Measurement of Piston Ring Lubricant Film Thickness in a Fired Engine using Ultrasonic Reflectometry
The lubricating film between piston rings and liners is crucial for correct and continued engine operation. With a worldwide drive to reduce emissions and reduce lubricant consumption in engines, whilst keeping wear to a minimum, understanding the lubricant film thickness has never been more important. Measurement of lubricant film thickness without disrupting the fluid film has been a significant challenge over the last number of decades. This paper presents a new technique for measurement of lubricant film thickness based on ultrasonic reflectometry. An ultrasonic sensor is mounted on the back of the component that is to be measured (for example, liner, bearing, piston ring, seal etc). The sensor is excited with a pulse of electrical energy and emits an ultrasonic wave into the components. The ultrasonic wave travels perpendicular to the sensor through the components. When the incident ultrasonic wave interacts with a thin embedded layer (in this case a lubricant film), some of the wave is reflected and some is transmitted. The reflected portion of the wave comes back to the sensor and is converted back to electrical energy. This electrical energy is amplified and acquired by an ultrasonic receiver and digitiser in a PC. The digitised signal is then processed in software to give a measure of the lubricant film thickness. The technique has been applied to a two stroke diesel engine under fired conditions. Ultrasonic sensors were mounted on the back of the piston ring and connected via cables through a linkage to external electronics. The film thickness over the entire stroke was measured and cyclic variations in the film observed. Results from the experiments are presented and discussed. Ultrasonic reflectometry is demonstrated to be a new technology that has exciting possibilities for many lubricant measurement and monitoring applications.
Phil Harper Matthias Stark
Tribosonics Ltd,UK W(a)rtsil(a) 2-Stroke Engines,Switzerland
国际会议
上海
英文
1-12
2013-05-13（万方平台首次上网日期，不代表论文的发表时间）