The Verification of Engine Analysis Model Accuracy by Measuring Oil Film Pressure in the Main Bearings of a Motorcycle High-Speed Engine Using a Thin-Film Sensor

Abstract

To improve the accuracy of the calculation analysis of crank journal bearings in motorcycle engines and accurately understand lubrication conditions, the oil film conditions of actual crankshafts and journal bearings should be measured. This research study focuses on the oil film pressure generated in the main bearing, and by using an original thin-film pressure sensor with improved durability achieved through the use of DLC (Diamond-like Carbon), it was possible to perform experiments at a maximum of 13,000 rpm and full load, which was not possible before. This established a method for measuring the oil film pressure generated in the main bearing of a high-speed motorcycle engine during operation without changing the surrounding environment. The maximum oil film pressure was 140 MPa, and the oil film pressure generated by each main bearing was successfully measured under different experimental conditions. The timing of pressure onset agreed well between the calculation and experiment stages, but the peak oil film pressure values were different. By varying the temperature of the engine in the calculation model, the calculated values approached the measured values. In the future, we plan to investigate ways to improve the accuracy of the current analytical model.