Effect of fuel injection pressure on the injection, combustion and performance characteristics of a DI diesel engine fueled with canola oil methyl esters-diesel fuel blends

In this study, the influence of injection pressure on the injection, combustion and performance characteristics of a single cylinder, four stroke, direct injection, naturally aspirated diesel engine has been experimentally investigated when using canola oil methyl esters (COME) and its blends with diesel fuel. The tests were conducted for four different injection pressures (18, 20, 22 and 24 MPa) at constant engine speed and different loads. The experimental results showed that the fuels exhibit different injection, combustion and performance characteristics for different engine loads and injection pressure. Investigation on the injection characteristics of the fuels showed that using COME instead of diesel resulted in earlier injection timings. The maximum cylinder pressure, the maximum rate of pressure rise and the maximum heat release rate are slightly lower for COME and its blends. The brake specific fuel consumption and brake specific energy consumption for COME are higher than that for diesel fuel while brake thermal efficiency of COME is generally lower than that of diesel fuel. The increased injection pressure gave better results for brake specific fuel consumption and brake thermal efficiency compared to the original and decreased injection pressures.

► Different injection pressures may be used for COME and its blends.
► Increased injection pressure gives better results for BSFC and thermal efficiency.
► COME and its blends result in earlier injection timings.
► Slightly lower cylinder gas pressures were obtained for COME and its blends.