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Regeneration of diesel particulate filters poses major challenges in developing the particulate matter emission control technology to meet EPA 2007/2010 emissions regulations. The problem areas are multifold due to the complexity involved in designing the filter system, developing regeneration strategies and controlling the regeneration process. This paper discusses the need for active regeneration systems. It also addresses several key limitations and trade-offs between the regeneration strategy, chemical kinetics, exhaust gas temperature and the regeneration efficiency. Passive regeneration of diesel particulate filter systems is known to be highly dependent on the engine-out [NOx/PM] ratio as well as exhaust temperature over the duty cycle. Using catalytic oxidation of auxiliary fuel injected into the system, the exhaust gas temperature can be successfully enhanced for filter regeneration.

Emissions regulations for 2007 will likely require engine manufacturers to use a diesel particulate filter (DPF) to meet particulate matter (PM) emission requirements. With the lower operating temperatures of light-duty diesel engines, some form of catalyst will be required to facilitate oxidation of accumulated soot PM to regenerate the DPF. This catalyst can either be permanently applied to the filter substrate in the manufacturing process, or be continuously delivered via the diesel fuel. In this study we examined the impact of using both forms of catalyst. A recently published study of the fuel-borne catalyst additive MMT [1] (Methylcyclopentadienyl Manganese Tricarbonyl), reviewed the performance of MMT in conjunction with an uncatalyzed DPF [2].