Experimental Study On Fuel Injection System Of Engine Fueled With DME/Diesel Blended Fuel

Based on the 4100 diesel engine,the DME/diesel fuel supply and injection system was developed to fit in with the physical characteristics of DME. By calculating the viscosity of DME diesel fuel blend,the proportion of DME/diesel fuel blends were determined.This article chooses D40 mixed fuel (dimethyl ether and diesel mass fraction is 4:6) as the research object.Fuel feeding amounts of pump have tested accurate on pump test-bed.This paper is concerning the numerical calculation on diesel engine fuel oil injection system with HYDSIM software.The mathematical model is established for the conventionalpump-pipe-injector fuel system.The fuel oil system injection the characteristic curve,such as the cam lifting,the high-pressure oil pipe pressure,the pin valve displacement,has obtained.Effects of main fuel injection system parameters such as plunger diameter and stoke,fuel supply advance angle,valve opening pressure of nozzle on performance of DME engine have been extensively investigated,which can offer theoretical basis for optimization.Through optimization of fuel injection system parameters match,D40 engine bench test was conducted.The results show that: The dynamic performance of the D40 engine decreased slightly compared with the original machine,the maximum power decreased by 4.7% in high engine speeds,but significantly increased torque at low speeds,increased 19.7%;The equivalent fuel consumption of D40 is lower than that of the diesel fuel at low engine speeds, higher than that of the diesel fuel at high engine speeds.By comparing the D40 engine and diesel engine combustion performance and emission characteristics,we can see,compared with diesel,D40 maximum cylinder pressure,maximum pressure rise rate,the maximum combustion temperature is lower than those of diesel;NOx emissions of the D40 engine is decreased remarkably,NOx decreases 21.3% averagely.PM reduced significantly,the maximum range decreases up to 50%;Little influence on emissions of HC and CO.Additionally,compared with diesel fuel, D40 has a lower line pressure,higher pressure fluctuations and has a pump side residual pressure.The simulation results of high-pressure fuel injection pressure are in relatively good agreement with the experimental ones.Needle lift curve shows that the phenomenon of secondary injection did not occur.