Diesel engine exhaust gas recirculation system for NO.sub.x control incorporating a compressed air regenerative particulate control system

A diesel engine exhaust gas recirculation and filtration system for reducing nitrogen oxide (NO.sub.x) and total particulate emissions in diesel exhaust from a diesel engine comprising:

• a diesel engine exhaust gas conduit having a diesel exhaust inlet port couplable to a diesel engine and a diesel exhaust outlet port couplable to ambient;
• a regenerable filter having pores sized to capture particles therewithin that are contained in the diesel exhaust, said filter disposed in said diesel engine exhaust conduit between said diesel exhaust inlet port and said diesel exhaust outlet port;
• a recirculation conduit having an upstream inlet coupled to said diesel engine exhaust conduit between said filter and said outlet port, said recirculation conduit further having a downstream outlet coupled to an inlet to the diesel engine, a recirculation control valve being further located downstream of said filter in said recirculation conduit near said upstream inlet of said recirculation conduit;
• a source of compressed air controllably coupled to said diesel engine exhaust gas conduit between said filter and said diesel exhaust outlet port;
• a particulate disposal unit coupled to said diesel engine exhaust gas conduit between said filter and said inlet port;
• and
• a controller, operatively coupled to said source of compressed air and said recirculation control valve in said recirculation conduit, operable in a filtration mode for coupling diesel exhaust in said diesel exhaust gas conduit through said filter and directing a portion of filtered exhaust gas to said recirculation conduit and a remainder portion of filtered exhaust gas out said diesel exhaust output port, and further operable in a regeneration mode to provide at least one pulse of high-pressure air from said source of compressed air that flows through said filter in a direction that dislodges soot (laden with PAH) and ash particles that are lodged within the pores thereof and that moves the soot (laden with PAH) and ash particles into said disposal unit.

A diesel engine exhaust gas recirculation and filtration system for reducing nitrogen oxide (NO.sub.x) and total particulate emissions in diesel exhaust from a diesel engine, comprising:

• an unfiltered diesel exhaust inlet port;
• an unfiltered diesel exhaust gas flow path defined by an exhaust gas line coupled between said inlet port and ambient;
• a recirculation flow path defined by a return line having an upstream inlet located along said unfiltered exhaust gas flow path and a downstream outlet couplable to an inlet to the diesel engine;
• a filter having pores sized to capture particles therewithin that are contained within the diesel exhaust;
• a recirculation control valve located in said recirculation flow path downstream of said filter;
• a source of compressed air controllably coupled to said recirculation flow path;
• a controller operatively coupled to said source of compressed air and said recirculation control valve, said controller being operative in a filtration mode for coupling a part of diesel exhaust along said unfiltered exhaust gas flow path through said filter along said recirculation flow path and to the engine intake and further operative in a regeneration mode for providing at least one pulse of high-pressure air that flows through said filter along said regeneration flow path in a direction that dislodges the soot (laden with PAH) and ash particles that are lodged within the pores in said filter during operation in said filtration mode and that moves the soot (laden with PAH) and ash particles into said unfiltered exhaust gas flow path.