Advanced Exhaust Gas Thermal Management for Lowest Tailpipe Emissions - Combining Low Emission Engine and Electrically Heated Catalyst 2012-01-1090

Further advancements in engine development lead to increased fuel efficiency and reduced CO₂ emission. Such low emission engine concepts require most advanced exhaust gas aftertreatment systems for lowest possible tailpipe emissions. On the other hand, the exhaust gas purification by catalytic measures experiences more and more challenges due to constantly reduced exhaust gas temperatures by more efficient engines. These challenges can be overcome by traditional catalyst heating strategies, which are known to increase fuel consumption and emissions. Alternatively, electrically heated catalysts ("EHC") can be utilized to provide a very efficient method to increase gas temperatures directly in the exhaust catalyst. This way the energy input can be tailored according to the component need and the energy loss in the system can be minimized. This advanced path of thermal management looks especially attractive considering increasing electrification of vehicles and utilizing more recuperative energy recovery practices in new vehicles. Depending on the application, electrically heated catalysts can give overall energy and emission benefits. The work in this paper describes the technology needed for direct exhaust gas temperature management with electrically heated catalysts and presents results for different applications in comparison to traditional engine heating measures.