The Impact Of Combustion Chamber And Fuel Injection Parameters And EGR On Performance Of Dme-methanol Engine

With energy crisis and environmental pollution problems grows, it has embarked on research of clean alternative fuel. Methanol, dimethyl ether is recognized as clean fuel, it will be applied to the engine after mixing with diesel fuel, which can effectively improve the soot and NOx emissions. Based on AVL_FIRE software to study the combustion chamber shape, effect of fuel injection parameters, exhaust gas recirculation(EGR) and a three reasonable matching on combustion, emissions and performance of Methanol-DME(dimethyl ether)-diesel blended fuel engine. The main contents are as follows:(1) Keeping compression ratio unchange, study the influence of five kinds of combustion chamber(Straight chamber B1, micro-exposure chamber B2, reentrant chamber with round bottom B3, reentrant chamber with flat bottom B4, reentrant chamber with tip bottom B5) on methanol-DME-diesel blended fuel combustion. Results show that, five kinds of combustion chamber on CO emissions are not obvious, NOx, Soot emissions worst of B2, but emissions of B1, B3, B4 are better. For methanol-DME fuel engine, B4 has better performance, greater torque, smaller fuel consumption.(2) Fuel injection parameters of methanol-DME-diesel blended were studied. Results show that, with injection timing advance, the ignition delay period is extended, combustion duration shortens, soot emissions improves, but NOx emissions increases, fuel consumption reduces, and torque increases. Appropriate to extend the injection duration, the engine work more gently, but a longer injection time, serious post-combustion, the torque decrease, increase fuel consumption. Properly increasing spray angle can improve the power and economy of methanol-DME fuel engine.(3) For NOx emissions, the effects of EGR on methanol-DME fuel engine, the results show that, with EGR rate increases, a significant improvement in NOx emissions, CO emissions increase slightly. Soot emission is first decreased and then rise with EGR rate increases. Therefore appropriate increase of EGR rate can reduce NOx and soot emissions.(4) By using the orthogonal design to study combustion chamber, fuel injection parameters, EGR effects on methanol-DME fuel engine primary and secondary order, and through comprehensive analysis to get optimization scheme.