Piston is the "heart" of automobile engine. It bears alternating mechanical load and thermal load. It is one of the key parts in the engine with the worst working conditions. The function of the piston is to bear the gas pressure and pass it to the connecting rod through the piston pin to drive the crankshaft to rotate. The top of the piston is also a part of the combustion chamber.

Piston is a reciprocating part in the cylinder block of automobile engine. The basic structure of piston can be divided into top, head and skirt. The top of the piston is the main part of the combustion chamber, and its shape is related to the type of combustion chamber selected. Flat top piston is widely used in gasoline engine, which has the advantage of small heat absorbing area. There are many kinds of pits on the top of the piston of diesel engine. The shape, position and size of the pits must meet the requirements of mixture formation and combustion.

Source: @dopeydraws