Jakub Czajka

Combustion process shaping by use of different strategies of multiple fuel injection in a CI model engine

Technological advancement in combustion systems of diesel engines triggers the need of fulfilling many contradictory requirements. Among those are such issues as maintenance of environmental standards in terms of the exhaust emissions with a simultaneous preservation of the thermodynamic properties of the combustion process and fuel consumption. The paper discusses the results of research on the influence of the strategies of fuel dose division on the combustion process and operational indexes in a model engine. The paper also contains an exhaust gas analysis conducted with the use of a rapid compression machine. The investigations of the combustion process (development of the self-ignition spots) were conducted using high speed camera. The recorded images related to the period from the onset of the injection to the beginning of the appearance of combustion spots have also been analyzed. The following have been varied: number of doses, size of doses, dwell times and excess air coefficient. The authors performed a comparative analysis of the thermodynamic indexes of the combustion process obtained from the indicator tracings. The achieved results show possibilities of the influencing on the combustion process course and emission of exhaust toxic compounds by application of multiple injection and its properly selected strategy containing proportions in fuel doses and dwell times between them.