Experimental Study Of Methanol Injection Timing On Combustion And Emission Characteristics Of A Methanol/Diesel Dual-Fuel Engine

Methanol/diesel dual-fuel combustion is achieved by adding methanol supply system,methanol injection control system and dual fuel mode electronic control system on a YC6G270-30 electric-controlled high-pressure common-rail diesel engine.The effect of methanol injection timing on the combustion characteristics and emission performance of the methanol/diesel dual fuel engine under different engine speed,load rate,co-combustion ratio and cylinder deactivation mode was experimentally studied.The main parameters contain cylinder pressure,heat release rate,pressure rise rate,in-cylinder temperature,maximum cylinder pressure cyclic variation,fuel economy,CO emission,HC emission,NOx emission and PN emission.The following conclusions are obtained based on the experimental research and analysis:1)Under the selected operating points,methanol injection timing has almost no effect on the cylinder pressure,heat release rate,pressure rise rate and in-cylinder temperature but shows slight effect on the maximum cylinder pressure cyclic variation,to be specific,the maximum cylinder pressure cyclic variation when the methanol injection timing being set as-350 °CA or-280 °CA is a little bit smaller than that of-120 °CA、40 °CA、200 °CA and 340°CA.2)Under the selected operating points,methanol injection timing has almost no effect on fuel economy.3)Under the selected operating points,methanol injection timing has almost no effect on CO emission,NOx emission and PN emission but shows slight effect on HC emission,to be specific,the HC emission when the methanol injection timing being set as-350 °CA or-280 °CA is a little bit lower than that of-120 °CA、40 °CA、200 °CA and 340°CA.4)Take both the effect of methanol injection timing on the combustion characteristics and emission performance into consideration,the methanol injection timing is supposed to set during the opening period of the intake valve.