Development of a zero-dimensional Diesel combustion model. Part 1: Analysis of the quasi-steady diffusion combustion phase

The aim of this work is to identify and quantify the influence of injection parameters and running conditions on Diesel combustion. This theoretical–experimental analysis is the basis for the development of a zero-dimensional Diesel combustion model. The objective of this first part is to analyze the physical variables and processes that control the central phase of the quasi-steady Diesel diffusion combustion. For that purpose, a parameter as the apparent combustion time (ACT) characteristic of a diffusion combustion process has been used. This parameter allows to obtain explicit relations between, on the one hand, the injection rate law and in-cylinder conditions (air density, oxygen concentration…), and on the other hand, the rate of heat release. Results show a good correlation between the ACT and the instantaneous values of in-cylinder gas density, injection velocity, oxygen concentration and the nozzle diameter.