Based on the application of 3-dimensional computational fluid dynamics software CONVERGE

a numerical simulation study of the effect of gasoline direct injection on the high load expansion of reactivity controlled compression ignition(RCCI) combustion mode was carried out under different injection parameters

including total fuel flow

direct-injected gasoline flow

premixed gasoline flow and gasoline/diesel injection timing. Results show that the intake pressure and diesel injection timing affect the concentration stratification in the cylinder

and then affect the combustion process

while the effect of gasoline using port injection and in-cylinder direct injection

increasing the amount of direct injected gasoline in the cylinder can further enhance the concentration stratification of the in-cylinder mixture

and prolong the combustion duration to reduce the in-cylinder peak pressure and pressure rise rate

resulting in a lower combustion temperature. The simulation calculations also show that if the soot and NOx emissions are kept within the emission limits

the IMEP can be increased to 1.6 MPa

but when the IMEP reaches 1.7 MPa

increasing the gasoline premixed ratio does not increase the IMEP

but slightly improve the emissions while responding to increased pressure rise rate and peak pressure.