Consequences of using biodiesel on the injection and air–fuel mixing processes in diesel engines

Abstract

A study of the injection process and spray behaviour was made for three different fuels. In particular, blends of rapeseed methyl ester and standard diesel fuel with 5% and 30% biodiesel were used for the current study, as well as pure rapeseed methyl ester. Hydraulic characterization of an eight-hole nozzle was carried out using these three fuels, in order to explore and analyse the influence of the fuel properties on the mass flow rate and the momentum flux at the nozzle exit. Additionally, spray visualization tests were performed in order to obtain information about the spray cone angle, which allows characterization of the air–fuel mixing process. Finally, a theoretical derivation was used to obtain further details of the microscopic characteristics of the spray and to compare the air–fuel mixing efficiencies for the different biodiesel blends.