Study on Chemical Kinetics Mechanism of Ignition Characteristics of Dimethyl Ether Blended with Small Molecular Alkanes

Dimethyl ether (DME)/C1-C4 alkane mixtures are ideal fuel for homogeneous charge compression ignition (HCCI) engines. The comparison of delay and multi-stage DME/C1-C4 can provide theoretical guidance expanding the load range controlling time DME HCCI However, interaction mechanism between C1-C4 under engine relevant high-pressure low-temperature conditions remains to be revealed, especially comprehensive negative temperature coefficient (NTC) characteristic. Therefore, CHEMKIN-PRO software is used calculate process (50%/50%) at different compressed temperatures (600–2000 K), pressures (20–50 bar), equivalence ratios (0.5–2.0) over 650 K, pressure 20 bar, ratio 0.3–0.5. results show that exhibits a typical NTC characteristic, which more prominent low range. initial DME/CH4 region highest. In region, shortest, whereas DME/C3H8 longest. At lean-burn conditions, exhibit distinct three-stage corresponding heat release rate peak shortest mixtures, it longest mixtures. Kinetic analysis indicates small molecular competes with OH radical produced in oxidation DME, inhibits promotes alkane. concentration active radicals production elementary reactions highest they lowest