汽车专业英语U1 L2(发动机部分)讲解
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汽车专业英语unit1
UNIT 1 AUTOMOTIVE BASICS 背景知识：本节主要介绍汽车的基本组件。
Four major categories: engine, body, chassis and electrical equipment.Engine:acts as the power unit. There are two types of engine: gasoline (also called a spark-ignition engine) and diesel (also called a compression-ignition engine).Body: I t provides a protective covering for the engine, passengers, and cargo.Chassis: support engine and any other assembly parts. It includes power train, running gear, and steering and brake system.Power train（传动系）：― conve ys the drive to the wheels. Include: clutch、gear box （变速器）、universal joint、propeller shaft（传动轴）、drive axle（驱动桥）。
Running gear（行驶系）：― support the vehicle and ensure it stable running. Include: frame（车架）、axle housing（桥壳）、suspension（悬架）、wheel（车轮）。
Steering（转向系）：― controls the direction of the movement. Include: steering wheel, column（转向管柱）,steering gears（转向器）, linkages（转向传动机构）.Brake（制动系）：― slows down the vehicle. Include: brake pedal, master cylinder, brake lines（油管），brake cylinder（制动缸）and brakes（制动器）。
汽车英语-发动机部分
汽车英语-发动机部分（个人整理版）作者:fiat0012008-12-15 13:16 星期一晴第一部分发动机一、汽车发动机 Automobile Engines内燃机发动机是通过汽油和空气的混合而运行的，理想的空燃比是14.7份质量的空气和1份质量的汽油混合。
Internal combustion gasoline engines run on a mixture of gasoline and air. The ideal mixture is 14.7 parts air to one part of gasoline（by weight.）由于汽油比空气重得多，因此我们一直笼统地说成大量的空气和少量的燃油。
Since gas weights much more than air, we are talking about a whole lot of air and tiny bit of gas.当发动机点火后，一份被完全汽化的燃油和14.7份质量的空气混合，就能产生出巨大的动力。
One part of gas that is completely vaporized into 14.7 parts of air can produce tremendous power when ignited inside an engine.让我们来看一下现代发动机的工作原理。
Let’s see how the modern engine uses that energy to make the wheels turn.空气通过空气滤清器进入发动机，并进入节气门。
Air enters the engine through the air cleaner and proceeds to the throttle plate.通过油门踏板，你能控制经过节气门进入发动机的空气量。
空气然后通过进气歧管进入各个气缸。
汽车发动机英语教程
Lesson 1. Petrol and Diesel Engines汽油发动机机和柴油发动机The explosive mixture of the petrol engine is provided by a carburettor, but in the case of the diesel engine the supply is effected by an injection or jerk pump which forces a shot of fuel into each cylinder in turn according to the correct firing sequence.翻译：汽油发动机由一个化油器输送可燃混合气体，而柴油发动机，由一个喷射泵或柱塞式燃油泵实现燃油供应，此泵根据正确的点火顺序把少量燃油依次压入每个汽缸。
The pump is actuated from a camshaft and the amount injected for each power stroke is extremely small at maximum output, indeed it may be less than 0.1 cm2 , Moreover, this charge must be metered with great and constant accuracy even while it is being variably controlled to regulate power from idling to maximum.It will be realised that efficient and economical running is largely dependent upon the fuel pump.翻译：通过凸轮轴驱动油泵。
每个功率冲程的燃油喷射量在最大输出功率时是非常微小的，实际上，可能小于0.1 cm2。
汽车专业英语--发动机
push rod
■ Valve gear tappet ■ Connecting rod
timing gears
connecting rod piston crankshaft flywheel
Engine cooling system
Engine lubricating system
Fuel supply system
Compression 压缩
Power 做功
Exhaust 排放
Stroke . /strəuk / n. 打击；中风；笔画；冲程；尝试；轻抚
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四、发动机的布置形式
发动机前置 前轮驱动
发动机前置 后轮驱动
发动机后置 后轮驱动
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课堂小结
需要记住的单词： Engine
发动机
Chassis
底盘
冷却系 cooling system
润滑系 lubrication system
[ˌlu:brɪ'keɪʃn]
润滑，加油; 油润;
起动系 starting system
点火系 Ignition system
[ɪgˈnɪʃn]
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燃油供给系 fuel supply system 进气系统 intake system 排气系统 exhaust system
• II. Text Explanation
The internal combustion engine, as its name indicates, burns fuel within the cylinders and converts the expanding force of the combustion into rotary force used to propel the vehicle.
Unit汽车专业英语(发动机)资料
Single-cylinder engine
cylinder piston Intake valve Exhaust valve Piston pin
Connecting rod
Timing gear
crankshaft Oil pipe
Oil pump
I. Pre-questions
what is the power source of automobile and how to produce? Engine
译文：内燃机，顾名思义，就是燃料在气缸内部 燃烧，并且把燃烧时的膨胀力转化为驱动车辆的 旋转力。
II. Text Explanation
Convert…..into…. ①转变；变换 That building has been converted into a school. 那座楼房改成学校了。 ②兑换 I want to convert some Hong Kong dollars into American dollars. 我想把一些港元换成美元。 ③改变信仰、党派或意见等 She managed to convert him to her opinion. 她终于设法说服了他接受她的意见。
crankshaft
I. Pre-questions
The engine comprises two mechanism and five systems, what are they ?
crankshaft and connecting rod mechanism（曲轴连 杆装置）, valve gear (阀动装置）, cooling system, lubricating system, fuel system, starting system, ignition system
Unit 2汽车专业英语(发动机)
译文：内燃机，顾名思义，就是燃料在气缸内部 燃烧，并且把燃烧时的膨胀力转化为驱动车辆的 旋转力。
II. Text Explanation
Convert…..into…. ①转变；变换 That building has been converted into a school. 那座楼房改成学校了。 ②兑换 I want to convert some Hong Kong dollars into American dollars. 我想把一些港元换成美元。 ③改变信仰、党派或意见等 She managed to convert him to her opinion. 她终于设法说服了他接受她的意见。
Fuel supply system
Valve gear
III. Exercises
•Translate the following expressions into Chinese. 活塞 piston 曲轴 crankshaft 分电器 distributor 油底壳 sump 正时齿轮 timing gear crankshaft and connecting rod mechanism 曲柄连杆机构 配气机构 valve gear 燃油系统 fuel system 火花塞 Spark plug 排气歧管 exhaust manifold
Reading
In other words, the piston completes a stroke each time it changes its direction of motion. 换句话说，活塞每完成一次冲程就会改变运动方向。
In other words
In other words, they remain relatively constant or static. 换句话说，它们相对的稳定、静止。 In other words, we have adhered to scientific socialism. 也就是说，我们坚持了科学社会主义
II. Text Explanation
Convert…..into…. ①转变；变换 That building has been converted into a school. 那座楼房改成学校了。 ②兑换 I want to convert some Hong Kong dollars into American dollars. 我想把一些港元换成美元。 ③改变信仰、党派或意见等 She managed to convert him to her opinion. 她终于设法说服了他接受她的意见。
Fuel supply system
Valve gear
III. Exercises
•Translate the following expressions into Chinese. 活塞 piston 曲轴 crankshaft 分电器 distributor 油底壳 sump 正时齿轮 timing gear crankshaft and connecting rod mechanism 曲柄连杆机构 配气机构 valve gear 燃油系统 fuel system 火花塞 Spark plug 排气歧管 exhaust manifold
Reading
In other words, the piston completes a stroke each time it changes its direction of motion. 换句话说，活塞每完成一次冲程就会改变运动方向。
In other words
In other words, they remain relatively constant or static. 换句话说，它们相对的稳定、静止。 In other words, we have adhered to scientific socialism. 也就是说，我们坚持了科学社会主义
汽车专业英语(发动机部分)
Engine surges or stalls
01
03 02
Fault symptoms and causes
• Engine runs rough or surges
Fault symptoms and causes
Engine leaks oil
Engine consumes oil excessively
01
02
03
04
定期检查机油、冷却液、 刹车液等是否充足。
定期更换空气滤清器、 机油滤清器和燃油滤清 器。
定期检查轮胎气压和磨 损情况，确保轮胎安全。
定期进行发动机和车身 的清洁，保持车辆整洁。
Engine oil and filter
01
02
03
04
正确选择机油的型号和粘度， 确保与发动机的要求相匹配。
used to connect to the OBD II port and retrieve diagnostic information.
Common troubleshooting
Check the battery and cables for corrosion or damage.
Check the air filter for blockage or damage.
电动汽车技术的应用
随着政府对环保政策的推动和消费者对环保的关注，电动汽车市场正在 不断增长。许多汽车品牌都在推出电动汽车或计划在未来推出相关车型， 如特斯拉、宝马和奥迪等。
Fuel cell technology
要点一
燃料电池技术
燃料电池是一种将燃料（通常是氢气 ）和氧化剂（通常是氧气）通过化学 反应转化为电能的装置。这种技术可 以提供清洁、高效的能源，并可用于 汽车和其他应用。
01
03 02
Fault symptoms and causes
• Engine runs rough or surges
Fault symptoms and causes
Engine leaks oil
Engine consumes oil excessively
01
02
03
04
定期检查机油、冷却液、 刹车液等是否充足。
定期更换空气滤清器、 机油滤清器和燃油滤清 器。
定期检查轮胎气压和磨 损情况，确保轮胎安全。
定期进行发动机和车身 的清洁，保持车辆整洁。
Engine oil and filter
01
02
03
04
正确选择机油的型号和粘度， 确保与发动机的要求相匹配。
used to connect to the OBD II port and retrieve diagnostic information.
Common troubleshooting
Check the battery and cables for corrosion or damage.
Check the air filter for blockage or damage.
电动汽车技术的应用
随着政府对环保政策的推动和消费者对环保的关注，电动汽车市场正在 不断增长。许多汽车品牌都在推出电动汽车或计划在未来推出相关车型， 如特斯拉、宝马和奥迪等。
Fuel cell technology
要点一
燃料电池技术
燃料电池是一种将燃料（通常是氢气 ）和氧化剂（通常是氧气）通过化学 反应转化为电能的装置。这种技术可 以提供清洁、高效的能源，并可用于 汽车和其他应用。
汽车专业英语U1 L2(发动机部分)
（2） The Cylinder Head The cylinder head is bolted to the cylinder block. The top of the cylinder block is covered with the cylinder head which contains the combustion chamber （Fig.2-1）.
（2） Flywheel The flywheel is a comparatively heavy wheel, bolted to the flywheel flange on the rear end of the crankshaft. The inertia of the flywheel tends to keep it rotating at a constant speed. The flywheel also has several other functions, for example, the flywheel has ring gear in its outer circumference,which mesh with teeth located on the starting motor drive pinion in order to crank the engine over. In addition, the rear surface of the flywheel serves as the driving member of the clutch assembly （Fig.2-2）.
III. Exercises
compression rings oil rings piston pin piston connecting rod
汽修专业英语Unit 2 PPT
PART THREE-TEXT(阅读资料)
1.By operating cycle: Engines can be divided into two groups based on the
number of piston strokes per cycle, either four or two. An engine which needs four strokes to complete one stroke is a four-stroke cycle engine. If it needs only two strokes to complete one cycle, it is a two-stroke cycle engine.
PART THREE-TEXT(阅读资料)
3.Power stroke: At the time the piston reaches to the top dead center, a
spark plug is fired to ignite the air-fuel mixture. The expanding gases of combustion force the piston down in the cylinder until the piston reaches the bottom dead center.
2.Phrase learning （短语学习）
the majority of
大多数
operating cycle
工作循环
according to
根据……
connecting rod assembly
曲柄连杆机构
valve gear
配气机构
汽车专业英语U1L3(发动机部分)
radiator pressure cap
upper tank
fin
lower tank
• 4．The Thermostat • In operation, the thermostat is designed to close off the flow of water from engine to radiator until the engine has reached the desired operating temperature.
The cooling system of a watercooled engine consists of the engine water jacket, thermostat, water pump, radiator, radiator cap, cooling fan and necessary hoses （Fig.3-1）
机油滤清器 The Oil Filter
4．The Oil Pan Engine oil is the fluid used to lubricate the engine. Several quarts of oil are stored in an oil pan bolted to the bottom of the engine block.
• 1．The Oil Pump • When the engine is running, an oil pump draws oil from the pan and forces it through oil galleries.
机油泵 oil pump
机油尺 dip stick
2．The Oil Galleries The oil galleries are
汽车专业英语U1 L1(发动机部分)
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一台汽车发动机往往具有3个以上的 汽缸，对于汽车发动机主要的分类方 式是根据汽缸的布局及排列方式来划 分。一般有直列L型、V型、W型以及 水平对置B型等几种。
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直列发动机(Line Engine)
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V型排列六缸发动机(V-shape)
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W型发动机(W-shape)
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水平对置发动机(Horizontally Opposed
Stroke . /strəuk / n. 打击；中风；笔画；冲程；尝试；轻抚
13
Clissfiled by cooled ways（按冷却方式分类）
水箱，通过水泵作用，水 通过水道流通整个汽缸体， 进行降温。
水冷却式发动机
Water coolet engine
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风冷，通过空气气流与风扇 作用，空气/风通过发动机整 个汽缸体，进行降温。
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Cooling
system (冷却系统)
ﮭStarting system (起动系统)
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Lubrication
system (润滑系统)
Ignition
system (点火系统)
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Fuel
supply system (燃油供给系统)
intake
system (进气系统)
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23
•汽油机包括哪两大系统？
Crank-connecting rod mechanism
曲柄 连杆 机构
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配气机构
Valve mechanism
气门 机构
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三、发动机的四大工作行程
Intake 进气
Compression 压缩
Power 做功
一台汽车发动机往往具有3个以上的 汽缸，对于汽车发动机主要的分类方 式是根据汽缸的布局及排列方式来划 分。一般有直列L型、V型、W型以及 水平对置B型等几种。
27
直列发动机(Line Engine)
28
V型排列六缸发动机(V-shape)
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W型发动机(W-shape)
30
水平对置发动机(Horizontally Opposed
Stroke . /strəuk / n. 打击；中风；笔画；冲程；尝试；轻抚
13
Clissfiled by cooled ways（按冷却方式分类）
水箱，通过水泵作用，水 通过水道流通整个汽缸体， 进行降温。
水冷却式发动机
Water coolet engine
14
风冷，通过空气气流与风扇 作用，空气/风通过发动机整 个汽缸体，进行降温。
19
Cooling
system (冷却系统)
ﮭStarting system (起动系统)
20
Lubrication
system (润滑系统)
Ignition
system (点火系统)
21
Fuel
supply system (燃油供给系统)
intake
system (进气系统)
22
23
•汽油机包括哪两大系统？
Crank-connecting rod mechanism
曲柄 连杆 机构
24
配气机构
Valve mechanism
气门 机构
25
三、发动机的四大工作行程
Intake 进气
Compression 压缩
Power 做功
汽车实用英语 汽车维修英语 第2讲 Engine systems(发动机系统)
2. The cylinder head fits on top of the cylinder block to close off and seal the top of the cylinder.
3. The biggest part of the engine is the cylinder block, which is also called an engine block.
Automobile Service English
（汽车维修英语） 第2讲 Engine systems
（发动机系统）
2 Engine systems （发动机系统）
一、Basic engine parts 发动机的基本零件 二、Four-stroke cycle engine 四冲程发动机 三、Fuel system 燃油系统 四、Cooling system 冷却系统 五、Lubrication system 润滑系统
» COMPRESSION STROKE
• Vocabulary
3. Power stroke
– The power stroke begins as the compressed air-fuel mixture being ignited. An electrical spark across the electrodes of a spark plug ignites the air-fuel mixture. The burning fuel rapidly expands, creating a very high pressure against the top of the piston. This drives the piston down toward BDC. The power of the piston downward movement is transmitted through the connecting rod to the crankshaft.
3. The biggest part of the engine is the cylinder block, which is also called an engine block.
Automobile Service English
（汽车维修英语） 第2讲 Engine systems
（发动机系统）
2 Engine systems （发动机系统）
一、Basic engine parts 发动机的基本零件 二、Four-stroke cycle engine 四冲程发动机 三、Fuel system 燃油系统 四、Cooling system 冷却系统 五、Lubrication system 润滑系统
» COMPRESSION STROKE
• Vocabulary
3. Power stroke
– The power stroke begins as the compressed air-fuel mixture being ignited. An electrical spark across the electrodes of a spark plug ignites the air-fuel mixture. The burning fuel rapidly expands, creating a very high pressure against the top of the piston. This drives the piston down toward BDC. The power of the piston downward movement is transmitted through the connecting rod to the crankshaft.
汽车专业英语原文翻译
第一单元发动机分类及工作原理课文A发动机的分类所有的汽车发动机都是内燃机（ICE),就是将燃油在气缸内进行燃烧，并将燃烧产生的膨胀压力转变成转动力，用来驱动汽车。
所以说，发动机是动力源, 并被认为是汽车的心脏。
汽车发动机根据工作方式分为往复式发动机和转子发动机：报据发动机燃烧的燃料分为汽油机和柴油机：根据发动机的气缸数量和气缸排列方式分为直列发动机、V型发动机、对置式发动机和W型发动机。
往复式发动机和转子发动机往复式发动机也称为活塞式发动机。
该发动机采用一个或多个活塞在气缸内上下运动或前后运动，将压力转变为转动动能传递给汽车驱动轮（见图1-1)。
往复式发动机广泛应用现代汽车上。
转子发动机是于1954年研发出来的。
如图1-2所示，在该发动机中，有个三角形的转子在燃烧室内旋转。
膨胀气体使转子旋转，产生动力并排出废气。
转子发动机没有活塞和气门等往复部件。
转子发动机产生马力大、无振动，但其燃油消耗比往复式发动机要高。
汽油机和柴油机汽油机以汽油作为燃料。
采用火花塞点燃缸内的可燃混合气，产生动力使汽车行驶，如图1-3a所示。
汽油机也称为火花点燃式发动机。
该发动机的特点是转速高，运行平顺，结构简单，重量轻，成本低。
几乎所有轿车都采用汽油机。
柴油机以柴油作为燃料。
该发动机的工作原理足通过压缩缸内的空气使其升温，冉使喷油嘴喷入的柴油燃烧，产生动力驱动汽车(见图1-3b)，所以也称为压燃式发动机。
柴油机要比汽油机的动力更强劲，燃油经济性更好。
常见于所有的大型货车、客车和部分轿车上。
直列发动机，V型发动机，水平对置式发动机，W型发动机通过气缸数最和气缸排列方式可以识别发动机结构。
当今所有的紧凑型轿车都配有4缸发动机，一些中型级轿车配有6缸发动机，大型轿车配有8缸或12缸发动机。
在多气缸发动机上，气缸通常以四种排列方式中的一种排列，有：直列式、V型、水平对置式和W型。
直列式发动机中的气缸按直线排列，采用一个气缸蓝。
几乎所有4缸发动机都采用该种排列（兄阁1-4)。
汽车专业英语U1-L1(发动机部分)
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. Camshaft forces the intake valve open automatically at or slightly before the piston starts down. The air-fuel mixture is drawn into the cylinder. At the same time, the exhaust valve remains closed during this downward movement. This valve closure prevents the entering air-fuel charge from escaping through the exhaust port. After the piston reaches the Bottom Dead Center （BDC） of its first stroke, the cylinder is practically full of an air-fuel charge. The drawing of an air-fuel charge into the cylinder in this manner, during the downward movement of the piston, constitutes the intake stroke （Fig.1-2a
• Which is called the “heart” of Automobile?
be called of ------ (被叫做------)； heart (心脏)；
中文：哪部分被称作是汽车的心脏？
发动机
5
Part one
Automobile Engine 汽车发动机
. Camshaft forces the intake valve open automatically at or slightly before the piston starts down. The air-fuel mixture is drawn into the cylinder. At the same time, the exhaust valve remains closed during this downward movement. This valve closure prevents the entering air-fuel charge from escaping through the exhaust port. After the piston reaches the Bottom Dead Center （BDC） of its first stroke, the cylinder is practically full of an air-fuel charge. The drawing of an air-fuel charge into the cylinder in this manner, during the downward movement of the piston, constitutes the intake stroke （Fig.1-2a
• Which is called the “heart” of Automobile?
be called of ------ (被叫做------)； heart (心脏)；
中文：哪部分被称作是汽车的心脏？
发动机
5
Part one
Automobile Engine 汽车发动机
汽车专业英语(发动机部分)33PPT课件
❖ What’s the function of the flywheel?
功能
❖ helping the engine to run smoothly(平稳) during the power stroke and releasing(释放) it during the other strokes；
Single-cylinder engine
Inlet valve Exhaust valve
Timing gear Oil pump
cylinder piston Piston pin Connecting rod
crankshaft Oil pipe
❖The engine comprises two mechanism and five systems, what are they ?
❖ Crankshaft, because it can change the reciprocating motion (往复运 动)of the piston into rotary(旋转) motion and handle(处理) the entire(全部) power output.
I. Pre-questions
the cylinder
crankcase
I. Pre-questions
Cylinder head cover
pad
cylinder head cylinder gasket
to fit spark plug
练一练
气缸体
气缸盖罩
பைடு நூலகம்
油底壳
气缸盖 气缸垫
1- cylinder head cover;
compression rings
功能
❖ helping the engine to run smoothly(平稳) during the power stroke and releasing(释放) it during the other strokes；
Single-cylinder engine
Inlet valve Exhaust valve
Timing gear Oil pump
cylinder piston Piston pin Connecting rod
crankshaft Oil pipe
❖The engine comprises two mechanism and five systems, what are they ?
❖ Crankshaft, because it can change the reciprocating motion (往复运 动)of the piston into rotary(旋转) motion and handle(处理) the entire(全部) power output.
I. Pre-questions
the cylinder
crankcase
I. Pre-questions
Cylinder head cover
pad
cylinder head cylinder gasket
to fit spark plug
练一练
气缸体
气缸盖罩
பைடு நூலகம்
油底壳
气缸盖 气缸垫
1- cylinder head cover;
compression rings
汽车专业英语第二版课件1-unit 1
气环
oil control rings are employed to scrape scrape 把...刮除
oil from the cylinder walls.(3)piston pin: It is used to connect piston to
piston pin 活塞销
connecting rod.(4)connecting rod: it is reciprocating motion
System Engine Ignition, Starting and
Charging System Engine Diagnosis System
Unit 1 Engine Mechanical
1. Cylinder Block
The engine block is the main supporting
consists of piston, compression rings, oil control rings, piston pin and connecting rod.(1)pisnecting rod 连杆 combustion 燃烧 consists of
(气缸体) 2- cylinder
(气缸) 3- crankcase area
（曲轴箱部分）
2. Cylinder Liners
The purpose of using a liner is that, if the cylinder is damaged, the liner can be removed and replaced rather easily. There
built within the block. These passageways, coolant 冷却液
轮机阅读 U1 L2
5. At about 10-20 °BTDC (firing), depending on the type and speed of the engine, the injector admits finely atomized fuel which ignites within 2-7 °(depending on the type again) and the fuel burns over a period of 30-50 °, while the piston begins to descend on the expansion stroke. (P.9. Para.1) 此句中“depend on”的意思为“取决于，依…而定”： e.g. 一切取决于天气。 All depends on the weather. 你的晋升取决于你自己的价值，即你的能力。 Your advancement depends on your worth ——your ability. 此外，本句中的“while”意为“同时” 翻译：依柴油机的型号和转速而定，大约在10 °~ 20 °BTDC(上止点 前），喷油器喷入精细雾化的燃油。喷入的燃油在2 °~ 7 °内着火 （也依机型而定），在30 °~ 50 °的期间内燃烧，同时活塞在膨胀 行程下行。
6. The rising piston expels the remaining exhaust gas and at about 7080°BTDC the inlet valve opens (IVO) so that the inertia of the outflowing gas, plus the positive pressure difference, which usually exists across the cylinder by now, produces a through flow of air to the exhaust to “scavenge” the cylinder. (P.9. Para.2) 本句中， across the cylinder指的是从气缸内到气缸外； a through flow of air to the exhaust 中的“through”是形容词，“贯穿的，直通的” 另外，本句中出现了两个“to”，第一个“to”是介词，表方向，第二 个“to”与动词“scavenge” 连用构成动词不定式，表目的。 翻译：上行的活塞驱赶残留的废气，在70-80°BTDC，进气阀打开，这 样向外流动的气体的惯性加上正的压差（此时通常在气缸内外是存在 的），就产生了空气对废气的贯穿气流以清扫气缸。
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2．Tappet, Pushrods and Rocker Arms
Tappet rests on a cam of the camshaft. The pushrod is a metal rod that fits between the tappet and the rocker arm. Its function is to transmit cam lobe lift to the rocker arm assembly. The rocker arm is nothing more than a lever. Its function is to convert the up wardmotion of a pushrod into downward motion that compresses the spring and opens the valve.
练一练
气缸体
气缸盖罩
油底壳
气缸盖 气缸垫
1- cylinder head cover;
2-cylinder head;
3- cylinder gasket; 4-cylinder block; 5- oil pan
Components of piston
piston top
活Pi塞shtoo销nlep孔in
（1） The Connecting Rod
The connecting rod links the piston to the crankshaft. The small end of connecting rod connects with the piston pin and the big end connects with the crank pin of the crankshaft.
3．Valves and Valve Springs
Modern engines have cylinder heads that contain valves. Each cylinder requires at least two valves：an intake valve and an exhaust valve. The valves are compressed and closed by valve springs. As the valve is opened by the camshaft, it compresses the valve spring.
oil rings piston pin piston connecting rod
crank bearing half shell曲 柄轴承半壳 connecting rod cap
2．Crankshaft Flywheel Group （1） Crankshaft The crankshaft is the main rotating shaft of the engine. Designed into the one-piece crankshaft are areas for main bearing journals, crankpins, counterweights, flywheel flange, and driving hub. The crankshaft and connecting rod convert the reciprocating motion of the piston to the rotary motion of crankshaft. Crankshafts have drilled oil passages, through which oil can flow from the main bearings to the connecting-rod bearings.
陈长梅
One. Crank-Connecting Rod Mechanism
Crank-connecting rod mechanism consists of pistonconnecting rod group, crankshaft flywheel group, engine block group.
valve
push rod
■ Valve gear阀装置 Tappet 挺杆 ■ Connecting rod
timing gears
connecting rod
piston crankshaft
flywheel
Engine Body
cylinder head
cylinder block
The cylinder gasket 气缸垫
The piston
Piston top piston ring piston pin
connecting rod
Two. The Valve Train
The valve train is a series of parts used to open and close the intake and exhaust valves. Meshing the timing gears or installing the timing chains onto the sprockets at a specific place will ensure the valves to open and close at the proper moment in the engine’s cycle. It consists of camshaft, tappet, pushrod, rocker arm, valve spring, valve and so on （Fig.2-4）.
Single-cylinder engine
Inlet valve Exhaust valve
Timing gear Oil pump
cylinder piston Piston pin Connecting rod
crankshaft Oil pipe
inlet valve exhaust
进水阀
piston head piston skirt
Small end小端 Connecting rod bushing连杆衬套 Connecting rod Big end
Connecting rod half shells半壳 Connecting rod cap
III. Exercises
compression rings
（2） The Piston The engine manufacturer fits a piston into each cylinder of the engine. The piston receives the pressure from the burning airfuel mixture and converts this pressure into up-and-down reciprocating motion. Because aluminum is half weight less than iron, most of pistons are made from aluminum alloy. （3） Piston Rings The piston ring is a springy split metal ring. It is used to provide the necessary seal to eliminate blowby and to control oil consumption. Engine pistons have two kinds of rings：gas rings and oil rings.
（2） Flywheel
The flywheel is a comparatively heavy wheel, bolted to the flywheel flange on the rear end of the crankshaft.
The inertia of the flywheel tends to keep it rotating at a constant speed. The flywheel also has several other functions, for example, the flywheel has ring gear in its outer circumference,which mesh with teeth located on the starting motor drive pinion in order to crank the engine over. In addition, the rear surface of the flywheel serves as the driving member of the clutch assembly （Fig.2-2）.
1．The Engine Block Group
（1） The Cylinder Block
The cylinder block is the basic part of the engine. It forms the main framework or foundation of the engine. Many parts of the engine are fixed to it. These items include water pump, oil pan, flywheel or clutch housing, ignition distributor, oil pump, fuel pump, and cylinder head.
1．Camshaft
The camshaft is another rotating shaft within the engine, it’s driven by the engine’s crankshaft through the timing gears. The camshaft has a series of cams that can change rotary motion to straight-line motion which cause the intake valves and exhaust valves to open. It rotates at the half speed of the crankshaft.