A KEY TO ACHIEVE IGNITION CARBON MONOXIDE GENERATION/CO NSUMPTION IN BLUE·FLAME PERIOD DURING HYDROCARBONCOMPRESSION IGNITION

A criterion between success and failure of marginal fuel/air compression ignition was searched for using a rapid compression machine. A barely achieved ignition process was compared to a case no ignition was established due to a slightly insufficient compression pressure level. The differential on the chemical species histories during the induction periods between both cases was examined by continual diff'erent-timing gas samplings. A distingu ished difference could be found only on the carbon-monoxide/carbon-dioxide ratio between the flammable and nonflammable critical conditions. The ratio increased continuously in the ignition success cases. There were no difference s in other species concentration, such as gaseous water. hydrogen, formaldehyde and ethy lene . At the tim e just before th e final hot-fl am e onset the carbon-monoxide concentration came up to around 7 000 ppm, independent of the mixture strength. A steady carbon-mo noxide/carbon­ dioxi de ratio was observed in the case no hot-flam e onset was establis hed . Conti nuous growing of carbon monoxide during the blue-flame period would be an indication fo r the transfer to the final hot-flame ign itio n .