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 firststage 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.