The effect of a H2/CO mixture at varying ratios on the diesel particulate filter regeneration process: Towards an optimised fuel reformer design – Diesel engine aftertreatment system

The work described in this paper aims to assist in the development of an exhaust gas fuel reformer for the enhancement of diesel particulate filter (DPF) aftertreatment performance. This was achieved by introducing H2 and CO at various mixture ratios at a concentration of 6% (v/v) to a standardised DPF regeneration process in order to identify an optimised mixture ratio. In addition to this, emission measurements were performed pre and post filter to identify the impact of the additional mixtures on various emission components. A mixture ratio of 60% H2 balanced with CO was identified as the optimised mixture ratio. This was due to this configuration demonstrating one of the most proficient regeneration profiles at a relatively low mean filter temperature of approximately 630 °C. Further to this, it was also noted that the addition of H2 or H2 and CO to the regeneration process resulted in an increase in NOx post filter while total hydrocarbons were reduced. Furthermore, the H2/CO mixture addition resulted in an increase in CO2 post filter, the levels of which were proportional to the volume of CO contained within the introduced mixture.

► Introduced H2/CO mixtures at various ratios to the regeneration process of a DPF. ► Identified an optimized mixture ratio which featured 60% H2 balanced with CO. ► Addition of optimised mixture ratio resulted in increased NOx formation post filter. ► CO2 level increased post DPF, proportional to CO volume within introduced mixture. ► Addition of optimised mixture ratio resulted in decreased THC formation post filter.