Technical Paper
Characterization of the Oil Film Behaviour Between the Liner and Piston of a Heavy-Duty Diesel Engine
1993-10-01
932784
An optical technique using laser-induced fluorescence (LIF) has been developed to measure the oil film thickness between a fixed point on the cylinder-liner and the piston of a single-cylinder diesel engine. Details are presented of an experimental layout for acquiring fluorescence data from the engine and a strategy for their conversion to oil film thickness. Engine tests have shown that the oil film thickness in the liner/piston contact depends critically on the temperature dependence of the oil viscosity and hence is sensitive to the engine's speed and torque output condition. Oil film thickness measurements were made for two fully formulated lubricants, a 15W/40 Universal Diesel Engine Oil (UDEO) and a 10W/30 Super High Performance Diesel Oil (SHPDO). From these oil film thickness measurements the analysis was extended so as to estimate the oil volumes present between the cylinder-liner and different portions of the piston as they pass the measurement point.