More than twice as much. According to the analysis of the answers to the training questions of factory and truck inspectors, the lifting speed of the fork of the secondary gantry is twice as high as the vertical speed of the cylinder piston. Piston is a reciprocating component in the cylinder block of automobile engine. The basic structure of piston can be divided into top, head and skirt. The piston crown is the main part of the combustion chamber, and its shape is related to the selected combustion chamber form. Gasoline engines mostly use flat-topped pistons, which have the advantage of small heat absorption area.