Compressor bypass to exhaust for particulate trap regeneration

An exhaust system for an internal combustion engine comprising:

• an exhaust driven, intake air compressor configured to receive an exhaust gas from the internal combustion engine and to deliver compressed air through a compressed air conduit to an intake system of the engine;
• an exhaust gas conduit in fluid communication with, and configured to receive an exhaust gas from an outlet of the exhaust driven, intake air compressor;
• an air conduit extending between and fluidly coupling the compressed air conduit of the exhaust driven, intake air compressor to the exhaust gas conduit;
• a valve disposed in the air conduit and configured to inject compressed air from the exhaust driven, intake air compressor into the exhaust gas conduit;
• a hydrocarbon supply connected to and in fluid communication with the exhaust gas conduit for delivery of a hydrocarbon thereto and formation of an exhaust gas, hydrocarbon and air mixture therein;
• an oxidation device downstream of the air conduit and the hydrocarbon supply, and configured to receive the compressed air, exhaust gas and hydrocarbon mixture and induce a rapid exothermic oxidation reaction of the mixture to thereby heat the exhaust gas;
• and
• a particulate filter assembly in fluid communication with the exhaust gas conduit, and configured to receive the heated exhaust gas from the oxidation device for combustion of carbon and particulates trapped therein.

A method for regenerating an exhaust gas particulate filter in an exhaust system for an internal combustion engine that comprises an intake air compressor configured to deliver compressed air, through a compressed air conduit, to an intake system of the engine, an exhaust gas conduit in fluid communication with, and configured to receive an exhaust gas from, the internal combustion engine, a air conduit extending between and fluidly coupling the compressed air conduit of the intake air compressor to the exhaust gas conduit, a valve disposed in the air conduit and configured to inject compressed air from the compressor into the exhaust gas conduit;

• a hydrocarbon supply connected to and in fluid communication with the exhaust gas conduit for delivery of a hydrocarbon thereto and formation of an exhaust gas, hydrocarbon and compressed air mixture therein;
• an oxidation device downstream of the air conduit and the hydrocarbon supply, and configured to receive the compressed air, exhaust gas and hydrocarbon mixture and induce a rapid exothermic oxidation reaction of the mixture to thereby heat the exhaust gas;
• a particulate filter assembly in fluid communication with the exhaust gas conduit, and configured to receive the heated exhaust gas from the oxidation device for combustion of carbon and particulates trapped therein;
• and
• a controller in signal communication with a plurality of sensors in fluid communication with exhaust gas conduit and configured to initiate delivery of the hydrocarbon and the air to assist the combustion of the carbon and particulates, comprising:
• operating the controller through signal communication with the sensors to determine if the exhaust system backpressure has reached a level indicative of the need to regenerate the exhaust gas particulate filter;
• operating the controller through signal communication with the sensors to determine the level of oxygen in the exhaust gas flow;
• operating the controller to activate the air injector to add compressed air from the air conduit to the exhaust gas flow if the level of oxygen in the exhaust gas flow is below that required for complete oxidation of hydrocarbon in the exhaust gas, regeneration of the particulate filter assembly, or both.