The impact of methanol substitution rate on emissions of two-stage injection Fischer-Tropsch diesel/methanol dual-fuel engine
Based on a high-pressure common rail diesel engine,a methanol injection system is installed at the intake manifold.A two-stage direct injection(pre-injection + main injection)of coal-to-Fischer-Tropsch(F-T)diesel is installed in the cylinder.A two-stage injection F-T diesel/methanol(F/M)dual-fuel engine test stand is built to explore the effect of different methanol substitution rates on engine emission performance at 2 000 r/min and loads of 25％,50％,75％and 100％.Simultaneously,the theoretical basis for realizing the F-T diesel/methanol reactivity controlled compression ignition(RCCI)mode is explored.The results indicates that the fuel economy of the F/M dual-fuel engine is better at medium and high loads.The emissions of HC,CO,Soot,methanol and formaldehyde increase in the F/M dual-fuel combustion mode compared with the single-fuel compression-ignition mode.These emissions increase with the augmentationmethanol substitution rate and decrease with an increase in load.In contrast,the emissions of CO2,NOx and NO decrease with an increase in methanol substitution rate but increase with an increase in load.The emissions of NO2 increase with both the rise in methanol substitution rate and load.The test results show that simply adding a methanol injection system to the intake manifold cannot achieve an efficient and low-emission RCCI combustion mode,and its fuel injection strategy needs to be calibrated.
万方数据
维普
