Effects of the compressed pressure and fuel concentration on ignition delay of DME mixture were investigated using a rapid compressor at compressed temperature of 656—814 K

compressed pressure of 1.2—3.5 MPa and equivalence ratio (φ) of 0.83—1.25. Kinetics model was built to predict the ignition delay and simulate the combustion process using CHEMKIN-PRO software

meanwhile

reaction kinetics analysis was conducted. The results show that with increasing compressed pressure and fuel concentration

the first-stage ignition delay decreases slightly

while a significant decrease in the total ignition delay is observed. The ignition delay of DME presents well known negative temperature coefficient (NTC) and which is noted to become more prominent at lower compressed pressure and fuel concentration. DME mixture presents three-stage heat release at lean-fuel(φ=0.83)

which includes low-temperature heat release and a two-stage high temperature heat release. Kinetics analysis indicates that the first-stage high temperature heat release is mainly caused by the production of CO from CH2O

and the reactions produce CO2 and H2O contribute to the second-stage high temperature heat release.