汽车专业英语课件-2cha.ppt

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1、复习1.Discribe the main parts of a car?说明汽车的主要组成部件（系统）有哪些？2.Vehicle classificatin 汽车分类提问提问学习内容学习内容本次课学习内容、目标和重点难点本次课学习内容、目标和重点难点学习目标学习目标难点重点难点重点1.Principle of Operation 2.Classifications3.Main parts and systems1.1.掌握内燃机的分类英文术语掌握内燃机的分类英文术语2.2.掌握机体、曲柄连杆机构、配气机构的英掌握机体、曲柄连杆机构、配气机构的英文术语文术语2.2.了解各个系统的主要功能了解各

2、个系统的主要功能1.1.重点为记忆分类和主要部件英文专业术语重点为记忆分类和主要部件英文专业术语2.2.难点需要记忆的生词偏多难点需要记忆的生词偏多3.3.准确汉译表达也是难点准确汉译表达也是难点Chapter 2 Internal Combustion Engine2.1 Principle of Operation Nicolaus August Otto尼古拉斯尼古拉斯奥古斯特奥古斯特奥托奥托Gottlieb Daimler戈特利布戈特利布戴姆勒戴姆勒associatesuieitn.伙伴，同事，合伙人伙伴，同事，合伙人pioneerpainin.拓荒者，先拓荒者，先驱者者,开拓者；开拓

3、者；v.开辟，倡开辟，倡导combustionkmbsnn.燃燃烧烧strokestrouk n.冲程冲程pistonpistnn.活塞活塞cylindersilindn.气缸气缸 New Words and PhrasesChapter 2 Internal Combustion Engine2.1 Principle of Operation valvevlv n.气气门门，阀门阀门，阀阀exhaustigz:st n.排气，排气，废废气气intakeinteik n.进进气，气，进进（引，吸）入（引，吸）入compressionkmpren n.压缩压缩crankshaftkrk:ftn

4、.曲曲轴轴cylindersilindn.气缸，气缸，圆圆筒筒 charget:dn.充气，充量，充充气，充量，充电电；v.充充电电，增增压压descenddisendv.下降，下下降，下倾，下斜，下行，下斜，下行Chapter 2 Internal Combustion Engine2.1 Principle of Operation aspiratespreitv.吸气，抽吸吸气，抽吸throttlertln.节气气门，节流流阀，油，油门，风门depressiondiprenn.萧条条(期期)，凹地，洼地，低（气），凹地，洼地，低（气）压atomisetmaizv.使使雾雾化，化，喷雾喷雾

5、，粉化，粉化innermostinmusta.最内的，最内部的，最深最内的，最内部的，最深处的，内的，内心深心深处的的outermostautmusta.最外最外边的，离中心最的，离中心最远的的maybemeibiad.大概大概,或或许,可能可能Chapter 2 Internal Combustion Engine2.1 Principle of Operation aspiratespreitv.吸气，抽吸吸气，抽吸throttlertln.节气气门，节流流阀，油，油门，风门depressiondiprenn.萧条条(期期)，凹地，洼地，低（气），凹地，洼地，低（气）压atomisetma

6、izv.使使雾雾化，化，喷雾喷雾，粉化，粉化innermostinmusta.最内的，最内部的，最深最内的，最内部的，最深处的，内的，内心深心深处的的outermostautmusta.最外最外边的，离中心最的，离中心最远的的maybemeibiad.大概大概,或或许,可能可能Chapter 2 Internal Combustion Engine2.1 Principle of Operationmotor vehicle汽汽车车，机，机动车动车petrol engine汽油机汽油机flammable mixture可燃混合气可燃混合气spark-ignition(S.I.)engine点燃

7、式（点燃式（S.I.）发动发动机机cylinder head气缸盖气缸盖inlet valve进进气气门门exhaust valve排气排气门门induction stroke进进气行程气行程Chapter 2 Internal Combustion Engine2.1 Principle of Operationatmospheric pressure大气大气压压力力naturally aspirated自然吸气自然吸气normally aspirated自然吸气自然吸气compression stroke压缩压缩行程行程air-and-petrol charge空气与汽油的混合气空气与汽油

8、的混合气power stroke做功行程做功行程exhaust stroke排气行程排气行程spark-plug火花塞火花塞Chapter 2 Internal Combustion Engine2.1 Principle of Operation The first internal-combustion engine to operate successfully on the four-stroke cycle used gas as a fuel and was built in 1876 by Nicolaus August Otto,a self-taught German eng

9、ineer at the Gas-motoreufabrik Deutz factory near Cologne,for many years the largest manufacturer of internal-combustion engines in the world.It was one of Ottos associates Gottlieb Daimler who later developed an engine to run on petrol which was described in patent number 4315 of 1885.He also pione

10、ered its application to the motor vehicle.Petrol engines take in a flammable mixture of air and petrol which is ignited by a timed spark when the charge is compressed.These engines are therefore sometimes called spark-ignition(S.I.)engines.TextChapter 2 Internal Combustion Engine2.1 Principle of Ope

11、ration These engines require four piston strokes to complete one cycle:an air-and-fuel intake stroke moving outward from the cylinder head,an inward movement towards the cylinder head compressing the charge,an outward power stroke,and an inward exhaust stroke.Induction stroke.The inlet valve is open

12、ed and the exhaust valve is closed.The piston descends,moving away from the cylinder head(Fig.2-1(a).The speed of the piston moving along the cylinder creates a pressure reduction or depression which reaches a maximum of about 0.3 bar below atmospheric pressure at one-third from the beginning of the

13、 stroke.The depression actually generated will depend on the speed and load experienced by the engine,but a typical average value might be 0.12 bar below atmospheric pressure.Chapter 2 Internal Combustion Engine2.1 Principle of Operation This depression induces(sucks in)a fresh charge of air and ato

14、mised petrol in proportions ranging from 10 to 17 parts of air to one part of petrol by weight.An engine which induces fresh charge by means of a depression in the cylinder is said to be normally aspirated or naturally aspirated.Compression stroke.Both the inlet and the exhaust valves are closed.The

15、 piston begins to ascend towards the cylinder head(Fig.2-1(b).The induced air-and-petrol charge is progressively compressed to something of the order of one-eighth to one-tenth of the cylinders original volume at the pistons innermost position.This compression squeezes the air and atomised-petrol mo

16、lecules closer together and not only increases the charge pressure in the cylinder but also raises the temperature.Chapter 2 Internal Combustion Engine2.1 Principle of Operation Typical maximum cylinder compression pressures will range between 8 and 14 bars with the throttle open and the engine runn

17、ing under load.Power stroke.Both the inlet and the exhaust valves are closed and,just before the piston approaches the top of its stroke during compression,a spark-plug ignites the dense combustible charge(Fig.2-1(c).By the time the piston reaches the innermost point of its stroke,the charge mixture

18、 begins to burn,generates heat,and rapidly raises the pressure in the cylinder until the gas forces exceed the resisting load.The burning gases then expand and so change the pistons direction of motion and push it to its outermost position.The cylinder pressure then drops from a peak value of about

19、60 bars under full load down to maybe 4 bar near the outermost movement of the piston.Chapter 2 Internal Combustion Engine2.1 Principle of Operation Exhaust stroke.At the end of the power stroke the inlet valve remains closed but the exhaust valve is opened.The piston changes its direction of motion

20、 and now moves from the outermost to the innermost position(Fig.2-1(d).Most of the burnt gases will be expelled by the existing pressure energy of the gas,but the returning piston will push the last of the spent gases out of the cylinder through the exhaust-valve port and to the atmosphere.Chapter 2

21、 Internal Combustion Engine2.1 Principle of Operation Fig 2-1 Four-stroke-cycle petrol engineChapter 2 Internal Combustion Engine2.2 Engine Classifications Fig 2-1 Four-stroke-cycle petrol engineChapter 2 Internal Combustion Engine2.2 Engine Classifications complicatedkmplikeitida.复复杂杂的，的，难难懂的，懂的，结结

22、构复构复杂杂的的valvetrainvlvtreinn.气气门门机构，配气机构，气机构，配气机构，气门组门组camshaftkm:ftn.凸凸轮轴轮轴dieseldi:zln.柴油柴油gasolinegsli:nn.汽油汽油methanolmenuln.甲醇甲醇propaneprupeinn.丙丙烷烷four-stroke-cycle engine四冲程（循四冲程（循环环）发动发动机机 New Words and PhrasesChapter 2 Internal Combustion Engine2.2 Engine Classifications road vehicle道路道路车辆车辆f

23、lat(horizontal-opposed)engine水平水平对对置式置式发动发动机机inline engine直列式直列式发动发动机机V-type engineV型型发动发动机机overhead camshaft(OHC)顶顶置凸置凸轮轴轮轴（OHC）overhead valve(OHV)顶顶置气置气门门（OHV）double overhead camshaft(DOHC)engine双双顶顶置凸置凸轮轴轮轴（DOHC）发动发动机机air-cooled engine风风冷冷发动发动机机liquid-cooled engine水冷水冷发动发动机机Chapter 2 Internal Com

24、bustion Engine2.2 Engine Classifications Todays automotive engines can be classified in several ways depending on the following design features:Operational cycles.There are two-stroke and four-stroke cycles.Four-stroke-cycle engines are widely used on road vehicles.However,a few older cars have used

25、 and some cars in the future will use a two-stroke engine.Number of cylinders.Current engine designs include 3-,4-,5-,6-,8-,10-,and 12-cylinder engines.Cylinder arrangement.An engine can be flat(horizontal-opposed),inline,or V-type.Other more complicated designs have also been used.See figure 2-2.2.

26、2.2 Text Fig.2-2 Cylinder arrangementsChapter 2 Internal Combustion Engine2.2 Engine Classifications Valvetrain type.Engine valvetrains can be either the overhead camshaft(OHC)type or the camshaft in-block overhead valve(OHV)type(Figure 2-3).Some engines separate camshafts for the intake and exhaust

27、 valves.These are based on the OHC design and are called double overhead camshaft(DOHC)engines.V-type DOHC engines have four camshaftstwo on each side.Figure 2-3(a)Overhead camshaft（OHC）Chapter 2 Internal Combustion Engine2.2 Engine Classifications Valvetrain type.Engine valvetrains can be either th

28、e overhead camshaft(OHC)type or the camshaft in-block overhead valve(OHV)type(Figure 2-3).Some engines separate camshafts for the intake and exhaust valves.These are based on the OHC design and are called double overhead camshaft(DOHC)engines.V-type D O H C e n g i n e s h a v e f o u r camshaftstwo

29、 on each side.Figure 2-3(b)Overhead valve(OHV)engines Chapter 2 Internal Combustion Engine2.2 Engine Classifications Ignition type.There are two types of ignition systems:spark ignition and compression ignition.Gasoline engines use a spark ignition system and are sorted to spark ignition engines.In

30、a spark ignition engine,the air-fuel mixture is ignited by an electrical spark.Diesel engines,or compression ignition engines,have no spark plugs.An automotive diesel engine relies on the heat generated as air is compressed to ignite the air-fuel mixture for the power stroke.Cooling systems.There ar

31、e both air-cooled and liquid-cooled engines in use.Nearly all of todays engines have liquid-cooling systems.Fuel type.Several types of fuel currently used in automobile engines include gasoline,natural gas,methanol,diesel,and propane.The most commonly used is gasoline although new fuels are being te

32、sted.Chapter 2 Internal Combustion Engine2.2 Engine Classifications Chapter 2 Internal Combustion Engine2.3 Engine block and head foundationfaundein n.基基础础，基地，基金，机座，基，基地，基金，机座，基础础件件accessoryksesrin.附属品，附件，附属品，附件，辅辅助装置助装置clutchkltn.离合器离合器housinghauzin.外壳，外壳，boltboultn.螺栓；螺栓；v.用螺栓用螺栓连连接接corek:n.核心，核心，

33、铁铁心，型芯，沙芯，（心，型芯，沙芯，（电缆电缆）芯芯线线aluminumljuminimn.铝铝linerlainn.衬衬套，套，衬衬里，里，衬衬板板 New Words and PhrasesChapter 2 Internal Combustion Engine2.3 Engine block and headengine block气缸体气缸体cylinder block气缸体气缸体clutch housing离合器壳离合器壳cast iron铸铁铸铁cylinder sleeve气缸套气缸套combustion chamber燃燃烧烧室室light vehicle轻轻型汽型汽车车Ch

34、apter 2 Internal Combustion Engine2.3 Engine block and head 2.3.1 Engine block The engine block(or cylinder block)serves as a rigid metal foundation for all parts of an engine(Fig.2-4).It contains the cylinders and supports the crankshaft and camshaft.Accessory units and the clutch housing are bolte

35、d to it.Blocks are made of either cast iron or aluminum.TextChapter 2 Internal Combustion Engine2.3 Engine block and head The cylinder is a round hole formed in the block.It forms a guide for the piston and acts as a container for taking in,compressing,firing,and exhausting the air-fuel charge.Cylin

36、ders have been made of both steel and cast iron.Cast iron is by far the most popular.When steel cylinders are desired in an aluminum block,they are installed in the form of cylinder sleeves(round,pipe-like liners).These sleeves may be either cast or pressed into the block.Some engines use removable

37、cylinder sleeves.When the cylinder becomes worn,the old sleeves can be pulled out and new sleeves can be pressed in.Chapter 2 Internal Combustion Engine2.3 Engine block and head2.3.2 Cylinder headThe cylinder head fastens to the top of the block(Fig.2-4).The underside forms the combustion chamber wi

38、th 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.Just as with engine blocks,cylinder heads can be made of cast iron or aluminum alloy.Chapter 2 Internal Combustion Engine2.3 Engine block and headFig.2-4 Cylinder block,cylinder head and camshaft小结与作业oMain engine parts,classificationo阅读并记住黑体字专业词汇；提出疑难问题o掌握发动机工作原理、主要组成和分类术语