Abstract
A wide experimental programme was developed on the engine test bench of the Dipartimento di Macchine, Sistemi Energetici e Trasporti of the University of Genova, in order to analyse the influence of turbocharger and exhaust gas recirculation control on combustion characteristics of an automotive turbocharged DI Diesel engine and to develop correlation for the evaluation of heat release rate and mechanical losses. Indicated pressure diagrams were measured in different engine part and full load operating conditions, for different settings of turbine waste-gate and EGR valves opening degrees, and heat release rate evaluation allowed to outline the influence of these control variables. Experimental heat release rates were then used for the development of a single zone combustion correlation, whose coefficients are expressed as functions of engine operating parameters such as engine speed, gas-fuel ratio and ignition delay, while in-cylinder pressure diagrams allowed to evaluate indicated mean effective pressure values, mechanical losses and efficiency; mechanical losses were then linked to mean piston speed and in-cylinder maximum pressure in a simple correlation for their calculation.
In the paper the analysis of the influence of turbocharger and EGR control on combustion is focused, while correlation are proposed, comparing calculated values of heat release, in-cylinder pressure and mechanical losses to experimental data.