汽车工程专业英语第二章

第二章：内燃机（INTERNAL COMBUSTION ENGINE）
1)Energy and power:
Engines used in automobiles are internal combustion heat engines. They convert the chemical energy of the gasoline into heat within a power chamber that is called a combustion chamber. Heat energy released in the combustion chamber raises the temperature of the combustion gases within the chamber. The increase in gas temperature causes the pressure of the gases to increase. The pressure developed within the combustion chamber is applied to the head of a piston to produce a usable mechanical force, which is then converted into useful mechanical power.
能源是用于生产电力。

化工能源是转化为燃料的燃烧的热量，这个过程被称为燃烧。

如果发动机燃烧发生在气缸内的地方，被称为发动机内部燃烧发动机。

如果燃烧发生在气缸外的地方，被称为发动机外部燃烧发动机。

用于汽车的能源叫内部燃烧高能源，高温能源在燃烧室里降低能缓解气体燃烧在气缸内的温度。

燃烧气体温度的升高引起气压变大，燃烧室内发展应用到了活塞产生一个可用的机械力，然后将其转换成有用的机械能。

2)Engine terms:
Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn. The power stroke "uses up" the gas, so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture: this control ofgas movement is the duty of the valves;
活塞通过连杆和曲轴连接，使得气体带动曲轴旋转半圈。

作功冲程耗尽了所有的气体，这样就必须采取相应的措施排出废气以及向气缸内充入新鲜的可燃混合气：气体的运动由气门来控制。

3) Engine block:
The engine block is the basic frame of the engine. All other engine parts either fit inside it or fasten to it. It holds the cylinders, water jackets, and oil galleries. The engine block also holds the crankshaft, which fastens to the bottom of the block.
气缸体是发动机的基体。

发动机其它的部件都安装在缸体内或固定在缸体上，它包容了气缸、水套和油道，以及固定在缸体底部的曲轴等。

4) Cylinder sleeve:
The dry sleeve can be cast in or pressed into a new block or used to recondition badly worn or damaged cylinders that cannot easily be rebored.
干缸套可以铸在或压入新缸体中，或者用于严重磨损或损坏而又不易重镗的缸体的修复。

5) Cylinder head:
The cylinder head fastens to the top of the block, just as a roof fits over a house. The underside forms the combustion chamber with the top of the piston. In-line engines of light vehicles have just one cylinder head for all cylinders; larger in-line engines can have two or more.
气缸盖扣在缸体的顶部，就像屋顶安在房子上一样。

缸盖的下方和活塞顶部形成燃烧室。

轻型车的直列发动机所有缸仅有一个气缸盖，较大的直列发动机有两个或更多缸盖。

6) Cylinder head:
The cylinder head carries the valves, valve springs and the rockers on the rocker shaft, this part of the valve gear being worked by push-rods.
缸盖上坐有气门、气门弹簧和摇臂轴上的摇臂，推杆推动这部分气门传动机构工作。

7) Oil pan:
The oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine. The oil drains off and runs down into the pan. Thus,there is constant circulation of oil between the pan and the working parts of the engine.
润滑系的机油泵从油底壳抽出机油，并把机油输送给发动机的所有工作部件。

机油从油底壳流进流出。

因
而在油底壳和发动机的工作部件之间有机油定向循环流动。

8) Piston assembly:
Most pistons are made from cast aluminum. The piston, through the connecting rod, transfers to the crankshaft the force created by the burning fuel mixture. This force turns the crankshaft.
大多数活塞由铝铸造而成。

通过连杆，活塞把可燃混合气燃烧所产生的力传递给曲轴，并带动曲轴旋转。

9) Piston :
In disel engines, the combustion chamber may be formed totally or in part in the piston crown, depending on method of injection.
柴油机发动机根据喷油方法不同，活塞头部可以形成全部燃烧室，也可以是燃烧室的一部分．
10)Piston rings:
In modern engines, each piston has three rings. (Piston in older engines sometimes had four rings, or even five.) The inside surface of the ring fits in the groove on the piston. The ring's outside surface presses against the cylinder walls.
在新型发动机上，每个活塞有三个活塞环。

（在老式发动机上，每个活塞有四个甚至五个活塞环。

）环的内边面紧贴在活塞的环槽里，环的外表面紧压在气缸壁上。

11)Connecting rod:
The connecting rod little end is connected to the piston pin. A bush made from a soft metal, such as bronze, is used for this joint. The lower end of the connecting rod fit the crankshaft journal. This is called the big end.
连杆小头与活塞销连接，小头孔处压有诸如青铜这种较软材料所制成的衬套，连杆下端连接在曲轴的连杆轴径处，称为连杆大头。

12)Cylinder number and firing order:
N.B. No.4 piston is always performing the companion stroke to No.1: when the inlet valve in No.4 cylinder is fully open, No.1 cylinder inlet valve is fully closed --- this feature is useful to remember when checking valve clearances.
注意4号活塞和1号活塞总是成对运行：4号气缸进气门全闭时，1号气缸进气门全开—这个特点在检查气门间隙时是很有用的。

13）As each cylinder fires, it causes the crank throw to speed up. The inertia of the rest of shaft cause it to stay slightly behind, resulting in a twisting action on the crankshaft.
当一缸点火时，使曲轴摆幅的速度提高，而其它轴的惯性阻碍它，使其滞后，从而导致曲轴扭转。

14）Inertial ring elastomer
The inertia ring is bonded to the hub through a flexible elastomer (rubber compound) insert. The inertial ring moves slightly in relation to crankshaft rotation as each cylinder fires, thereby dampening the torsional vibration of the crankshaft over a wide range of engine speed.
惯性盘通过一层由橡胶合成的可变形人造橡胶层与减振器圆盘相连．在每个汽缸点火时，惯性盘相对于曲轴运动做微小转动，用以削减发动机较大速度范围内的曲轴扭转振动．
1) Valve operation:
The cam is an egg-shaped piece of metal on a shaft that rotates in coordination with the crankshaft. The metal shaft, called the camshaft, typically has individual cams for each valve in the engine. As the camshaft rotates, the lobe, or high spot of the cam, pushes against parts connected to the stem of the valve. This action forces the valve to move downward. This action could open an inlet valve for an intake stroke, or open an exhaust valve for an exhaust stroke.
凸轮是一个蛋形的金属块，它安装在同曲轴协调运转的一根金属轴上，该轴称为凸轮轴，其上有同发动机每一个气门对应的凸轮。

当凸轮轴旋转时，凸轮的最高点，也就是凸圆，推动连接气门杆的部件，使得气门向下运动，在进气冲程打开进气门，在排气冲程打开排气门。

2) Valve operation: In this arrangement, the cam lobes push against round metal cylinders called cam follower. As the lobe of the cam comes up under the cam follower, it pushes the cam follower upward (away from the camshaft). The cam follower rides against a push rod, which pushes against a rocker arm. The rocker arm pivots on a shaft through its center. As one side of the rocker arm moves up, the other side moves down, just like a seesaw. The downward-moving side of the rocker arm pushes on the valve stem to open the valve. （p27）
在这种方案中，凸轮基圆推动圆形的金属筒，也就是挺柱。

凸轮凸圆运动到挺柱下方时，推动挺柱远离凸轮轴向上运动。

挺柱带着推杆，推杆推动摇臂，摇臂绕摇臂轴的中心转动。

摇臂的一端升起，另一端就落下，这类似于跷跷板。

摇臂向下运动的一端推动气门杆打开气门。

3) Valve clearance:
When the engine runs in compression stroke and power stroke, the valves must close tightly on their seats to produce a gas-tight seal and thus prevent the gases escaping from the combustion chamber. If the valves do not close fully the engine will not develop full power. Also the valve heads will be liable to be burnt by the passing hot gases, and there is the likelihood of the piston crown touching an open valve, which can seriously damage the engine.
当发动机在压缩冲程和作功冲程工作时，气门必须紧贴在气门座上，形成良好的气密性以防止燃烧室漏气。

如果气门关闭不严，发动机就不能发挥出全部的功率。

而且气门头部容易被经过的高温气体烧蚀，活塞顶部也可能会碰到气门使发动机严重损坏。

4) Valve clearance:
So that the valves can close fully some clearance is needed in the operating mechanism. This means that the operating mechanism must be able to move sufficiently far enough away from the valve to allow the valves to be fully closed against its seat by the valve spring. However, if the clearance is set too great this will cause a light metallic tapping noise.
所以在气门传动机构中要预留一些间隙使气门得以完全关闭。

这就是说，气门传动机构运动要与气门有一个充分远的距离，使得气门在气门弹簧作用下紧闭气门座。

可是如果间隙过大，会引起轻微的金属敲打声。

5) Valve timing:
It is apparent from this description that the exhaust valve stays open for a short period of time during which the intake valve is also open. In other words, the end of the exhaust stroke and the beginning of the intake stoke overlap for a short period of time. This is called valve overlap. Valve timing and valve overlap vary on different engines.
由上显而易见，排气门在进气门打开的一小段时间内也打开着。

换句话说，排气冲程终了和进气冲程初期有一小段时间的重叠，这称为气门重叠。

不同的发动机，其配气相位和气门重叠是不一样的。

6) Valve timing:
Opening the intake valve before TDC and closing it after BDC increases the fill of air-fuel mixture in the cylinder. Opening the intake valve early helps overcome the static inertia of the air-fuel mixture at the beginning of the intake stroke, while leaving the intake valve open after BDC takes advantage of the kinetic inertia of the moving air-fuel mixture. This increases volumetric efficiency.
在上止点前打开进气门和在下止点后关闭进气门可增加气缸内可燃混合气的进气量。

提前打开进气门有助于克服进气冲程初期的惯性，同时在下止点后打开进气门可充分利用可燃混合气运动时的惯性，这可增加容积效率。

7)Cam design and control dynamic:
The entire valve-train assembly can be viewed as a spring/mass system in which the conversion from stored to free energy causes forced vibration. Valve-train assemblies with overhead camshafts can be represented with sufficient accuracy by a 1-mass system (consisting of the moving mass, the valve-train assembly stiffness and corresponding damping).
整个气门机构可看成一个弹簧-质量系统，其储存的能量转化为自由能量时会引起受迫振动。

带有顶置凸轮轴的气门机构可非常精确地用单质量系统来表示，由运动质量、气门机构的刚度和相应的阻尼组成。

8) Camshaft drive mechanism:
Each cam must revolve once during the four-stroke cycle to open a valve. A cycle, remember, corresponds with two revolutions of the crankshaft. Therefore, the camshaft must revolve at exactly half the speed of the crankshaft. This is accomplished with a 2:1 gear ratio. A gear connected to the camshaft has twice the number of teeth as a gear connected to the crankshaft.
在一个四冲程的循环里，每个凸轮转动一次来打开一个气门。

在一个循环里曲轴是转动两圈的。

因此，凸轮轴正好以曲轴转速的一半旋转，这是由2:1的传动比来实现的。

连接凸轮轴的齿轮齿数是连接曲轴的齿轮齿数的两倍。

9) Electronic valve control system:
An electronic valve control system replaces the mechanical camshaft, controlling each valve with actuators for independent valve timing. The EVC system controls the opening and closing time and lift amount of each intake and exhaust valve with independent actuators on each valve. Changing from a mechanical driven valve into independently controlled actuator valve provides a huge amount of flexibility in engine control strategy.
电控气门系统代替机械式的凸轮轴，用执行器控制每个气门独立的进、排气正时。

EVC通过每个气门上的独立执行器控制进气门和排气门的开启、关闭时间以及升程量。

由机械式驱动气门到独立控制执行器的气门改变，极大的增加了发动机控制策略的灵活性。

1)Gasoline :
Gasoline must vaporize easily. This characteristic, called volatility, is important. However, it must not vaporize too easily, or it will turn to vapor inside the fuel tank or fuel lines. Inside the fuel line, fuel vapor may block the flow of liquid gasoline. This is called vapor lock. Vapor lock is common in fuel lines where the inlet side of the pump is exposed to high temperatures.
汽油应易于蒸发，这个重要的特性称为挥发性。

但是汽油也不能挥发得过快，不然它会在油箱或油管里转变为蒸气。

在油管中汽油蒸气会阻碍液态汽油的流动，这称为气阻。

汽油泵的入口处承受着高温，就经常出现气阻。

2) gasoline:
Increasing the pressure of the fuel mixture in the combustion chamber before ignition helps to increase the power of an engine. This is done by compressing the fuel mixture to a smaller volume. Higher compression ratios not only boost power but also give more efficient power. But as the compression ratio goes up, knocking tendency increases.
在点火前增加燃烧室内可燃混合气的压力有助于提高发动机的功率，这是通过把可燃混合气压缩到一个极小的体积来实现的。

高的压缩比不仅增加发动机的功率，而且会带来更多的有效功率。

但随着压缩比的增加，爆震的可能性也会增加。

3) gasoline:
Two primary standard reference fuels, normal heptane and iso-octane arbitrarily assigned 0 and 100 octane number, respectively, are then blended to produce the same knock intensity as the test sample. The percentage of isooctane in blend is considered the octane number of the test sample. Thus, if the matching reference blend is made up of 15% n-heptane and 85% isooctane, the test sample is rated 85 motor or research octane number, according to the test method used.
两种基准参考燃料正庚烷和异辛烷分别被定义成辛烷值为0和辛烷值为100，将它们混合产生与实验样本相等敲缸强度的爆震。

混合物中异辛烷的百分比就认为是实验样本的辛烷值。

这样，依照实验方法，如果匹配的混合物由15%的正庚烷和85%异辛烷组成，那么按照所用的实验方法，对比实验样本的辛烷值就是85。

4) Fuel pump: Most cars today have a mechanical fuel pump. This pumps fuel out of the tank and through the fuel lines to the carburetor or injection system. In most cars, the pump is mounted on the engine block. Some cars have an electric fuel pump. This pump mounts in the fuel tank with the fuel pickup and the fuel-gauge-sending unit.
当前大多数汽车采用机械汽油泵，汽油泵从油箱抽出汽油，通过油管送到化油器或喷射系统。

大部分汽车的汽油泵安装在缸体上。

一些汽车采用电动汽油泵，汽油泵安装在油箱上，附带有油量传感器和燃油表油量传送装置。

5) Fuel pump: The rotation of the lobe moves a rocker arm in the pump. Inside the pump, a flexible diaphragm connects to the rocker arm though a diaphragm spring, pull rod and link.
凸圆旋转带动油泵中的摇臂运动。

油泵中可膜片变形的泵膜通过膜片回位弹簧和膜片拉杆与摇臂相连
6) carburetor: A carburetor delivers fuel in proportion to the amount of air flowing through it. As you press on the accelerator pedal, the throttle valve opens wider to draw more air through the carburetor. The carburetor provides richer or leaner mixtures, depending on a number of factors: engine speed, load, temperature, and throttle position. To meet complicated demands, a carburetor is a highly intricate device, with many internal passages and parts.
化油器输送的燃油与流经化油器的空气量成一定比例。

踩下加速踏板，节气门开度变大，化油器吸入的空气增加。

化油器可提供较浓或较稀的混合气，这取决于发动机转速、负荷、温度和油门开度等因素。

为满足复杂的要求，化油器的结构也很复杂，其上有很多内部通道和部件。

7) carburetor: An automobile carburetor is designed with a venturi chamber. The venturi is simply a narrowed portion in the air passage. Air moving through the throat of the carburetor speeds up as it travels through this narrowed passageway. The increased air speed through the venturi creates a low-pressure area at the opening of the fuel nozzle. Atmospheric pressure pushes down on a fuel reservoir within the carburetor known as the float chamber. Fuel is forced through a tube that extends into the low-pressure area of the venturi. Thus, fuel sprays through the end of the tube into the air stream.
化油器设计成带有喉管的形式，喉管是空气通道中一段狭窄的部分。

空气流过化油器的喉管时速度增加，在喷嘴的开口处形成低压区。

大气压力作用在储存汽油的浮子室上。

燃油便被压入伸向喉管低压区的喷管里。

这样燃油从喷管末端喷射到气流中。

8) carburetor: The float chamber is a reservoir for storing and supplying fuel to the carburetor. As the engine uses fuel, the float chamber replenishes it automatically. The float chamber works on the same basic principle as the holding tank in a flushing toilet. A float rests on top of the fuel in the reservoir. As fuel is used, the float level drops. When the float drops, a needle valve is opened.
浮子室用于储存燃油以及向化油器提供燃油。

发动机消耗燃油时，浮子室会自动进行补充。

浮子室和抽水马桶储水箱的工作原理是相同的。

浮子停留在浮子室的油面上。

消耗燃油时，浮子下落。

浮子下落时，针阀打开。

9) carburetor: The pressure differential between the float chamber and the venturi causes fuel to flow. However, to maintain the proper air-fuel ratio, the carburetor must provide just the right amount of fuel. To do so, the main discharge tube has a small hole (called a jet or main jet). This allows a precise amount of fuel to enter the airstream. In most cases, this small hole is in the float chamber at the end of the main discharge tube. There, its small size limits fuel flow.
浮子室和喉管之间的压力差引起燃油的流动。

然而，为维持合适的空燃比，化油器必须提供适量的燃油。

为此，在主喷管上有一个小孔，称作量孔或主量孔，它使得精确数量的燃油进入到气流中。

量孔一般在主喷管末端的浮子室里，控制着燃油的流量。

10)throttle mechanism:
The throttle mechanism controls the flow of the air-fuel mixture. The throttle has several parts, including the
throttle shaft and the throttle plate. By opening and closing, the throttle plate controls the flow of the air-fuel mixture into the engine. More air flows in as the plate opens; less air flows in as the plate closes.
节气门机构控制着可燃混合气的流量，包括节气门轴和节气门等部件。

节气门的开启和关闭控制着可燃混合气进入发动机的流量。

节气门开启，空气流量增加；节气门关闭，空气流量减少。

11) Gasoline direct injection（GDI）:
Conventional gasoline engines are designed to use an electronic fuel injection system, replacing the traditional mechanical carburetion system. Multi-point injection (MPI), where the fuel is injected through each intake port, is currently one of the most wider used systems. Although MPI provides a drastic improvement in response and combustion quality, it is still limited due to fuel and air mixing prior to entering cylinder.
常规的汽油发动机用电控燃油喷射系统代替传统的机械化油作用系统。

现在，通过每个进口喷射燃料的多点喷射（MPI）系统是现在最广泛使用的系统之一。

尽管MPI系统在燃料反应及燃烧质量上有很大的改善，但是进入汽缸前的空燃气混合仍然限制了它的发展。

1) Differences between diesel and gasoline engines:
Diesel engine gets this name from the pioneer work done by Dr Rudolf Diesel . The diesel is used for the majority of heavy vehicles and the excellent fuel economy makes it an attractive alternative to the petrol engine for lightcommercial vehicles, delivery vans and taxis.
柴油发动机的名称来源于Rudolf Diesel博士所完成的开拓性工作。

大多数重型车辆使用柴油，优良的燃油经济性使得柴油机成为最有吸引力的替代品,来代替轻型商用车、厢式货车和出租车上汽油机。

2)Diesel fuel mixture formation and combustion chambers:
As diesel engines always deal with interior mixture formation only a heterogeneous mixture is obtained in the combustion chamber. In heterogeneous mixtures the excess-air factor λ extends from pure air in the spray periphery (λ= infinite) to pure fuel in the spray core (λ= 0).
由于柴油机总是只在气缸内部形成可燃混合气，在燃烧室内会得到不均匀的混合气。

不均匀混合气的过量空气系数范围从喷射外围纯空气的无穷大到喷射中心纯燃料的零。

3) in-line pump fuel-injector system:
The fuel -injection system on a diesel engine must do a number of important things. First, it must meter the correct amount of fuel to run the engine at the speed and load demanded by the driver. Then it must deliver the metered fuel equally to all cylinders, at exactly the right time. Next, it must inject the fuel at the correct rate and spray pattern for the best burning in the combustion chamber.
柴油机的燃油喷射系统要完成许多重要的工作。

首先，它必须定量供应精确数量的燃油，以满足发动机在驾驶员所要求的转速和负荷条件下运行。

然后，它必须在合适的时刻把定量供应的燃油平均分配给每一个气缸。

为使燃烧室里燃烧效果最好，它又必须以合适的速率和喷射方式喷油。

、
4) Operation of the pumping element:
With the injector pump on the low part (base circle) of the camshaft, the inlet and spill ports are open. This allows fuel to flow at 268 kPa into the venturi on top of the plunger. As the camshaft turns, the lobe moves the plunger upward. This raised the fuel pressure, forcing fuel through the delivery valve and on through the lines. The lobe continues to move the plunger upward to a point where the spiral groove in the plunger uncovers the spill port in the venturi. At this point, fuel above the plunger drains through the spill port. This is the end of injection.
当喷油泵处于凸轮轴基圆时，进油孔和回油孔都打开，柴油以268KPa的压力流入柱塞上方的柱塞腔。

凸轮轴旋转时，凸圆使柱塞向上移动，油压增加，柴油从出油阀流出送入高压油管。

凸圆继续推动柱塞向上移动，直到柱塞运动到螺旋槽打开柱塞腔上的回油孔时的位置，此时，柱塞上方的柴油从回油孔流出，喷油过程结束。

5) Mechanical governor:
At equilibrium, the control rod assumes a position for a supply of fuel which corresponds to engine power at that operating point. If engine speed drops as a result of increased load, for example, the centrifugal force is also reduced and the governor springs move the flyweights, and thus the control rod, in the direction of increased fuel delivery until equilibrium is again established.(p52)
平衡时，控制杆的供油位置由该工况点发动机功率决定．例如，如果由于负载增加，发动机速度下降，飞块的离心力会随之下降．此时，调速器弹簧压动飞块，带动控制杆向加油方向运动直至平衡从新建立．６) Common rail (共轨) injection system:
All previous injection systems have one disadvantage in common [Fig. 2-30]: the pressure generation and the supply of the injection quantity are not mutually independent. The result is that the injection pressure increases with the engine speed and also increases during injection (approximately linearly). Consequently, smaller injection quantities are injected with low pressure. The peak pressure is almost twice as high as the average injection pressure, which is responsible for the quality of the fuel swirl in the combustion chamber.
前述所有的喷射系统都有一个共同的缺点（图2-30）：油压的产生和喷射的油量不是相互独立的，这样喷油压力随转速而增加，在喷油期间几乎会呈线性增加。

因此，少量柴油会以低压喷射。

最高喷油压力几乎是平均喷油压力的两倍，这会影响燃烧室内柴油涡漩质量。

７) Common rail (共轨) injection system:
A pressure accumulator is supplied with fuel by a high-pressure pump (Common Rail). The pressure in the common rail is measured with a pressure sensor and settled to a constant value by a pressure-control valve in the high-pressure pump. Depending on the requirements of combustion, the pressure in the rail can be maintained, largely independent of the engine speed, at a constant value in the range between 15~ 140MPa.
高压油泵（共轨管）向压力存储器供油。

压力传感器测量共轨管的压力，高压油泵的油压控制阀将压力控制为一个常数。

根据燃烧的要求，共轨管内的油压维持在15～140MPa范围内的一个固定值，这基本上与发动机转速无关。

８) turbo charger （涡轮增压器）system:
At exhaust-gas turbo- charging, the exhaust-gas energy which would have been lost is used to drive a turbine. This turbine drives a compressor which aspirates the combustion air and supplies it pre-compressed to the engine. In this way, more fuel can be supplied to the larger air mass and the engine power is increased. A positive effect is also exerted on the combustion process.
在废气涡轮增压中，原本要丧失的废气能量用来驱动涡轮，涡轮驱动压缩机，压缩机吸入助燃空气，预压缩后送给发动机。

这样，空气量多，供油也多，发动机功率就会增加，对燃烧过程也会带来积极影响。

1) Thermostat circulation:
When the engine is cool, the thermostat remains closed so that coolant cannot circulate through the radiator. Instead, coolant is recirculated within the engine block and cylinder head until the coolant reaches a predetermined temperature. At that temperature, a wax-like pellet expands inside the thermostat to open it and allow the coolant to flow. [Fig. 2-34]. Today, most original-equipment thermostats open at approximately 85ºC to 90ºC. In hotter climates, a “cooler” thermostat may be used to help avoid overheating.
当发动机温度较低时，节温器保持关闭，冷却水不能流通散热器进行循环，而是在发动机缸体和缸盖之间循环流动，一直到冷却水达到预定的温度为止。

在该温度下，节温器中的蜡芯膨胀，从而打开节温器，使得循环水流经节温器。

目前，多数原装节温器的开启温度大约在85～90ºC。

气温较高时，可采用低温节温器防止发动机过热。

2) anti-freeze: This is a solution which is added to the cooling system to lower the temperature at which freezing of the coolant occurs: the actual freezing temperature is governed by the quantity of anti-freeze added to the system. Ice increases its volume as its temperature decreases, so extensive damage to the cylinder block will result if the coolant freezes. Most modern anti-freeze solutions contain special chemical additives called
inhibitors to reduce corrosion of the metal parts. Care must be taken to avoid splashing anti-freeze on the vehicle paintwork, since some of the chemicals can soften the paint.
防冻剂溶液添加到冷却系统中，可降低冷却水冷冻的温度。

冷却水实际的冷冻温度是由添加的防冻剂的数量来控制的。

温度降低时，冰的体积会增加，所以冷却水一旦冷冻会给发动机缸体带来极大的损害。

现在多数的防冻剂都含有特殊的化学添加剂（称为抑制剂）用于减小对金属部件的腐蚀。

由于有些化学剂会软化油漆，因此一定要避免把防冻剂溅到汽车的漆面上。

3) The purpose of the lubrication system is to circulate oil through the engine. An engine must have a good lubrication system. Without it, the friction heat from the contact of the moving parts would wear the parts and cause power loss. Oil, when placed between two moving parts, separates them with a film. This oil film prevents the parts from rubbing against each other. This oil film also cushions the parts, giving quieter and smoother engine operation.
润滑系统的作用是使机油在发动机里循环流动。

发动机必须要有良好的润滑系统，不然移动部件相互接触摩擦而产生的热量会损害发动机部件，并损失发动机功率。

机油位于两个移动部件之间，通过油膜隔开两部件。

油膜防止部件之间的相互摩擦，它垫在两个不部件之间，使得发动机工作安静、平稳可靠。

4) In most cars, the oil pump is in the crankcase above the sump. It draws oil through a tube that extends downward into the sump. This tube has a filter screen over its bottom end. The screen keeps large pieces of sludge and dirt from being drawn into the pump. The tube may be hinged on the pump end so that it can move up and down as the oil level changes in the sump. Thus, the pump always draws oil from the top of the sump, not from the bottom where the dirt and sludge tend to settle. Modern cars use one of two common types of oil pumps --- the gear-type and the rotor-type.
在多数汽车上，机油泵位于油底壳上方的曲轴箱里。

机油泵通过向下延伸到油底壳里的一根油管吸油，该油管底端有滤网，可防止大块的沉淀物和污垢吸入机油泵。

油管铰接在机油泵的末端，这样在油底壳里的油面变化时油管可上下移动。

机油泵总是从油底壳的上部吸油，而不是从污垢和沉淀物所在的底部吸油。

目前的汽车一般有齿轮式和转子式两类机油泵可供使用
5)Type of harmful emission:
There are many causes for emissions. Some emissions are caused by poor air quality. Other emissions are caused by engine fuels, such as diesel fuel or gasoline. These are hydrocarbon fuels, made up primarily of hydrogen and carbon. Emissions are colorless and odorless. Sunlight, though, will transform them into smog.
产生排放的原因有很多，一部分排放物是由于空气质量差引起的，另一部分是由柴油或汽油等发动机燃料产生的。

这些碳氢化合物燃料主要由碳和氢两种元素组成。

这些排放物是无色无味的，在阳光的作用下会转变为烟雾。

6）three-way catalytic converter:
The catalytic converter (or more correctly the catalytic exhaust converter) consists of metal housing, a substrate and the actual active catalytic layer. The active catalytic substances are platinum and rhodium. [Fig. 2-39]. Platinum accelerates the oxidation of the hydrocarbons and the carbon monoxide, and rhodium accelerates the reduction of the oxides of nitrogen.
催化转化器(或更准确的叫废气催化转化器)由金属外壳、基底和活性催化层组成。

活性催化剂是铂和铑两种物质。

铂加速碳氢化合物和一氧化碳的氧化，铑加速氮氧化合物的还原。

7) Exhaust-gas recirculation :
Exhaust-gas recirculation is a method of reducing emissions of oxides of nitrogen that has been known and applied for years. In its essential components, engine exhaust is an inert gas, i.e. a non-combustible gas.
废气再循环可降低氮氧化合物的排放，这种技术早已为人所知并应用多年。

发动机废气的主要成分是一种惰性气体，也就是一种不易燃烧的气体
8）evaporative emission control: For vehicles used in the U.S。