Heat Flow Through Piston Rings and Its Influence on Shape

Apart from its many other functions, the piston ring also has the task of dissipating heat from the piston to the cylinder wall. This heat flow alters the contact pressure of the piston ring against the cylinder and can result in a lack of effective sealing with extremely high pressure at the ring ends. The work presented in this paper enables the effect of the heat flow on the ring shape as a function of piston ring material and dimensions to be calculated from the temperature difference between piston and cylinder wall and to integrate these findings into the manufacturing process, i.e., noncircular shaping. This makes it possible for the first time to produce piston rings that do not have the disadvantages in engine application of the uncontrolled thermal deformation -scuffing marks and leakage at the ring ends.