Investigation on lubrication condition of piston pin in real engine block with ultrasonic technique
Investigation on lubrication condition of piston pin in real engine block with ultrasonic technique
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DOI：
10.1002/ls.159
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发表时间：
2011-11
影响因子：
1.9
通讯作者：
A. Takeuchi
中科院分区：
文献类型：
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作者：
A. Takeuchi
通过测量由安装在圆柱形活塞销中的超声探头检测的回波高度，对在低转速下操作的真实的汽车发动机缸体中的活塞销和销毂之间的润滑条件的变化进行现场观察，例如在发动机的激活期间。通过从活塞销表面反射的回波高度比，可以在1 µm的精度内直接估计油膜厚度。包含气泡的条件下的反射波的振幅（回波高度）比不包含气泡的条件下的反射波的振幅（回波高度）高，并且波的相位接近于干燥条件下的波的相位。因此，可以检测活塞销和销座之间的气穴现象。特别是，在300 rpm运行下，在上冲程中的反推力侧连续观察到气穴。然而，至少清楚的是，在稳定条件下支撑负载的活塞销的推力侧中的润滑条件足以维持安全操作，因为即使对于低旋转速度，也在推力侧处形成没有空腔的连续油膜。版权所有© 2011约翰威利父子有限公司.
In situ observations of variations in the lubrication conditions between a piston pin and a pin boss in a real automotive engine block operating under low rotational speeds, such as during activation of the engine, were carried out by measuring the echo height detected by an ultrasonic probe installed into the cylindrical piston pin. It was possible to estimate the oil film thickness directly within an accuracy of 1 µm by the echo height ratio reflected from the piston pin surface. The amplitude of the reflected wave (echo height) under the condition including an air bubble was higher than that without an air bubble, and the phase of the wave approached that of the dry condition. It thus became possible to detect cavitation between the piston pin and the pin boss. In particular, cavitations were continuously observed at the anti‐thrust side in the upstroke under 300 rpm operation. However, it was at least clarified that the lubrication condition in the thrust side of the piston pin supporting a load under a stable condition was sufficient to maintain safe operation, since a continuous oil film without a cavity was formed at the thrust side even for a low rotational speed. Copyright © 2011 John Wiley & Sons, Ltd.