Heat Transfer in a Piston of a Four Stroke Diesel Engine

A design tool for analyzing heat flow rates through pistons is presented.

Tests on a Petter PJIW engine were carried out over a range of conditions covering different fuel inputs, speeds, boost pressures and intake temperatures. The steady state temperatures were determined by stainless steel inserts and these, with an aid of an electrolytic analogue, provided isothermal plots of a PJIW piston. The isotherms were optimized numerically by a two-dimensional relaxation program giving master temperature and heat flux patterns that are valid for all engine conditions.

The calculated mean heat transfer rates through the piston tend to support the trends suggested by Annand's semi-analytical correlation.