4-cylinder high pressure common rail diesel engine test bench was modified to have reactivity controlled compression ignition(RCCI) combustion. A coordination-control strategy of injection for RCCI combustion was developed to adjust gasoline and diesel injections at the whole operating conditions. The effects of different gasoline fraction on the combustion and emissions of diesel engine operated with RCCI mode at different operating conditions were studied. The results show that the diesel/gasoline RCCI combustion control strategy can achieve an efficient and clean combustion. With the increase of gasoline fraction

the peak in-cylinder pressure increases gradually and appears late

the peak heat release rate decreases

the combustion duration is prolonged

the brake specific fuel consumption(BSFC) declines

and the effective thermal efficiency becomes great. And the emissions of hydrocarbon and CO increases remarkably due to the unburned fuel at low load operating conditions. Operating with the RCCI mode

the engine has higher volatility and better overall fuel-air mixing

resulting in improved combustion and reduced nitrogen oxide(NOx) and soot emissions. A good trade-off between NOx and soot emissions is achieved perfectly.