Title: Oil starvation in piston ring pack for an SI engine

Authors: Sungwoo Cho

Addresses: School of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea

Abstract: 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.

Keywords: FMEP; friction mean effective pressure; friction forces; oil starvation; piston ring; ring pack; SI engines; spark ignition engines; flooded lubrication; compression rings; oil control ring; hydrodynamic lubrication.

DOI: 10.1504/IJVD.2005.008464

International Journal of Vehicle Design, 2005 Vol.39 No.4, pp.299 - 310

Published online: 21 Dec 2005 *

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