An Alternative Way to Reduce Fuel Consumption During Cold Start: The Electrically Heated Catalyst 2011-24-0178

It is well known that the optimal management of cold start is crucial to fulfill present and future emission legislation. During past years the catalytic converter has left its original under floor position to get increasingly closer to the engine in order to exploit higher exhaust gas temperature. Simultaneously, the exhaust gas temperature is becoming significantly lower, both in gasoline engines due to the extensive use of turbo charging, and in diesel engines thanks to very high combustion efficiency and in some cases the use of two stage turbo charging. A well established way to reach the catalyst light-off temperature fast enough to fulfill emission limits consists of artificially increasing the exhaust gas temperature. This has the drawback of a higher fuel consumption which conflicts with the tight CO2 targets now required of the OEMs. This paper describes an alternative way to warm up the catalytic converter in a fast and efficient manner using the electrical heated catalyst (EHC) with only minor increases of fuel consumption. Additionally, the application of the electrical heated catalyst is very effective in combination with a hybrid vehicle where the EHC itself can be activated via energy recuperation thus increasing the total energy efficiency.