The Effects of Design Factors of the Combustion Chamber on Heat Balance in a Gasoline Engine

Measuring technique of the cooling loss in a gasoline engine was developed. Using this technique, the effect caused by swirl and squish in the cylinder and the material around the cylinder head on heat balance was examined. It was clarified that the effect for the shaft output Qw is small, but the effect for cooling loss Qc is large when gas flow and head material are changed, and much portion of the change of Qc seems to convert in exhaust loss Qex. Cooling loss from the exhaust port Qp is estimated to occupy over 40 % of cooling loss in the cylinder head side Qh.