Computational research on load extension route of diesel homogeneous charge compression ignition engine

A quasi-dimension combustion that considers fuel film evaporation is built to simulate rate of heat release of diesel HCCI combustion. The calculation results are in good qualitative and quantitative agreement with the experiment results. Load extension route of HCCI engine is studied based on the validated simulation model. In the process of load extension, the maximum combustion temperature and pressure rise ratio are the single limitation condition in low and high intake pressure respectively. The transformation boundary of single limitation condition is at intake pressure about 1.4 bar. The matching relation between intake pressure and excessive air ratio indicates that excessive air ratio can be taken as feedback signal to control load extension route. Along the ultimate load extension route, load of HCCI engine (IMEP) can be extended to 0.889 MPa by single supercharging mean and be further extended from 0.889 MPa to 1.029 MPa by combined supercharging and LIVC means.