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US 9,429,060 B2Granted
Systems and methods for control of engine NOx emissions using liquid and dry reductant sources
AssigneeCummins Emission Solutions Inc.
InventorsCary Henry, Steven J. Kolhouse
Life of this patent
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Abstract
Reductant delivery systems are disclosed that include a dry reductant source and a liquid reductant source which are operable to selectively provide gaseous reductant and liquid reductant to an exhaust aftertreatment system for treatment and reduction of NOx emissions. The gaseous reductant is provided to the exhaust aftertreatment system for treatment of NOx emissions under a first temperature condition associated with the exhaust system and the liquid reductant for treatment of NOx emissions under a second temperature condition associated with the exhaust system.
Claims25
A method, comprising:
- producing an exhaust gas in an exhaust flow path including a selective catalytic reduction (SCR) catalyst, wherein producing the exhaust gas includes operating an internal combustion engine;
- determining a temperature condition of the exhaust gas;
- determining an engine shut-down condition, wherein the engine shutdown condition includes a pre-shutdown condition and a post-shutdown condition;
- and
- selectively providing one of a gaseous reductant released from a dry reductant source and a liquid reductant from a liquid reductant source to the exhaust flow path upstream of the SCR catalyst in response to the engine shutdown condition, wherein the gaseous reductant is provided from the dry reductant source in response to the post-shutdown condition and the liquid reductant is provided from the liquid reductant source in response to the pre-shutdown condition.
2 more elements
A method, comprising:
- producing an exhaust gas in an exhaust flow path including a selective catalytic reduction (SCR) catalyst;
- determining a temperature condition of the exhaust gas, wherein determining the temperature condition includes determining an amount of key-off time;
- and
- selectively providing one of a gaseous reductant released from a dry reductant source and a liquid reductant from a liquid reductant source to the exhaust flow path upstream of the SCR catalyst in response to the temperature condition of the exhaust gas, wherein the gaseous reductant is provided when the key-off time exceeds a predetermined amount of time and an ambient temperature is below a predetermined threshold.
1 more element
A system, comprising:
- an internal combustion engine operable to produce an exhaust stream, the exhaust stream including an amount of NOx emitted into an exhaust flow path;
- a first reductant source that stores a NOx reductant in a solid storage media and a second reductant source that stores the NO reductant in a liquid medium;
- a selective catalytic reduction (SCR) conversion catalyst in the exhaust flow path, wherein the first reductant source and the second reductant source are each connected to the exhaust flow path upstream of the SCR catalyst to provide the NOx reductant to the SCR catalyst;
- and
- a controller connected to one or more sensors associated with the exhaust stream operable to indicate a temperature condition of the exhaust stream, wherein the controller is configured to:
- determine an engine shut-down condition of the internal combustion engine, wherein the engine shutdown condition includes a pre-shutdown condition and a post-shutdown condition,
- control the first reductant source to dose the NOx reductant in a gaseous form from the solid storage media into the exhaust stream in response to the post-shutdown condition, and
- control the second reductant source to dose the NOx reductant from the liquid medium in a liquid form in response to the pre-shutdown condition.
5 more elements
An apparatus, comprising:
- an electronic controller structured to receive operating parameters from at least one sensor associated with an exhaust system that is connected with a first reductant source for storing a gaseous reductant in a solid storage media and a second reductant source for storing a liquid reductant in a liquid storage medium, wherein the controller includes:
- an exhaust system temperature condition module structured to determine a temperature condition associated with the exhaust system and determine the temperature condition in response to a shutdown of an internal combustion engine connected to the exhaust system, wherein the temperature condition includes a pre-shutdown condition and a post-shutdown condition;
- and
- a reductant source selection module structured to selectively dose gaseous reductant from the first reductant source and liquid reductant from the second reductant source in response to the temperature condition and to provide gaseous reductant from the first reductant source in response to the post-shutdown condition and to provide liquid reductant from the second reductant source in response to the pre-shutdown condition.
1 more element
Dependencies are inferred from the claim text.