| Abstract:Numerical simulation of second generation biodiesel/gasoline reactivity controlled compression ignition(RCCI) combustion mode with dual-direct injection strategy at low loads was carried out based on the fluid simulation software CONVERGE. The combustion characteristics of RCCI with dual-direct injection and RCCI with conventional intake port injection were compared, and the effect of dual fuel injection timings on combustion was discussed. The results show that compared with the conventional intake port gasoline injection RCCI, the dual-direct injection RCCI can effectively control the distribution of in-cylinder gasoline mixture and reduceincomplete combustion. With the delay of start of injection(SOI) of gasoline, stratified combustion weakens, combustion duration shortens, combustion efficiency is reduced, indicated thermal efficiency declines first and then increases and finally decreases again, NOx emissions is reduced and soot emissions increases. With the delay of SOI of the second generation biodiesel, stratified combustion intensifies, combustion duration is prolonged, combustion efficiency increases, indicated thermal efficiency increases first and then decreases, NOx emissions rise and soot emissions fall. |