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US 8,555,617 B2Granted
Exhaust gas treatment system including a four-way catalyst and urea SCR catalyst and method of using the same
AssigneeGM Global Technology Operations LLC
InventorRahul Mital
Life of this patent
Estimating the term…
Abstract
The present invention is directed towards methods and systems for treatment of exhaust gas from an engine. In one embodiment, an exhaust gas treatment system for a diesel engine includes a four-way catalyst in fluid communication with a diesel engine to receive an exhaust gas flow therefrom, the four-way catalyst comprising a lean nitrogen oxides (NOX) trap and a diesel particulate filter (DPF). The system also includes a urea selective catalytic reduction (U-SCR) catalyst in fluid communication with the four-way catalyst to receive the exhaust gas flow therefrom.
Claims17
An exhaust gas treatment system for a diesel engine, comprising:
- a diesel oxidation catalyst (DOC) in fluid communication with the diesel engine to receive an exhaust gas flow therefrom, the DOC disposed in a DOC housing;
- a hydrocarbon injection device located between the engine and the DOC that is configured to inject a hydrocarbon, CO, or H2 material, or combination thereof, into the exhaust gas flow;
- a four-way catalyst in fluid communication with the DOC to receive the exhaust gas flow therefrom, the four-way catalyst comprising a lean nitrogen oxides (NOX) trap and a diesel particulate filter (DPF);
- and
- a urea selective catalytic reduction (U-SCR) catalyst in fluid communication with the four-way catalyst to receive the exhaust gas flow therefrom;
- a second injection device that is configured to inject urea or ammonia, or a combination thereof, into the exhaust gas flow between the four-way catalyst and the U-SCR;
- and
- a controller that is configured to control operation of the exhaust gas aftertreatment system and periodic and selective injection of the hydrocarbon, CO or H2 material, or combination thereof, using the hydrocarbon injection device, and periodic and selective injection of the urea or ammonia, or combination thereof using the second injection device, and determine an amount of NOX in the exhaust gas flow, the controller configured to selectively operate in a first mode to minimize consumption of the urea or ammonia, or a combination thereof, and minimize NOX conversion in the U-SCR catalyst or in a second mode to minimize consumption of the hydrocarbon, CO or H2 material, or combination thereof, and minimize NOX conversion in the four-way catalyst.
5 more elements
A method of using an exhaust gas treatment system for a diesel engine comprising a diesel oxidation catalyst (DOC) in fluid communication with the diesel engine to receive an exhaust gas flow therefrom, the DOC disposed in a DOC housing;
- a hydrocarbon injection device located between the engine and the DOC that is configured to inject a hydrocarbon, CO, or H2 material, or combination thereof, into the exhaust gas flow;
- a four-way catalyst in fluid communication with the DOC to receive the exhaust gas flow therefrom, the four-way catalyst comprising a lean nitrogen oxides (NOX) trap and a diesel particulate filter (DPF);
- a urea selective catalytic reduction (U-SCR) catalyst in fluid communication with the four-way catalyst to receive the exhaust gas flow therefrom;
- a second injection device that is configured to inject urea or ammonia, or a combination thereof, into the exhaust gas flow between the four-way catalyst and the U-SCR;
- and a controller that is configured to control operation of the engine and periodic and selective dosing of the hydrocarbon, CO or H2 material, or combination thereof, and periodic and selective dosing of the urea or ammonia, or combination thereof, and determine an amount of NOX in the exhaust gas flow;
- the method comprising:
- configuring the controller to operate in a first mode to minimize consumption of the urea or ammonia, or a combination thereof, and minimize NOX conversion in the U-SCR catalyst or in a second mode to minimize consumption of the hydrocarbon, CO or H2 material, or combination thereof, and minimize NOX conversion in the four-way catalyst;
- operating the engine to produce the exhaust gas flow, and
- periodically and selectively injecting at least one of the hydrocarbon, CO or H2 material, or combination thereof, or the urea or ammonia, or combination thereof, into the exhaust gas flow using the controller to operate the exhaust gas treatment system in the first mode or the second mode.
6 more elements
An exhaust gas treatment system for a diesel engine, comprising:
- a diesel engine;
- a diesel oxidation catalyst (DOC) in fluid communication with the diesel engine to receive an exhaust gas flow therefrom, the DOC disposed in a DOC housing;
- a hydrocarbon injection device located between the engine and the DOC that is configured to inject a hydrocarbon, CO, or H2 material, or combination thereof, into the exhaust gas flow;
- a four-way catalyst in fluid communication with the DOC to receive the exhaust gas flow therefrom, the four-way catalyst comprising a lean nitrogen oxides (NOX) trap and a diesel particulate filter (DPF);
- and
- a urea selective catalytic reduction (U-SCR) catalyst in fluid communication with the four-way catalyst to receive the exhaust gas flow therefrom;
- a second injection device that is configured to inject urea or ammonia, or a combination thereof, into the exhaust gas flow between the four-way catalyst and the U-SCR;
- and
- a controller that is configured to control operation of the exhaust gas aftertreatment system and periodic and selective injection of the hydrocarbon, CO or H2 material, or combination thereof, using the hydrocarbon injection device, and periodic and selective injection of the urea or ammonia, or combination thereof using the second injection device, and determine an amount of NOX in the exhaust gas flow, the controller configured to selectively operate in a first mode to minimize consumption of the urea or ammonia, or a combination thereof, and minimize NOX conversion in the U-SCR catalyst or in a second mode to minimize consumption of the hydrocarbon, CO or H2 material, or combination thereof, and minimize NOX conversion in the four-way catalyst.
6 more elements
Dependencies are inferred from the claim text.