Reliable Catalytic Particulate Trap Regeneration by Exhaust Hydrocarbon Enrichment

The role of the catalyst in regeneration of catalytic particulate traps was found to be the oxidation of gaseous fuel species, such as carbon monoxide and hydrocarbons, in the exhaust. Energy released by the oxidation of fuel on the catalyst surface heats the trap to the temperature at which combustion of trapped particulate matter can occur. Experiments with both commercial and prototype catalytic particulate traps demonstrated that the traps could be reliably regenerated by enriching the exhaust with either propane or diesel fuel.

Using a DD6V-71N coach engine and a prototype catalytic particulate trap, a trap regeneration system was developed which delivers vaporized diesel fuel to the exhaust, upstream of the catalytic particulate trap. The system has no moving parts in contact with the exhaust gas and allows reliable trap regeneration under full exhaust flow. An un-optimized fuel efficiency penalty of less than 1.6% was demonstrated for this regeneration method.