Development of Automatic Trap Oxidizer Muffler Systems

Systems have been developed for medium and heavy duty diesel engines, which perform the combined operations of exhaust particle collection, trap regeneration, and exhaust noise attenuation. These systems are microprocessor based and fully automatic requiring no operator intervention. The developmental efforts centered on the use of a vehicle voltage, electrically heated bypassed regeneration technique. One of the keys to achieving successful system operation, reliability and durability was the regeneration control algorithm. This program monitors trap status in a particle accumulation mode and restrains the rate and intensity of the regeneration reaction by limiting the amount of oxygen availability in a regeneration mode, resulting in the avoidance of ceramic filter damage. The design of the systems were enhanced by the use of several analytical tools, including: computational fluid dynamic flow analysis, regeneration thermal profile prediction, and finite element stress analysis. Continued effort is being placed on further durability demonstrations in laboratory and vehicular applications.