A Study on the Oil Loss Past a Series of Piston Rings

A study was carried out on the mechanis, of oil loss past a piston ring series on account of its oil scraping ability. It was made clear that (1) oil scraping ability of the ring series was not given as the sum of each ring's ability and was attected by the mutual arrangement of rings in the series, (2) oil loss past the ring series was divided into two different parts : the one being a hydrodynamic loss nad the other a loss caused by the gas flow through the ring series, (3) the longer the length of the piston top land and the smaller the clearance between the piston and the cylinder wall was, the more effectively the oil loss was decreased, (4) to decrease the oil loss which was caused by the gas flow, oil scraping ability of the 2nd ring was much more important than that of top ring.