The piston of a car engine is one of the main components in the engine. It forms a piston group with piston rings, piston pins, and other parts, and together with the cylinder head, it forms a combustion chamber. It bears the force of gas and transmits power to the crankshaft through piston pins and connecting rods to complete the working process of an internal combustion engine. Due to the harsh working environment of high-speed, high-pressure, and high-temperature, as well as considering the smooth and durable operation of the engine, the piston must also have sufficient strength and stiffness, good thermal conductivity, high heat resistance, small coefficient of expansion (small size and shape changes), low relative density (light weight), wear resistance and corrosion resistance, and low cost. Due to the high demands and some conflicting requirements, it is difficult to find a piston material that can fully meet all the requirements. The pistons of modern engines are generally made of aluminum alloy because aluminum alloy has outstanding advantages such as low density and good thermal conductivity, but at the same time, it has disadvantages such as a relatively large coefficient of expansion and poor high-temperature strength. These disadvantages can only be met through reasonable structural design to meet usage requirements. So, the quality of a car engine depends not only on the materials used, but also on the rationality of the design.
