Measurements of Oil Film Thickness and Liner Temperature at Top Ring Reversal ina Diesel Engine

摘要

An investigation into factors influencing top-ring oil film thickness at TDC, ina diesel engine, was carried out using capacitance probes and surface thermocouples installed in the liner. Short term and long term trends in the data were observed, and many unexpected features were found. Significant, consistent differences in the film thickness around the cylinder were detected, and the thermocouples, showed that for this engine, the top ring unexpectedly cools the wall for a short time near TDC. Due to irreproducibility of the data, two different data acquisition techniques were used. Acquiring consecutive cycles, for a short period of time, provided a 'high solution snapshot' of the process. This method however, was not sufficient to characterize the data, and it was found that taking non-consecutive cycles, over a longer period of time, provided much more knowledge about the long term trends in the data. (JES)