The analysis of the possibilities of increasing the share of propane in the fuel mixture supplied to a dual fuel diesel engine

The paper presents the main reasons for the limitations as to the share of gaseous fuel in dual fueling in commercial engine applications. It also indicates the proposals of solutions aiming at increasing of the share of this fuel. The investigations were conducted in two stages. The first stage of the investigations involved gradual increase in the share of propane at a simultaneous phasing out of the amount of diesel fuel so that the excess air coefficient remained on the same level. The second stage of the investigations involved a maximum possible share of propane with a simultaneous adjustment of the diesel fuel injection parameters. The investigations were performed for three different values of the charging pressure: 200, 400, 600 mbar and for a naturally aspirated variant. The obtained results led to a conclusion that modifying diesel fuel injection parameters and increasing the charging pressure allow a significant increase in the share of gaseous fuel up to 70% of the total energy contained in both fuels.