What does the CYPR mark on the first gas ring of piston ring mean?

Making the piston skirt oval is called anti-oval design, which is one of the methods to prevent the piston skirt from deformation. The main function of piston skirt is to guide and bear lateral force, so the design requirement of piston skirt is to ensure the fit clearance with cylinder. In the early days, the piston skirt was made into a right-angled circle, but when the engine was running, the piston skirt and the cylinder often had the phenomenon of hair pulling in the direction of the piston pin, which was mainly caused by the large deformation of the axis of the skirt pin at work. When the piston works in the engine, the piston will produce three kinds of deformation in the direction of the pin shaft of the skirt: lateral force. It is the surface of the skirt that bears the lateral force, so the skirt tends to flatten and its size increases in the direction of the piston pin. Fracture pressure and inertia force at the top of piston. The joint action of these two forces makes the top of the piston bend within the span of the piston pin, which makes the size of the whole piston larger in the direction of the piston pin seat. Thermal expansion caused by high temperature. Among them, the piston pin seat part has thicker wall thickness and greater stiffness than other parts, so it is more deformed when thermal expansion occurs.