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Radiation heat transfer, apart from convection, is an important mode of heat transfer in diesel engines. In the paper a method for calculation of radiative heat flux distribution on the walls of the combustion chamber has been presented. Shape and volume of the burned zone as well of the combustion chamber are varying according to variation in a crank angle during the whole combustion process. Analysis of influence of degree of the burned zone transparency and value of the crank angle on radiative heat flux distribution has been presented and discussed. It allowed to find out that different parts of the combustion chamber may be differently thermally loaded.

An experimental study was conducted in order to determine some heat transfer coefficients and to measure temperatures and heat fluxes in exhaust valves of 4C90 diesel engine. Measurements were performed both on a model stand and on a firing engine. The experimental stand for model studies was built with use of 4C90 engine parts. The thermal contact conductance between a valve face and a seat as a function of mechanical load was determined. Heat transfer between valve face and seat and between valve stem and guide was measured in some range of valve gear speed. The temperatures and heat fluxes, measured in exhaust valves and valve seat of firing 4C90 diesel engine, were presented as a function of its torque and speed.