes are documented for Utrecht in 1244, Antwerp in 1263, Brugge in 1288 and Hamburg in 1291, while in England the treadwheel is not recorded before 1331.Generally, vertical transport could be done more safely and inexpensively by cranes than by customary methods. Typical areas of application were harbors, mines, and, in particular, building sites where the treadwheel crane played a pivotal role in the construction of the lofty Gothic cathedrals. Nevertheless, both archival and pictorial sources of the time suggest that newly introduced machines like treadwheels or wheelbarrows did not completely replace more labor-intensive methods like ladders, hods and handbarrows. Rather, old and new machinery continued to coexist on medieval construction sites and harbors.Apart from treadwheels, medieval depictions also show cranes to be powered manually by windlasses with radiating spokes, cranks and by the 15th century also by windlasses shaped like a ship's wheel. To smooth out irregularities of impulse and get over 'dead-spots' in the lifting process flywheels are known to be in use as early as 1123.The exact process by which the treadwheel crane was reintroduced is not recorded, although its return to construction sites has undoubtedly to be viewed in close connection with the simultaneous rise of Gothic architecture. The reappearance of the treadwheel crane may have resulted from a technological development of the windlass from which the treadwheel structurally and mechanically evolved. Alternatively, the medieval treadwheel may represent a deliberate reinvention of its Roman counterpart drawn from Vitruvius' De architectura which was available in many monastic libraries. Its reintroduction may have been inspired, as well, by the observation of the labor-saving qualities of the waterwheel with which early treadwheels shared many structural similarities.In contrast to modern cranes, medieval cranes and hoists - much like their counterparts in Greece and Rome - were primarily capable of a vertical lift, and not used to move loads for a considerable distance horizontally as well. Accordingly, lifting work was organized at the workplace in a different way than today. In building construction, for example, it is assumed that the crane lifted the stone blocks either from the bottom directly into place, or from a place opposite the centre of the wall from where it could deliver the blocks for two teams working at each end of the wall. Additionally, the crane master who usually gave orders at the treadwheel workers from outside the crane was able to manipulate the movement laterally by a small rope attached to the load. Slewing cranes which allowed a rotation of the load and were thus particularly suited for dockside work appeared as early as 1340. While ashlar blocks were directly lifted by sling, lewis or devil's clamp (German Teufelskralle), other objects were placed before in containers like pallets, baskets, wooden boxes or barrels.It is noteworthy that medieval cranes rarely featured ratchets or brakes to forestall the load from running backward.[25] This curious absence is explained by the high friction force exercised by medieval treadwheels which normally prevented the wheel from accelerating beyond control.目前，塔式起重机是建筑工程进行起重运输作业的重要设备，塔机事故关系国计民生、危害重大，而目前众多的塔机司机虽然有上岗证，由于缺少监督和复核手段，实际工作中违规严重。

【机械类文献翻译】柴油发动机工作原理

Keywords: Piston; Technology; processing equipment; cutting; Fixture
Any type ofmachinethat obtains mechanicalenergy directly from the expenditure of the chemical energy of fuel burned in acombustionchamber that is an integral part of the engine. Four principal types of internal-combustion engines are in general use: the Otto-cycle engine, the diesel engine, the rotary engine, and thegas turbine. For the various types of engines employing the principle of jet propulsion,seeJet Propulsion;Rocket. The Otto-cycle engine, named after its inventor, the German technician Nikolaus August Otto, is the familiar gasoline engine used in automobiles and airplanes; the diesel engine, named after the French-born German engineerRudolf Christian Karl Diesel, operates on a different principle and usually uses oil as a fuel. It is employed in electric-generating and marine-power plants, in trucks and buses, and in some automobiles. Both Otto-cycle and diesel engines are manufactured in two-stroke and four-stroke cycle models.The essential parts of Otto-cycle and diesel engines are the same. The combustion chamber consists of a cylinder, usually fixed, that is closed at one end and in which a close-fitting piston slides. The in-and-out motion of the piston varies the volume of the chamber between the inner face of the piston and the closed end of the cylinder. The outer face of the piston is attached to a crankshaft by a connecting rod. The crankshaft transforms the reciprocating motion of the piston into rotary motion. In multicylindered engines the crankshaft has one offset portion, called a crankpin, for each connecting rod, so that the power from each cylinder is applied to the

机械工程毕业设计外文翻译

毕业设计论文外文资料原文及译文学院：机电工程学院专业：机械设计制造及其自动化班级：学号：姓名：Mechanical engineering1.The porfile of mechanical engineeringEngingeering is a branch of mechanical engineerig,it studies mechanical and power generation especially power and movement.2.The history of mechanical engineering18th century later periods,the steam engine invention has provided a main power fountainhead for the industrial revolution,enormously impelled each kind of mechznical biting.Thus,an important branch of a new Engineering – separated from the civil engineering tools and machines on the branch-developed together with Birmingham and the establishment of the Associantion of Mechanical Engineers in 1847 had been officially recognized.The mechanical engineering already mainly used in by trial and error method mechanic application technological development into professional engineer the scientific method of which in the research,the design and the realm of production used .From the most broad perspective,the demend continuously to enhance the efficiencey of mechanical engineers improve the quality ofwork,and asked him to accept the history of the high degree of education and training.Machine operation to stress not only economic but also infrastructure costs to an absolute minimun.3.The field of mechanical engineeringThe commodity machinery development in the develop country,in the high level material life very great degree is decided each kind of which can realize in the mechanical engineering.Mechanical engineers unceasingly will invent the machine next life to produce the commodity,unceasingly will develop the accuracy and the complexity more and more high machine tools produces the machine.The main clues of the mechanical development is:In order to enhance the excellent in quality and reasonable in price produce to increase the precision as well as to reduce the production cost.This three requirements promoted the complex control system development.The most successful machine manufacture is its machine and the control system close fusion,whether such control system is essentially mechanical or electronic.The modernized car engin production transmission line(conveyer belt)is a series of complex productions craft mechanizationvery good example.The people are in the process of development in order to enable further automation of the production machinery ,the use of a computer to store and handle large volumes of data,the data is a multifunctional machine tools necessary for the production of spare parts.One of the objectives is to fully automated production workshop,three rotation,but only one officer per day to operate.The development of production for mechanical machinery must have adequate power supply.Steam engine first provided the heat to generate power using practical methods in the old human,wind and hydropower,an increase of engin .New mechanical engineering industry is one of the challenges faced by the initial increase thermal effciency and power,which is as big steam turbine and the development of joint steam boilers basically achieved.20th century,turbine generators to provide impetus has been sustained and rapid growth,while thermal efficiency is steady growth,and large power plants per kW capital consumption is also declining.Finally,mechanical engineers have nuclear energy.This requires the application of nuclear energy particularly high reliability and security,which requires solving many new rge power plants and the nuclear power plant control systems have become highly complex electroonics,fluid,electricity,water and mechanical parts networks All in all areas related to the mechanical engineers.Small internal combustion engine,both to the type (petrol and diesel machines)or rotary-type(gas turbines and Mong Kerr machine),as well as their broad application in the field of transport should also due to mechanical enginerrs.Throughout the transport,both in the air and space,or in the terrestrial and marine,mechanial engineers created a variety of equipment and power devices to their increasing cooperation with electrical engineers,especially in the development of appropration control systems.Mechanical engineers in the development of military weapons technology and civil war ,needs a similar,though its purpose is to enhance rather than destroy their productivity.However.War needs a lot of resources to make the area of techonlogy,many have a far-reaching development in peacetime efficiency.Jet aircraft and nuclear reactors are well known examples.The Biological engineering,mechanical engineering biotechnology is a relatively new and different areas,it provides for the replacement of the machine or increase thebody functions as well as for medical equipment.Artficial limbs have been developed and have such a strong movement and touch response function of the human body.In the development of artificial organ transplant is rapid,complex cardiac machines and similar equipment to enable increasingly complex surgery,and injuries and ill patients life functions can be sustained.Some enviromental control mechanical engineers through the initial efforts to drainage or irrigation pumping to the land and to mine and ventilation to control the human environment.Modern refrigeration and air-conditioning plant commonaly used reverse heat engine,where the heat from the engine from cold places to more external heat.Many mechanical engineering products,as well as other leading technology development city have side effects on the environment,producing noise,water and air pollution caused,destroyed land and landscape.Improve productivity and diver too fast in the commodity,that the renewable naturalforces keep pace.For mechanical engineers and others,environmental control is rapidly developing area,which includes a possible development and production of small quantities of pollutants machine sequnce,and the development of new equipment and teachnology has been to reduce and eliminate pollution.4.The role of mechanical engineeringThere are four generic mechanical engineers in common to the above all domains function.The 1st function is the understanding and the research mechanical science foundation.It includes the power and movement of the relationship dynamics For example,in the vibration and movement of the relationship;Automatic control;Study of the various forms of heart,energy,power relations between the thermodynamic;Fluidflows; Heat transfer; Lubricant;And material properties.The 2nd function will be conducts the research,the desing and the development,this function in turn attempts to carry on the essential change to satisfy current and the future needs.This not only calls for a clear understanding of mechanical science,and have to breakdown into basic elements of a complex system capacity.But also the need for synthetic and innovative inventions.The 3rd function is produces the product and the power,include plan,operation and maintenance.Its goal lies in the maintenance eitherenhances the enterprise or the organization longer-tern and survivabilaty prestige at the same time,produces the greatest value by the least investments and the consumption.The 4th function is mechanical engineer’s coordinated function,including the management,the consultation,as well as carries on the market marking in certain situation.In all these function,one kind unceasingly to use the science for a long time the method,but is not traditional or the intuition method tendency,this is a mechanical engineering skill aspect which unceasingly grows.These new rationalization means typical names include:The operations research,the engineering economics,the logical law problem analysis(is called PABLA) However,creativity is not rationalization.As in other areas,in mechanical engineering,to take unexpected and important way to bring about a new capacity,still has a personal,marked characteristice.5.The design of mechanical engineeringThe design of mechanical is the design has the mechanical property the thing or the system,such as:the instrument and the measuring appliance in very many situations,the machine design must use the knowledge of discipline the and so on mathematics,materials science and mechanics.Mechanical engineering desgin includeing all mechanical desgin,but it was a study,because it also includes all the branches of mechsnical engineering,such as thermodynamics all hydrodynamics in the basic disciplines needed,in the mechanical engineering design of the initial stude or mechanical design.Design stages.The entire desgin process from start to finish,in the process,a demand that is designed for it and decided to do the start.After a lot of repetition,the final meet this demand by the end of the design procees and the plan.Design considerations.Sometimes in a system is to decide which parts needs intensity parts of geometric shapesand size an important factor in this context that we must consider that the intensity is an important factor in the design.When we use expression design considerations,we design parts that may affect the entire system design features.In the circumstances specified in the design,usually for a series of such functions must be taken into account.Howeever,to correct purposes,we should recognize that,in many cases thedesign of important design considerations are not calculated or test can determine the components or systems.Especially students,wheen in need to make important decisions in the design and conduct of any operation that can not be the case,they are often confused.These are not special,they occur every day,imagine,for example,a medical laboratory in the mechanical design,from marketing perspective,people have high expectations from the strength and relevance of impression.Thick,and heavy parts installed together:to produce a solid impression machines.And sometimes machinery and spare parts from the design style is the point and not the other point of view.Our purpose is to make those you do not be misled to believe that every design decision will needreasonable mathematical methods.Manufacturing refers to the raw meterials into finished products in the enterprise.Create three distinct phases.They are:input,processing exprot.The first phase includes the production of all products in line with market needs essential.First there must be the demand for the product,the necessary materials,while also needs such as energy,time,human knowledge and technology resourcess .Finall,the need for funds to obtain all the other resources. Lose one stage after the second phase of the resources of the processes to be distributed.Processing of raw materials into finished products of these processes.To complete the design,based on the design,and then develop plans.Plan implemented through various production processes.Management of resources and processes to ensure efficiency and productivity.For example,we must carefully manage resources to ensure proper use of funds.Finally,people are talking about the product market was cast.Stage is the final stage of exporting finished or stage.Once finished just purchased,it must be delivered to the users.According to product performance,installation and may have to conduct further debugging in addition,some products,especially those very complex products User training is necessary.6.The processes of materials and maunfacturingHere said engineering materials into two main categories:metals and non-ferrous,high-performance alloys and power metals.Non-metallic futher divided into plastice,synthetic rubber,composite materials and ceramics.It said the productionproccess is divided into several major process,includingshape,forging,casting/ founding,heat treatment,fixed/connections ,measurement/ quality control and materal cutting.These processes can be further divide into each other’s craft.Various stages of the development of the manufacturing industry Over the years,the manufacturing process has four distinct stages of development, despite the overlap.These stages are:The first phase is artisanal,the second Phase is mechanization.The third phase is automation the forth Phase is integrated.When mankind initial processing of raw materials into finished products will be,they use manual processes.Each with their hands and what are the tools manuslly produced.This is totally integrated production take shape.A person needs indentification,collection materials,the design of a product to meet that demand,the production of such products and use it.From beginning to end,everything is focused on doing the work of the human ter in the industrial revolution introduced mechanized production process,people began to use machines to complete the work accomplished previously manual. This led to the specialization.Specialization in turn reduce the manufacture of integrated factors.In this stage of development,manufacturing workers can see their production as a whole represent a specific piece of the part of the production process.One can not say that their work is how to cope with the entire production process,or how they were loaded onto a production of parts finished.Development of manufacting processes is the next phase of the selection process automation.This is a computer-controlled machinery and processes.At this stage,automation island began to emerge in the workshop lane.Each island represents a clear production process or a group of processes.Although these automated isolated island within the island did raise the productivity of indivdual processes,but the overall productivity are often not change.This is because the island is not caught in other automated production process middle,but not synchronous with them .The ultimate result is the efficient working fast parked through automated processes,but is part of the stagnation in wages down,causing bottlenecks.To better understand this problem,you can imagine the traffic in the peak driving a red light from the red Service Department to the next scene. Occasionally you will find a lot less cars,more than being slow-moving vehicles,but the results can be found by thenext red light Brance.In short you real effect was to accelerate the speed of a red Department obstruction offset.If you and other drivers can change your speed and red light simultaneously.Will advance faster.Then,all cars will be consistent,sommth operation,the final everyone forward faster.In the workshop where the demand for stable synchronization of streamlined production,and promoted integration of manufacturing development.This is a still evolving technology.Fully integrated in the circumstances,is a computer-controllrd machinery and processing.integrated is completed through computer.For example in the preceding paragraph simulation problems,the computer will allow all road vehicles compatible with the change in red.So that everyone can steady traffic.Scientific analysis of movement,timing and mechanics of the disciplines is that it is composed of two pater:statics and dynamics.Statics analyzed static system that is in the system,the time is not taken into account,research and analysis over time and dynamics of the system change.Dynameics from the two componets.Euler in 1775 will be the first time two different branches: Rigid body movement studies can conveniently divided into two parts:geometric and mechanics.The first part is without taking into account the reasons for the downward movement study rigid body from a designated location to another point of the movement,and must use the formula to reflect the actual,the formula would determine the rigid body every point position. Therefore,this study only on the geometry and,more specifically,on the entities from excision.Obviously,the first part of the school and was part of a mechanical separation from the principles of dynamics to study movement,which is more than the two parts together into a lot easier.Dynamics of the two parts are subsequently divided into two separate disciplines,kinematic and dynamics,a study of movement and the movement strength.Therefore,the primary issue is the design of mechanical systems understand its kinematic.Kinematic studies movement,rather than a study of its impact.In a more precise kinematic studies position,displacement,rotation, speed,velocity and acceleration of disciplines,for esample,or planets orbiting research campaing is a paradigm.In the above quotation content should be pay attention that the content of the Euler dynamics into kinematic and rigid body dynamics is based on the assumptionthat they are based on research.In this very important basis to allow for the treatment of two separate disciplines.For soft body,soft body shape and even their own soft objects in the campaign depends on the role of power in their possession.In such cases,should also study the power and movement,and therefore to a large extent the analysis of the increased complexity.Fortunately, despite the real machine parts may be involved are more or less the design of machines,usually with heavy material designed to bend down to the lowest parts.Therefore,when the kinematic analysis of the performance of machines,it is often assumed that bend is negligible,spare parts are hard,but when the load is known,in the end analysis engine,re-engineering parts to confirm this assnmption.机械工程1.机械工程简介机械工程是工程学的一个分支，它研究机械和动力的产，尤其是力和动力。

外文翻译----柴油机的工作原理

Keywords: Piston; Technology; processing equipment; cutting; Fixture
Any type ofmachinethat obtains mechanicalenergy directly from the expenditure of the chemical energy of fuel burned in acombustionchamber that is an integral part of the engine. Four principal types of internal-combustion engines are in general use: the Otto-cycle engine, the diesel engine, the rotary engine, and thegas turbine. For the various types of engines employing the principle of jet propulsion,seeJet Propulsion;Rocket. The Otto-cycle engine, named after its inventor, the German technician Nikolaus August Otto, is the familiar gasoline engine used in automobiles and airplanes; the diesel engine, named after the French-born German engineerRudolf Christian Karl Diesel, operates on a different principle and usually uses oil as a fuel. It is employed in electric-generating and marine-power plants, in trucks and buses, and in some automobiles. Both Otto-cycle and diesel engines are manufactured in two-stroke and four-stroke cycle models.The essential parts of Otto-cycle and diesel engines are the same. The combustion chamber consists of a cylinder, usually fixed, that is closed at one end and in which close-fitting piston slides. The in-and-out motion of the piston varies the volume of the chamber between the inner face of the piston and the closed end of the cylinder. The outer face of the piston is attached to a crankshaft by a connecting rod. The crankshaft transforms the reciprocating motion of the piston into rotary motion. In multicylindered engines the crankshaft has one offset portion, called a crankpin, for each connecting rod, so that the power from each cylinder is applied to the crankshaf

发动机工作原理中英文对照解释

发动机工作原理（中英文对照）发动机工作原理大多数汽车的发动机是内燃机，往复四冲程汽油机，但是也有使用其它类型的发动机，包括柴油机，转子发动机，二冲程发动机和分程燃烧发动机。

往复的意思就是上下运动或前后运动，在往复发动机中，气缸中活塞的上下运动产生发动机的动力，这种类型几乎所有的发动机都是依赖气缸体即发动机缸体，缸体是铸铁或铸铝制的，它包括发动机气缸和冷却液循环用的水套。

缸体的顶部是气缸盖，它组成了燃烧室，缸体底部是油底壳。

气缸内活塞的直线运动产生动力，然而，必须将直线运动转化成旋转运动，使汽车车轮转动，活塞销将活塞连接在连杆顶部，连杆底部与曲轴连接，使汽车车轮转动，活塞销将活塞连杆顶部，连杆底部与曲轴连接，连杆将活塞的往复运动传递给曲轴，曲轴将其转化为旋转运动，连杆是用连杆曲轴安装在曲轴上的，用类似的轴承即主轴承将曲轴固定在缸体内。

气缸的直径称为发动机的内径，排量和压缩比是两个常用的发动机参数，排量是指发动机的大小，压缩比是气缸总容积与燃烧室压缩容积之比。

术语:冲程是用来说明活塞在气缸内的运动，也就是活塞行程的距离根据发动机类型的需要二冲程或四冲程来完成一个工作循环四冲程发动机也叫做奥托发动机，为了纪念德国工程师奥托，他是在1876年第一个应用该原理的，在四冲程发动机中，要求气缸活塞四冲程来完成一个完整的工作循环，每个冲程根据其行为命名分别为:进气冲程，压缩冲程，做功冲程和排气冲程。

1、进气冲程当活塞下移时，雾化后的可燃混合气通过打开的进气门进入气缸，为了达到最大的进气量，进气门在活塞到达上止点前10°打开，使进、排气门有20°打开重叠角，进气门一直打开到活塞到达下止点充分进入混合气之后50°左右。

2、压缩冲程活塞开始向上移动时，进气门关闭，混合气在燃烧室中压缩，根据不同因素包括压缩比，节气门开度，发动机转速压力上升到约1兆帕，接近冲程顶部时，火花塞产生的电火花击穿点火间隙点燃可燃混合气。

机械设计外文翻译---往复式发动机

中文2100字外文翻译外文翻译原文：The Reciprocating EngineMy Internet research eventually led me to the American Stirling Company．While cruising their website for engine kits I ran across，an ad that said they wanted a technical writer who would trade some writing of instructional material and plans for engine kits．I shot them a quick email．I am a technical writer in my day job，and I write instructional material for computer software．Now that I was designing my own Stirling engines，I thought I would be a perfect match for them!Well，I didn’t end up working for them，but after afew conversations with the owner of the company I was on a mission to complete my quest for a hand built LTD Stirling engine，and I was going to write a book about it at the same time．Brent Van Arsdell of The American Stirling Company was very helpful．He gave me some very good advice about how to increase the efficiency of my engine designs．He knew a lot a bout friction．He knew how to calculate its impact，and how to overcome some of the problems it can cause．He didn’t really need a technical writer any more，but he did offer me some great encouragement on my efforts to design an efficient hand built engine．He suggested that if I could build a Stirling engine that met these criteria，it would make a great selling book．Here is what my designs had to do：·The engine had to run from the heat of a warm hand．·The engine had to be made from common materials that would be easy for anyone to obtain．·It had to be affordable to build．·It had to be built without the aid of a machine shop．I could only use the kinds of tools that most folks already have in their garage．I stumbled across the website of an engineer in France who was working on a similar project．The only problem was the website was entirely in French!I had a brief email exchange with the author and asked him if his website was available i n English．He replied。

发动机基本原理发动机结构发动机工作原理大学毕业论文外文文献翻译及原文

毕业设计（论文）外文文献翻译文献、资料中文题目：1.发动机基本原理2.发动机结构3.发动机工作原理文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14Engine FundamentalsAutomobiles have operated successfully by electric motors，steam engines and internal combustion engines.The internal combustion engine burns fuel within its cylinders and converts the expanding force of the burning fuel,or combustion,into a rotary force used to propel the vehicle.There are several types of internal combustion engines: two-and four-cycle reciprocating piston engines,gas turbine engines. However,four-cycle reciprocating engines have been refined to such a degree that they have almost complete dominance of the automotive field.Engines of other types are described later,Diesel and Other Engines.Many things are demanded of an engine used to propel an automobile.Some of the requirements are:(1)Ease of Starting.(2)Reliability.(3)Power.(4)Responsiveness.(5)Economy in fuel,oil,and,repairs.(6)Ease of handing.(7)Quiet operation.Some of these factors conflict.For example,a great amount of power can be saved from an engine of sufficient size,but a super-size engine is not economical to operate. Therefore,all automobile engines are a compromise in order to obtain the desirable combination of performance and economy.Engine FuelsInternal combustion engines can be made to operate on almost anything that can be converted into a combustible gas,such as wood,coal,alcohol,vegetable gas,mineral oils,etc. However,because of convenience,a variety of petroleum products are commonly used as fuels:gasoline,kerosene,fuel oil,liquefied petroleum gas(LP-Gas) etc.What kerosene,fuel oil,or LP-Gas is used it is necessary to alter the design of the engine to achieve efficient operation.Engine DesignGasoline engines used in automotive vehicles are of two basic types:four-cycle engines and two-cycle engines.Either type may be water-cooled,or air-cooled.Four-,six-,and eight-cylinder engine are common.However,three-,five-,ten-,and twelve-cylinder engine are available.Almost all automobile engines have more than one cylinder.These cylinders can be arranged in an inline,opposed,or V-type configuration.Engines for other purpose,such as aviation,are arranged as radial,inverted inline,inverted V ,and X-shaped configurations.Reciprocating EnginesIn the typical automobile engine,a piston reciprocates(moves back and forth)within each cylinder,Each piston is connected to the crankshaft by means of a link known as a connecting rod.Other types of reciprocating engines substitutes an eccentric,an inclined plate,or a cam mechanism for the crankshaft.The piston engine has no crankshaft or connecting rods.Engine ComponentsThe typical automotive engine is made up of several essential components.These components are designed to provide efficient and reliable engine operation.The basic components in a four-cycle automotive engine include the following:(1)Cylinder block.(2)Crankshaft.(3)Piston.(4)Piston rings.(5)Connecting rods.(6)Piston pin.(7)Cylinder head.(8)Valve train(includes valves and valve operating mechanism).发动机基本原理汽车已经工作地非常成功通过电子马达，蒸汽机和内燃机，内燃机在气缸里燃烧并且将燃料燃烧发出的膨胀力转换成旋转力来推动汽车。

机械毕业设计英文外文翻译44变速器油温的控制

附录ATransmission oil temperature controlFor people who buy the car, reliability and fuel efficiency is the second oftwoimportant price considerations. No doubt, for the new owner is concerned, the most terrifying thing on the way to remove car. In addition, owner and expect the car can try to durable. Meanwhile, due to current global fuel prices have risen to make owners pay more attention。

thefuelefficiency, and hope to try to reduce carbon emissions. Auto power transmission system includes an internal combustion engine, transmission and more than a gear than wheels. Engine torque and speed will be needed for the railway traction power and car in the transmission of conversion. In addition, the transmission can also control wheel rotation direction. Manual and automatic transmission speed generally fall into two. Automatic transmission can automatically control friction unit, selection of gear ratios and shift. Automatic transmission will adopt hydraulic oil to achieve lubrication and frozen effect, hydraulic oil is a very special liquid, can be in any severe conditions operation. Automatic transmission oil (the main function of ATF) from the motivation for: transferred engine torque converter power transmission device; Absorb the torque converter produces thermal and moved to the front of a frozen device; car As clutch friction of the coolestrefrigerants, it can absorb and by clutch or take out meshing the heat energy produced; Through a complex hydraulic control system, the liquid pressure transmission to the system USES valve, servo machines, pump, clutch always pump, hydraulic pipe and pipe to control; As a planetary gears, bearings, servo machines, clutch and target group-exact marketing of lubricant and coolant.Automatic transmission oil in operating temperature (about 90 °C / ° F) viscosity 195 is general very low. But if the oil temperature is too low (for example is 0 ° C / 30 ° F below), its viscosity will greatly increased, lead to a very high drag torque (dragtorque). As a result, gear meshing, it can cause is commonly synchronous devices of this couldn't cope with high torque force. If gear can't mesh or shift, car will not start. For this reason, "cold start" program will respond to the oil temperature and activated, to ensure that at least one gear can succeed mesh. Warm car driving car started after process when, unless required by obvious acceleration or dragged heavy objects (such as trailer), otherwise the hydraulic oil temperature will only slowly rising, but it also means drag torque will slowly rising. If the car is chronically high drag torque environment, synchronous devices will overload and damaged. In gearbox to add some loss, will shift some moved to higher speed valve and improve the quality of the gearbox lubricant, these all canaccelerate the process of car warm up. Thus, engine, gearbox and catalyst can be quickly reach best operation temperature. The faster transmission is the optimum operating temperature, can be used to save fuel consumption and faster start the gear shift program. Gear shifting part through hydraulic or electronic is starting valve to control, these shifting unit start-up will significantly by the influence of the temperature of automatic transmission oil, reason is with the temperature and the viscosity will rise significantly, so the temperature can influence the degree of pressure and time characteristics. Once the automatic transmission oil gets hot, its temperature variation of amplitude will increase, so the shift when the set standard oil, must consider the problems about the oil temperature. Under high temperature operation, no doubt, automatic transmission oil very vulnerable to the influence of the temperature of cryogenic, but compared to the reaction of the reaction temperature, the much more. The process of automatic transmission will produce a lot of friction, and these will generate a lot of friction heat. Liquid will constantly stir in torque converter and pump in the mouth and current meters of hydraulic circuits. Whenever variable speed shift, clutch components will produce more than box of oil can take the heat. The transmission, the greater the load of the heat generated by then, box of oil will become more heat. Generaltraditional transmission oil temperature can allow maximum temperature for 80 to 100 °C or 175 °F, and to 212 special transmission oil temperature can be as high as 110 ℃ to 130 ° F or 230 to 265. However, nowadays advanced automobile transmission oil temperature could be as high as 120 to 150 ℃ or 250 to 300 ° F, and for heavy trucks for example is 18 rounds of freight trains, if it in hot weather, the oil temperature under driving even to 170 °C 160 ° F or 320 to 340. Such a high oil temperature can cause box of oil and variable speed component damage. Transmission oil working life, in the high temperature environment, the working life of the transmission oil can be reduced. Once the temperature above normal operation level (90 ° C / 195 ° F above), lubricants oxidation speed will increase, so the effective life be shortened. Based on the law 娒designated, when the temperature above normal operation temperature 。

机械专业毕业设计--外文资料和翻译

Metal heat treatmentA, annealingIn front of the description lengba processing materials and softening plastic treatment methods, it has been used the word, the word annealing with similar meanings. The purpose is to reduce completely annealing, hardness, plastic, sometimes also increased to improve the cutting performance, high this steel is difficult to processing. This method is used to reduce heat stress, refined grains, improve the structure of the material.Annealing is not always can improve the cutting machining, cutting processing a word used to describe several factors, including material cutting when good finish (i.e. smaller surface roughness - the ability of the translator. When fully annealing, ordinary low hardness, low intensity of cutting resistance smaller, less, but usually due to the plasticity and toughness is too big to chip away when the surface of workpiece surface of workpiece surface quality, scratch, leads to poor cutting processing. For this kind of steel, annealing may not be the most appropriate treatment. Many of the most high and cutting steel processing usually can be greatly improved by annealing except in the soft, because of their condition, high hardness and strength for processing.And the annealing method is GongXi just slow to the steel wire, insulation above about for a period of time, make the same temperature uniformity, forming materials, then the austenitic or buried with furnace lime or other insulating materials in slow cooling. To precipitation of ferrite and pearlite bulky iron, steel in the soft, the strain of toughness and minimum, must slow cooling.Second, normalizingHow much is the fire of similar purposes, but not the annealing steel soft and fine pearlite state. Not bulky. Steel is refined grains, fire can release of stress, improve structural homogeneity and restore some plastic, high toughness. This method is often used to improve cutting machining, reduce stress, reduce part machining or limitation of deformation.Is the fire will chromatography method is GuoGongXiGang steel or slow heatedto Ac3 respectively, Accm line or on-line insulation for a period of time to form, and in the austenitic stationary air slow cooling. Should notice more, GongXi composition of carbon steel needs to be heated to Accm line above, not Ac1 line above the annealing. The purpose is in the process of austenitic to dissolve all cementite, thus to minimize the boundaries on hard and brittle iron carbon compounds, and get little grain of ferrite pearlite, minimum free cementite and freedom.Third, the ball annealingThrough the steel ball annealing can get minimum hardness and the biggest plastic, it can make the iron carbon compounds with small globular distribution in ferritic matrix. In order to make the ball easier small particles, usually for fire steel ball annealing. Ball annealing available in several different methods, but all the methods are needed in A1 line near (usually slightly low temperature preservation) for a long time, make the iron carbon compounds formed more stable, low level of small ball.Ball annealing method of the main objective is to improve the cutting processing, and drawing of hardened steel pretreatment, make it more uniform structure quenching. Because of the heat treatment for a long time, so the cost is higher than that of ball annealing is common or annealing.Four, steel sclerosisThe most hardened steel heat treatment method is based on the production of martensite high. Therefore, the first step to most other treatment with commonly used method -- austenitic. YaGongXiGang heated to Ac1 liquidus temperature, heat preservation, more about that temperature uniformly, austenitic evenly. GuoGongXiGang Ac1 above liquidus temperature preservation in steel, while about still remain iron carbon compounds.The second step is to avoid rapid cooling in the nose produces isothermal curve transformation pearlite. The cooling speed depends on the temperature and hardened steel quenching medium heat can be taken away from the surface of the ability of heat transfer and steel itself. Table 1-11 is some common medium and cooling method, cooling ability of the sequence.High temperature gradient produces high stress, deformation and cracking causes,so only in the very need to produce quenching specific structures are used. When the quenching heat uniform, care must be taken to reduce the heat stress diffusion. For example, a thin stick to end its vertical quenching, is inserted into the cooling medium, so whole section and temperature changes. If the shape of a side of the workpiece cooling, and on the other side of the earlier than size change is likely to cause high stress, produce plastic flow and permanent deformation.With several special quenching method can reduce stress, deformation and cracking quenching decreases. One called hierarchical quenching, the method is: will the austenitic steel in temperature is higher than that of martensite transformation temperature (Ms), salt bath time until the temperature uniformity, at the beginning of forming bainite, then put before air cooling, heat generated from the start when the same hardware quenching cracking, martensite and warpage cause of high thermal stress or eliminate stress have been quenched.In a similar method of temperature, then, is called the isothermal quenching (austenitic steel in salt bath), keep for a long time, the result is formed with the isothermal bainite. Bainite structure in the same ingredients as the formation of martensite hard, but in normal hardened steel, reduce the heat shock, by further processing, unnecessary in high hardness can be obtained when good impact toughness.Five, temperingTo adjust hardened steel used the third step is often backfire. Besides the isothermal quenching steel quenching condition usually used in most all can use in production. To produce martensite steel to quench make hard, macro and micro stress, stress, low plasticity materials. To reduce the harm that can be heated to steel again by low-temperature shift (A1) below a certain temperature. Hardened steel structure change of tempering time and temperature is the function of temperature, which is the most important. Must be hardened piece.it is emphasized, method, but the reverse is true. Steel is tempered by heat treatment of hardened steel, through the tempering of heating, to release stress again, soften and improve plastic.The structural change and tempering causes change depending on performance of the heating temperature steel back. The higher the temperature, the temperatureeffect, so the choice is often sacrificed for the hardness and strength plasticity and toughness. Again, to quench heating to influence of carbon-steel, in between, structure, changes will occur in the above, the structure and properties of the significant changes. In the next time the temperature of the A1 heat will produce and process of ball annealing of similar structures.In industry, usually avoid to scope, because the tempering within the scope of tempering steel often produced unexplained brittleness or plastic loss. Some alloy in to scope, also can produce "temper brittleness, especially from" (or by) the temperature range slow cooling will appear. When these steel heat temper, they must usually heated to rapid cooling and above. Of course, from the temperature of cold won't produce sclerosis, fast because no austenitic.金属热处理一、退火在前面描述冷拔加工材料的软化并重新获得塑性的热处理方法时，就已使用退火这个词，该词具有相似的意义。

机械制造工艺外文文献翻译、中英文翻译、外文翻译

中国地质大学长城学院本科毕业设计外文资料翻译系别：工程技术系专业：机械设计制造及其自动化姓名：侯亮学号：052115072015年 4 月 3 日外文资料翻译原文Introduction of MachiningHave a shape as a processing method, all machining process for the production of the most commonly used and most important method. Machining process is a process generated shape, in this process, Drivers device on the work piece material to be in the form of chip removal. Although in some occasions, the workpiece under no circumstances, the use of mobile equipment to the processing, However, the majority of the machining is not only supporting the workpiece also supporting tools and equipment to complete.Machining know the process has two aspects. Small group of low-cost production. For casting, forging and machining pressure, every production of a specific shape of the workpiece, even a spare parts, almost have to spend the high cost of processing. Welding to rely on the shape of the structure, to a large extent, depend on effective in the form of raw materials. In general, through the use of expensive equipment and without special processing conditions, can be almost any type of raw materials, mechanical processing to convert the raw materials processed into the arbitrary shape of the structure, as long as the external dimensions large enough, it is possible. Because of a production of spare parts, even when the parts and structure of the production batch sizes are suitable for the original casting, Forging or pressure processing to produce, but usually prefer machining.Strict precision and good surface finish, machining the second purpose is the establishment of the high precision and surface finish possible on the basis of. Many parts, if any other means of production belonging to the large-scale production, Well Machining is a low-tolerance and can meet the requirements of small batch production. Besides, many parts on the production and processing of coarse process to improve its general shape of the surface. It is only necessary precision and choose only the surface machining. For instance, thread, in addition to mechanical processing, almost no other processing method for processing. Another example is the blacksmith pieces keyhole processing, as well as training to be conducted immediately after the mechanical completion of the processing.Primary Cutting ParametersCutting the work piece and tool based on the basic relationship between the following four elements to fully describe : the tool geometry, cutting speed, feed rate, depth and penetration of a cutting tool.Cutting Tools must be of a suitable material to manufacture, it must be strong, tough, hard and wear-resistant. Tool geometry -- to the tip plane and cutter angle characteristics -- for each cutting process must be correct.Cutting speed is the cutting edge of work piece surface rate, it is inches per minute toshow. In order to effectively processing, and cutting speed must adapt to the level of specific parts -- with knives. Generally, the more hard work piece material, the lower the rate.Progressive Tool to speed is cut into the work piece speed. If the work piece or tool for rotating movement, feed rate per round over the number of inches to the measurement. When the work piece or tool for reciprocating movement and feed rate on each trip through the measurement of inches. Generally, in other conditions, feed rate and cutting speed is inversely proportional to.Depth of penetration of a cutting tool -- to inches dollars -- is the tool to the work piece distance. Rotary cutting it to the chip or equal to the width of the linear cutting chip thickness. Rough than finishing, deeper penetration of a cutting tool depth.Rough machining and finishing machiningThere are two kinds of cuts in machine- shop work called, respectively, the "roughing cut" and the "finishing cut". When a piece is "roughed out", it is quite near the shape and size required, but enough metal has been left on the surface to finish smooth and to exact size." Generally speaking, bars of steel, forging, castings, etc. are machined to the required shape and size with only one roughing and one finishing cut. Sometimes, however, certain portions of a piece may require more than one roughing cut. Also, in some jobs, for example, when great accuracy is not needed, or when a comparatively small amount of metal must be removed, a finishing cut may be all that is required. The roughing cut, to remove the greater part of the excess material, should be reasonably heavy, that is, all the machine, or cutting tool, or work, or all three, will stand. So the machinist’s purpose is to remove the excess stock as fast as he can without leaving, at the same time, a surface too torn and rough, without bending the piece if it is slender, and without spoiling the centers. The finishing cut, to make the work smooth and accurate, is a finer cut. The emphasis here is refinement - very sharp tool, comparatively little metal removed, and a higher degree of accuracy in measurement. Whether roughing or finishing, the machinist must set the machine for the given job. He must consider the size and shape of the work and the kind of material, also the kind of tool used and the nature of the cut to be made, then he proceeds to set the machine for the correct speed and feed and to set the tool to take the depth of cut desired.Automatic Fixture Design外文资料翻译译文机械制造工艺机械加工是所有制造过程中最普遍使用的而且是最重要的方法。

发电机工作原理英文作文

“Working Principle of Generators”Generators are essential devices that convert mechanical energy into electrical energy. They operate on the principle of electromagnetic induction, discovered by Michael Faraday in the early 19th century.The basic components of a generator include a conductor, a magnetic field, and relative motion between them. When a conductor moves through a magnetic field or when the magnetic field surrounding the conductor changes, an electric current is induced in the conductor.This process can be explained by Faraday’s law of electromagnetic induction, which states that the magnitude of the induced electromotive force (EMF) in a circuit is directly proportional to the rate of change of the magnetic flux through the circuit. Mathematically, it is expressed as:[ \text{EMF} = -N \frac{d\Phi}{dt} ]Where:●( \text{EMF} ) is the induced electromotive force.●( N ) is the number of turns in the coil.●( \frac{d\Phi}{dt} ) is the rate of change of magnetic flux.In a generator, a coil of wire (often wound around an iron core) is rotated within a magnetic field produced by either permanent magnets or electromagnets. As the coil rotates, the magnetic flux through the coil changes, inducing an alternating current (AC) in the wire.To produce direct current (DC), which is commonly used in many applications, such as charging batteries or powering electronic devices, the AC output of the generator is rectified using devices like diodes or rectifier circuits. This process converts the alternating current into a unidirectional flow of current.Generators play a crucial role in various sectors, including power generation, industrial processes, and transportation. Understanding their working principle is fundamental for their design, operation, and maintenance.。

中英文文献翻译-发动机工作原理概述

附录A 外文文献Engine operating principlsMost automobile dngines are internal combustion, reciprocating4-stroke gasoline engines, but other types have been used, including the diesel, the rotary (wankel),the 2-stroke ,and stratifild charge.Recipprocating means up and down or banck and forth, it is the up an down action of a piston in the cylinder blick ,or engine block . the blick is an iron or aluminum casting that contains engine cylinders and passage called water jackets for coolant circulation .the top of the block is covered with the cylinder head. Which forms the combustion chanber. The bottom of the block is covered with an oil pan or oil sump.Power is produced by the linear motion of a piston in a cylinder.however, this linear motion must be changed into rotary motion to turn the wheels of cars of trucks. The pistion is attached to the top of a connecting rod by a pin, called a pistion pin or wrist pin the bottom of the connecting rod is attached to the crankshaft . the connecting rod transmits the up-and-down motion of the piston to the crankshaft , which changes it into rotarymotion.The connecting rod is mounted on the crankshaft with large beaings called rod bearings. Similar bearings, called main bearings, are used to mount the crankshaft in the block .shown in fig ,1-1.The diameter of the cylinder is called the engine bore. Displacement and compression ratio are two frequently used engine specifications. Displacement indicates engine size , and compression ratio compares the total cylinder volume to compression chamber volume.The term stroke is uesd to describe the movement of the iston within the cylinder, as well as the distance of pistion travel. Depending on the type of engine the operating cycle may require either two or four strokes to complete. The 4-strokes engine is also called otto cycle engine ,in honor of the german enginner , Dr. Nikolaus otto , who first applied the principle in 1876 . In the 4-stroke engine ,four strokes of the piston in the cylinder are required to complete one full operating cycle .Each stroke is named after the action it performes instake , compression ,power, and exhaust in that order, shown in Fig1-2.1、Instake strokeAs the piston moves down , the vaporized mixture of fuel and air enters the cylinderthrough open instake vavle. To obtain the maximum filling of the cylinder the instake valve opens about 10° before t.b.c ,giving 20° overlap. The inlet valve remains open until some 50° after b.d.c to take advantage of incoming mixture.2、Compression strokeThe pieton turns up , the instake valve closes, the mixture is compressed within the combustion chamber, while the pressure rise to ahout 1 Mpa, depending on various factors inclouding the compression ratio, throttle opening and engine speed. Near the top of the stroke the mixture is ignited by a spark which bridge the gap of the spark plug.3、Power strokeThe expanding gases of combution produces a rise in pressure of the gas to some 3.5Mpa, and the piston is forced down in the cylinder. The exhaust valve opens near the bottom of the stroke.4、Exhust strokeThe piston moves back up with the exhause valve open some 50°before b.d.d.,allowing the pressure within the cylinder to fall and to reduce ‘back’ pressure on the piston during the exhaust stroke, and the burned gases are pushed out to prepare for the next instake stroke. The instake valve usually opens just before the exhaust stroke.This 4-stroke cycle is continuously repared in every as long as the engineremains runningA-2-stroke engine also goes through four actions to complete one operating cycle.However , the instake and the compression actions are combined in one seroke,and the power and exhaust actions are combined in the other stroke. The term2-stroke cycle or 2-stroke cycle or 2-stroke is preferred to the term 2-cycle, which is really not accurate.In automobile engines, all pistons are attached to a single crankshaft. The more cylinders an engine has ,the more power strokes produced for cach revolusion. This means that means that an 8-cylinder engine runs more smoothly because the power atrokes are closer together in time and in degrees of engine rotation.The cylinder of multi-cyclinder automotive engines arranged in one of three ways.1、Inline engine use a single block of cylinder. Most 4-cylinder and 6-cylinder engines areof this design. The cylinder do not have to be vertical. They can be inclined either side.2、V-type engine use two equal bands of cylinder , usually inclined 60degrees or 90degreesfrom the cach other. Most V-type engines have 6 or 8 cylinders, although V-4 and V-12engine have been built.3、Horizontally opposed or pancake engine have two equal banks of cylinders 180degreesapart . these space saving engine designs are often air-cooled,and are found in the chevrolet carvair porsches, Subaus,and V olkswagens. Subaus design is liquid ter –model V olkswagen vans use a liquil-cooled VWhorizontally opposed engine.附录B 中文翻译发动机工作原理大多数汽车的发动机是内燃机，往复四冲程汽油机，但是也有使用其他类型的发动机，包括柴油机，转子发动机二冲程发动机和分程燃烧发动机。

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Engine Operating PrinciplesMost automobile engines are internal combustion,reciprocating 4-stroke gasoline engines,but other types have been used,including the diesel,the rotary(wankel),the 2-srtoke,and stratified charge.Reciprocating means up and dowm or banck and forth ,It is the up and down action of a piston in the cylinder blick,or engine block.The bilck is an iron or aluminum casting that contains engine cylinders and passges called water jackets for coolant circulation.The top of the block is convered with the cylinder head.Which forms the combustion chanber.The bottom of the block is covered with an oil pan or oil sump.Power ia produced by the linear motion of a piston in a cylinder.However,this linear motion must be changed into rotary motion to turn the wheels of cars of trucks.The piston is attached to the top of a connecting rod by a pin ,called a piston pin or wrist pin.The bottom of the connecting rod is attached to the crankshaft.The connecting rod transmits the up-and-down motion of the piston to the crankshaft,which changes it into rotary motion.Term: stroke is used to indicate the movement within thecylinder piston, piston stroke is the distance from the engine type according to need two-stroke or four-stroke cycle to finish a job and four stroke engines are also called otto engine, in order to commemorate German engineers otto, he is the first application in 1876, the principle of in four stroke engines, cylinder piston required to complete a four-stroke cycle, each stroke work according to their behavior named respectively: intake stroke, compression stroke, function and exhaust stroke.1. Intake strokeWhen the piston moves down, spray the mixture through open after entering the inlet valve, in order to achieve maximum cylinder amount of inlet in Detroit, arrive before BDC 10 °, open and exhaust has 20 ° to open the inlet valve overlap, has been opened to the pistons to come fully into the mixture after about 50 °.2. Compression strokeThe piston start moving up huge inlet valve closed, and the mixture in the combustion chamber, according to the different factors including compression compression ratio, the throttle valve, pressure revs up to about 1 mpa, close to the top, the spark plug stroke produces the spark gap in the breakdown ignition mixture lighting.3. Doing workBurning gas pressure of inflation rose to 3.5 mpa, promote the piston moves to the cylinder, and exhaust door open.4 gas strokeWith exhaust before more open about 50 °, piston, make up in the air pressure drops in exhaust stroke, reduce backpressure, discharge waste piston stroke, for the next intake, normally, inlet in exhaust before opening.Only the engine keep running, each cylinder within four four-stroke cycle continuously.Two stroke engine also through the four-stroke cycle to complete a job but intake stroke, compression stroke for a stroke, do work schedule another stroke, the four-stroke cycle and two terms two travel itinerary is called the term two-cycle but actually not so accurate. However,the intake and the compression actions are combined in one seroke,and the power and exhaust actions are combined in the other stroke.The term 2-stroke cyde or 2-stroke is preferred to the term 2-cyde,which is really not accurate.In automobile engines,all pistons are attached to a single crankshaft.the more cylinders an engine has,the more power strokes produced for cach revolution.This means that an 8-cylinder engine runs more smoothly bacause the poweratrokes are closer togther in time and in degrees of engine rotation.The cylinders of multi-cylinder automotive engines arranged in one of three ways.1.Inline engines use a single block of cylinder.Most 4-cylinder and any 6-cylinder engines are of this design.The cylinders do not have to be vertical.They can be inclined either side.2.V-type engines use two equal bands of cylinders,usually inclined 60 degrees or 90 degrees from the cach other.Most V-type engines have 6 or 8 cylinders,although v-4 and v-12 engines have been built.3.Horizontally opposed,or pancake engines have two equal banks of cylinders 180 degrees apart.These space saving engine designs are often air-cooled,and are found in the Chevrolet Carvair,Porsches,Subaus,and Volkswagens.Subaus design is liquid cooled.are often air-cooled,and are found in the Chevrolet Carvair,Porsches,Subaus,and Volkswagens.Subaus design is liquid te-model Volkswagen vans use a liquid-cooled version of the air cooled VWhorizontally opposed engine.发动机工作原理大多数汽车的发动机是内燃机，往复四冲程汽油机，但是也有使用其它类型的发动机，包括柴油机，转子发动机，二冲程发动机和分成燃烧发动机。