Variations in piston second land pressure as a function of ring gap position

Abstract

The inter-ring pressure and the potential reverse blow-by flow that can drive oil towards the combustion chamber can strongly influence the in-cylinder oil consumption in diesel engines. This paper reports on an experimental investigation of the effect of both cycle-to-cycle variations and variations over a longer period on inter-ring pressure. The inter-ring pressure and piston ring movement were also simulated as a function of ring gap position. The experimental part of the project showed small cycle-to-cycle variations in the second land pressure as well as large variations over time. Simulations of the second land pressure with different ring gap positions showed a similar range of variation in second land pressure as the experimental variation. © 2010 IMechE.