Diesel Exhaust Particulate Control System Development

Control of Nitrogen Oxides in Diesel Engine Exhaust by Catalytic Reduction

“…The control of NOx has been achieved by the improvements in the engine design and combustion chamber modifications etc. But most of those modifications resulted in increase of pollution by particulate emissions [7,8] and deterioration of fuel economy [9].…”

Design and development of a microwave-enhanced diesel soot oxidation system

“…The filtration media for a regeneration system must be capable of collecting most of the particulate matter in the exhaust stream, capable of withstanding high temperatures, have a high filtration surface-to-volume ratio, be inexpensive, durable, and must impose a low pressure loss even when loaded (MacDonald et al, 1988). Ludecke and Dimick (1983) listed the ceramic fiber filter, ceramic foam filter, metal mesh, and wall-flow monolith as the filters that were considered to have the properties necessary for particulate entrapment and incineration. The ceramic fiber and wall-flow monolith are surface collection materials that build a layer of soot on the filtration surfaces.…”

“…The ceramic foam and metal mesh filters were considered difficult to regenerate without overheating due to the high concentration of soot near the front of the filter. Another observed difficulty was that transient engine cycles tended to dislodge particles from the trap (Ludecke and Dimick, 1983). Clogging can be a problem with surface collection filters, and backpressure levels can become high enough to stall an engine (Kiyota et al 1986).…”

“…Test results demonstrated that the exhaust temperatures were sufficient for regeneration even at moderate engine load conditions (Kiyota et al, 1986). An intake air throttling system was also developed and tested by Ludecke and Dimick (1983) who had employed a flowthrough, catalyzed, metal mesh trap, and a ceramic foam trap. Significant engine loading was required for regeneration if the filter was not catalyzed.…”

“…One of the methods of decreasing the ignition temperature of the soot collected within a filter is through the use of a fuel-borne catalyst. Ludecke and Dimick (1983) performed laboratory tests with manganese fuel additives in which the ignition temperature of the soot was decreased by 80 o C (144 o F).…”