Energy assessment of an electrically heated catalyst in a hybrid RCCI truck

Abstract

Reactivity controlled compression ignition (RCCI) combustion showed great advantages in terms of engine-out NOx and soot emissions reduction. However, HC and CO emissions are larger than with conventional diesel combustion. Commercial oxidation catalysts can deal with the amount of HC and CO generated during the RCCI combustion only at warm conditions, thus limiting the implementation of this concept in conventional vehicles and in RCCI hybrid applications due to the large engine stop periods. This work aims to study the behaviour of an electrically heated catalyst used in a hybrid medium-duty truck operating with diesel-gasoline RCCI combustion. A parallel P2 full hybrid medium-duty truck is studied in transient conditions by means of numerical simulations validated with experimental data. The results are compared to those from the commercial diesel non-hybrid truck and the RCCI non-hybrid concept with a commercial oxidation catalyst. The results show that the fuel consumption increases about 2 % in combined cycles and 5 % in urban cases with respect to the non-hybrid RCCI case with a commercial oxidation catalyst. Finally, it was found that the RCCI hybrid concept with the electrically heated catalyst allows to achieve the EUVI targets for all the pollutant emissions with CO2 levels of 15 %.