A Development of Measurement System for Piston Ring Sliding Surface Pressure 2018-32-0022
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. Engine Lubricating oil consumption causes particulate matter, a negative effect on engine after treatment devices, and an increase in users running cost. Furthermore, a negative effect on combustion is reported recently. Therefore, elucidation of the mechanism of those phenomena is still an urgent task. It is widely known that the cylinder bore shape during the actual operation, and the distribution of the sliding face pressure in between the piston ring and the cylinder bore largely influence the oil flow via the sliding face of the piston ring. However, there are many unclear points about the conformability of the piston ring to the cylinder bore and the behavior of the lubricating oil around 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. Authors, through the examination of film deposition methods, succeeded in forming the Thin Film Sensor with a total thickness of 4-5mm by the sputtering method on the sliding face of the piston ring. Additionally, it was confirmed that the output property of thin film sensor formed on the piston ring is equivalent to them of thin film sensor formed on test piece. Furthermore, for expanding the measurement range into the lower pressure range, the noise reduction of the measurement system was developed and the signal noise ratio could be greatly improved compared with the measurement system of the conventional.