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Hydrodynamic pressure under a piston ring


CASTLEMAN postulated1 that the lubrication of piston rings might be hydrodynamic. Recently it has become possible to measure the oil film thickness directly, using a capacitance transducer2. Oil film thicknesses of the order of 1 µm have been measured in a small diesel engine: theory predicts thicknesses of the order of 10 µm. To investigate this discrepancy it was decided to measure the pressure in the oil film, since this provides an independent check on the theory.

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  1. Castleman, R. A., Physics, 7, 364–367 (1936).

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  2. Hamilton, G. M., and Moore, S. L., Proc. Inst. Mech. Eng., 188, 253–268 (1974).

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BROWN, S., HAMILTON, G. & MOORE, S. Hydrodynamic pressure under a piston ring. Nature 253, 341–342 (1975).

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