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US 8,783,017 B2Granted
System, method, and apparatus to engage alternate reductant in a NOx reduction system
AssigneeCummins Inc.
InventorsAleksey Yezerets, Zheng Liu, Neal W. Currier, J. Stephen Wills
Life of this patent
Estimating the term…
Abstract
An exhaust aftertreatment process including providing a selective catalytic reduction (SCR) catalyst disposed in an exhaust stream of an internal combustion engine; determining that a temperature of the exhaust stream is not within an NH3 based SCR range; and providing an amount of unburned hydrocarbon (UHC) to the SCR catalyst in response to the temperature of the exhaust stream not being within an NH3 based SCR range.
Claims21
A method, comprising:
- providing a selective catalytic reduction (SCR) catalyst disposed in an exhaust stream of an internal combustion engine;
- determining that a temperature of the exhaust stream is not within an ammonia (NH3) based SCR range when the temperature of the exhaust stream is below a lower temperature threshold and when the temperature of the exhaust stream is above an upper temperature threshold;
- and
- providing an amount of unburned hydrocarbon (UHC) to the SCR catalyst in response to determining the temperature of the exhaust stream is not within the ammonia (NH3)based SCR range while reducing an amount of urea injected into the exhaust stream in response to the amount of UHC provided.
1 more element
A system, comprising:
- a selective catalytic reduction (SCR) catalyst disposed in an exhaust stream of an internal combustion engine;
- and
- a controller structured to:
- determine that a temperature of the exhaust stream is not within an ammonia (NH3) based SCR range in response to the temperature of the exhaust stream being below a lower temperature threshold and in response to the temperature of the exhaust stream being above an upper temperature threshold;
- and
- provide an unburned hydrocarbon (UHC) addition command for the SCR catalyst in response to determining the temperature of the exhaust stream is not within the NH3 based SCR range while reducing an amount of urea injected into the exhaust stream in response to the amount of UHC provided.
3 more elements
An apparatus, comprising:
- a selective catalytic reduction (SCR) catalyst disposed in an exhaust stream of an engine;
- an off-nominal temperature module structured to determine an off nominal temperature indicator in response to determining that a temperature of the exhaust stream is not within an ammonia (NH3)based selective catalytic reduction (SCR) range when the temperature of the exhaust stream is below a lower temperature threshold and when the temperature of the exhaust stream is above an upper temperature threshold;
- and
- a secondary NOx reduction module structured to provide an unburned hydrocarbon (UHC) addition command for the SCR catalyst in response to the off nominal temperature indicator and to provide a urea reduction command for the SCR catalyst in response to the UHC addition command.
1 more element
Dependencies are inferred from the claim text.