Oil film thickness measurement system of crankshaft based on ultrasonic reflection signal
ZHANG Yun1, LIANG Guangshun1, CAO Cong2, TANG Zhiyong3
1. Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China; 2. School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China; 3. Neijiang Jinhong crankshaft Co., Ltd., Neijiang 641000, China
Abstract：The performance of an internal combustion engine is related to the lubrication state of the crankshaft. In this paper, a thickness measurement system is developed using an ultrasonic reflection signal to monitor the change of oil film thickness in real time. Based on acoustic theory, the relationship between oil film thickness and acoustic reflection coefficient in multilayer media is derived, and the application methods of the spring, resonance, and phase shift models are given. For the crankshaft, the oil film thickness ranges from 0 to 50 μm, an ultrasonic double crystal straight probe with a center frequency of 1.056 MHz is used to generate and receive the ultrasonic signal, and a long axis with four annular grooves with different depths is processed to obtain the functional relationship between the oil film thickness and the spectral peak of the acoustic reflection signal. To calculate the oil film thickness, the fitted linear model is embedded into LabVIEW software. The test shows that the relative error of the measurement system is less than 10%, and the oil film thickness can be measured well.
张云, 梁光顺, 曹聪, 唐志勇. 基于超声波反射信号的曲轴油膜厚度测量系统[J]. 清华大学学报（自然科学版）, 2022, 62(9): 1484-1491.
ZHANG Yun, LIANG Guangshun, CAO Cong, TANG Zhiyong. Oil film thickness measurement system of crankshaft based on ultrasonic reflection signal. Journal of Tsinghua University(Science and Technology), 2022, 62(9): 1484-1491.
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2022, Vol. 62 
