The optimal blendings of diesel, biodiesel and gasoline with various exhaust gas recirculations for reducing NO_x and smoke emissions from a diesel engine

For the purpose of reducing both NO_x and smoke from diesel engine exhaust, the blendings of gasoline into diesel/biodiesel mixture were studied to determine the optimal ratio of diesel/biodiesel/gasoline at various speeds and loads under different exhaust gas recirculations (EGRs) in an electronic-controlled common-rail injection turbocharged diesel engine. With blending biodiesel, the modification of EGR suppressed the NO_x emission but increased the opacity at higher load. With the increase in gasoline addition, the biodiesel proportion needs to be higher for promoting the oxidation of soot. Considering the emission reductions of opacity and NO_x, as well as the issues of cost and lubricity, it is recommended that 20% biodiesel and 5% gasoline would be the optimal blending ratio.