Abstract
To investigate the effects of the piston ring rotation on a lubricant oil consumption rate and a thermal load of piston, ring gap positions, piston temperatures and oil consumption rate are measured simultaneously. The locations of a piston ring gap are measured by the radio-tracer method, and an oil consumption rate is measured by analyzing a CO2 concentration of exhaust gases in a hydrogen fuel engine. A piston temperature is also measured by thermocouples and scissors-type linkage system in a direct injection diesel engine. From these experiments, following facts are concluded. 1) The relative position of each ring gap is the dominant factor of dynamic changes of oil consumption rate. An oil consumption rate, when two ring gaps are located in the same angular position, is 2-3 times higher than that when those are separated by 180 degree. 2) The fluctuations of a piston temperature are mainly affected by the top ring gap position irrelevant to the second ring gap position. A piston temperature can fluctuate around 12-15##o##C according to the top ring gap position.