汽车专业英语（二）.ppt

1、汽车专业英语 Specialty English for Automobile,Chapter 2 Internal combustion engine,2.1 Principle of Operation,Energy Power Chemical energy Burn / combustion Internal (external) combustion engine Cylinder Heat engine Chamber Mechanical,Inlet valve,piston,connecting rod,TDC,BDC,Exhaust valve,crank,Engine Te

2、rms,TDC（Top Dead Center）: the position of the crank and piston when the piston is farthest away from the crankshaft.,BDC（Bottom Dead Center）: the position of the crank and piston when the piston is nearest away from the crankshaft.,2.1.2 Engine terms,缸径 bore,stroke,TDC,BDC,Clearance volume,Swept vol

3、ume,Clearance volume（余隙/燃烧室容积）: the volume of space above the piston when it is at TDC.,Engine capacity（排量）: this is the swept volume of all cylinders.,Compression ratio（压缩比）: (swept vol + clearance vol) /(clearance vol),活塞行程,Swept volume（有效/工作容积）: the volume between TDC and BDC.,TDC BDC Stroke Bore

4、 Swept volume Engine capacity Clearance volume Compression ratio,Two-stroke: a power stroke every revolution of the crank Four-stroke: a power stroke every other revolution of the crank 每隔一个,2.1.3 The four-stroke spark-ignition engine cycle,1. Intake/Induction stroke 进气行程 2. Compression stroke 压缩行程

5、3. Power stroke 作功行程 4. Exhaust stroke 排气行程,2.1.4 Engine overall mechanics,Crankshaft and Connecting rods system 曲柄连杆机构 Valve system 配气机构 Fuel system 供给系 Intake system 进气系统 Cooling system 冷却系 Ignition system 点火系 Starting system 起动系 Lubrication system 润滑系 Exhaust system 排气系统,2.2 Engine block and cyli

6、nder head,发动机缸体是发动机的基本骨架，发动机其余的零件或安装在缸体内部，或固定在缸体上。缸体里有气缸、水套和油道，曲轴也固定在缸体底部。除了顶置凸轮轴发动机以外，凸轮轴都固定在缸体内部。大多数汽车上，缸体采用灰铸铁或者灰铸铁和其他金属（例如镍或铬）的合金铸造而成。,The engine block is the basic frame of the engine. All other engine parts either fit inside it or fasten to it. It holds the cylinders, water jackets, and oil ga

7、lleries. The engine block also holds the crankshaft, which fastens to the bottom of the block. The camshaft also fits inside the block, except on overhead-cam engines (OHC). In most cars, this block is made of gray iron, or an alloy (mixture) of gray iron and other metals, such as nickel or chromium

8、. Engine blocks are castings.,Be made of / manufactured with Line with: 不满；给加 The path to the house is lined with bushes. 通向那所房子的小径长满了灌木丛。 The coat is lined with silk. 这件外套用绸子作衬里。 Cylinder sleeves 气缸套,Cylinder sleeves are used in engine blocks to provide a hard wearing material for pistons and pisto

9、n rings. The block can be made of one kind of iron that is light and easy to cast while the sleeves uses another that is better able to stand up wear and tear. There are two main types of sleeves: dry and wet.,发动机缸体中的气缸套为活塞和活塞环提供一种坚硬耐磨的材料。缸体可以采用较轻且易铸造的铁，而气缸套采用更耐磨和耐冲击的材料。气缸套分为两种：干式和湿式。,2.2.2 Cylinder

10、 sleeves,Components of a typical, four stroke cycle, D(dual)OHC piston engine. (E) Exhaust camshaft, (I) Intake camshaft, (S) Spark plug, (V) Valves, (P) Piston, (R) Connecting rod, (C) Crankshaft, (W) Water jacket for coolant flow.,2.2.3 Cylinder head,The cylinder head fastens to the top of the blo

11、ck, just as a roof fits over a house. The underside forms the combustion chamber with 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.,气缸盖固定在气缸体的顶部，就像房子的房顶一样。气缸盖底部与活塞头部之间的空间形成了燃烧室。轻型汽车的直列式发动机采用一个气缸盖，较

12、大的直列式发动机采用两个或多个气缸盖。,in-line 直列式,V型,Hemi 半球形,Wedge 楔形,Basin 盆形,Flat engine Pancake engine 对置式,arrangement,Cylinder head In-line engine Petrol 英 gasoline 美 Combustion chamber,Gasket Sandwich Asbestos 石棉 Copper 铜 Oil pan or sump 油底壳 / 集油槽 油底壳 Oil pan Crankcase Oil pump Lubricating system Circulation,Th

13、e oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine. The oil drains off and runs down into the pan. Thus, there is constant circulation of oil between the pan and the working pats of the engine.,润滑系的机油泵从油底壳抽出机油，并把机油输送给发动机的所有工作部件。机油从油底壳流进流出。

14、因而在油底壳和发动机的工作部件之间就有机油定向循环流动。,Oil Pan / Sump 油底壳,Oil Pan,Engine block and Cylinder head,曲轴箱,气缸盖罩,气缸,气缸套,气缸体,油底壳,气缸盖,衬垫,水套,油道,Crankshaft 曲轴,Piston ring 活塞环,Piston (crownskirt) 活塞（头部裙部）,Piston pin 活塞销,Connecting rod连 杆,Big-end 连杆大头,Small-end 连杆小头,Cap 连杆盖,Shell bearing 轴 瓦,Main bearing journals 主轴颈,Conn

15、ecting rod journal 连杆轴径,Flywheel 飞轮,2.3 Piston, Connecting rod and Crankshaft,The piston is an important part of a four-stroke cycle engine. Most pistons are made from cast aluminum. The piston, through the connecting rod, transfers to the crankshaft the force created by the burning fuel mixture. Th

16、is force turns the crankshaft. Thin, circular, steel bands fit into grooves around piston to seal the bottom of the combustion chamber. These bands are called piston rings. The grooves into which they fit are called ring grooves. A piston pin fits into a round hole in the piston. The piston pin join

17、s the piston to the connecting rod. The thick part of the piston that holds the piston pin is the pin boss.,大多数活塞由铝铸造而成。通过连杆的作用，活塞把可燃混合气燃烧产生的力传递给曲轴，带动曲轴旋转。,Piston Assembly,Flat Concave Dome Recessed,In diesel engines, the combustion chamber may be formed totally or in part in the piston crown, depen

18、ding on method of injection.,柴油机发动机根据喷油方法不同，活塞头部可以形成全部燃烧室，也可以是燃烧室的一部分,Piston,Compression ring: 气环 压缩环 压环 Oil ring： 油环,Piston rings,The connecting rod is made of forged high-strength steel. It transmits force and motion from the piston to the crankpin on the crankshaft. The connecting rod little end

19、is connected to the piston pin. A bush made from a soft metal, such as bronze, is used for this joint. The lower end of the connecting rod fit the crankshaft journal. This is called the big end.,连杆采用高强度锻造钢。连杆将活塞的力和运动传递给曲轴上的曲柄销。连杆小头与活塞销连接，连接处有像青铜这样软金属制成的衬套，连杆下端连接在曲柄轴径上，称为连杆大头。,2.3.3 connecting rod,2.

20、3.4 crankshaft,Reciprocating: 往复 bearing journal 轴颈 throw：半径，行程 TDC BDC Vice versa,2.3.5 cylinder numbering and firing order,A single-cylinder engine provides only one power impulse for every two-crankshaft revolution. The engine is delivering power only one-fourth of the time. A smoother flow of po

21、wer from the crankshaft is obtained when more than one cylinder is used. The extra power impulses are spaced out evenly throughout the two revolutions of the four-stroke cycle. Four-cylinders commonly used on cars.,2.5 Valve system,The valve system is made up of those parts needed to open and close

22、the valves at just the right time. To coordinate the four-stroke cycle, a group of parts called the valve trains opens and closed the valves (moves them down and up, respectively). These valve movements must take place at exactly the right moments. The opening of each valve is controlled by a camsha

23、ft.,The cam is an egg-shaped piece of metal on a shaft that rotates in coordination with the crankshaft. The metal shaft, called the camshaft, typically has individual cams for each valve in the engine. As the camshaft rotates, the lobe, or high spot of the cam, pushes against parts connected to the

24、 stem of the valve. This action forces the valve to move downward. This action could open an inlet valve for an intake stroke, or open an exhaust valve for an exhaust stroke.,凸轮是一个蛋形的金属块，它安装在同曲轴协调运转的一根金属轴上，该轴称为凸轮轴，其上有同发动机每一个气门对应的凸轮。当凸轮轴旋转时，凸轮的最高点，也就是凸圆，推动连接气门杆的部件，使得气门向下运动，在进气冲程打开进气门，在排气冲程打开排气门。,Valv

25、es in modern car engines are located in the cylinder head at the top of the engine. This is known as an overhead valve (OHV) configuration. In addition, when the camshaft is located over the cylinder head, the arrangement is known as an overhead camshaft (OHC) design. Some high performance engines h

26、ave two separate camshafts, one for each set of inlet and exhaust valves. These engines are known as dual overhead-camshaft (DOHC) engine.,In this arrangement, the cam lobes push against round metal cylinders called cam follower. As the lobe of the cam comes up under the cam follower, it pushes the

27、cam follower upward (away from the camshaft). The cam follower rides against a push rod, which pushes against a rocker arm. The rocker arm pivots on a shaft through its center. As one side of the rocker arm moves up, the other side moves down, just like a seesaw. The downward-moving side of the rock

28、er arm pushes on the valve stem to open the valve.,Push-rod valve train,Rocker-arm（摇臂）,Camshaft,Tappet (Cam follower),Push-rod,Valve clearances,Valve Spring,Valve stem,Valve seat （气门座）,Valve head,Piston,Rocker-shaft,2.5.2 Valve clearance,When the engine runs in compression stroke and power stroke, t

29、he valves must close tightly on their seats to produce a gas-tight seal and thus prevent the gases escaping from the combustion chamber. If the valves do not close fully the engine will not develop full power. Also the valve heads will be liable to be burnt by the passing hot gases, and there is the

30、 likelihood of the piston crown touching an open valve, which can seriously damage the engine.,当发动机处于压缩行程或做功行程时，气门必须紧闭在气门座上，提供很好的密封性，从而防止气体从燃烧室中溢出。如果气门不能完全关闭，则发动机不能产生最大的功率。另外气门头容易被流经的高温气体烧蚀，有可能导致活塞头部冲击打开的气门，会严重破坏发动机。,为保证气门能完全关闭，必须在气门工作机构中留有间隙。这就意味着气门传动机构和气门之间有足够远的距离，从而保证气门能够在弹簧的作用下紧闭气门座。但是如果气门间隙过大，会

31、产生轻微的金属敲打声。,So that the valves can close fully some clearance is needed in the operating mechanism. This means that the operating mechanism must be able to move sufficiently far enough away from the valve to allow the valves to be fully closed against its seat by the valve spring. However, if the cl

32、earance is set too great this will cause a light metallic tapping noise.,2.5.3 valve timing,The time at which valves open and close (valve timing) and duration of valve opening is stated in degrees of crankshaft rotation. For example, the intake valve normally begins to open just before the piston h

33、as reached top dead center. The valve remains open as the piston travels down to BDC and even past BDC. This is intake valve duration. An example of this could be stated as follows: IO at 17oBTDC, IC at 51oABDC (or, intake opens 17obefore top dead center, intake closes 51o after bottom dead center).

34、 Intake valve duration in this case is 248o of crankshaft rotation.,It is apparent from this description that the exhaust valve stays open for a short period of time during which the intake valve is also open. In other words, the end of the exhaust stroke and the beginning of the intake stoke overla

35、p for a short period of time. This is called valve overlap. Valve timing and valve overlap vary on different engines.,从上述描述显而易见，排气门开启时，有一小段时间，进气门也是开启的。换句话说，排气行程终了和进气行程初期有一短时间的重叠，这就称之为气门重叠。不同的发动机具有不同的气门正时和气门重叠。,The entire valve-train assembly can be viewed as a spring/mass system in which the convers

36、ion from stored to free energy causes forced vibration. Valve-train assemblies with overhead camshafts can be represented with sufficient accuracy by a 1-mass system (consisting of the moving mass, the valve-train assembly stiffness and corresponding damping).,整个气门传动机构可以被看做成一个弹簧/质量系统，其储存的能量转换为自由能量时产

37、生了受迫振动。顶置凸轮轴的气门传动总成可非常精确地用单质量系统（包含移动的质量、气门机构总成的刚度和相应的阻尼）表示。,2.5.4 cam design and control dynamics,2.5.5 camshaft drive mechanism,Each cam must revolve once during the four-stroke cycle to open a valve. A cycle, remember, corresponds with two revolutions of the crankshaft. Therefore, the camshaft mus

38、t revolve at exactly haft the speed of the crankshaft. This is accomplished with a 2:1 gear ratio. A gear connected to the camshaft has twice the number of teeth as a gear connected to the crankshaft.,Belt drive Cog-type belt 齿形带 Reinforce：加强 Fiberglass：玻璃纤维 Slotted：开槽 Chain drive Gear drive,Variabl

39、e valve timing In internal combustion engines, variable valve timing, often abbreviated to VVT, is a generic term for an automobile piston engine technology. VVT allows the lift, duration or timing (in various combinations) of the intake and/or exhaust valves to be changed while the engine is in ope

40、ration. The profile, or position and shape of the cam lobes on the shaft, is optimized for a certain engine revolutions per minute (RPM), and this tradeoff normally limits low-end torque, or high-end power. VVT allows the cam timing to change, which results in greater efficiency and power, over a wi

41、der rev-range. 通用、专业术语；轮廓、型线；转速/分； 低端扭矩；高端功率,At high engine speeds, an engine requires large amounts of air. However, the intake valves may close before all the air has been given a chance to flow in, reducing performance. On the other hand, if the cam keeps the valves open for longer periods of tim

42、e, as with a racing cam, problems start to occur at the lower engine speeds. This will cause unburnt fuel to exit the engine since the valves are still open. This leads to lower engine performance and increased emissions. For this reason, pure racing engines cannot idle at the low speeds (around 800

43、rpm) expected of a road car, and idle speeds of 2000 rpm are not unusual. Pressure to meet environmental goals and fuel efficiency standards is forcing car manufacturers to turn to VVT as a solution. Most simple VVT systems advance or retard the timing of the intake or exhaust valves. Others (like H

44、ondas VTEC) switch between two sets of cam lobes at a certain engine RPM. Furthermore Hondas I-VTEC can alter intake valve timing continuously.,VTEC (Variable Valve Timing and Lift electronic Control) 可变气门配气相位和气门升程电子控制系统 is a valvetrain system developed by Honda to improve the volumetric efficiency

45、of a four-stroke internal combustion engine. This system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R take place 发生 the accident occurred at about 3.30 p.m. exist or be found to be present in a place or under a particular set of conditions 存在

46、；出现 radon occurs naturally in rocks such as granite. 氡自然存在于花岗岩等岩石中。 (occur to)(of a thought or idea) come into the mind of (someone)（想法）产生 with clauseit occurred to him that he hadnt eaten. 他想到他还没吃东西。,Fuel consumption 燃油消耗 Fuel economy 燃油经济性 Pollutant emission 废气排放 Emission 排放 Acceleration performan

47、ce 加速性能,fuel tank 油箱,fuel filter 汽油滤清器,fuel pump 汽油泵,Carburetor (mix) 化油器,air filter 空气 滤清器,burn,Basic parts of a carburetor fuel system,2.6.4 Carburetor fuel system,Fuel pump: Most cars today have a mechanical fuel pump. This pumps fuel out of the tank and through the fuel lines to the carburetor o

48、r injection system. In most cars, the pump is mounted on the engine block. Some cars have an electric fuel pump. This pump mounts in the fuel tank with the fuel pickup and the fuel-gauge-sending unit.,当前大多数汽车采用机械汽油泵，汽油泵从油箱抽出汽油，通过油管送到化油器或喷射系统。大部分汽车的汽油泵安装在缸体上。一些汽车采用电动汽油泵，汽油泵安装在油箱上，附带有油量传感器和燃油表油量传送装置。,

49、Diaphragm spring,Rocker arm,Inlet port,Outlet port,Diaphragm,Cam (lobe),A carburetor delivers fuel in proportion to the amount of air flowing through it. As you press on the accelerator pedal, the throttle valve opens wider to draw more air through the carburetor. The carburetor provides richer or l

50、eaner mixtures, depending on a number of factors: engine speed, load, temperature, and throttle position. To meet complicated demands, a carburetor is a highly intricate device, with many internal passages and parts.,化油器传输的燃料和流经化油器的空气流量成一定比例。踏下加速踏板，节气门开度变大，化油器吸入的空气量增加。化油器可提供过浓或过稀的混合物，这取决于许多因素：发动机转速，

51、负载，温度和节气门位置。为满足复杂的要求，化油器是高度复杂的装置，包含了许多内部管路和部件（图2.21）。,Carburetor,needle valve 针阀,float chamber 浮子室,float 浮子,venturi 喉管,discharge tube 喷管,throttle 节气门,Jet 喷嘴 量孔,air filter 空气滤清器,Venturi: An automobile carburetor is designed with a venturi chamber. The venturi is simply a narrowed portion in the air passage. Air moving through the throat of the carburetor speeds up as it travels through this narrowed passageway. The increased air speed through the venturi creates a low-pressure area at the opening of the fuel nozzle. Atmospheric pressure pushes down on a fuel r