汽车专业英语2分析解析.docx

1、汽车专业英语2分析解析Unit 2The Basic Principle of EngineText A Classification and Main Components of Engine 游海龙The internal combustion engine is an engine in which the combustion of fuel occurs with oxygen(usually air) in a combustion chamber, as shown in Fig.2.1. Fig.2.1 Internal Combustion Engine1the cap of

2、 the cylinder head 2valve 3engine block 4flywheel5crankshaft 6oil pan 7pulley 8cylinder 9timing gearClassification of EngineThe engine can be classified in following ways: By Fuel System李鹏Gasoline engine and diesel engine are used. In a gasoline engine, the air-fuel mixture is exploded in the engine

3、. A diesel engine uses diesel fuel. It generates high power at low speeds. The fuel efficiency is better than that of a gasoline engine. By Cylinder Arrangement曾昭昕Most cars have more than one cylinder. Four, six and eight cylinders are common used. In a multi-cylinder engine, the cylinders are usual

4、ly arranged in one of three ways: in-line, V-type, or flat (Fig.2.2). Today the number of cylinders is growing, the cylinders also can be arranged as W-type.(a)flat (b)V-type (c)in-lineFig.2.2 Cylinder Arrangement By Cooling System 梁松雨Liquid-cooled engines and air-cooled engines are being used. Liqu

5、id-cooled engines are the most common in the engine industry.There are also other ways to classify the engines. Despite of these classifications, the structure of the engine is basically the same. Main Components曾润泽The engine consists of several different mechanisms and systems including cylinder bl

6、ock, crankshaft and connecting rod mechanism, valve mechanism, fuel supply system, lubrication system, cooling system, ignition system and starting system.张永德 Cylinder BlockThe core of the engine is the cylinder, with the piston moving up and down inside the cylinder. Crankshaft and Connecting Rod M

7、echanismThe crankshaft changes the linear movement of the piston into a rotational movement via a connecting rod. The connecting rod connects the piston to the crankshaft. It can rotate at both ends so that its angle can change as the piston moves and the crankshaft rotates.张进 Valve MechanismA valve

8、 mechanism is a group of components that opens and closes the intake and exhaust valves in the cylinder head at the appropriate time. The main functions of the valve gear are to provide timely admission of the fresh charge into the cylinders and exhaust of spent gases from them.夏磊 Fuel Supply System

9、The fuel system supplies fuel to the engine. It also has the functions to regulate the volume of fuel supply. The fuel systems in diesel and gasoline engines are different.于晨雪 Lubrication SystemThe lubrication system uses an oil pump to continuously supply engine oil throughout the inside of the eng

10、ine. This system reduces friction between parts with a film of oil. If the engine is run without oil, the friction can cause poor running, or cause even meltdown. In addition to lubrication, engine oil cools and cleans the engine.滕兆磊 Cooling SystemThe cooling system regulates the engine temperature

11、to an optimal level (80 to 90 at coolant temperature) by circulating the coolant throughout the engine under all operating conditions and during all seasons of the year. The cooling fan cools the coolant in the radiator and water pump circulates the coolant through the cylinder head and the cylinder

12、 block.吕庆怡 Ignition SystemInternal combustion engines require ignition of the mixture, either by spark ignition (SI) or compression ignition (CI). Starting SystemThe starting system forces the engine to crank with an electric motor, and starts the engine.Text B Engine Operating Principleszhuangjihui

13、A four-stroke engine, also known as four-cycle, is an internal combustion engine in which the piston completes four separate strokes：intake, compression, power and exhaustduring two separate revolutions of the engines crankshaft, and one single thermodynamic cycle.The main parts in four stroke engin

14、e are shown in Fig.2.3.Fig.2.3 Main Parts in Four Stroke Engine1intake valve 2spark plug 3exhaust valve 4combustion chamber 5piston headwangxiaolongAs their name implies, four-stroke internal combustion engines have four basic steps that repeat with every two revolutions of the crankshaft: Intake st

15、roke Compression stroke, Power stroke, Exhaust stroke. The four strokes will be illustrated in Fig.2.4.liyangThey draw in an air-fuel mixture to the cylinders, compress it, ignite and combust it, then discharge it. Repeating these four actions gives gasoline engines their power. The cycle begins at

16、Top Dead Centre (TDC), when the piston is farthest away from the crankshaft. A cycle refers to the full travel of the piston from TDC to Bottom Dead Centre (BDC). renwenjie Intake StrokeOn the intake stroke of the piston, the piston descends from (TDC,BDC) to (TDC, BDC), reducing the pressure inside

17、 the cylinder. A mixture of fuel and air, or just air in a diesel engine, is forced by atmospheric pressure into the cylinder through the intake port. The intake valve(s) then (open,close). zhangshuai Compression StrokeWith both intake and exhaust valves (open,close), the piston returns to the top o

18、f the cylinder compressing the fuel-air mixture into the combustion chamber of the cylinder head.zhantianbao Power StrokeIt is also named as combustion stroke. While the piston is close to (TDC,BDC), the compressed airfuel mixture is ignited. The resulting massive pressure from the combustion of the

19、 compressed fuel-air mixture forces the piston back down toward (TDC,BDC). zhangzhikai Exhaust StrokeDuring the exhaust stroke, the piston once again returns to (TDC,BDC) while the exhaust valve is (open,close). This action evacuates the burnt products of combustion from the cylinder by expelling th

20、e spent fuel-air mixture out through the exhaust valve(s). .(1)intake (2)compression (3)power (4)exhaustFig.2.4 Four Stroke CycleheguangbinyouhailongNEW WORDS AND PHRASESprinciple n. 原理，法则classification n. 种类，类别configuration n. 布局，构造oxygen n. 氧气combustion n. 燃烧chamber n. 室，房间component n. 成分，部件，零件for

21、ce n. 力gasoline n. 汽油diesel n. 柴油；柴油机 explode n. 爆炸，爆发rotational adj. 旋转的in-line adj.(汽缸)直列的flat adj.(汽缸)水平对置cooling system冷却系liquid-cooled水冷air-cooled风冷cylinder block汽缸体crankshaft n. 曲柄轴，机轴connecting rod连杆valve mechanism 配气机构fuel supply system燃油供给系lubrication 润滑lubrication system润滑系ignition system点

22、火系starting system起动系linear adj. 线性的piston n. 活塞intake n. 吸入；进气口，入口exhaust n. 排气；废气valve n. 气门，阀门oil pump机油泵friction n. 摩擦(力)part n. 零件, 部位appropriate adj. 恰当的，适当的volume U.S. n. 容量，容积a film of oil一层油膜meltdown n. 熔毁optimal adj. 最佳的，最优的coolant n. 冷却液，冷冻剂radiator n. 散热器water pump抽水机，水泵spark ignition (SI

23、)火花点火compression ignition (CI)压缩点火four-stroke四冲程的(内燃机)power n. 做功 illustrate vt. 说明，阐明revolution n. 旋转(一周) spark plug火花塞discharge vt. 释放；排出Top Dead Centre (TDC)上止点Bottom Dead Centre (BDC)下止点descend vi. 下降，降临evacuate vi. 散离，释放NOTES TO THE TEXT1. The internal combustion engine is an engine in which th

24、e combustion of fuel occurs with oxygen(usually air) in a combustion chamber.内燃机是一种由燃料和氧气(通常是空气)在燃烧室中燃烧而产生动力的发动机。2. The engine consists of several different mechanisms and systems including cylinder block, crankshaft and connecting rod mechanism, valve mechanism, fuel supply system, lubrication syst

25、em, cooling system, ignition system and starting system.发动机由不同的机构和系统构成，包括汽缸体、曲轴和连杆机构、配气机构、燃油供给系、润滑系、冷却系、点火系和起动系。3.The crankshaft changes the linear movement of the piston into a rotational movement via a connecting rod.曲轴把活塞的线性运动通过连杆转换成旋转运动。4.A four-stroke engine, also known as four-cycle, is an int

26、ernal combustion engine in which the piston completes four separate strokes, intake, compression, power and exhaustduring two separate revolutions of the engines crankshaft, and one single thermodynamic cycle.四冲程发动机也叫做四循环发动机，这种内燃机在发动机曲轴转两周和一个热力学循环中完成四个独立的冲程即进气、压缩、做功和排气。5.While the piston is close to

27、 Top Dead Center, the compressed airfuel mixture in a gasoline engine is ignited, usually by a spark plug, or fuel is injected into the diesel engine, which ignites due to the heat generated in the air during the compression stroke.活塞接近上止点时，汽油机中的压缩空气与燃料混合气通常被火花塞点燃，而柴油机中燃油直接喷入发动机，由压缩冲程压缩空气产生的热量压燃。6.T

28、hey draw in an air-fuel mixture to the cylinders, compress it, ignite and combust it, then discharge it. 空气与燃料混合气被吸入汽缸里，被压缩，点燃、燃烧，然后被排出。EXERCISES1.Translate the following words to English.发动机工作原理发动机结构内燃机起动系曲轴和连杆机构配气机构燃油供给系统上止点四冲程发动机空燃混合气活塞汽缸排列水冷多缸发动机柴油机上下运动润滑系统冷却系统点火系油膜2.Translate the following sent

29、ences to Chinese. (1)In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion apply direct force to some component of the engine.(2)The air-fuel mixture is exploded in the engine, and this force is converted into a rotational movement to

30、move the vehicle.(3)In a multi-cylinder engine, the cylinders usually are arranged in one of three ways: inline, V-type or flat.(4)The crankshaft changes the linear movement of the piston into a rotational movement via a connecting rod.(5)Almost all cars currently use what is called a four-stroke combu