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Abstract

This study aims to develop an algorithm for designing the piston ring profile and pressure distribution using an inverse method. The proposed algorithm needs to obtain load and boundary conditions for estimating not only a smooth curve in the piston ring profile, but also in the pressure distribution. The algorithm is developed from Reynolds integral and force balance equations. The least-squares error method, variational method, Gauss-Seidel method and Newton-Raphson method are employed to calculate the piston ring profile. Simulation results reveal that the greater the degree of the polynomial function used, the greater the maximum pressure ( Pmax ), load and friction coefficient are, and the smaller the minimum film thickness ( H min ) is. However, as the degree of the polynomial function and the number of grid points increase, the estimated piston ring profile and pressure distribution become more accurate. The initial guessed values of the coefficients of the estimated piston ring profile (Cj ) and the position of maximum pressure ( X m ) have more obvious effects upon the present algorithm. The initial guessed value of Cj can allow greater error than that of X m when estimating Pmax and H min using the present algorithm. Consequently, the present algorithm is capable of providing accurate results in terms of piston ring profile and pressure distribution.

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