Inthisstudy,ahomogeneousmixtureofnatural-gasandairwasusedinacompressionignitionenginetoreduceNOxemissionsandimprovethermalefficiency.Inordertocontrolignitiontimingandcombustion,asmallamountofDMEwasmixedwiththenatural-gas.Engineperformanceandtheexhaustcharacteristicswereinvestigatede