Processes And Devices For Regenerating Gasoline Particulate Filters

Abstract

Processes and devices for regenerating a gasoline particulate filter utilized in filtering an exhaust stream of a direct-injection gasoline engine operating at substantially stoichiometric conditions include introducing an amount of oxygen into the exhaust stream downstream of the engine and upstream of the gasoline particulate filter, and regenerating the gasoline particulate filter by passing the exhaust stream enriched with the amount of oxygen through the gasoline particulate filter.

1 . A process for regenerating a gasoline particulate filter utilized in filtering an exhaust stream of a direct-injection gasoline engine operating at substantially stoichiometric conditions, the process comprising:
 introducing an amount of oxygen into the exhaust stream downstream of the engine and upstream of the gasoline particulate filter; and   regenerating the gasoline particulate filter by passing the exhaust stream enriched with the amount of oxygen through the gasoline particulate filter.   
     
     
         2 . The process of  claim 1 , further comprising providing an oxygen sensor and at least one of an engine control system and a pump control system that receives an input from the oxygen sensor and selects and maintains a desired oxygen concentration in the exhaust stream passing through the gasoline particulate filter. 
     
     
         3 . The process of  claim 1 , further comprising providing a temperature sensor and at least one of an engine control system and a pump control system that receives an input from the temperature sensor and selects and maintains a desired oxygen concentration in the exhaust stream passing through the gasoline particulate filter. 
     
     
         4 . The process of  claim 1 , further comprising providing a pressure sensor and at least one of an engine control system and a pump control system that receives an input from the pressure sensor and selects and maintains a desired oxygen concentration in the exhaust stream passing through the gasoline particulate filter. 
     
     
         5 . The process of  claim 1 , wherein the exhaust stream passing through the gasoline particulate filter has a volumetric concentration of oxygen in a range of about 1.0% to about 2.0%. 
     
     
         6 . The process of  claim 5 , wherein the volumetric concentration of oxygen is about 1.5%. 
     
     
         7 . The process of  claim 1 , wherein an air injection pump is used to introduce the amount of oxygen into the exhaust stream. 
     
     
         8 . The process of  claim 7 , wherein the amount of oxygen is provided in the form of air from the surrounding environment. 
     
     
         9 . The process of  claim 1 , wherein a cylinder deactivation is used to introduce the amount of oxygen into the exhaust stream. 
     
     
         10 . The process of claim of  claim 9 , wherein the cylinder deactivation is coordinated with a fuel economy function. 
     
     
         11 . The process of  claim 1 , further comprising introducing a selected dose of hydrocarbon into the exhaust stream upstream of the gasoline particulate filter. 
     
     
         12 . The process of  claim 11 , further comprising controlling operational parameters of the engine to introduce the selected dose of hydrocarbon into the exhaust stream. 
     
     
         13 . A process for regenerating a gasoline particulate filter utilized in filtering an exhaust stream of a direct-injection gasoline engine, the process comprising:
 providing an engine control system for controlling operational parameters of the direct-injection gasoline engine to produce an exhaust stream containing a desired oxygen concentration; and   regenerating the gasoline particulate filter by passing the exhaust stream containing the desired oxygen concentration through the gasoline particulate filter.   
     
     
         14 . The process of  claim 13 , further comprising providing at least one of an oxygen sensor, a temperature sensor and a pressure sensor that provide at least one input to the engine control system. 
     
     
         15 . The process of  claim 13 , wherein the exhaust stream containing the desired oxygen concentration is produced by a partial lean-burn operation. 
     
     
         16 . The process of  claim 13 , wherein the exhaust stream passing through the gasoline particulate filter has a volumetric concentration of oxygen in a range of about 1.0% to about 2.0%. 
     
     
         17 . The process of  claim 16 , wherein the volumetric concentration of oxygen is about 1.5%. 
     
     
         18 . A regeneration device for a gasoline particulate filter which traps particulate matter contained in an exhaust gas of a direct-injection gasoline engine, the regeneration device comprising:
 a mechanism which raises and lowers an oxygen concentration of the exhaust gas in order to facilitate a burning of particulate matter trapped in the filter;   at least one sensor selected from a group comprising an oxygen sensor, a temperature sensor and a pressure sensor; and   at least one of an engine control system and a pump control system that receives input from the at least one sensor and controls the mechanism to raise and lower the oxygen concentration of the exhaust gas.   
     
     
         19 . The regeneration device of  claim 18 , wherein the mechanism is an air injection pump that is employed to introduce air into the exhaust stream downstream of the engine and upstream of the gasoline particulate filter. 
     
     
         20 . The regeneration device of  claim 18 , wherein the mechanism is an engine operation control.