Abstract
The piston rings, the engine sliding parts, are required to further contribute on mechanical loss reduction in order to improve fuel economy. However, many cases of the abnormal combustion due to the oil upward flow, as well as the increase in oil consumption are been reported. It is widely known that the cylinder bore shape during the actual operation, and the distribution of the sliding surface pressure in between the piston ring and the cylinder bore largely influence the oil flow via the sliding surface of the piston ring. Accordingly, verification of the sliding surface pressure during the actual operation is necessary in order to elucidate the mechanism of oil consumption. The thin film sensor is widely used as a measurement method of the sliding surface pressure between two different faces, however this method has never been applied to the piston ring in the past. For application of thin film sensing technique, Authors, through the examination of film deposition methods, succeeded in forming the thin film sensor with a total thickness of 4-5 micron by the sputtering method on the sliding surface of the piston ring. In addition, by improvement of the each device of the measurement system, the noise reduction of the measurement system was developed and the signal noise ratio could be greatly improved. Furthermore, it was confirmed that the thin film pressure sensor, was developed in this study, is able to perform as a sensor for measurement of the piston ring sliding surface pressure.
