Piston-type aircraft engines evolved from piston engines used in automobiles.
Due to their high rotational speed and large piston acceleration, the requirements for piston strength are extremely stringent. While the close fit between the piston and cylinder improves energy efficiency, it also leads to wear on the cylinder walls.
Recent simulation studies (2026) have shown that by altering the piston's motion characteristics-increasing its upward velocity and shortening its residence time near top dead center-the tendency and intensity of engine knock can be significantly reduced. Utilizing optimized piston motion characteristics, coupled with a high compression ratio of up to 14, the engine's thermal efficiency can be improved to some extent.
