Heat release model for the combustion of diesel oil emulsions in DI diesel engines

Abstract

Diagnosing the combustion process in internal combustion engines using cylinder pressure, fuel delivery pressure and injector needle lift data is a well-established and widely used procedure in engine and fuel performance tests. Of the models developed, the first law single zone is the simplest and easiest tool to use for quick preliminary analysis of engine performance. It can yield valuable information about the effect of engine design changes, fuel injection system, fuel type and engine operating conditions on the combustion process and engine performance. The model described in this paper is based on a model designed for both SI and CI engines burning liquid and gaseous hydrocarbon fuels. In its current form, the model can be used for diesel engines burning water/diesel emulsions and allows for the effect of the presence of “inert” water in the combustion products on the ratio of specific heats and heating value of the fuel. The output from the model includes the apparent heat release, fraction of fuel burned, fuel burning rate, heat losses, indicated parameters and average gas temperature. Some results of analysis of the performance of a DI diesel engine burning a standard diesel fuel (referred to in the texts as certified diesel fuel CDF, or simply diesel fuel) and diesel oil emulsion (DOE) are presented.