Automotive engineering English 2.1 Principle of Operation 2.2 Engine Block and Cylinder Head 2.3 Piston, Connecting Rod and Crankshaft 2.4 Engine and Transmission Mounting 2.5 Valve System 2.1 工作原理 2.2 发动机体和气缸盖 2.3 活塞、连杆和曲轴 2.4 发动机和变速器组件 2.5 气门系统 Chapter 2 Internal Combustion Engine Automotive engineering English 2.6 Gasoline Fuel System 2.7 Diesel Engine 2.8 Engine Cooling 2.9 Engine Lubrication 2.10 Emission 2.6 汽油燃料系统 2.7 柴油发动机 2.8 发动机的冷却 2.9 发动机的润滑 2.10 排放 第二章 内燃机 Automotive engineering English Chapter 2 Internal Combustion Engine Automotive engineering English 2.1 Principle of Operation 2.1.1 Energy and power: Energy is used to produce power. The chemical energy in fuel is converted to heat by the burning of the fuel at a controlled rate. This process is called combustion. 21 工作原理 211 能源和动力 能源用于产生动力。燃料以控制的速率燃烧，燃料中的化学 能转换为热能。这个过程叫做燃烧。 Chapter 2 Internal Combustion Engine Automotive engineering English If engine combustion occurs within the power chamber, the engine is called an Internal combustion Engine. If engine takes place outside the cylinder, the engine is called an external combustion engine. 如果发动机燃烧发生在动力室内，这种发动机叫做内燃机。 如果燃烧发生在气缸外，这样的发动机叫做外燃发动机。 Chapter 2 Internal Combustion Engine Automotive engineering English Engines used in automobiles are internal combustion heat engines. Heat energy released in the combustion chamber raises the temperature of the combustion gases within the chamber. 汽车使用的发动机是内燃热发动机。在燃烧室内释放的热能 提高了室内燃烧气体的温度。 Chapter 2 Internal Combustion Engine Automotive engineering English The increase in gas temperature causes the pressure of the gases to increase. The pressure developed within the combustion chamber is applied to the head of a piston to produce a usable mechanical force, which is then converted into useful mechanical power. 气体温度的增加使气体的压力增加。在燃烧室内产生的压力 作用于活塞的顶部，产生机械力，这个力转换成有用的机械 动力。 Chapter 2 Internal Combustion Engine Automotive engineering English 2.1.2 Engine terms Linking the piston by a connecting rod to a crankshaft causes the gas to rotate the shaft through half a turn. The power stroke “uses up“ the gas, so means must be provided to expel the burnt gas and recharge the cylinder with a fresh petrol-air mixture: this control of gas movement is the duty of the valves; 活塞通过连杆和曲轴连接，使得气体带动曲轴旋转半圈。作功 冲程耗尽了所有的气体，这样就必须采取相应的措施排出废气 以及向气缸内充入新鲜的可燃混合气：气体的运动由气门来控 制. Chapter 2 Internal Combustion Engine Automotive engineering English 2.1.2: Engine Terms TDC（top dead center）: the position of the crank and piston when the piston is farther away from the crankshaft. BDC（bottom dead center）: the position of the crank and piston when the piston is nearest away from the crankshaft. Chapter 2 Internal Combustion Engine Automotive engineering English Chapter 2 Internal Combustion Engine swept volume: the volume between TDC and BDC. Clearance volume: the volume of space above the piston when it is at TDC. Engine capacity: this is the swept volume of all cylinders. Automotive engineering English Chapter 2 Internal Combustion Engine Automotive engineering English 2.1.3: The four strokes Spark-ignition Engine cycle Intake (induction) stroke Compression stroke Power stroke Exhaust stroke Chapter 2 Internal Combustion Engine Automotive engineering English Chapter 2 Internal Combustion Engine 2.1.4:Engine Overall Mechanics Crankshaft and connecting rods system Valve system Fuel system Ignition system Cooling system Lubrication system Starting system Automotive engineering English 2.2： Engine block and cylinder head Chapter 2 Internal Combustion Engine Automotive engineering English 2.2.1: Engine block: 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 galleries. The engine block also holds the crankshaft, which fastens to the bottom of the block. 气缸体是发动机的基体。发动机其它的部件都安装在缸体内 或 固定在缸体上，它包容了气缸、水套和油道，以及固定在缸 体 底部的曲轴等。 Chapter 2 Internal Combustion Engine Automotive engineering English 2.2.1: Engine block: The camshaft also fits inside the block, except on overhead-cam engine (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. Engine blocks are casting. Chapter 2 Internal Combustion Engine Automotive engineering English 2.2.1: Engine block: Some engine block, especially those in smaller cars, are made of cast aluminum. This metal is much lighter than iron. However, iron wears better than aluminum. Therefore, the cylinders in most aluminum engine are lined with iron or steel sleeves. These sleeves are called cylinder sleeves. Some engine blocks are made entirely of aluminum. Chapter 2 Internal Combustion Engine Automotive engineering English 2.2.1: Engine block: Chapter 2 Internal Combustion Engine Automotive engineering English 2.2.2: Cylinder sleeve: The dry sleeve can be cast in or pressed into a new block or used to recondition badly worn or damaged cylinders t