1、Chapter 2 AUTOMOTIVE ENGINEu 背景知识背景知识 发动机发动机最早诞生在英国,所以,发动机的概念也源于英语,最早诞生在英国,所以,发动机的概念也源于英语,它的本义是指那种它的本义是指那种“产生动力的机械装置产生动力的机械装置”。随着科技的进步,。随着科技的进步,人们不断地研制出不同用途多种类型的发动机人们不断地研制出不同用途多种类型的发动机,如:如:活塞活塞式式,转转子式子式,涡轮喷气式涡轮喷气式,涡轮风扇涡轮风扇式式等等。但是但是,不管哪种发动机,它,不管哪种发动机,它的基本前提都是要以某种燃料燃烧来产生动力。所以,以电为能的基本前提都是要以某种燃料燃烧来产生动力。
2、所以,以电为能量来源的电动机,不属于发动机的范畴。量来源的电动机,不属于发动机的范畴。回顾发动机产生和发展的历史,它经历了回顾发动机产生和发展的历史,它经历了外燃机外燃机和和内燃机内燃机两两个发展阶段。个发展阶段。Chapter 2 AUTOMOTIVE ENGINEu 背景知识背景知识 外外燃机,就是说它的燃料在发动机的外部燃烧,发动机将燃机,就是说它的燃料在发动机的外部燃烧,发动机将这种燃烧产生的热能转化成动能,瓦特发明的蒸汽机就是一种典这种燃烧产生的热能转化成动能,瓦特发明的蒸汽机就是一种典型的外燃机,当大量的煤燃烧产生热能把水加热成大量的水蒸汽型的外燃机,当大量的煤燃烧产生热能把水加热
3、成大量的水蒸汽时,高压便产生了,然后这种高压又推动机械做功,从而完成了时,高压便产生了,然后这种高压又推动机械做功,从而完成了热能向动能的转变。热能向动能的转变。蒸汽机蒸汽机 steam engine(steamer)Watt invented the steam engine.瓦特发明了蒸汽机。瓦特发明了蒸汽机。Chapter 2 AUTOMOTIVE ENGINEu 背景知识背景知识 内燃机与内燃机与外燃机的最大不同在于它的燃料在其内部燃烧。内外燃机的最大不同在于它的燃料在其内部燃烧。内燃机的种类十分繁多,我们常见的汽油机、柴油机是典型的内燃燃机的种类十分繁多,我们常见的汽油机、柴油机是典
4、型的内燃机。我们不常见的火箭发动机和飞机上装配的喷气式发动机也属机。我们不常见的火箭发动机和飞机上装配的喷气式发动机也属于内燃机。不过,由于动力输出方式不同,前两者和后两者又存于内燃机。不过,由于动力输出方式不同,前两者和后两者又存在着巨大的差异。一般地,在地面上使用的多是前者,在空中使在着巨大的差异。一般地,在地面上使用的多是前者,在空中使用的多是后者用的多是后者。当然当然有些汽车制造者出于创造世界汽车车速新纪录的目的有些汽车制造者出于创造世界汽车车速新纪录的目的,也在汽车上装用过喷气式发动机,但这总是很特殊的例子,并,也在汽车上装用过喷气式发动机,但这总是很特殊的例子,并不存在批量生产的适
5、用性。不存在批量生产的适用性。Internal combustion内燃机作为汽车内燃机作为汽车.拖拉拖拉机机.摩托车摩托车.工程机械工程机械.船舶船舶.航空航空.农业农业.林业林业.军队军队.等各行各业的动等各行各业的动力装置,应用极为广力装置,应用极为广泛,泛,Chapter 2 AUTOMOTIVE ENGINE New Wordslongitudinal lnditju:dinl adj.纵向的,经度的纵向的,经度的transverse trnsv:s adj.横向的,横断的横向的,横断的reciprocate rsprket v.往复,来回往复,来回spin spin v.旋转;旋转
6、;n旋转旋转piston pistn n.活塞活塞 ignite inait v.点火,点燃点火,点燃rub rb v.摩擦,擦摩擦,擦quart kw:t n.夸脱夸脱(容量单位容量单位)reservoir rezvw:n.油箱油箱mechanical miknikl adj.机械的,机械制的,机械似的,呆机械的,机械制的,机械似的,呆板的板的enclosed inkluzd adj.被附上的被附上的gallon ln n.加仑加仑stroke struk n.冲程,行程冲程,行程Chapter 2 AUTOMOTIVE ENGINE New Wordsrub rb v.摩擦,擦摩擦,擦ca
7、mshaft km:ft n.凸轮轴凸轮轴combustion kmbstn n.燃烧,着火燃烧,着火disengaged dsn ged d adj.脱开的,脱离啮合的脱开的,脱离啮合的flywheel flaiwi:l n.飞轮,惯性轮,储能轮飞轮,惯性轮,储能轮 PHRASES AND EXPRESSIONSinternal-combustion engine 内燃机内燃机diesel-fuel 柴油机燃料,柴油柴油机燃料,柴油LPG=Liquefied Petroleum Gas 液化石油气体液化石油气体CNG=Compressed natural gas 压缩天然气压缩天然气spar
8、k ignition 火花点火火花点火 PHRASES AND EXPRESSIONScompression ignition 压缩点火压缩点火spark plug 火花塞火花塞gas-turbine engine 燃气涡轮发动机燃气涡轮发动机steam engine 蒸汽机蒸汽机Stirling engine 斯特灵发动机斯特灵发动机lubricating system 润滑系统润滑系统oil pan 油底壳油底壳oil pump 机油泵机油泵exhaust system 排气系统排气系统emission-control system 排放控制系统排放控制系统Chapter 2 AUTOMO
9、TIVE ENGINE PHRASES AND EXPRESSIONSenergy conversion 能量转换能量转换air/fuel ratio 空燃比空燃比connecting rod 连杆连杆TDC=Top Dead Center 上止点上止点BDC=Bottom Dead Center 下止点下止点intake stroke 进气冲程进气冲程compression stroke 压缩冲程压缩冲程power stroke 作功冲程作功冲程exhaust stroke 排气冲程排气冲程compression ratio 压缩率,压缩比压缩率,压缩比Chapter 2 AUTOMOTIV
10、E ENGINE The purpose of an automotive engine is to supply the power needed to move the vehicle.The engine produces this power by burning fuel inside it.Because the engine burns fuel inside,or internally,the engine is known as an internal combustion engine(ICE).Chapter 2 AUTOMOTIVE ENGINE2.1 Purpose
11、and Locations of Engines译文:译文:汽车发动机的功用是汽车行驶提供必需的汽车发动机的功用是汽车行驶提供必需的动力。发动机通过它内部的燃料燃烧来产生动力。动力。发动机通过它内部的燃料燃烧来产生动力。由于发动机在其内部燃烧燃料,所以发动机被称由于发动机在其内部燃烧燃料,所以发动机被称作内燃机。作内燃机。Engines may be fueled by gasoline,propane(LPGliquefied petroleum gas),or diesel fuel.Compressed natural gas(CNG)may also be used in some v
12、ehicles.译文:译文:发动机燃料可以是汽油、丙烷(液化石油汽体)发动机燃料可以是汽油、丙烷(液化石油汽体)或柴油。压缩天燃气也可以用在一些车辆上。或柴油。压缩天燃气也可以用在一些车辆上。be fueled by 通过通过得到燃料得到燃料Most automotive engines are located at the front of the vehicle.Many engines drive the rear wheels.This requires a long drive shaft extending form the front wheels to the rear whe
13、els.Other engines drive the front wheels.In the rearwheeldrive arrangement,the engine sits longitudinally.Its long dimension is from front to back.译文:译文:大多数汽车发动机位于汽车前方。许多发动机大多数汽车发动机位于汽车前方。许多发动机由后轮驱动。这需要一根长传动轴从前轮延伸到后轮。由后轮驱动。这需要一根长传动轴从前轮延伸到后轮。其它发动机由前轮驱动。在后轮驱动布置中,发动机纵其它发动机由前轮驱动。在后轮驱动布置中,发动机纵向放置。它前后尺寸最长
14、。向放置。它前后尺寸最长。In the frontwheeldrive arrangement,the engine sits crosswise,transversely.With either arrangement,the power is carried to the drive wheels(rear or front)by gears and shafts.译文:译文:在前轮驱动布置中,发动机横向放置。不管哪在前轮驱动布置中,发动机横向放置。不管哪种放置方式,动力都是通过齿轮和轴传递到驱动轮。种放置方式,动力都是通过齿轮和轴传递到驱动轮。Some cars have the eng
15、ine mounted in back of the front seat.This is called a midengine arrangement.Other cars have been built with the engine mounted at the rear,in back of rear seat.The Volkswagen beetle is an example of rear.译文:译文:一些轿车把发动机安装在前排座位的后面,这一些轿车把发动机安装在前排座位的后面,这称为中置发动机布置。其它轿车发动机安装在车的尾部称为中置发动机布置。其它轿车发动机安装在车的尾部,
16、也就是后排座的后面。比如:大众汽车甲壳虫就是采,也就是后排座的后面。比如:大众汽车甲壳虫就是采用这种发动机后置布置。用这种发动机后置布置。Various kinds of engines are used in automotive vehicles.The two major types are:1.The piston engine in which pistons move up and down,or reciprocate,in the engine cylinders.This is the engine used in all cars today,except for some
17、 models of Mazda.Chapter 2 AUTOMOTIVE ENGINE2.2 Engine Types译文:译文:机动车辆上采用各种各样的发动机,其两机动车辆上采用各种各样的发动机,其两种主要类型为:种主要类型为:1 1、活塞发动机,活塞在其气缸内上下或往复运动。活塞发动机,活塞在其气缸内上下或往复运动。这就是现今轿车所采用的发动机形式,除了马自这就是现今轿车所采用的发动机形式,除了马自达的一些型号发动机。达的一些型号发动机。cylinderpistonPiston pinConnecting rodcrankshaftOil pipeIntake valveExhaust
18、valve Timing gearOil pump2.The Wankel rotary engine in which rotors rotate,or spin.The Mazda Motor Corporation of Japan is the major manufacturer of this engine.译文:译文:汪克尔转子发动机,由其转子回转。日本马自汪克尔转子发动机,由其转子回转。日本马自达发动机公司是这类发动机的主要生产商。达发动机公司是这类发动机的主要生产商。There are two types of piston enginesspark ignition(SI)
19、and compression ignition(CI).Sparkignition engines use an electric ignition system with spark plugs.Electric sparks at the spark plugs ignite,or set fire,the fuel in the engine cylinders.译文:译文:有两种类型的活塞发动机:火花点火和压缩点有两种类型的活塞发动机:火花点火和压缩点火。火。火花点火火花点火发动机采用带有火花塞的电子点火系统。发动机采用带有火花塞的电子点火系统。火花塞的火花塞的电火花电火花点燃发动机
20、气缸中的燃料。点燃发动机气缸中的燃料。The combustion of the fuel makes the engine run and produce power.This is the type of engine used in most produce power.This is the type of engine used in most automotive vehicles.译文:译文:燃料燃烧使发动机运转并产生动力。这是在大燃料燃烧使发动机运转并产生动力。这是在大多数产生动力的发动机所采用的形式,这种类型的发动多数产生动力的发动机所采用的形式,这种类型的发动机在大部分机动
21、车辆上使用。机在大部分机动车辆上使用。The compressionignition engine the diesel uses the heat of compression to ignite the fuel.When air is compressed,it gets very hot.In the diesel engine,the air is compressed so much that its temperature goes up to 1,000 degrees Fahrenheit(538 degrees Celsius)or higher.译文:译文:压缩点火发动机
22、,压缩点火发动机,柴油机柴油机使用压缩产生的热量使用压缩产生的热量来点燃燃料。当空气被压缩时,会变得非常热。柴油机来点燃燃料。当空气被压缩时,会变得非常热。柴油机内空气压缩温度可过内空气压缩温度可过10001000华氏以上(华氏以上(538538摄氏度)。摄氏度)。一般情况下一般情况下,柴油的柴油的燃点燃点220 汽油的汽油的燃点燃点427The diesel fuel is sprayed into this very hot air and is ignited by the heat.Some automobiles have diesel engines.Many heavyduty
23、trucks and buses are powered by diesel engines.译文:译文:然后柴油被喷射到这种热空气中,并被这种热然后柴油被喷射到这种热空气中,并被这种热度点燃。一些汽车上采用柴油机。大多重型卡车和客车度点燃。一些汽车上采用柴油机。大多重型卡车和客车由柴油机提供动力。由柴油机提供动力。There are other engines still in the experimental stage that might someday become important.These include gasturbine engines,steam engines,St
24、irling engines,and electric motors.译文:译文:还有一些其它的发动机仍处于实验阶段,总有还有一些其它的发动机仍处于实验阶段,总有一天会变得重要。它们包括一天会变得重要。它们包括燃气涡轮发动机燃气涡轮发动机、蒸汽、蒸汽机机、斯特林(热气体)发动机和电动机。斯特林(热气体)发动机和电动机。A sparkignition engine requires four basic systems to run.Diesel engines require three of these systems.They are fuel system,ignition system
25、(except diesel),lubricating system and cooling system.Each performs a basic job in making the engine run.These are described briefly below.Chapter 2 AUTOMOTIVE ENGINE2.3 Basic Engine Systems译文:译文:火花点火发动机运转需要火花点火发动机运转需要4 4个基本系统。柴个基本系统。柴油发动机需要其中的油发动机需要其中的3 3个。它们是燃料系统,点火个。它们是燃料系统,点火系统(除了柴油机),润滑系统和冷却系统。
26、其每系统(除了柴油机),润滑系统和冷却系统。其每个系统在使发动机运转时完成一个基本工作。简要个系统在使发动机运转时完成一个基本工作。简要介绍如下:介绍如下:2.3.1 Fuel SystemsThe fuel system supplies gasoline or diesel fuel to the engine.This fuel is mixed with air to make a combustible mixture(a mixture that will burn).Each cylinder is repeatedly filled with the mixture.译文:译文
27、:燃料系统给发动机提供汽油或柴油燃料。燃料燃料系统给发动机提供汽油或柴油燃料。燃料与空气混合形成可燃混合气(一种会燃烧的混合物)。与空气混合形成可燃混合气(一种会燃烧的混合物)。气缸被反复填充这种混合气体。气缸被反复填充这种混合气体。Then,the mixture is ignited and burned,producing high pressure.The high pressure makes the pistons move(or rotors spin).This turns shafts that rotate the wheels,causing the vehicle to
28、 move.译文:译文:然后被点燃、燃烧,产生高压,推动活塞运动然后被点燃、燃烧,产生高压,推动活塞运动(或转子旋转)。这使车轴带到车轮旋转,从而使车辆(或转子旋转)。这使车轴带到车轮旋转,从而使车辆移动。移动。2.3.2 Ignition systemEvery time the fuel system delivers air/fuel mixture to a cylinder,the ignition system follows up by delivering an electric spark.This ignites the mixture which creates the
29、high pressure that moves the pistons and turns the car wheels.The action is repeated many times each second while the engine is running.译文:译文:每当燃料系统传送可燃混合气给气缸,点火系每当燃料系统传送可燃混合气给气缸,点火系统随后会产生电火花来点燃混合气,从而产生高压,使统随后会产生电火花来点燃混合气,从而产生高压,使活塞运动和车轮运转。当发动机运转时,每秒钟这个动活塞运动和车轮运转。当发动机运转时,每秒钟这个动作重复多次。作重复多次。The igniti
30、on system takes the low voltage,of the battery and builds it up to a very high voltage:as high as 47,000 volts in some systems.This high voltage jumps the gaps in the spark plugs,producing the sparks that ignite the air/fuel mixture in the engine cylinders.译文:译文:点火系统把蓄电池的低压增到高压,在一些系点火系统把蓄电池的低压增到高压,在
31、一些系统中可达到统中可达到4700047000伏。高压击穿火花塞(两电极之间)伏。高压击穿火花塞(两电极之间)间隙,产生电火花,点燃发动机气缸内的可燃混合气。间隙,产生电火花,点燃发动机气缸内的可燃混合气。2.3.3 Lubricating systemThe engine has many moving metal parts.If metal parts rub against each other,they will wear rapidly.To prevent this,engines have lubricating oil.The oil gets between the met
32、al parts so they slide on the oil,and not on each other.译文:译文:发动机有许多运动金属部件发动机有许多运动金属部件。如果金属部件之。如果金属部件之间相互磨擦,会加速磨损。为防止这样,发动机带有润间相互磨擦,会加速磨损。为防止这样,发动机带有润滑油。润滑油充斥在金属部件之间,从而使它们在油面滑油。润滑油充斥在金属部件之间,从而使它们在油面上滑动,而不是在其表面。上滑动,而不是在其表面。The lubricating system has an oil pan at the bottom of the engine which holds
33、several quarts(liters)of oil.An oil pump,driven by the engine,sends oil from this reservoir through the engine.After circulating through the engine,the oil drops back down into the oil pan.The oil pump continues to circulate the oil as long as the engine is running.译文:译文:润滑系统油底壳位于发动机的底部,它可保存润滑系统油底壳位
34、于发动机的底部,它可保存几夸脱(升)的润滑油。油泵由发动机驱动把润滑油从几夸脱(升)的润滑油。油泵由发动机驱动把润滑油从油底壳送到发动机各个部件,润滑油在发动机内循环后油底壳送到发动机各个部件,润滑油在发动机内循环后,回落到油底壳中。只要发动机不断运转,油泵就会连,回落到油底壳中。只要发动机不断运转,油泵就会连续循环润滑油。续循环润滑油。夸脱夸脱(容量单位容量单位=1/4 加仑加仑,约约1.14升升)2.3.4 Cooling systemWhere there is fire(combustion),there is heat.Burning of the air/fuel mixture
35、raises the temperature inside the engine cylinders several thousand degrees.译文:译文:有火(燃烧)的地方有火(燃烧)的地方,就会有热。可燃混合气,就会有热。可燃混合气的燃烧会把发动机气缸内的温度提升到几千摄氏度。的燃烧会把发动机气缸内的温度提升到几千摄氏度。Some of this heat produces the high pressure that moves the pistons to produce power.Some of the heat leaves the cylinders with the
36、exhaust gas.The exhaust gas is what is left after the air/fuel mixture burns.It is cleared out of the cylinders after combustion is complete.译文:译文:其中一部分热量产生高压推动活塞运动来产生其中一部分热量产生高压推动活塞运动来产生动力。另外一部分热量随着废气排出气缸。废气是指可动力。另外一部分热量随着废气排出气缸。废气是指可燃混合气燃烧后残留的气体。它在燃烧完成后被排出气燃混合气燃烧后残留的气体。它在燃烧完成后被排出气缸。缸。Some of the h
37、eat is removed by the circulating oil.After the hot oil drops down into the oil pan,the oil gives up some of this heat to the air passing under the oil pan.The rest of the heat is removed by the cooling system.译文:译文:还有一部分热量由循环润滑油带走。灼热的还有一部分热量由循环润滑油带走。灼热的润滑油落到油底壳后,会把部分热量传给通过油底壳润滑油落到油底壳后,会把部分热量传给通过油底壳
38、下方的空气。其余热量由冷却系散发。下方的空气。其余热量由冷却系散发。2.3.5 Other engine systemsAn engine will run with the four basic systems described abovefuel,ignition,lubricating,and cooling.However,three other related systems are also necessary.These are the exhaust system,the emissioncontrol system,and the starting system.译文:译文
39、:发动机运转需要上述发动机运转需要上述4 4个基本系统燃料、点个基本系统燃料、点火、润滑和冷却。但是,还有另外三个相关系统也是火、润滑和冷却。但是,还有另外三个相关系统也是必需的。它们是排放系统、废气处理(排气净化)系必需的。它们是排放系统、废气处理(排气净化)系统和起动系统。统和起动系统。The exhaust system reduces the noise of the burned gases leaving the engine cylinders and carries these exhaust gases safely away from the people in the c
40、ar.The emissioncontrol system is required by law to reduce the air pollution the engine could produce.译文:译文:排放系统功能,一方面减小燃烧废气排出气排放系统功能,一方面减小燃烧废气排出气缸时所产生的噪声,另一方面把这些废气从车中乘客缸时所产生的噪声,另一方面把这些废气从车中乘客身边安全带走。废气处理(排放控制)系统是法规所身边安全带走。废气处理(排放控制)系统是法规所要求的用来降低发动机所产生的空气污染。要求的用来降低发动机所产生的空气污染。The starting system is n
41、eeded to crank the engine.A battery provides the electric power to operate the starting motor and the ignition system during cranking.译文:译文:起动系统起动系统用来转动发动机曲轴。蓄电池在起用来转动发动机曲轴。蓄电池在起动时为开动起动机和点火系统提供电力。动时为开动起动机和点火系统提供电力。The internal combustion engine is a device used to convert the chemical energy of the
42、fuel(gasoline or diesel fuel)into heat energy,and then to convert this heat energy into usable mechanical energy.Chapter 2 AUTOMOTIVE ENGINE2.4 Energy Conversion译文:译文:内燃机是一种把(汽油或柴油)燃料的化学内燃机是一种把(汽油或柴油)燃料的化学能转变成热能,再转换成可利用的机械能的装置。能转变成热能,再转换成可利用的机械能的装置。This is achieved by combining the appropriate amoun
43、ts of air and fuel,and burning the mixture in an enclosed cylinder at a controlled rate.A movable piston in the cylinder is forced down by the expanding gases of combustion.译文:译文:这通过混合适量的空气和燃料,并在密闭的这通过混合适量的空气和燃料,并在密闭的汽缸中按照控制速度燃烧来实现。气缸中活塞由燃烧汽缸中按照控制速度燃烧来实现。气缸中活塞由燃烧气体膨胀作功来压下。气体膨胀作功来压下。An average air/fu
44、el ratio for good combustion is about 15 parts of air to 1 part of fuel by weight.This means that for every gallon of gasoline burned,the oxygen is about 9,000 to 10,000 gallons of air is required.Air is about 21%oxygen and 78%nitrogen.译文:译文:燃烧良好的空燃比,按质量平均大约是燃烧良好的空燃比,按质量平均大约是1515:1 1。这意味着每加仑汽油完全燃烧所需
45、的空气质量大约。这意味着每加仑汽油完全燃烧所需的空气质量大约在在90009000到到1000010000加仑。空气中氧气成份点加仑。空气中氧气成份点21%21%,氮气占,氮气占78%78%。Diesel engines operate on a much wider air/fuel ratio,since air intake is not regulated on most diesels.Ratios may range from about 20:1 to about 100:1.The fact,plus the high compression of the diesel,make
46、s it a very fuel efficient engine.译文:译文:因为进气量在大多数内柴油机上不规则的,因为进气量在大多数内柴油机上不规则的,柴油机有更宽的空燃比。其范围大约在柴油机有更宽的空燃比。其范围大约在2020:1 1到到100100:1 1之间。实际上,加上柴油机的高压缩比,使其成为极之间。实际上,加上柴油机的高压缩比,使其成为极其节约燃油的发动机。其节约燃油的发动机。fuel efficient节约燃油的,燃油经济性高的节约燃油的,燃油经济性高的The movable piston in the cylinder is connected to the top of
47、a connecting rod.The bottom of the connecting rod is attached to the offset portion of a crankshaft.As the piston is force down,this force is transferred to the crankshaft,causing the crankshaft to rotate.译文:译文:气缸活塞与连杆上端相连。连杆底部则连到气缸活塞与连杆上端相连。连杆底部则连到曲轴的偏心部。当活塞被压下时,驱动力被传递到曲曲轴的偏心部。当活塞被压下时,驱动力被传递到曲轴,并带动
48、曲轴旋转。轴,并带动曲轴旋转。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.译文:译文:活塞的往复运动转化成曲轴的旋转运动,从活塞的往复运动转化成曲轴的旋转运动,从而为驱动车辆提供动力。而为驱动车辆提供动力。The efficiency of the internal combustion,reci
49、procating piston engine in converting the potential energy in fuel into mechanical energy is only about 33%.Of the available heat energy in the fuel,about onethird is lost through the exhaust system and onethird is absorbed and dissipated by the cooling system.Of the remaining onethird,about onehalf
50、 is lost through available at the vehicles drive wheels.译文:译文:活塞发动机在转化燃料的势能为机械能时的活塞发动机在转化燃料的势能为机械能时的效率大约只有效率大约只有33%33%。对于燃料的可用热能,大概有。对于燃料的可用热能,大概有1/31/3损失在排放系统中,另外损失在排放系统中,另外1/31/3被冷却系统吸收和散发。被冷却系统吸收和散发。在剩余的在剩余的1/31/3中,约有一半完全利用在车辆的驱动轮上中,约有一半完全利用在车辆的驱动轮上。The overall efficiency of the diesel engine is