Experimental Study of HCCI Combustion Process Fueled with DME

Experimental study of homogeneous charge compression ignition(HCCI)combustion process is carried out on a single-cylinder direct injection diesel engine fueled with dimethyl ether (DME).The research results indicates that the load range of HCCI engine can be extended from 0.05 MPa to 0.35 MPa when 30% CO_2 is inducted into the charging air. The HCCI combustion of DME presents remarkable character of two-stage combustion process. As the concentration of inert gas increases, the ignition timing of the first combustion stage delays, the peak of heat release rate decreases, and the combustion duration extends. Emission results show that under HCCI operation, a nearly zero NO_x emissions can be obtained while with no smoke emissions. But the HC and CO emissions are high.