Exhaust Aftertreatment Technologies for Hybrid Electrical Vehicles

The automotive industry is undergoing a deep transformation that will shape its future for the next decades. In order to achieve the CO₂ fleet average requirements, the share of electrified powertrain is rising. It is now possible to design powertrains using not only the highly efficient internal combustion engines (ICE) but also the newly developed electrical motors (eMotor) and batteries. This variety of technologies allows the design of sophisticated powertrain to better fulfill the requests not only regarding CO₂ regulations but also of different markets, customer expectations and emission legislations. The increased variety of powertrains causes, on the other hand, some challenges regarding the exhaust after treatment systems (EATS) layout and emission control, considering the almost infinite possibilities to combine ICE and eMotor’s toque delivery to fulfill the customer desired drive profile. In this work the authors will show how it is possible to design an EATS to fulfill future and very stringent emission legislation, using state of the art technology and taking in consideration the different types of electrified powertrains, from start and stop to serial hybrid. The position of the electrical heated catalyst (EHC) and his heating strategy will be investigated together with the possibility to use hydrocarbon traps (HC-T) and innovative passive metallic substrates. Moreover, a deep investigation of the cold start and high-power cold start will be carried out in order to find the best heating strategy with minor impact on the drive-ability of the vehicle, both under typical emission cycle, like the WLTC, and real driving emissions (RDE).