Operating indicators in diesels with reduced heat and energy losses

Abstract

Abstract The foregoing explains the experimentally established fact that in a heat-insulated diesel engine, diffusion combustion is of great importance - both in terms of the share of heat release and the duration of combustion. To compensate for the decrease in the efficiency of a thermally insulated diesel engine due to an increase in the duration of combustion, the injection advance is increased. The economic effect achieved in this way by increasing the maximum cylinder pressure cannot be considered due to thermal insulation. For typical compression end temperatures in a thermally insulated diesel engine, diffusion combustion, especially in the near-wall layers, is limited by transfer processes. This fact, in addition to the need to eliminate re-enriched zones in the near-wall layers, urgently requires additional turbulization of the working fluid during mixture formation and combustion in thermally insulated engines. The difficulty in solving this problem lies in the fact that one of the most important turbulence generators is the intake process, and one of the most effective solutions is special intake channels. However, the averaged motion and turbulence in the combustor decay significantly during compression. This process is enhanced in a thermally insulated diesel engine due to an increase in the molecular viscosity of the air. The same applies to the generation of turbulence at the end of compression-beginning of expansion. Thus, turbulization of the charge in the combustion chamber of a thermally insulated diesel engine is an urgent problem.