Piston is the "heart" of the automobile engine, to withstand alternating mechanical and thermal loads, one of the key parts of the worst working conditions in the engine.The function of the piston is exposed to gas pressure, and transmitted via a piston pin to connecting rod driven by the crankshaft rotates, the top of the piston or the combustion chamber part.
    Piston types are generally divided into: diesel engine piston, gasoline piston, Universal piston.
    The function of the piston is exposed to gas pressure, and transmitted via a piston pin to connecting rod driven by the crankshaft rotates, the top of the piston or the combustion chamber part. The working conditions piston work in high-temperature, high-pressure, high-speed, poor lubrication conditions. Pistons direct contact with high temperature gas instantaneous temperature up to 2500K therefore, heated serious, and cooling conditions poor, so the piston work when the temperature is high, the top of the up to 600 ~ 700K, and the temperature distribution is very uneven; piston top bear gas pressure, in particular the greatest pressure, as a power stroke gasoline up to from 3 ~~ 5 MPa, diesel engine up to 6 to 9MPa, which makes the piston an impact, and to withstand the side pressure; piston within the cylinder at a high speed (8 ~ 12m / s) reciprocating motion, and the speed in the constantly changing, which produced a large inertial force, the piston subject to significant additional load. The work of the piston in such harsh conditions, will produce a deformation and accelerated wear, but also produce the additional load and thermal stress, while by the chemical corrosion of the gas.