Piston effect

Piston effect

With the automobile engine power, economic, environmental protection and reliability requirements are more and more strict, piston has developed into a set of lightweight and high strength new materials, special cylindrical compound surface, special pin hole and other new technologies in one of the high-tech products, to ensure the heat resistance, wear resistance, smooth directivity and good sealing function of the piston, Reduce engine friction work loss, reduce fuel consumption, noise and emissions. In order to meet the above functional requirements, the outer circle of the piston is usually designed as a special shape outer circle (medium convex variable ellipse), that is, the cross section perpendicular to the axis of the piston is ellipse or corrected ellipse, and the ovality varies along the axis according to a certain rule (as shown in Figure 1), with the ovality accuracy up to 0.005mm. The external profile of piston profile is the fitting curve of higher order function, and the contour accuracy is 0.005 ~ 0.01mm. In order to improve the bearing capacity of piston and lift power of engine, pin holes of high-load piston are usually designed as micro inner cone type or normal stress curved type (special type pin holes). The size accuracy of pin holes is up to IT4 level, and the contour accuracy is 0.003mm.