Oil starvation in piston ring pack for an SI engine

摘要

The friction forces of piston rings for a typical spark ignition engine under flooded lubrication were measured independently by using a floating liner system. The friction forces of a ring pack, which consisted of two compression rings and an oil control ring, were also measured. The oil starvation in the ring pack was observed by comparing the friction force of ring pack and the sum of friction forces of the individual rings. The friction force of each ring in the ring pack was calculated from the friction forces of ring combinations. The oil starvation of each ring was estimated by comparing the friction forces in a ring pack and the friction forces measured independently under oil flood conditions. The oil starved on the compression rings when the hydrodynamic lubrication was dominant in mid-stroke. Oil starvation was severe especially on the top ring. Oil starvation slightly increased the frictional loss of the ring pack under steady operating conditions.