Flash temperature and anti-wear tribofilm growth mechanisms by asperity contact in top-ring/liner conjunction of IC engines. (June 2020) - Pu, Wei
Abstract: Understanding the growth mechanism of tribofilms at the top of the liner in IC engines is of great importance to protecting the sealing function of the top ring. In present study, the transient heat transfer is investigated between the ring and the liner in the top dead center (TDC) area with considerations of asperity contact pressure, boundary friction coefficient and reciprocating piston motion. A 3D transient model is developed to predict the evolutions of effective heat partition and conduction between the contact surfaces. It is revealed that the flash temperature in the asperity contact pairs of the top-ring/liner conjunction is remarkably higher than the steady-state liner temperature, therefore significantly enhancing the growth rate of anti-wear film formation based on a stress-activated Arrhenius model. The results show that the asperity contact model and the flash temperature model can be employed as an engineering tool for anti-wear tribofilm prediction in top-ring/liner conjunction of IC engines. Highlights: A 3D transient model is developed to predict the evolutions of effective heat partition and conduction between the contact surfaces. The transient heat transfer between the ring and the liner in the top dead center (TDC) area is investigated with considerations of asperity contact pressure, boundary friction coefficient. The results show that the flash temperature effect is more important than the asperity contact pressure for tribofilm growth in the top-ring/liner conjunction due to relatively low contact pressure.