Low Mileage Evaluation of an Electrically Regenerable Diesel Particulate Trap

A woven fiber Diesel particulate filter has been developed which demonstrates good low-mileage soot-trapping and regeneration efficiencies. The fiber filters are wound around electric heating elements, which provide uniform energy in close proximity to the soot-laden fiber during regeneration. The filters are loaded with particulate to a target backpressure and energized one at a time with intermittent particulate loading to the target backpressure between successive filter regenerations. These design features were utilized to help minimize regeneration power requirements, and maximize mileage accumulation between regenerations. Regenerations are performed with unbypassed exhaust flow and can be accomplished under high vehicle speed operation as well as under idle conditions. The passenger car system contains four filters which are approximately 20 inches long and 3.0 inches in diameter. EPA evaluation of this particulate regeneration system has included determination of cyclic and steady-state filter efficiency, regeneration efficiency, the affect on regeneration power requirements of various exhaust flow rates, and emissions and fuel economy characteristics of a test vehicle equipped system over standard Federal test procedures.