It forms a piston group with piston rings, piston pins and other parts, and forms a combustion chamber with the cylinder head. It bears the pressure of the gas, transmits power to the crankshaft through the piston pin and connecting rod, and completes the working process of the internal combustion engine.
The top of the piston is the main part of the combustion chamber, and its shape is related to the selected combustion chamber form. The piston, piston ring, piston pin, connecting rod and connecting rod bearing constitute the piston-connecting rod group. The piston-connecting rod group, as a transmission component of the
New Car engine, converts the reciprocating motion of the piston into the rotational motion of the crankshaft, which acts on the piston. The power of the crankshaft is converted into the driving force for the rotation of the external output wheel of the crankshaft.
The piston must be able to withstand the high temperature of combustion and the heat generated by friction, and can slide freely in the cylinder. Otherwise, the New Car engine will overheat and may be "stuck". On the contrary, if the fit clearance is too large, the piston will shake and hit.
The piston works under high temperature, high pressure, high speed and poor lubrication. The piston is in direct contact with the high-temperature gas, and the instantaneous temperature can reach more than 2500K, with serious heat generation and poor heat dissipation conditions. Therefore, the temperature of the piston is very high when working, up to 600-700K at the top, and the temperature distribution is very uneven.
The top of the piston of a
Fuel Car is subjected to a large amount of gas pressure, especially the pressure of the power stroke, which is as high as 3-5M Pa for Fuel Car engines and 6-9M Pa for diesel engines, which makes the piston impacted and subjected to lateral pressure.
The piston of a Fuel Car reciprocates at a very high speed (8-12m/s) in the cylinder, and the speed is constantly changing, generating a large inertial force, which makes the piston bear a large additional load. Working under such harsh conditions, the piston will deform, accelerate wear, generate additional loads and thermal stress, and be chemically corroded by the gas.
