Role of Intermediate Species in Controlling Ignition Timing of HCCI 18ICES/026
Authors
Mitsuaki Ohtomo - The University of Tokyo Takehiro Yamaguchi - The University of Tokyo
Masataka Yoshii - The University of Tokyo Hiroyuki Yamada - National Traffic Safety and Environment Laboratory
Atsumu Tezaki - The University of Tokyo
Abstract
The chemical mechanism responsible for controlling ignition timing by using additives in HCCI has been investigated. Dimethyl ether (DME) and methanol were used as the main fuel and the additive, respectively. Fuel consumption and intermediate formation in the first stage (cool ignition) were measured with crank angle resolved pulse-valve sampling and exhaust gas analysis, where HCHO, HCOOH, CO, H2O2 and other species were detected as the intermediate. The effect of methanol addition retarding ignition is represented by an analytical model in which the growth rate of the chain reaction is reduced by the methanol addition.