Thermodynamic simulation and optimization of diesel engines operating with diesel and biodiesel blends using experimental data

Abstract

Internal combustion engines are responsible for most of the pollution encountered in major urban centres, thereby increasing health problems and the greenhouse effect. Although they are not a significant source of carbon oxides or hydrocarbon emissions, diesel engines are responsible for high levels of nitrogen oxides and particulate matter. One of the ways to reduce the amount of soot in diesel engines is by using blends of diesel and biodiesel fuel, although this can increase the amount of nitrogen oxides. Biodiesel's use in diesel engines has increased recently and is now readily found in several countries. However, one of the main problems of biodiesel is its lower heating value, which is lower than that of diesel. The objective of this study is to simulate the pressure inside a combustion chamber of a diesel engine operating under several conditions and using different blends of diesel and biodiesel. The model is based on First Law of Thermodynamics analysis, and the results are verified against experimental measurements. An initial approach is presented to optimize the behaviour of such an engine when operating with different fuels. For this optimization task, a very accurate response surface model was employed together with a hybrid optimization algorithm.