2冲程和4冲程有什么区别（Whats the difference between a 2 stroke and a 4 stroke）.doc

2冲程和4冲程有什么区别（Whats the difference between a 2 stroke and a 4 stroke） First, the structure is different The thermal part of two stroke motorcycle is mainly composed of cylinder head, cylinder, piston, piston ring and other parts. The main part of the four stroke motorcycle consists of the cylinder head, the cylinder head, the cylinder, the piston, the piston ring and the valve train. The valve train comprises a valve, an air valve guide, an air valve seat, a valve spring, an air distribution cam, a gas distribution chain, a gas distribution sprocket, a chain tensioner, a rocker arm and other parts. Comparatively speaking, the two stroke motorcycle is smaller than the four stroke motorcycle, has the advantages of simple structure, light weight, and convenient manufacture and maintenance. Two, the work process is different In order for the engine to work and burn continuously, a series of actions are required to be repeated in a certain order. First, the mixture is sucked into the cylinder, and the gas is compressed to produce expansion, and the combustion gas is expelled from the cylinder. Thus, the four processes of air intake, compression, combustion, and exhaust are repeated as the cycle of the engine. Two stroke engine crank rotation 360 degrees to complete a work cycle, that is, crank rotation, engine combustion work once, it is on the cylinder wall of the scavenging air port, exhaust port to complete the process of intake and exhaust (Figure 2). Four stroke engine crank rotation 720 degrees to complete a work cycle, that is, crank rotation two times, the engine combustion work once, it is by the air distribution cam to control the intake and exhaust valve to complete the process of intake and exhaust. The two stroke engine crank rotates a circle a, four stroke engine crank rotation two to do a work, so the two stroke engine four stroke engine torque is uniform; at the same rotational speed of the crankshaft and the same working volume under the condition that th