Oil consumption of an engine causes particulate matter, poisoning catalysts and sometimes abnormal combustion like pre-ignition. One of the factors of oil consumption is oil transport via a piston ring-gap. Coincident of ring-gaps at a same position may cause an increase in oil consumption.
In this research, the effect of coincident the ring gaps on oil consumption was measured using with/without the a stopper pin for the ring rotation by sulfur tracer method. A lot of spikes was found in the wave form of sulfur concentrate for the rings without the stopper pin, and higher value of oil consumption was simultaneously measured. Then the force which caused ring rotation (hereafter ‘rotational force’) was measured by a newly developed method. A cantilever was installed in the ring gap, and the strain gauges were pasted on the cantilever. Therefore, the rotational force was measured as the bending stress of the cantilever. It was found that the rotational force showed a periodic wave form against the crank angle. Furthermore, it was also found that the amplitude of the rotational force was strong affected by the engine operating conditions. The rotational force was also affected by the gap position. It was assumed that not only the piston lateral motion but also the cylinder bore shape affected the rotational force. The mechanism of generating the rotational force is the future subject.