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The measurement of liner - piston skirt oil film thickness by an ultrasonic means

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posted on 06.09.2011, 08:59 by R.S. Dwyer-Joyce, D.A. Green, Sashi Balakrishnan, P. Harper, R. Lewis, S.J. Howell-Smith, Paul KingPaul King, Homer Rahnejat
The paper presents a novel method for the measurement of lubricant film thickness in the piston-liner contact. Direct measurement of the film in this conjunction has always posed a problem, particularly under fired conditions. The principle is based on capturing and analysing the reflection of an ultrasonic pulse at the oil film. The proportion of the wave amplitude reflected can be related to the thickness of the oil film. A single cylinder 4-stroke engine on a dyno test platform was used for evaluation of the method. A piezo-electric transducer was bonded to the outside of the cylinder liner and used to emit high frequency short duration ultrasonic pulses. These pulses were used to determine the oil film thickness as the piston skirt passed over the sensor location. Oil films in the range 2 to 21 μm were recorded varying with engine speeds. The results have been shown to be in agreement with detailed numerical predictions.



  • Mechanical, Electrical and Manufacturing Engineering


DWYER-JOYCE, R.S.....et al., 2006. The measurement of liner - piston skirt oil film thickness by an ultrasonic means. SAE Technical Paper 2006-01-0648


© 2006 SAE International


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Copyright © 2006 SAE International. This paper is posted on this site with permission from SAE International, and is for viewing only. Further distribution and use of this paper is not permitted without permission from SAE. This paper was part of 2006 World Congress, Detroit, Michigan, April 3-6, 2006



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