| As the most abundant vegetable oil resource in the world,palm oil has been recognized as one of the ideal alternative fuels for internal combustion engines due to its characteristics of reproducability and environmental friendliness.However,the high viscosity and poor fluidity of palm oil restrict its application in internal combustion engines.Ethanol has low viscosity and high evaporability,which can be used to improve the high viscosity of palm oil and poor evaporability,and it has good intersolubility with diesel/palm oil blend fuels.However,low energy density of ethanol markedly affects the power performance and the running mileage of vehicles.Gasoline has high energy density and low viscosity.Blending gasoline with diesel /palm oil / ethanol blend fuels can improve the energy density and reduce the viscosity of the fuel,which is expected to improve the power performance and running mileage of vehicles as well as the emission.Therefore this paper devoted to reform diesel and palm oil blends with gasoline and ethanol additive.In this paper,diesel / palm oil / ethanol / gasoline blends were prepared with the volume ratio of 6:2:1:1 and 6:1:1:2,which were represented by D60P20 and D60P20;Turbocharged intercooled diesel engine with EGR was used to investigate combustion and emission characteristics of D100、D60P20、D60G20 under different loads,pilot-main interval intervals and EGR valve opening.The results are as follows:(1)Compared with D100,the cetane number,heating value,freezing point,and density of D60P20 and D60G20 are all reduces.With the increase of the proportion of palm oil,the blended fuels evaporation and fluidity will decrease slightly,and with the increase of the proportion of gasoline,blended fuels evaporation and fluidity will be improved.(2)With the increase of load,the ignition delays(IDs)of D100,D60P20 and D60G20 decreases,the combustion durations(CDs)increases,and the peak pressure,peak heat release rate(PHRR)and peak temperature(PCT)increases.Under the same load,the ID shows the law of D60G20 > D60P20 > D100,and the CD shows the law of D100 > D60P20 > D60G20.The PHRR and PCT of D60P20 and D60G20 are higher than D100.(3)With the increase of the pilot-main interval(PMI),the IDs and CDs of D100,D60P20 and D60G20 increases,while the peak pressure,PHRR and PCT have little change.Under the same load and PMI,the ID shows the law of D60G20 > D60P20 > D100,the CD shows the law of D100 > D60P20 > D60G20,the PHRR shows the law of D60P20 > D60G20 > D100,and the PCT of D60P20 and D60G20 are higher than D100.(4)With the increase of EGR valve opening,the IDs and CDs of D100,D60P20 and D60P20 increases,while the peak pressure,PHRR and PCT decreases.Under the same load and EGR valve opening,the ID shows the law of D60G20 > D60P20 > D100,and the CD shows the law of D100 > D60P20 > D60G20.The PHRR and PCT of D60P20 and D60G20 are higher than D100.(5)With the increase of load,the NOx emission of D100,D60P20 and D60G20 increases,and the emission of particulate matter also increases.Under the same load,the NOx emissions shows the law of D60G20 > D60P20 > D100,and particle number concentrations(PNCs)shows the trend of D100 > D60P20 > D60G20.(6)With the increase of the PMI,the NOx emissions of D100,D60P20 and D60G20 tends to be stable,but the PNCs shows the tendency declining at the begining and rising up in late.Under the same load and PMI,the NOx emissions still shows the law of D60G20>D60P20>D100.The PNCs still showes a trend of D100>D60P20>D60G20.(7)With the increase of EGR valve opening,the NOx emissions of D100,D60P20 and D60G20 decrease S,and the PNCs shows the tendency stabilizing at the begining and increasing rapidly in late.When the EGR valve opening is 0% and 10%,the NOx emissions shows the law of D60G20>D60P20>D100;when the EGR valve opening is 20% and 30%,the NOx emission shows the law of D60G20>D100>D60P20.The PNCs always shows the law of D100>D60P20>D60G20. |
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