Recent Advances in Utilizing the Plasma Fuel Reformer for NOx Trap Regeneration

This paper describes recent progress in our program to develop an emissions technology allowing diesel engines to meet the upcoming stringent worldwide regulations for NO x . The Plasma Fuel Reformer (PFR) has the ability to rapidly convert diesel fuel (with air), to a hydrogen rich gas on-board a vehicle, which is then utilized to efficiently regenerate a NO x trap. We have made several advances on the PFR as well as on the NO x reducing system. The Plasma Fuel Reformer operating range has been extended by 120% up to 1.5 g/s fuel flow rate while retaining the high hydrogen and low soot characteristics. The plasma power consumption has been further reduced and the high voltage design has been made more robust. The Too start-up time during regenerations has been reduced to less than 4 seconds. The NO x reducing system utilizes a novel algorithm for NO x trap regeneration that reduces the fuel penalty by 25% while increasing NO x conversion by 10%. The new method can also be utilized to reduce the NO x trap volume significantly in a dual leg arrangement. Based on a detailed understanding of the NO x trap regeneration process, a new method to reduce the magnitude of NO x spikes has also been developed. Finally, optimization was performed at some steady state points utilizing maps on trap capacity and reductant breakthrough.