汽车英语Engine.ppt

2.2： engine block and cylinder head  Basic words（１） 2.3 　piston, connecting rod and crankshaft Piston : Crank arrangement of engines: Torsional vibration balancer: * SEA—Special English for Automobile CHAPTER 2 INTERNAL COMBUSTION ENGINE * Review 1: 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. 2.1: principle of operation Stroke: the distance between BDC and TDC; stroke is controlled by the crankshaft. Four-stroke Two-stroke swept volume: the volume between TDC and BDC. Bore: the internal diameter of the cylinder. engine capacity compression ratio Clearance volume: the volume of space above the piston when it is at TDC. Engine capacity: this is the swept volume of all cylinders. Compression ratio: (swept vol+clearance vol) / (clearance vol) The spark-ignition engine is an internal –combustion engine with externally supplied in ignition, which converts the energy contained in the fuel to kinetic energy. The cycle of operations is spread over four piston strokes. To complete the full cycle it takes two revolutions of the crankshaft. 火花点火式发动机是一个外部提供点火的内燃发动机，它把燃料中的能量转化成动能． 工作循环分布在活塞的四个行程，完成整个行程曲轴需要转两周． Intake(induction) stroke Review 2: List the four strokes of a four-stroke engine . Compression stroke Power stroke Exhaust stroke Crankshaft and connecting rods system Review 3: List the main systems of a gasoline engine . Valve system Fuel system Ignition system Lubrication system Cooling system Starting system Energy and power: Engines used in automobiles are internal combustion heat engines. They convert the chemical energy of the gasoline into heat within a power chamber that is called a combustion chamber. Heat energy released in the combustion chamber raises t