An Alternative Method for Fast Light-Off of Catalysts - Cranking Exhaust Gas Ignition

Recent stringent emission regulations need fast light-off of catalysts to reduce HC and CO emissions during cold start. Cranking Exhaust Gas Ignition (CEGI) system, developed in this study, cuts off the ignition signals for 10 seconds during the cranking period for the unburned mixture to bypass the combustion chamber and flow through the exhaust manifold. When the unburned mixture reaches two glowplugs mounted upstream of the catalyst, it is ignited and releases thermal energy to warmup the catalyst. Results from the vehicle tests showed that the catalyst reaches the light-off temperature within 20 seconds and the reduction of exhaust emission was 47.7% for THC and 88.6% for CO in the cold-transient phase of the FTP-75 mode.