The Research On Basic Characteristics Of Biomass Oil Applied In Internal Combustion Engines

Clean renewable energy resources,for example,biomass,are mid-and long-term solutions for the depletion of fossil fuels and environmental pollution.Fast pyrolysis biofuel is considered as one of the promising alternative fuels.Recently,a refined pyrolysis biomass liquid fuel for vehicles was produced from rice husk at Zhejiang University,which consists of ethanol,ethyl acetate,diethyl ether,acetone and2-butanone with mass ratios of 9:6:2:1:1.Before this refined pyrolysis biomass liquid fuel is used in practical engine,basic application characteristics of which should be studied,especially explosion characteristics and laminar burning speed.Basic application characteristics of the mixed fuel is studied on constant volume combustion chamber and Z-type schlieren system at three initial temperatures(358 K,388 K,418K),three initial pressure(0.1 MPa,0.2 MPa,0.4 MPa)and eight equivalence ratios(0.7-1.4).The main contents are as followed:Firstly,explosion characteristics,namely explosion pressure,maximum pressure rise rate,deflagration index and explosion duration time were obtained from pressure variation of mixture’s combustion procedure in combustion chamber.Linear relationships between explosion characteristics and initial pressure,initial temperature,equivalence ratio were obtained and corresponding fitting parameters were given;Secondly,laminar burning speed was calculated by constant volume method from pressure curve in combustion chamber and was compared with laminar burning speed from constant pressure method in literature to verify the reliability of results.The impact of initial pressure,initial temperature,equivalence ratio to laminar burning speed was discussed;Thirdly,factors that lead to flame instability and conditions under which cellularization occurs were analysed by flame schlieren images.Cellular flame speed was also obtained by constant volume method.Flame tends to be cellular under high pressure and rich mixture;Lastly,laminar flame speed was obtained under conditions closer to practicalinternal combustion engine(490 K,0.8 MPa)using twelve-term formula which benefits from fitting of power function and the advantage of constant volume method that results at elevated pressure and temperature can be obtained in one experiment.