Abstract
Intermediate species formed in the low temperature heat release (LTR) of autoignition were evaluated in a test engine by exhaust eas analysis with FT-IR at hot ignition suppressed conditions. PRF (iso - octane/n-heptane) and NTF (toluene/n-heptane) were used as the fuels. The LTR fuel consumption decreases with increasing iso - octane content in PRF. whereas the effect of toluene in NTF is weaker. Formaldehyde generation yield increases with increasing iso - octane content in PRF but the opposite trend was found in NTF. The chain reaction mechanism of LTR accounts for the observations; i.e.. the chain carrier OH reproduced bv n - heptane is consumed bv iso - octane. toluene and intermediates such as formaldehyde. Reaction pathways for product species characteristic to each fuel component are also discussed.
