Local heat transfer in diesel combustion chamber converted to operate on natural gas and hydrogen

The conversion of diesel engines into gas engines is a promising way to solve environmental and energy problems. In this paper, we first posed and solved the problem of nonstationary local heat transfer in a diesel combustion chamber converted to run on natural gas and hydrogen. The main characteristics of the working process and local heat transfer in the converted engines with respect to the used alternative fuel are studied by 3D modeling of the internal cylindrical processes and the thermal state of the pistons. The measurements of nonstationary pressure in the cylinder and the local temperatures of the piston on a running engine are used to verify the mathematical models. It is established that the features of the working process, due to the transition to forced ignition of a homogeneous combustible mixture, significantly affect the magnitude and nature of the change and the distribution of local heat loads on the piston surface. Based on comparative analysis of the thermal state of the pistons of converted engines, practical recommendations are issued to ensure the efficient conversion of diesel engines to operate on gas fuels.