AVERAGE HEAT TRANSFER COEFFICIENTS ON A CYLINDER WALL IN THE INTAKE AND EXHAUST PROCESSES OF MOTORING TEST.

Abstract

The analysis of a gas exchange process by computer simulations of an engine cycle shows that the total amount of heat transferred from a cylinder wall during the intake process is related to the product of volumetric efficiency and an average gas temperature in an inlet port, independent of the heat transferred in the exhaust process. An average heat transfer coefficient in an intake process is obtained on this principle, based on the result that the calculated volumetric efficiency agrees very well with the experimental value under the condition that the heat transfer is negligible. An average heat transfer coefficient in the exhaust process obtained from an average exhaust gas temperature is less than that in the intake process over most of the engine speed range tested.