Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

The combustion characteristics and emission behaviors of RP-3 jet fuel were studied and compared to commercial diesel fuel in a single-cylinder compression ignition(CI)engine.Engine operational parameters,including engine load(0.6,0.7,and 0.8 MPa indicating the mean effective pressure(IMEP)),the exhaust gas recirculation(EGR)rate(0%,10%,20%,and 30%),and the fuel injection timing(–20,–15,–10,and–5°crank angle(CA)after top dead center(ATDC))were adjusted to evaluate the engine performances of RP-3 jet fuel under changed operation conditions.In comparison to diesel fuel,RP-3 jet fuel shows a retarded heat release and lagged combustion phase,which is more obvious under heavy EGR rate conditions.In addition,the higher premixed combustion fraction of RP-3 jet fuel leads to a higher first-stage heat release peak than diesel fuel under all testing conditions.As a result,RP-3 jet fuel features a longer ignition delay(ID)time,a shorter combustion duration(CD),and an earlier CA50 than diesel fuel.The experimental results manifest that RP-3 jet fuel has a slightly lower indicated thermal efficiency(ITE)compared to diesel fuel,but the ITE difference becomes less noticeable under large EGR rate conditions.Compared with diesel fuel,the nitrogen oxides(NOx)emissions of RP-3 jet fuel are higher while its soot emissions are lower.The NOx emissions of RP-3 can be effectively reduced with the increased EGR rate and delayed injection timing.