Direct-energy-regenerated particulate trap technology. Final report

The objective of this CRADA between Lockheed Martin and Cummins Engine Company was to develop fiber-reinforced silicon carbide (SiC) composite materials for use as diesel engine particulate traps. Chemical vapor deposition techniques were used to partially densify and rigidize a thin fibrous substrate and produce the porous SiC- based filter. Microwave energy was used to directly couple to the deposited SiC to uniformly heat the filter and oxidize the collected carbon particulates. For commercial usage particulate traps must: (1) filter carbon particulates from a high temperature diesel exhaust at an acceptably low backpressure, (2) survive thousands of thermal transients due to regeneration or cleaning of the filter by oxidizing the collected carbon, (3) be durable and reliable over the expected life of the filter (300,000 miles or 10,000 hours), and (4) provide a low overall operating cost which is competitive with other filtering techniques. The development efforts performed as part of this CRADA have resulted in a very promising new technology for Cummins Engine Company. Ceramic fiber based filter papers were developed at Fleetguard, Inc., (a Cummins Subsidiary) and used to produce the spiral wound, corrugated filter cartridges. Optimized SiC coatings were developed at Lockheed Martin which couple with 2.45 GHz microwaves. Prototype particulate filter cartridges fabricated at Fleetguard and rigidized at Lockheed Martin performed well in single cylinder engine tests at Cummins. These prototype filters obtained filtering efficiencies greater than 80% at acceptably low backpressures and could be successfully headed and regenerated using a conventional in-home microwave oven