An experimental investigation into the effect of early injection and port fuel injection（PFI) on combustion and emissions of a modified single cylinder test engine fueled with gasoline was carried out under low load conditions. Two injection strategies

the main direct injection with early injection and with FPI

were used respectively

and the injection parameters included the early injection time

early injection ratio and PFI ratio. Results show that the fuel injected by early injection and PFI mainly affected the later stage of the combustion and heat release process while the main injection mainly controlled the combustion starting point and the rapid heat release in the early stage of combustion process. Increased early injection ratio and PFI ratio will lead to retarded ignition

reduced combustion duration and increased combustion rate in the later stage of combustion process

and hence a low NOx emissions. The spray wall impingements caused by early injection can reduce the combustion efficiency and increase the unburned THC and CO emissions.