Analysis of the Influence of Injection Rate and Running Conditions on the Heat Release Rate in a D.I. Diesel Engine

The aim of this paper is to identify and quantify the influence of injection parameters and running conditions on the air/fuel mixing and diffusion combustion process in a D.I. Diesel engine. With this work, it is intended to improve the understanding of some of the processes that take place in the combustion chamber of D.I. Diesel engines. An analysis of the relationship between the injection rate and the rate of heat release through the physical variables that directly participate in the injection-combustion process is performed.

To approach the problem, a parameter called “Apparent Combustion Time (ACT)” is defined. A theoretical analysis that allows the identification and quantification of the main physical variables that directly affect the air/fuel mixing process has been performed. This theoretical approach enabled to find out the relationship between the ACT and the injection and in-cylinder conditions in the diffusion combustion phase. This theoretical analysis has been compared with the results obtained from an experimental parametric study.