Development And Reduction Of Detailed Chemical Kinetic Mechanism Suitable For Gasoline Surrogates Compression Combustion

The requirements for green development in modern society has brought increasingly strict emission regulations and technical requirements to the automobile industry.Compression combustion of gasoline is one of the efficient and clean combustion methods in the field of internal combustion engines,and has a broad application prospect.However,it still has the disadvantages of poor working stability at low load and prone to knock at high load which need to be solved urgently.At present,many experimental studies have been conducted on the gasoline compression combustion,but there are few studies on its numerical simulation.One of the reasons is that the existing gasoline chemical reaction mechanisms do not completely conform to the gasoline compression combustion process,which leads to the inaccuracies simulating the combustion process of gasoline in the compression ignition engine.In this study,a detailed chemical kinetics mechanism composed of isooctane,n-heptane,1-hexene and toluene and a detailed chemical kinetics mechanism composed of isooctane,nheptane,1-hexene,toluene,and di-tertiary butyl peroxide(DTBP)are developed using reaction mechanism generator(RMG)according to the characteristics of gasoline compression combustion.A shock tube experiment was conducted to measure the ignition delay times of gasoline and gasoline-DTBP mixture,focusing on the influences of temperature,pressure,additive content on the ignition delay time of gasoline.Then the detailed mechanisms were validated against shock tube experiment data and compared with the mechanisms of other researchers.Based on the developed detailed mechanisms,characteristics of different conditions during gasoline combustion process were analyzed,the specific influences of temperature,pressure,additive content on the chemical reaction kinetics of gasoline combustion process were discussed.Finally,the detailed chemical kinetics mechanisms of gasoline were reduced using ANSYS Chemkin Reaction Workbench,a 436-species gasoline surrogate fuel mechanism and a 439-species modified gasoline surrogate fuel mechanism with DTBP were obtained.Then an eight-zone combustion model was established using Chemkin,on which the compression combustion processes of gasoline and modified gasoline were simulated and compared under engine conditions.The results show that the gasoline surrogate fuel mechanism with DTBP can reflect the actual compression combustion process and the further revised pure gasoline surrogate fuel mechanism can also reflect the actual gasoline compression combustion process.