HC和CO排放量。 Combining the advantages of HCCI combustion and in-cylinder direct injection combustion for a diesel engine fuelled with DME，a new concept combustion system, namely compound charge compression ignition (CCCI) combustion by port introduction and direct injection of DME，was proposed，a diesel engine was modified to carry out this test. The results showed that CCCI combustion process comprised HCCI combustion and pre-mixing combustion, diffusion combustion. And different combustion characteristic was presented by it with the variation of premixed fuel ratio. With the increasing of premixed fuel ratio, the peak value of mean temperature, pressure, rise rate of pressure as well as NOx emissions decreased first and increased later. With the increasing of fuel delivery advance angle, CO and HC emissions decreased and NOx emissions increased, the fuel consumption has been improved. Compared with HCCI combustion mode，under a certain premixed fuel ratio and fuel delivery advance angle, CCCI combustion could extend the operating range with a little change of NOx emissions and a reduction in HC and CO emissions.