2. Gas/wall energy exchanges

A significant proportion of the power released by combustion of the fuel mixture is lost through heat exchange between the gas and the engine walls, and ends up in the coolant (water power). This proportion varies according to the engine's operating point and thermal state. These exchanges are of the convective and radiative type, and take place in different parts of the engine. Firstly, within the combustion chamber, between the combustion gases and the liner, cylinder head and piston walls, but also within the cylinder head with the intake and exhaust gases.