Effects of DME addition to biodiesel on combustion, performance and emissions of a diesel engine at idle and medium loads

The effects of using dimethyl ether (DME) on the combustion, performance and emission parameters of biodiesel in a diesel engine operating at idle and medium loads that was used to drive an electrical power generator were experimentally investigated. Biodiesel was produced from safflower oil. 75% of the biodiesel was blended with 25% of DME, volumetrically, which was called here as B75DME25. Pure biodiesel (B100), B75DME25 and ultra-low sulfur diesel fuel (D2) was used as test fuels. Experiments were carried out at constant loads of 60% and idle conditions. Cylinder pressure, heat release rate (HRR), cylinder pressure rise rate(CPRR) and mean gas temperature(MGT) variations of test fuels at both idle and 60% load conditions were presented here. It was found that peak values of derived pressure for all test fuel are similar while the positions of peak pressure were changed and was found earliest for D2. Similar trends were also observed for HRR, CPRR and MGT parameters. CO, HC, NOx and CO2 emission were found and compared for test fuels at both idle and medium loads. In the performance tests, brake specific fuel consumption (bsfc), mass fuel consumption and thermal efficiency values were tested and compared for test fuels.