Research on the effect of diesel fuel injection parameters on the exhaust emissions in the turbocharged CI engine operating on propane

The article presents results of the studies on the charged, dual-fuel CI compression ignition engine fuelled with propane. The main goal of the studies was to fuel the engine so that the amount of energy provided with propane is possibly highest at the high efficiency, low emission of harmful exhaust constituents and proper combustion. As the studies conducted so far have shown, with the increase of energy from propane we observe crucial changes in the combustion process. As these changes may be a barrier in the further increase of energy, we decided to change the injection parameters of the diesel fuel. The changes introduced allowed for the 70% energetic contribution of gas fuel at the subsequent elimination of unfavourable phenomena. The fuel injection was realized divided into two doses. Both proportions and angle at the beginning of the injection for both doses were variable. The angle at the beginning of injection for the first dose was changed in a wide range and depended on the value of charging pressure. The angle at the beginning of injection for the second dose was changed in a much narrower range, mainly due to very clear changes in the nature of combustion process. The studies have been conducted for three values of charging pressure, namely 200; 400 and 600 [mbar], and also for the naturally aspirated version. Study results have been presented in a form of regulation characteristics for the angle of the beginning of injection of the pilot dose for the chosen charging variants, as well as volume and angle of the beginning of injection for the main dose. The obtained results show that the content of exhaust constituents for the dual-fuel CI engine depends highly on assumed regulations of injection parameters of the fuel dose initiating the ignition, as well as engine charging pressure.