Measurement of the Oil Film Thickness Between the Cylinder Liner and the Piston Rings in a Heavy Duty Directly Injected Diesel Engine 952469

An electrical capacitance measuring method has been used to obtain the cylinder liner oil film thicknesses for various speeds and loads in a heavy duty directly injected diesel engine.
Interesting facts have been observed:
  • Increased oil film thickness for the top ring distance to wall during idling.
  • A gas pocket appearing between top ring and liner at increasing speeds and loads
  • movement of the piston in the liner when combustion sets in, the motion is not parallel.
  • temperature seems to have little effect on the oil film thickness.
A computer model of the top ring showed good conformance with the measurements over the speed and load range, but the calculated oil film thickness is about 3 to 6 times higher.


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