运行工况对甲醇压燃发动机燃烧和排放的影响OA

In order to explore the combustion and emission characteristics of the methanol compression ignition engine under different operating conditions,based on a methanol compression ignition engine modified from a 7.7 L diesel engine with compression ratio of 21.5,the effects of operating conditions on combustion and emissions of methanol compression ignition engine at intake temperature of 150℃were investigated.The results indicate that the effective thermal efficiency is the highest at medium loads(0.8～1.2 MPa break mean effective pressure),and the highest effective thermal efficiency is 38.6%.The effective thermal efficiency decreases with the increase of the rotational speed.As the load increases,NOx emissions first increase and then decrease,while the CO emissions first decrease and then increase.N2O,HC,unburned methanol emissions gradually decrease,and soot emissions decrease rapidly and tend to zero.Formaldehyde emissions first increase and then decrease at low speeds,and gradually decrease at medium and high speeds.As the speed increases,NOx emissions decrease significantly,and there is little difference in NOx emissions at medium and high speeds.There is little difference in soot,CO,HC,N2O,unburned methanol and formaldehyde emissions at different speeds.