汽车工程专业英语（汉化版）

Automotive Engineering English （Chinese Edition ）汽车⼯程专业英语（汉化版）

CONTENTS

Chapter 1 Automotive basics (2)1.1 The history of automotive (2)1.2 Classification of automotives (3)1.3 Principal Components (6)Review questions (13)Chapter 2 Engine (14)2.1 Overview (14)

2.2 Engine construction (15)2.3 The engine operation (26)2.4 Basic engine systems (29)2.5 Air induction System (31)2.6 Gasoline fuel System (32)2.7 Engine Cooling (40)2.8 Engine Lubrication (44)2.9 Diesel engine (46)2.10 Emission Control (53)Review questions (61)⽬录

第⼀章汽车的基础 (2)1.1 汽车的历史 (2)1.2. 汽车的分类 (3)1.3 汽车的主要组成部分 (6)复习题 (13)第⼆章发动机 (14)2.1 概述 (14)2.2 发动机的结构 (15)2.3 发动机的运转 (26)2.4 发动机的基本系统 (29)2.5 进⽓系统 (31)2.6 汽油供给系统 (32)

2.7 发动机冷却系统 (40)2.8 发动机润滑系统 (44)2.9 柴油发动机 (46)2.10 排放控制 (53)复习题 (61)

Capture 1 Automotive basis第⼀章汽车的基础

1.1 The history of automobile1.1汽车的历史

The automotive industry affects many areas of the economy. Starting with the first patented gasoline-powered Benz

Motorwagen in 1886(Figure 1.1)，the automotive industry has seen continuous and exciting changes for over a century. Theearly gasoline-powered automobile generated 1.5hp(1.1kW)，it reaches top speed of 3~5mph(5~8km/h).Today's averagevehicles have 110~450hp(80~330kW )engines and cruise at 106~120km/h，depending on the legal speed limit. For manypeople around the world，automotives are the most important means of personal transportation.

汽车⼯业影响经济的许多领域。从1886年第⼀个汽油发动的专利，奔驰Motorwagen(图1.1)开始，汽车⾏业已经经历连续的和激动⼈⼼的变化超过⼀个世纪。早期的汽油动⼒汽车产⽣1.5 hp(1.1 kw)，它的最⾼时速为每⼩时3 ~ 5英⾥(5 ~ 8公⾥/⼩时)。今天的汽车平均拥有110 -450马⼒(80-330千⽡)的发动机，速度在106 ~ 120公⾥/⼩时,根据法定限速。对于世界各地的许多⼈⽽⾔，汽车是最重要的个⼈交通⼯具。

Modern automotives are highly complex vehicles with multiple computer-controlled systems. A car today has more

computers in it than the first spaceship. It may have as many as 15 computers operating everything from the engine to theradio.

现代汽车是拥有多个计算机控制系统的⾼度复杂的汽车。⼀辆现代汽车⽐世界上第⼀架宇宙飞船拥有更多的电脑。从发动机到收⾳机，它可能有多达15个电脑操作。

Automotives are available in a wide variety of models，sizes，and body styles. Vehicles range from compacts to full-sizecars and from minivans to sport utility vehicles(SUV).There are also sedans，station wagons，and light-duty trucks. Luxurymodels are also available.

汽车有各种各样的式样,尺⼨和车⾝风格。汽车从⼩型汽车到全尺⼨轿车的范围涵盖了从⼩货车到运动型多功能车(SUV)。也有轿车,旅⾏车和轻型卡车，豪华车型也可⽤。

Technology has improved vehicles over the past century. Vehicles are designed according to a variety of factors，includingthe number of engine cylinders，the type of drive train system，and vehicle application.

科学技术提⾼了汽车在过去的⼀个世纪。汽车设计是根据多种因素，包括发动机⽓缸的数量、汽车传动系的类型系统和汽车的运⽤。

About 15000 separate parts are assembled to make an automotive vehicle. These components are grouped in to severalsystems, known as automotive vehicle systems. An automotive system is a system made up of two or more parts that worktogether to perform a specific task.

⼀辆汽车⼤约由15000个独⽴的部分组成。这些组件组合成多个系统，称为汽车系统。⼀个汽车系统是由两个或两个以上的部件⼀起⼯作来执⾏特定的任务。1.2 Classification of automotives1.2汽车的分类

Motor vehicles may be classified by a number of different criteria. The most commonly used system of classification is

detailed. Where applicable, the equivalent European New Car Assessment Programme (NCAP)classifications are shown.The United States Environmental Protection Agency (EPA)has another set of classification rules based on interior passengerand cargo volumes.

汽车可以由许多不同的标准进⾏分类。最常⽤的分类系统，在适⽤情况下,相当于欧洲新车评估项⽬(NCAP)分类系统。美国环境保护署(EPA)拥有另⼀套基于室内客货量的分类规则。

1.Microcar1.微型车

Microcars are motor vehicles straddling the boundary between cars and motorbikes. These vehicles have engines under 1.0liter, typically seat only two passengers, and are sometimes unorthodox in construction. Although some microcars are three-wheeled, they are not classified into the category of motorbike. A microcar has seats rather than a saddle and is operated bya steering wheel instead of a handle bar. Microcars were popular in post-war Europe, where their appearance led them to becalled \"Bubble cars\". Figure 1.2 shows examples of the microcar.

微型车是横跨汽车和摩托车边界之间的机动车。这些汽车发动机在1.0升,通常只有两个座位乘客,有时在建造上是⾮正规的。虽然⼀些微型车是三轮的,但它们并不属于摩托车的类别。微型车拥有座位,⽽不是⼀个靠座。微型车拥有⽅向盘，⽽不是⼀个把⼿。微型车在战后的欧洲很受欢迎,它们的外表使它们被称为“泡泡车”。图1.2展⽰了微型车的例⼦。2.City car2.城市车

A city car is a small vehicle intended for use primarily in urban areas. City cars are sold worldwide and most manufacturershave one or two models in their line-up. Unlike microcars，a city car's greater speed, capacity and occupant protection aresafer in mixed traffic environments and weather conditions. In Japan, city cars are called kei cars，they have to meet strictsize and engine requirements: engines have a maximum displacement of 660cc and the car's length must be less than3400mm. Examples of city cars are Ford Ka and Citroen C1(Figure 1.3).

城市车是⼀个⼩交通⼯具，主要使⽤在城市地区。城市车在全世界⼴泛销售，并且⼤多数制造商有⼀个或两个模型在它们的阵容中。与微型车不同,城市车拥有更快的速度、更⼤的容量和更安全的乘客保护，在混合交通环境和恶劣天⽓条件下更安全。在⽇本,城市汽车被称为轻型车，它们必须满⾜严格的⼤⼩和发动机要求：发动机的最⼤位移不能超过660 cc，整车的长度必须⼩于3400毫⽶。城市汽车的例⼦有福特Ka和雪铁龙CI(图1.3)3.Subcompact car3.低端紧凑型轿车

Subcompact car is a term used to describe vehicles whose class size is smaller than that of a compact car，usually not

exceeding 4191mm in length, but larger than a microcar. According to EPA, a passenger car is classified as subcompact if ithas between 2,407L and 2,803L of interior volume. Many contemporary cars branded as \"subcompact\" fall into either thesupermini or the city car category in Europe. Examples of subcompact cars are Peugeot 207 and Ford Fiesta(Figure 1.4).低端紧凑型轿车是⼀个术语，⽤于描述车汽车的整体规模⼩于紧凑型轿车,通常长度不超过4191mm,但⼜⽐微型车⼤。根据EPA的规定,轿车被归为低端紧凑型轿车如果它的内部体积介于2407L和2803L之间。许多当代的汽车都是“低端紧凑型轿车”。在欧洲，它分为两类：或是超级迷你车，或是城市车。微型汽车的例⼦有标致4.Compact car4.紧凑型轿车

A compact car or small family car is a classification of cars which are larger than a subcompact car but smaller than or equalto a mid-size car.

紧凑型轿车或⼩型家庭轿车⼀个汽车的类别，⽐低端紧凑型轿车⼤,但⼩于或等于⼀辆中型轿车。

Current compact car size, for US and international models respectively, is approximately 4100mm and 4450mm long forhatchbacks, or 4400mm and 4750mm long for convertibles, sedans or station wagons. Multi-purpose vehicles and sportutility vehicles based on small family cars (often called compact MPVs and compact SUVs)have similar sizes.⽬前紧凑型轿车的⼤⼩,在美国与国际车型中,分别是：⼤约在4100mm和4450mm长之间（对于掀背式车）；介于4400mm和4750mm长之间（对于敞篷车、轿车和旅⾏车）。基于⼩型家庭轿车的多⽤途汽车和运动型多功能车(通常被称为紧凑型MPV和紧凑型SUV)也有类似的尺⼨。

Common engines are 1.5 to 2.4-litre straight-4s,using either gasoline or diesel fuel,with a range between

75kW and 127kW.High-performance versions may have turbocharged 2.0 or 2.5-liter engines,or even V6 3. 2-liter units,ranging maximum outputs from 127kW to 224kW. Examples of compact cars are Volkswagen Golf and Ford Focus( Figure1.5).

紧凑型轿车常见的发动机是1.5到2.4升的直列式四缸发动机,它们使⽤汽油或柴油作为燃料,输出功率在75千⽡和127千⽡之间。⾼性能版本是2.0或2.5升涡轮增压发动机,甚⾄六缸3.2升的单元，最⼤的输出功率在127千⽡到224千⽡不等。⼩型汽车的例⼦是⼤众⾼尔夫和福特福克斯(图1.5)。5.Sedan5.轿车

A sedan or saloon is a passenger car in a three-box configuration with A，B& C-pillars and principal volumes articulated inseparate compartments for engine, passenger and cargo. The passenger compartment features two rows of seats and

adequate passenger space in the rear compartment for adult passengers. The cargo compartment is typically in the rear withthe exception of some rear-engined models. It is one of the most common car body styles. Figure 1.6 shows the typical pillarconfigurations of a sedan(three box),station wagon(two box) and hatchback (two box) from the same model range.轿车是⼀部载客汽车，拥有三厢车的配置：A柱、B柱、C柱分别和主容积互相铰接成的单独的隔间,分别放置发动机,乘客和货物。乘客舱的特点是拥有两排座椅和后舱⾜够⼤的乘客空间。除了⼀些发动机后置车型以外，货舱通常在后⾯。这是最常见的⼀种车⾝样式。图1.6显⽰了典型⽀柱轿车(三厢),旅⾏车(两厢)和掀背车(两厢)的配置，它们来⾃于相同的车型范围。6.Station wagon(SW)6.旅⾏车

A station wagon or estate car is a body style variant of a sedan with its roof extended rearward over a shared passengercargo volume with access at the back via a third or fifth door, instead of a trunk lid. The body style transforms a standardthree-box design into a two-box design ——to include an A, B& C-pillar, as well as

a D pillar. Station wagons feature flexibility to allow configurations that either favors passenger or cargo volume,e.g., fold-down rear seats.

旅⾏车或以旅⾏车为⼀体的风格变异的轿车，在它的车顶上扩展乘客数或者是货运量，并通过⼀个共享的第三门或第五门，⽽不是⾏李箱盖。车⾝风格从标准三厢车设计转换成⼀个两厢的设计——包括A、B、C⽀柱,以及D⽀柱。旅⾏车功能灵活，允许容纳更多的乘客或更⼤的货物体积的配置，如：可折叠式后座。

When a model range includes multiple body styles such as sedan, hatchback and station wagon, the models typically sharetheir platform, drivetrain and bodywork forward of the A-pillar.

当⼀个车型范围包括多种车⾝风格如轿车、掀背车和旅⾏车，车型通常分享它们的⼯作平台、动⼒传动系统和车⾝的a柱。7.Truck7.卡车

A truck or lorry is a motor vehicle designed to transport heavy goods. Trucks vary greatly in size, power and configuration.Modern trucks are powered by either gasoline or

diesel engines, with diesel dominant in commercial applications. Commercial trucks can be very large and powerful, andconfigured to mount specialized equipment, such as in thecase of fire trucks, concrete mixers and suction excavators.

卡车或货车是设计⽤来运输沉重的货物的。卡车在体型、功率和配置上都⾮常强⼤。现代的卡车由汽油或柴油发动机提供动⼒,柴油占商业应⽤的主导地位。商业卡车都⾮常强⼤有⼒,配置安装专⽤设备,如在消防车中,混凝⼟搅拌机和吸⼊式挖掘机上。The cab of a truck is an enclosed space where the driver is seated. There are several possible configurations of cab in

common use: cab over engine(COE) or flat nose，conventional cabs or long nose. In the case of COE, the driver's seat andthe control devices are located above the front axle and the engine. This design is almost ubiquitous in Europe and widelyused in the rest of the world. To access the engine, the whole cab tilts forward. In the case of conventional cabs, the driver isseated behind the engine, as in most passenger cars or pickup trucks. This type provides some front panels such as a longhood and fender to cover the engine and front wheels. They are the most common in North America. This type is also called

cab behind engine (CBE). These trucks provide somewhat poorer visibility than COE counterparts(Figure 1.7).

⼀辆卡车的驾驶室是司机坐在那⾥的⼀个封闭空间。驾驶室有如下⼏个常⽤配置：驾驶室坐落在发动机上⽅(COE)，呈扁平的形状，传统的驾驶室呈长形。在COE的情况下，司机的座位和控制设备位于前轴和发动机的上⽅。这个设计在欧洲⼏乎是⽆处不在的，并⼴泛⽤于世界其它国家。为了接近发动机,整个驾驶室向前倾斜。在⼤多数轿车或卡车的传统驾驶室内，司机坐在发动机的后⾯。这种类型的驾驶室提供了⼀些前置的挡板，例如较长的发动机罩和挡泥板来覆盖发动机和前轮，它们在北美是最常见的。这种类型也被称为驾驶室位于发动机下⽅(CBE)。与COE相⽐，这些卡车的能见度相对不⾜。(图1.7)。Special vehicles are built on the chassis of mass production motor vehicle to meet particular requirements. Many of them areprovided with special equipments for particular purposes.

专⽤汽车都是建⽴在⼤规模⽣产的汽车底盘上⾯，来满⾜特定的需求。它们中的很多都提供特定的设备来满⾜特殊的⽬的。The first type is used to carry special goods. Such as vehicle with a closed body for easy-contaminated goods, vehicles witha refrigerator body for perishable food stuff, dump truck for sand, soil or stones, flat-bed semi-trailer for large-size cargo andtanker for liquefied loads, dry bulk cargo or gases, powder.

第⼀类是⽤来携带特殊物品的汽车。这类汽车⽤⼀个封闭的车⾝装载易受污染的货物，汽车⽤带制冷功能的车⾝来装载易腐坏的货物，车⾝⾃动倾卸沙⼦、泥⼟或⽯块，平板车和半挂拖车⽤来装载⼤件货物，油罐车⽤户来运输液体、⼲散货、⽓体和粉末。

The vehicles for special work have special equipments to meet the specific requirements, such as mobile-shop, ambulance,fire engine and vehicles for urban sanitation and road cleaning.

特殊的汽车有特殊的设备，以满⾜特定的⼯作需求，例如移动收货车、救护车、消防车和⽤于卫⽣设施和道路清洁的城市汽车。

A modern firetruck (Figure 1.8)is usually a multi-purpose vehicle carrying professionals and equipment for a wide range offirefighting and rescue tasks. Many fire engines are based on standard truck or lorry models with heavy duty suspensions,brakes, tires, alternator, transmission and cooling systems；audible and visual warnings such as sirens, horns, and flashinglights.

现代救⽕车(图1.8)通常是⼀台多⽤途汽车，携带专业⼈员和救援设备范围，⽤于消防和⼴泛的救援任务。许多消防车以标准卡车为基准，拥有重型悬架、刹车系统、轮胎、交流发电机、输电和冷却系统；声光报警装置如警报器、喇叭和闪光灯。1.3 Principal Components1.3 汽车的主要组成部分

The automotive chassis provides the strength necessary to support the vehicular components and the payload placed uponit.

汽车的底盘提供了必要的⼒量来⽀持汽车的组件和在其上的有效负载。

The suspension system contains the springs, the shock absorbers, and other components that allow, the vehicle to pass overuneven terrain without an excessive amount of shock reaching the passengers or cargo.

悬架系统包括弹簧、减震器和其它组件，允许汽车在凹凸不平的地形通过，⽽不使过量的冲击到达乘客或货物部位。The steering mechanism is an integral portion of the chassis, as it provides the operator with a means of controlling thedirection of travel.

转向装置是底盘的⼀个部分，它为司机提供了⼀种控制⾏进⽅向的⼿段。

The tires grip the road surface to provide good traction that enables the vehicle to accelerate, brake, and make turns withoutskidding. Working in conjunction with the suspension，the tires absorb most of the shocks caused by road irregularities.轮胎抓住路⾯，为汽车提供⾜够的牵引⼒,使汽车加速、刹车和转弯不打滑。轮胎与悬架⼀起⼯作，轮胎吸收了因路⾯不平⽽造成⼤部分冲击。

The body of the vehicle encloses the mechanical components and passenger compartment. It is made of relatively light sheetmetal or composite plastics. The components that make up the chassis are held together in proper relation to each other bythe frame.

汽车的车⾝围绕着机械零件和乘客舱。它由相对较轻的薄钢板或合成塑胶制成。底盘的组件通过车⾝框架互相合适地组合在⼀起。

An automobile body is a sheet metal shell with windows, doors, a hood and a trunk deck built into it.It provides a protectivecovering for the engine, passengers and cargo. It is designed to keep passengers safe and comfortable. The body stylingprovides an attractive, colorful, modern appearance for the vehicle.

车⾝是⼀个⾦属板壳，车窗、车门、发动机盖和⾏李箱建造在它的上⾯。它提供了⼀个发动机、乘客和货物的保护层。它的⽬的是保证乘客安全舒适。车⾝造型提供了⼀个有吸引⼒的、丰富多彩的、现代化的外观。

A sedan has an enclosed body with a maximum of 4 doors to allow access to the passenger compartment. The design alsoallows for storage of luggage or other goods. A sedan can also be referred to as a saloon and traditionally has a fixed roof.There are soft-top versions of the same body design except for having 2 doors, and these are commonly referred to asconvertibles.

轿车有⼀个封闭的车⾝，车⾝上最多有4扇车门⽤以允许访问乘客舱。这样的设计还允许存储⾏李或其它物品。轿车也可以称为豪华汽车，它们的传统是有⼀个固定的车顶。同⼀车⾝设计还有敞篷版，但它只有2扇车门，这通常被称为有活动帐篷的汽车。

The utility or pick-up carries goods. Usually it has stronger chassis components and suspension than a sedan to supportgreater gross vehicle mass.

多⽤途汽车或⽪卡车⽤来运输货物。通常它具有较强的底盘组件和与轿车相⽐更⼤的悬架，以⽀撑更⼤的汽车总质量。Light vehicle vans can be based on common sedan designs or redesigns so that maximum cargo is available.轻型货车可以基于普通轿车的设计，或者重新设计，以便最⼤限度的载货。

The bodies of commercial vehicles that transport goods are designed for that specific

purpose. Tankers transport fluids, tippers carry earth or bulk grains, flatbeds and vans are used for general goods transport.运输货物⽤的商⽤车的车⾝,为特定的⽬的⽽重新设计。油罐车运输液体，翻⽃车装载⼟壤或散装⾕物，平板车或运输货车⽤于普通货物运输。

Buses and coaches are usually 4-wheel rigid vehicles, but a large number of wheels and axles can be used. Sometimesarticulated buses are used to increase capacity. Buses and coaches can be single-deck or double-deck. Buses arecommonly used in cities as commuter transports while coaches are more luxurious used for long distances.

公共汽车和长途客车通常是4轮车,但更多的轮⼦和轴也是可以使⽤的。有时⼈们使⽤铰接式公共汽车，⽤来提⾼载客能⼒。公共汽车和长途客车可以分为单层或双层。公共汽车通常⽤于在城市通勤，⽽长途客车更豪华的⽤于长途旅⾏。

The engine acts as the power unit. The internal combustion engine is most common: this obtains its power by burning a

liquid fuel inside the engine cylinder. There are two types of engine: gasoline (also called a spark-ignition engine) and diesel(also called compression-ignition engine). Both engines are called heat engines. the burning fuel generates heat whichcauses the gas inside the cylinder to increase its pressure and supply power to rotate a shaft connected to the power train.发动机作为汽车的动⼒装置。内燃机是最为常见的：它通过在发动机⽓缸内燃烧液体燃料获得⼒量。发动机分为两个类型：汽油机(也称为⽕花点燃式发动机)和柴油机(也称为压缩点燃式发动机)，两类发动机都被称为热机。燃料燃烧产⽣热量使得⽓缸内的⽓体增压，并使得连接在动⼒系统上的传动轴转动。

The way engine cylinders are arranged is called the engine configuration. In-line engines have the cylinders in a line. Thisdesign creates a simply cast engine block. In vehicle applications, the number of cylinder is normally from 2 to 6. Usually thecylinders are vertical. As the number of the cylinder increases, the length of the block and crankshaft can become a problem.One way to avoid this is with a V configuration. This design makes the engine block and crankshaft shorter and more rigid.发动机⽓缸排列⽅式称为发动机布置。直列式发动机的⽓缸呈直线形。这个设计使发动机组的铸造变得简单。在汽车上,⽓缸的数量通常从2缸到6缸。通常⽓缸是垂直的。随着圆筒的数量增加,⽓缸的长度和曲轴会成为⼀个问题。避免这种情况的⼀个⽅法是⽤V字形配置，这种设计的好处是使发动机缸体和曲轴变得更短、更精确。An engine located at the front can be mounted longitudinally and can drive either the

front or rear wheels. Rear engine vehicles have the engine mounted behind the rear wheels. The engine can be transverseor longitudinal and usually drives the rear wheels only.

发动机前置时可以纵向布置，可以驱动前轮或后轮。发动机后置的汽车的发动机安装在后轮下，这种发动机可以横向或纵向布置，通常只驱动后车轮。

Most small trucks such as pickups, and even light medium-duty truck use gasoline engines, but many diesel engined modelsare now being produced. Heavier trucks use four stroke diesel engines with a turbocharger and aftercooler. In the European

Union, all new lorry engines must comply with Euro 5 emission regulations.

⼤多数⼩型卡车，例如⽪卡，甚⾄轻型、中型卡车使⽤的是汽油发动机,但是很多柴油机车型正在⽣产。重卡使⽤包含涡轮增压器和⼆次冷却器的四冲程柴油机。在欧盟国家,所有新卡车发动机必须符合欧5排放法规。1.3.3 Chassis1.3.3 底盘

Chassis is the frame on which the engine, body, wheels etc. are built. The chassis is an assembly of those systems that arethe major operating parts of a vehicle. It includes power train which conveys the drive to the wheels, steering which controlsthe direction of movement，suspension and wheels which absorb the road shocks, and brake which slows down the vehicle.底盘是⼀个框架，发动机、车⾝、车轮等建造在它的上⾯。底盘将这些系统组合在⼀起，它是汽车的⼀个主要操作部分。它包括传动系，将驱动⼒传递给驱动轮；转向系，控制汽车的运动⽅向；悬架和车轮，吸收路⾯冲击；制动系，使汽车减速。1.Power train system1.传动系统

The power train transfers turning effort from the engine to the driving wheels. It include a clutch ( manual transmission) or atorque converter (automatic transmission), a transmission drive shaft, final drive and differential gear s and driving axles.Alternatively, a transaxle may be used. A transaxle is a self-contained unit with a transmission, final drive gears anddifferential located in one casing.

传动系统将驱动⼒从发动机传递⾄车轮。它包括离合器(⼿动变速器)或变矩器(⾃动变速器)，传输驱动轴、主减速器、差速齿轮和驱动轴。或者可以使⽤变速驱动桥。⼀个变速驱动桥是⼀个独⽴单元，它包含传动装置、主减速器和差速器，这些装置位于⼀个箱体内。

A vehicle with a manual transmission uses a clutch to engage and disengage the engine from the power train. Engine torqueis transmitted through the clutch to the transmission or transaxle. The transmission contains sets of gears that increase ordecreases the torque before it is transmitted to the rest of the power train. The lower the gear ratio selected, the higher thetorque transmitted. A vehicle starting from rest needs a lot of torque, but once it is moving, it can maintain speed with only arelatively small amount of torque. A higher gear ratio can then be selected, and engine speed is reduced.

⼿动变速器的汽车使⽤离合器来使传动机构接触和脱离发动机。发动机输出的转矩通过离合器传递给传动机构或变速驱动桥。传动系统包含若⼲组齿轮，⽤来增加或减少传输到剩余传动机构的转矩。选⽤的齿轮⽐率越低,传输的转矩越⾼。汽车从静⽌到启动需要⼤量的转矩，但⼀旦开动，它能保持⼀定的速度，只需要相对少量的转矩。选择的齿轮⽐率变⼤，发动机转速会降低。

A conventional vehicle with the engine at the front and driving wheels at the rear uses a drive shaft, called a propeller shaft totransmit torque from the transmission to the final drive.

传统汽车的发动机前置，驱动车轮在后⾯并使⽤传动轴相连，称为驱动轴，⽤来将扭矩从传动系统传输到主减速器上。The final drive provides a final gear reduction to multiply the torque before applying to the driving axles. On front engine rearwheels drive vehicles the final drive changes the direction of driven by 90 degrees. Inside the final drive，a differential gearset divides the torque to the axles and allows for the difference in speed of each wheel when cornering. Axle shafts transmitthe torque to the driving wheels. In a rear-wheel drive vehicle, the axle can be solid or contain joints to allow for movement ofsuspension. For a front-wheel drive vehicle, the drive shaft has universal joints to allow for suspension and steeringmovement.

主减速器提供了⼀个最终齿轮减速，增加了施加到传动轴上的转矩。在前置发动机、后驱动轮驱动汽车上，主减速器使驱动⽅向改变了90°。在主减速器中设置了⼀组差速器，使传递⾄两个驱动轴的转矩分开,并允许每个车轮在转弯的时候有速度的差异。半轴将转矩传递给驱动轮。在后轮驱动的汽车中,驱动轴可以是固定的或包含允许悬架运动的接头。在前轮驱动的汽车中,传动轴包含万向节，允许悬架和转向机构运动。

An automatic transmission or transaxle performs similar functions to a manual transmission or transaxle except that gearselection is controlled either hydraulically or electronically. The automatic transmission uses a torque converter, which actsas a hydraulic coupling to transfer the drive.

⾃动变速器或驱动桥执⾏与⼿动变速器类似的功能，除了齿轮的选择是依靠液压或电⼦控制。⾃动变速器使⽤液⼒变矩器，它充当了⼀个传递驱动⼒的液压离合器。

Small trucks use the same type of transmissions as almost all cars, having either an automatic transmission or a manualtransmission with synchronizers. Larger trucks often use manual transmissions without synchronizers for saving bulk and

weight.

与⼤多数汽车类似，⼩型卡车使⽤相同类型的传动装置。分为⾃动变速器和装有同步器的⼿动变速器两种类型。⼤型卡车经常使⽤没有同步器的⼿动变速器，以减⼩整车的体积和重量。

Transmissions without synchronizers, known as \"crash boxes\gears which doesn't use the clutch, except for starts and stops.

没有同步器的传动装置，被称为“碰撞盒”，要求每次换挡时踩两次离合器踏板。这是⼀种改变齿轮（换挡）时不使⽤离合器的⽅法，除了汽车启动和停⽌时。

Automatic and semi-automatic transmissions for heavy trucks are becoming more and more common, due to advances bothin transmission and engine power. Common North American setups include 9, 10, 13, 15 and 18 speeds. In Europe,8, 10, 12and 16 gears are common on larger trucks with manual transmission, while automatic or semi-automatic transmissions wouldhave anything from 5 to 12 gears.

由于传动装置和发动机功率都在进步，⾃动和半⾃动变速器在重型卡车上正变得越来越普遍。常见的北美设置包括9、10、13、15和18档变速。在欧洲，8、10、12和16档⼿动变速器在⼤卡车上是常见的。⽽⾃动或半⾃动变速器的变速范围会从5档到12档。

2. Steering system2.转向系统

The directional motion of vehicle is controlled by a steering system. A basic steering system has 3 main parts: a steering boxconnected to the steering wheel, the linkage connecting the steering box to the wheel assembly at the front wheels and frontsuspension parts to let the wheel assemblies pivot. When the driver turns the steering wheel，a shaft from the steering

column turns the steering gear. The steering gear moves tie-rods that connect to the front wheels. The tie-rods move the frontwheels to turn the vehicle right or left.

转向系统控制汽车的定向运动。⼀个基本的转向系统有三个主要部分：连接到⽅向盘的转向箱，使转向箱与前车轮上的总成和前悬架部分相连接的连接装置来使车轮总成旋转。当驾驶员转动⽅向盘，转向柱上的⼀根轴转动转向齿轮。转向齿轮移动连接到前轮上的轴拉杆。拉杆将前轮转向，使汽车左或右运动。3. Suspension system and wheels3.悬架系统和轮胎

The purpose of the complete suspension system is to isolate the vehicle body from road shocks and vibrations, which willotherwise be transferred to the passengers and load. It must also keep the tires in contact with the road regardless of roadsurface. A basic suspension system consists of springs, axles, shock absorbers, arms, rods and ball joints.

完整的悬架系统的⽬的是使汽车从道路的冲击和振动中隔开，否则将被转移到乘客和负载。它还必须保持轮胎与路⾯接触，⽆论路⾯的情况如何。⼀个基本的悬架系统由弹簧、轴、减震器、减震臂、棒和球关节组成。

The spring is the flexible component of the suspension. Basic types are: leaf springs, coil springs and torsion bars. Modernpassenger vehicles usually use light coil springs. Light commercial vehicles have heavier springs than passenger vehiclesand can have coil springs at the front and leaf springs at the rear. Heavy commercial vehicles usually use leaf springs or airsuspension.

弹簧是悬架中⼀个灵活的组件。其基本类型有：膜⽚弹簧、螺旋弹簧、扭转弹簧。现代乘⽤车通常⽤螺旋弹簧。轻型商⽤车采⽤⽐乘⽤车更重的弹簧，并且在车前安装有线圈弹簧，在车尾安装有钢板弹簧。重型商⽤车通

Wheels must be strong enough to support the vehicle and withstand the forces caused by normal operation. At the sametime, they must be as light as possible to help keep unsprung weight to a minimum. Wheels can be made from pressed-steeling two sections, and also be made from cast aluminum alloy. Alloy wheels are popular because of their appearanceand because they are lighter than similar steel wheels. Aluminum is a better conductor of heat, so alloy wheels can dissipateheat from brakes and tires more effectively than steel ones.

车轮必须强⼤到⾜以⽀持汽车和承受正常操作所造成的⼒量。与此同时,它们必须⾜够轻,可以帮助簧下重量降到最低。轮⼦可以由压制钢分成两部分，它们也可由铸造铝合⾦制成。铝合⾦车轮是受欢迎的,因为它们的外观，因为它们⽐类似的钢制车轮更轻。铝是⼀种更好的的热导体,所以铝合⾦车轮可以⽐钢制车轮驱散来⾃刹车和车轮的更多的热量。

The tire provides a cushion between the vehicle and the road to reduce the transmission of road shocks. It also providesfriction to allow the vehicle to perform its normal operations. Modern tires are manufactured from a range of materials. Therubber is mainly synthetic. Two types of tire construction are common: cross-ply and radial. Most passenger cars now use

radial tires, and radials are replacing cross-ply tires on 4-wheel drives and heavy vehicles.

轮胎为汽车和路⾯之间提供了⼀个缓冲，来减少路⾯冲击的传播。它还提供了摩擦⼒,允许汽车执⾏它的正常操作。现代轮胎由⼀系列材料制成，最主要的材料是合成橡胶。两种类型的轮胎很常见：斜交轮胎和⼦午线轮胎。现在⼤多数乘⽤车采⽤⼦午线轮胎,⼦午线轮胎已经在4轮汽车和重型汽车上取代了斜交轮胎。

Tube tires require an inner tube to seal air inside the tire. Tubeless tires are eliminating the inner tube by making the

complete wheel and tire assembly airtight. A special airtight valve assembly is needed. This can be a tight fit into the rim orcan be held with a nut and sealing washers.

管状轮胎需要轮胎内胎，⽬的是在轮胎内部密封空⽓。⽆内胎轮胎通过使整个车轮和车胎密封装配来消除内胎。⼀个特殊的密封阀总成是必要的。它可以使轮胎边缘紧密配合或者可以紧固螺母和密封垫圈。4. Braking system4.刹车系统

Drum brakes have a drum attached to the wheel hub, and braking occurs by means of brake shoes expanding against theinside of the drum. With disc brakes, a disc attached to the wheel hub is clenched between two brakepads. On light vehicles,both of these systems are hydraulically operated. The brake pedal operates a master cylinder. Hydraulic lines and hosesconnect the master cylinder to brake cylinders at the wheels. Most modern light vehicles have either disc brakes on the frontwheels and drum brakes on the rear or disc brakes on a11 4 wheels. Disc brakes require greater forces to operate them. Abrake booster assists the driver by increasing the force applied to the master cylinder when the brake is operated.

⿎式制动器将制动⿎附加到轮毂上，制动的发⽣依靠制动蹄⽚在制动⿎内的扩张来完成。在盘式制动器上,靠近轮毂的制动盘紧靠在两个刹车⽚之间。在轻型汽车上，这两个系统依靠液压操作。刹车踏板操作制动缸，连接在制动缸上的液压管和软管使制动缸制动车轮。⼤多数现代轻型汽车。要么在前轮安装盘式制动器，在后轮安装⿎式制动器；要么所有的4个车轮都是盘式制动器。盘式制动器需要更多的⼒量来操作它们。当实施制动操作时，在直径⽓封上的刹车助⼒器帮助驾驶员增加作⽤在制动缸上的制动⼒。

Air operated braking system are used on heavy vehicles. Compressed air operating on large diameter diaphragms providesthe large forces to the brake assembly that are needed. An air compressor pumps air to storage tanks. Driver controlled

valves then direct the compressed air to different wheel units to operate the friction brakes. On articulated vehicles, any delayin applying the trailer brake should be minimized. This is achieved by using a relay valve and a separate reservoir on thetrailer. This arrangement also applies the brakes if the trailer becomes disconnected from the prime mover.

⽓动制动系统应⽤于重型汽车。压缩空⽓操作直径⽓封，使刹车装置具有很⼤的⼒量。⼀个空⽓压缩机泵将空⽓抽取到储存罐中。司机控制阀门，压缩空⽓直接到达不同的车轮总成来操作摩擦式制动器。在拖挂车上,应⽤在拖车制动器的任何延迟都应该最⼩化。这是通过在拖车上使⽤⼀个继动阀和⼀个单独的储⽓罐来实现的。这样的设计也使得制动继续有效，如果拖车从拖车头断开。

All vehicles must be fitted with at least 2 independent braking systems. They were once called the service brake and theemergency brake. Now they are usually referred to as the foot brake and the park brake. Most light vehicles use a foot brakethat operates through a hydraulic system on all wheels and a hand operated brake that acts mechanically on the rear wheelsonly. One common use of the hand brake system is to hold the vehicle when it is parked. The systems are designed to beindependent so that if one fails, the other is still available.

所有汽车必须配备⾄少2个独⽴的制动系统。它们曾经被称为⾏车制动和紧急制动。现在,通常称为脚刹制动和驻车制动。⼤多数轻型汽车使⽤脚制动，通过它操作作⽤在所有车轮上的⼀个液压系统，同时还有⼀个⼿制动，机械地作⽤于后轮。⼿制动系统的⼀个常见的使⽤是当汽车停放时，使汽车静⽌。系统被设计成独⽴的，因此如果⼀个失效，其它制动系统仍然可⽤。1.3.4 Electrical and electronic system1.3.4 电器和电⼦系统

Electrical is related to the electricity while electronic related to the semi-conductor or microcomputers. The electrical systemprovides electricity to the starter, ignition, lights and heater. The electricity level is maintained by a charging circuit.

电器系统与电⼒相关⽽电⼦系统与半导体或微处理器相关。电⼦系统为起动机、点⽕系统、照明系统和加热系统供电。供电⽔平由充电电路来维持。

The charging system provides electrical energy for all of the electrical components on the vehicle. A typical charging systemincludes: a battery, an alternator, a voltage regulator which is usually integral to the alternator, a charging warning or

indicator light and wiring that complete the circuits. The battery provides electrical energy for starting, then once the engine isrunning the alternator powers all the electrical components of the vehicle. The alternator also charges the battery to replacethe energy used to start the engine. The voltage regulator prevents overcharging.

充电系统为汽车上所有的电器元件提供电能。⼀个典型的充电系统包括：蓄电池、交流发电机、电压调节器，通常与交流发电机合成⼀个整体，⼀个充电警告装置或指⽰灯和接线完成了整个电路。蓄电池为起动机提供电能,然后⼀旦发动机运⾏，交流发电机便为汽车上所有的电器元件供电。交流发电机也为蓄电池充电，来补充蓄电池因启动发动机⽽消耗的电量。电压调节器可以防⽌过度充电。

The starting system consists of the battery, starter, flywheel ring gear, cables，and the ignition switch. The starter motor ispowered by the battery. During starting, the pinion of the starter motor engages with the flywheel ring gear and the startermotor then operates to crank the engine.

起动系统包括电池、起动器、飞轮齿圈、电线和点⽕开关。起动机由蓄电池供电。在起动时,起动机上的⼩

A basic ignition system consists of the battery, low-tension cables, the ignition coil, distributor, coil high-tension cable, sparkplug cables and spark plugs. The ignition system provides high intense sparks to spark plugs to ignite the fuel charges in thecombustion chambers. The sparks must be supplied at the right time and they must have sufficient energy over a range ofconditions to ignite the charges. The electricity comes from the battery and the voltage is increase by the ignition coil. Theprimary or low-tension circuit initiates the spark. The secondary or high-tension circuit produces the high voltage anddistributes it to the spark plugs.

⼀个基本的点⽕系统由蓄电池、低压电缆、点⽕线圈、分电器、⾼压线圈、⽕花塞点⽕线和⽕花塞组成。点⽕系统为⽕花塞提供⾼压⽕花，来点燃装载在燃烧室内的燃料。⽕花必须在正确的时间提供,它们必须在⼀系列条件下提供⾜够的能量来点燃燃烧室内的燃料。蓄电池提供电流，点⽕线圈升⾼电压，⼀级电路或低压电路创造⽕花，⼆级电路或⾼压电路产⽣⾼电压，并把它们分配给各个⽕花塞。Review questions:

1. List the main parts of a vehicle.

2. List the main components of a powertrain.

3. What are the common types of a vehicle according to body styling?

4. Which systems does a chassis include and what are the main functions of a chassis?5. Why are suspension used on vehicles?

6. How does an internal combustion engine convert fuel energy to mechanical energy?7. How does an air-operated braking system work?8. List the main parts of charging system.9. What's the purpose of the ignition system?复习题：

1.列举汽车的主要组成部分。2.列举动⼒系统主要组成部分。

3.根据车⾝样式，有哪些常见类型的汽车?4.底盘包括哪些系统？底盘的主要功能是什么?5.为什么汽车上使⽤悬架?

6.内燃机如何将热能转换为机械能?7.⽓动制动系统是如何⼯作的?8.列举充电系统的主要组成部分。9.点⽕系统的⽬的是什么?Chapter 2 Engine第⼆章发动机2.1 Overview

2.1 概述

An engine is a machine that turns heat energy into mechanical energy. The heat produced from burning a fuel creates thepower that moves the vehicle. Engines used in vehicles are of internal combustion type in which the combustion of the fueloccurs internally.

发动机是⼀种将热能转换为机械能的机器。由燃料燃烧的热能产⽣的⼒量使汽车移动。⽤于汽车的发动机是内燃式，燃料的燃烧发⽣在发动机内部。

Internal combustion engines (ICE) differ in the type of the fuel they use and the way ignition of the air-fuel mixture occurs.There are two main types of ICEs：spark-ignition (gasoline)engines and compression ignition(diesel) engines.

内燃机(ICE)所使⽤的燃料类型是不同的并且混合⽓的点燃⽅式也不同。有两种主要类型的内燃机：⽕花点⽕式发动机(汽油机)和压缩点⽕式发动机(柴油机)。

Some spark-ignition engines run on liquid fuels other than gasoline, such as alcohol, or a gasoline-alcohol blend. Somespark-ignition engines run on gaseous fuel, such as propane and natural gas.

⼀些⽕花点⽕式发动机除了使⽤汽油作为燃料之外还可使⽤其它液体燃料，如汽油、酒精，或汽油与酒精的混合物等。⼀些⽕花点⽕式发动机使⽤⽓体燃料,如丙烷和天然⽓。

Air and fuel enter the engine cylinders to form a combustible mixture. Then the mixture is compressed to a small part of itsoriginal volume by the pistons. The compressed mixture is ignited by a spark produced at the spark plug by the ignition

system. As the mixture burns, temperature and pressure increase in the cylinder. The high pressure forces the piston down inthe cylinder and causes the crankshaft to rotate.Gears and shafts transfer this motion to the road wheels that drive thevehicle.

空⽓和燃料进⼊发动机⽓缸形成可燃混合⽓。紧接着混合⽓通过活塞压缩到原来体积的很⼩⼀部分。压缩混合⽓被点⽕系统中的⽕花塞产⽣的⽕花点燃。随着混合物的燃烧, ⽓缸中的⽓体的温度和压⼒增加。⾼压迫使⽓缸中的活塞向下运动，使曲轴旋转。齿轮和驱动轴将这种运动传递⾄驱动轮，驱动轮驱动汽车。

A diesel engine runs on a light fuel similar to kerosene. In this type of engine, the piston compressed only the air.Compressing air to about one-twentieth of its original volume raises its temperature. Then the fuel is injected into thecylinder, where it is ignited by the hot air. As the mixture burns, the pressure forces the piston down in the cylinder.柴油发动机使⽤类似于煤油的轻质燃料。在这种类型的发动机中，活塞仅被空⽓压缩。空⽓被压缩到约原来体积的⼆⼗分之⼀，它的温度提⾼。然后燃料注⼊⽓缸，被空⽓的热量点燃。随着混合物的燃烧，迫使活塞在⽓缸中向下运动。

Engines are made in many sizes and power ratings. Four-cylinder engines power smaller vehicles, where fuel economy ismore important. Larger and more powerful six and eight-cylinder engines power most medium- and full-size vehicles. Ten-and twelve-cylinder engines put the performance in high performance sport models.

发动机可制造成各种⼤⼩和各种功率。使⽤⼩功率四缸发动机的汽车,其燃油经济性更加重要。更⼤、更强2.2 Engine construction2.2 发动机的结构

Gasoline engines and diesel engines are similar in basic construction (Figure 2.1).Both of them have engine blocks,cylinders，pistons，connecting rods, crankshaft, camshaft and cylinder heads etc.

汽油发动机和柴油发动机在基本结构上是相似的(图2.1)。它们都有发动机体,⽓缸,活塞,连杆,曲轴、凸轮轴、⽓缸盖等。Most automotive engines are also called reciprocating engines because their pistons move up and down inside the

cylinders. A piston is a cylindrical plug that fits inside the cylinder. It receives and transmits motion as a result of pressurechanges applied to its top. The cylinders or cylinder bores are machined opening through the engine block. A cylinder headcovers the top of the cylinders. The pistons are connected to the crankshaft through the bottom of each cylinder opening.⼤多数汽车发动机也称为往复式发动机，因为它们的活塞在⽓缸内上下移动。活塞是⼀个圆柱形的塞⼦，与⽓缸相配合。它接收和传递运动是由于它顶部压⼒变化的结果。在发动机体中，⽓缸或⽓缸内径被加⼯成开放式的，⼀个⽓缸盖覆盖在⽓缸的顶部。曲轴与活塞相连，并穿过每⼀个开放式⽓缸的底部。

The two travel limits for a piston are termed as top dead center (TDC) and bottom dead center (BDC). A piston stroke takesplace when the piston moves from one limit to the other limit of the travel. Engine capacity is the volume between TDC anBDC of all the cylinders.

活塞的两个运动被称为上⽌点(TDC)和下⽌点(BDC)。活塞⾏程是指活塞从⼀个运动的⽌点到另⼀个运动的⽌点。发动机

容量是指各个⽓缸中上⽌点和下⽌点之间的体积。2.2.1 Engine Block and crankcase2.2.1 发动机体和曲轴

The engine block(Figure 2.2) is the basic framework of the engine to which other engine parts are attached. It is usually aprecision casting made of gray iron or lighter aluminum alloy. The engine block and crankcase unit supports the force-transfer mechanism between cylinder head and crankshaft assembly. It bears the crankshaft support bearings, and holds thecylinder sleeves. Also included in the block are separated water jackets, sealed oil galleries and the upper part of thecrankcase. The engine block also acts as a mounting and support surface for most of the ancillary units.

发动机体(图2.2)是发动机的基本框架，其它的发动机部件均连接在它的上⾯。它通常是⼀个精密铸件，由灰⼝铸铁或更轻的铝合⾦铸造⽽成。发动机体和曲轴单元组成了⼒的传递机制，该传递机制介于⽓缸盖和曲轴之间的配合。它⽀撑曲轴来承受轴荷。并⽀撑⽓缸套。发动机体中还包括分开的冷却管、密封油的回油孔和上⽅的曲轴箱。发动机体还可以作为⼤部分辅助单元安装和⽀撑的表⾯。

Whereas all blocks for commercial vehicles continue to made of gray cast iron, aluminum engine block for modern passengercars are becoming increasingly popular owing to the virtue of weight-saving.，然⽽所有商业汽车的发动机体都持续使⽤灰⼝铸铁,。现代轿车的铝制发动机体正变得越来越受欢迎，因为它能有效控制重量。

Crankcase is the lower part of the engine that surrounds the crankshaft. It contains the crankshaft, piston cylinders,connecting rods and other moving parts of the engine. As well, in non-air-cooled engines, it has a number of internalpassages for the coolant and oil transfer. In air-cooled engines, it has internal oil passages; but usually it has fins on theexterior to dissipate the heat. Bolted to the bottom of the crankcase is an oil pan，a thin steel cover containing the oil.曲轴箱在发动机的下部，周围环绕着曲轴。它包含曲轴、活塞筒、连杆和发动机的其它运动部件。同时，在没有风冷装置的发动机中,它有许多冷却剂内流通道和润滑油道。在风冷发动机中,它只有润滑油道；但通常它在外部安有散热⽚来消散热量。曲轴箱的底部⽤螺栓固定着⼀个油盘，它是⼀个含有机油的薄钢盖。2.2.2 The cylinder head2.2.2 ⽓缸盖

Bolted to the top of the engine block is a cylinder head(Figure 2.3). It seals off the upper end of the block and cylinders. Inmany cases the cylinder head houses the intake and exhaust valves, spark plugs or fuel injectors. On most engines a valvecover or rocker arm over is located on top of the cylinder head.

⽤螺栓栓在发动机体顶端的是⼀个⽓缸盖(图2.3)。它密封了发动机体和⽓缸的上端。很多情况下,⽓缸盖覆盖住了进⽓管、排⽓阀、⽕花塞和喷油嘴。在⼤多数发动机上，阀盖或摇臂罩位于⽓缸盖的顶部。

With the top of the piston, cylinder head provides the desired combustion-chamber shape. It has water and oil passages forcooling and lubrication.

在活塞顶部,⽓缸盖提供了燃烧室所需的形状。它含有⽔管和⽤来冷却和润滑。

Some engines have just one cylinder head covering several cylinders, while others have separate heads for each cylinder.⼀些发动机只有⼀个⽓缸盖覆盖在若⼲个⽓缸上,⽽其它发动机则为每个⽓缸配有单独的⽓缸盖。

Most cylinders have two ports in the combustion chamber area of the cylinder head, one is for intake and the other is forexhaust. The combustion chamber is the space between the top of the piston and the cylinder head. The air-fuel mixtureenters the cylinder through the intake port. Burned gases leave the cylinder through the exhaust port. Some engines havemultiple intake and exhaust ports and valves.

⼤多数⽓缸在⽓缸盖的燃烧室区域内有两个端⼝, ⼀个是吸⽓端⼝,另⼀个是排⽓端⼝。活塞顶部和⽓缸盖之间的空间是燃烧室。混合⽓通过进⽓⼝进⼊⽓缸。燃烧过的⽓体通过排⽓⼝离开⽓缸。⼀些发动机有多个进⽓端⼝、排⽓端⼝以及阀门。In the vast majority of passenger car engines, the entire valve gear is also mounted in the cylinder head. Each cylinder hasone or more intake valves and exhaust valves. The intake valve controls the flow of the air-fuel mixture into the cylinder,while the exhaust valve controls the flow of exhaust gas from the cylinder. These valves fit in the intake and exhaust ports ofthe cylinder head.

在绝⼤多数轿车发动机上,整个配⽓机构也安装在⽓缸盖上。每个⽓缸都有⼀个或多个进⽓阀和排⽓阀。进⽓阀控制混合⽓进⼊⽓缸的流量,⽽排⽓阀控制废⽓排出⽓缸的流量。这些阀门与⽓缸盖上的进⽓⼝和排⽓⼝相配合。

When a valve closes, it seals tightly against the valve seat. A seat is the surface against which the valve face comes in

contact to provide a seal against leakage. In the closed position, the valve face and seat should form an air-tight seal. Whena valve moves off its seat, the port is open. The air-fuel mixture or exhaust gas can then pass through the port.

当阀门关闭时,它牢固地密封在阀座中。阀座是⼀个牢固地表⾯，当阀⾯和阀座接触时，阀座使其密封，防⽌泄漏。在关闭的位置时,阀⾯和阀座应该形成密封。当阀门离开阀座时,阀⼝打开，混合⽓或废⽓就可以通过阀⼝。

Excellent heat dissipation and lower weight have combined to make aluminum alloy the material of choice in the constructionof cylinder heads for virtually all gasoline and diesel engines for passenger cars.

铝合⾦材料有优秀的散热能⼒和较轻的重量，使得它成为⼏乎所有乘⽤车上的汽油机或柴油机建造⽓缸盖的选择。

The cylinder head is attached to the block with high-tensile steel studs. In order to insure proper sealing to keep the coolantout of the combustion chamber and retain compression inside the cylinder, the joint between the engine block and cylinderhead must be air-tight. This is achieved by using gasket; it keeps the coolant out of the combustion chamber and retainscompression in the cylinder. This sandwich element is a sheet of asbestos, cardboard, cork, paper, rubber, or soft metal

between two sheets of cooper, both these material being able to withstand the high pressure and high temperature within theengine. There is a similar gasket fitted between the engine block and the oil pan.

⽓缸盖与发动机体通过⾼强度钢相连。为了保证妥善的密封从⽽使冷却剂离开燃烧室，并保持⽓缸内的压⼒，发动机体和⽓缸盖之间的配合必须是密封的。这是通过使⽤垫⽚来实现的。它使冷却剂离开燃烧室,并保持⽓缸内的压⼒。这个夹层结构是⼀张⽯棉、硬纸板、软⽊、纸张、橡胶、或软⾦属夹在两个部件中间。这些材料能够承受发动机的⾼压和⾼温。发动机体和油底壳之间也安装有⼀个类似的垫圈。

As shown in Figure 2.4, the combustion chamber is the space in the cylinder above the piston when the piston is at TDC inthe compression stroke. Combustion of the fuel-air mixture begins here when ignited by a spark plug.

如图2.4所⽰,燃烧室是当活塞位于在压缩冲程的上⽌点时，⽓缸中活塞上⽅的空间。混合⽓的燃烧从这⾥开始，当它们被⽕花塞点燃后。

The design and shape of the combustion chamber have considerable effect on the power, fuel efficiency, and emissions ofan engine. As shown in Figure 2.5, Several combustion chamber shapes have been used including hemispherical

combustion chamber, bathtub combustion chamber, wedge combustion chamber, squish combustion chamber, and piston-crown combustion chamber.

燃烧室设计的形状对输出功率、燃油经济性和废⽓排放都有相当⼤的影响。如图2.5所⽰,⼏个已经投⼊使⽤的燃烧室的形状包括半球形燃烧室、浴盆型燃烧室,楔形燃烧室,挤流燃烧室和活塞顶燃烧室。

Hemispherical combustion chamber is a round, dome-shaped chamber. This shape permits larger valves and straighterintake and exhaust ports for improved breathing. Its small surface area in comparison to volume reduces the amount of heatloss. It is used in high performance cars and racing cars engines.

半球形燃烧室是⼀个圆的、圆顶状的燃烧室。这种形状允许容纳更⼤更直的进⽓⼝和排⽓⼝，从⽽提⾼吸排⽓能⼒。与体积相⽐，它的表⾯积很⼩，减少了热量损失。它⽤于⾼性能汽车和赛车的发动机。

Bathtub combustion chamber is shaped like an inverted bathtub with the valves in the bottom of the tub. Since all the valvescan be arranged in a single row，the valve-operating camshaft and/or rocker gear are simple to design and operate. Thelong, oval shape of the bathtub controls excessive turbulence, and the flat areas where the piston comes right up to the headsurface supply the squish needed to swirl the mixture. The wide cylinders and short piston strokes in modern engines make itpossible to use large valves with bathtub heads for efficient gas flow.

浴盆型燃烧室形状像倒置的浴缸，在浴缸底部装有阀门。因为所有的阀体可以排成⼀⾏，因此阀控凸轮轴和/或摇臂齿轮的设计和操作将会是简单的。长的、椭圆形的浴盆控制过多的⽓流,且与活塞顶部的表⾯相接触的平整区域提供了压扁来使混合⽓产⽣漩涡。在现代发动机上，宽的⽓缸和短的活塞⾏程可以在浴盆型燃烧室盖上使⽤⼤型阀门，从⽽使⽓流更加⾼效。Wedge combustion chamber takes a wedge shape. It is quite efficient and lends itself to mass production and widely used.The valve is in the longer sloping surface and the spark plug in the shorter. The tapered part of the wedge forms a squishzone. The squish produces swirling turbulence as the piston forces the mixture away from the narrow area of the wedge.Turbulence keeps the fuel and air mixed thoroughly for even burning. Squish also cools the mixture in the corners to reducehot spots. It has a short flame path which reduces the tendency of the burning fuel to knock or pre-ignite.

楔形燃烧室呈楔形。它⾮常适合⼤规模⽣产和⼴泛使⽤。阀体在很长的坡⾯上，且⽕花塞很短。楔形燃烧室锥形的部分形成了⼀个压扁区。压扁区产⽣旋转⽓流作⽤在活塞上，迫使混合⽓远离楔形燃烧室狭窄的区域。旋转⽓流使燃料和空⽓彻底混合，即使在燃烧时也是如此。压扁区同样也冷却在⾓落⾥的混合⽓来减少过热。它的⽕焰传播路径很短，减少了混合⽓爆震或预先燃烧的倾向。

Squish combustion chamber can be a variation on almost any of the standard forms of combustion chambers. The squish

area that gives it its name is the flat surface of the cylinder head that almost contacts the piston crown. When the piston riseson the compression stroke，it squishes ,or squirts, the gas from this area into the combustion compression chamber with aswirling motion. This mixes the air-fuel mixture thoroughly for more complete vaporization and combustion. At the same time,the mixture is cooled as it swirls past the chamber walls, which are kept relatively cool by the water passages.

挤流燃烧室⼏乎可以由任何⼀种标准形式的燃烧室变形⽽来。被压扁区域赋予了它的名字,它的⽓缸盖是⼀个平整的表⾯，⼏乎与活塞顶相接触。当活塞在压缩冲程上升时,它发出嘎吱声,或喷出⽓体，来⾃这个区域的⽓体以旋涡流动进⼊到燃烧室内。这种对混合⽓彻底地混合是为了让它更好的喷雾和燃烧。同时,混合⽓经过缸壁时，被它⾃⾝的旋涡运动所冷却。在⽔冷系统的作⽤下，它将会相对地保持冷却。

Piston-crown combustion chamber is used in diesel truck engines and in some European gasoline engines. The advantagein simply machining a flat surface on the cylinder head is offset by the added cost of machining the bowl in each piston andby increased piston weight.

活塞顶燃烧室被⽤于柴油卡车的发动机和⼀些欧洲国家的汽油发动机。它的优势是：在⽓缸盖上加⼯平⾯是⽐较简单的，然⽽这种优势被每个活塞需要加⼯成碗状、且增加了活塞的重量的劣势所抵消。2.2.3 Pistons and piston rings2.2.3 活塞和活塞环

Piston is a cylindrical plug, which closed at one end and open at the other(Figure 2.6). The piston is slightly smaller than thecylinder so that it can slide up，and down freely inside the cylinder. It is attached to the connecting rod and when the fuelcharge is fired, will transfer the force of the explosion to the connecting rod then to the crankshaft.活塞是⼀个圆柱形的塞规,⼀端封闭、另⼀端开放(图2.6)。活塞略⼩于⽓缸,这样就可以在⽓缸中滑动，并能