车辆工程专业英语.pdf

Unit 2 The Basic Principle of Engine Text A Classification and Main Components of Engine 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. 9 1 2 8 3 4 7 6 5 Fig.2.1 Internal Combustion Engine 1—the cap of the cylinder head 2—valve 3—engine block 4—flywheel 5—crankshaft 6—oil pan 7—pulley 8—cylinder 9—timing gear Classification of Engine The engine can be classified in following ways:  By Fuel System Gasoline engine and diesel engine are used. In a gasoline engine, the air-fuel mixture is exploded in the engine. A diesel engine uses diesel fuel. It generates high power at low speeds. The fuel efficiency is better than that of a gasoline engine. Unit 2 The Basic Principle of Engine  By Cylinder Arrangement Most cars have more than one cylinder. Four, six and eight cylinders are common used. In a multi-cylinder engine, the cylinders are usually 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 (