An extended Elrod-Adams model to account for backpressure and blow-by inception

摘要

The Piston-Ring-Liner system is the main tribological component of internal combustion engines. Hydrodynamic models are customarily used to numerically assess the performance of different ring designs and liner surface treatments. However, available models do not properly incorporate the backpressure boundary condition, which corresponds to the combustion chamber pressure and is quite significant. A new model is proposed here that imposes the combustion-chamber pressure in a mass-conserving and physically realistic way, together with an effective algorithm for its numerical approximation. The new model incorporates the pressure difference across the ring, which is shown to have a substantial effect on the predicted friction force and film thickness. The model is further elaborated so as to provide a criterion for predicting blow-by inception.