The combustion characteristics and heat release of a direct injection (DI) compression ignition engine fuclled with diesel dimethyl carbonate blends were investigated on a compression ignition engine. The study showed that the premixed combustion is prolonged and the duration of the diffusive combustion is shortened with increase in the dimethyl carbonate (DMC) addition. For a specific brake mean effective pressure (b.m.e.p.), the maximum cylinder gas pressure, the maximum rate of pressure rise and the maximum rate of heat release increase with increase in the DMC addition at medium and high loads, while they exhibit less variation with the DMC addition at small load. Meanwhile, the maximum gas temperature decreases with increase in the DMC addition, The ignition delay increases while the rapid combustion. duration and the total combustion duration show lss variation with the DMC addition. The brake speeific fuel consumption (b.s.f.c.) inereases while the diesel equivalent b.s.f.e. deereases and the thermal efficiency increases with increase in the DMC addition. The CO and smoke decrease with increase in the DMC addition, and NOx does not inerease with increase in DMC.