Piston Slap Noise of Indirect Combustion Diesel Engine

Diesel trucks have four major noise sources engine, cooling fan, exhaust systems and tyres.

It is generally found that on current trucks engine radiated noise is the most important source, the latter being mainly produced by piston slap. Particularly for reducing the noise of IDI engines, where combustion noise is comparatively low, control of piston slap is most important.

This paper gives some calculated results to predict piston behavior and compares them with measured information on engine noise and cylinder liner vibration where piston slap control measures have been taken.

From the experiments carried out at Mitsubishi Motors Corporation it is concluded that offsetting the piston pin is both the easiest and cheapest method of controlling piston slap on current production engines.