Abstract
Emission characteristics were carried out on a compression ignition, dimethyl ether engine (DME) with exhaust gas recirculation (EGR) and on a diesel engine with a dimethyl carbonate (DMC) additive. The results show that the DME engine with EGR can simultaneously reduce smoke and Nox emissions. The Nox can be decreased by about 20 percent for every 10 percent of EGR introduction, while smoke remains at zero. The diesel equivalent brake specific fuel consumption shows a slight decrease when DMC is added, while the effective thermal efficiency shows a slight improvement. It is found that the smoke reduction rate and smoke show a linear relationship with DMC percentage or oxygen mass percentage in the diesel fuel. For the specific brake mean effective pressure (b.m.e.p), smoke will be reduced by 20 percent for every 10 percent DMC added and by 40 percent when the oxygen mass percentage in the fuel reaches 10 percent. The CO decreases when DMC is added, while Nox shows an increase. This difference is pronounced at a high b.m.e.p. For the specific b.m.e.p., CO and Nox show a linear relationship with DMC mass percentage in the fuel; CO will be reduced by 20 percent while Nox will be increased by 20 percent for every 10 percent DMC added.