Variation of Heat Flux through a Combustion Chamber Wall of Pre-chamber type Diesel Engine : Heat Flux through Piston Crown, Cylinder Head, Suction Valve, Exhaust Valve, Pre-combustion Chamber and Exhaust Port Wall

Abstract

The heat flux through the combustion chamber wall varies periodically with thermodynamical cycle of engine and locally according to various places of the wall. In this research project the heat flux was measured at the walls of piston crown, cylinder head, suction valve, exhaust valve, pre-combustion chamber and exhaust port, and the result was compared with the calculated value of heat loss based on cooling water. The heat flux at any point and at any period during the cycle depends on gas temperature, the surface temperature of wall and gas flow. Especially, it is affected by a jet flow from the pre-chamber and the arrival of a burning flame at these points. The percentage of heat loss from piston crown is about 7%, from cylinder head 4%, from prechamber wall 4%, from suction valve 1%, from exhaust valve 0.5% and from exhaust port 5% of the heat energy supplied by fuel at full load.