Compression ignition mechanisms of methane/DME composite fuel

Abstract

Combustion mechanism of the methane/dimethyl ether (DME)/air homogeneous charge compression ignition (HCCI) combustion was investigated by in-cylinder gas sampling tests and numerical kinetics calculations. The results showed that the main functions of DME for methane ignition were the temperature rising effect by low temperature reactions of DME and the supply of OH radicals. It was possible to extend the operation range to an overall equivalence ration of 0.54 without knocking, when ignition was retard after the top dead center, by controlling the DME quantity.