US20170370259A1 - NOx REDUCTION SYSTEM - Google Patents
NOx REDUCTION SYSTEM Download PDFInfo
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- US20170370259A1 US20170370259A1 US15/542,839 US201615542839A US2017370259A1 US 20170370259 A1 US20170370259 A1 US 20170370259A1 US 201615542839 A US201615542839 A US 201615542839A US 2017370259 A1 US2017370259 A1 US 2017370259A1
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- nox
- nox trap
- reducing agent
- adding means
- engine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
- F01N13/0097—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
- F01N3/0842—Nitrogen oxides
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0871—Regulation of absorbents or adsorbents, e.g. purging
- F01N3/0885—Regeneration of deteriorated absorbents or adsorbents, e.g. desulfurization of NOx traps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
- F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
- F01N2570/14—Nitrogen oxides
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/06—Adding substances to exhaust gases the substance being in the gaseous form
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
- F01N2900/1402—Exhaust gas composition
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
- F01N2900/1602—Temperature of exhaust gas apparatus
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Definitions
- the invention relates to a system and method for reducing the nitrogen oxides found in the exhaust gas produced by a vehicle engine.
- Known emission control technologies include systems for reducing the nitrogen oxides (i.e. NO, NO 2 ) of exhaust gas produced by a vehicle engine.
- Such technologies include Selective Catalytic Reduction (SCR) and Lean NOx Traps (LNT).
- SCR Selective Catalytic Reduction
- LNT Lean NOx Traps
- the SCR and LNT systems are provided in the exhaust line of a vehicle.
- Selective Catalytic Reduction is a process used for converting the nitrogen oxides (NOx) produced by a vehicle engine into diatomic nitrogen (N 2 ) and water (H 2 O).
- Suitable catalysts for use in Selective Catalytic Reduction include base metal catalysts such as vanadium and tungsten.
- the reduction of the NOx generally takes place in a catalytic chamber. Before the NOx gases pass into this chamber they are mixed with a reducing agent.
- Suitable reducing agents include liquid urea solution (for example, AdBlue®) and gaseous ammonia.
- a SCR catalyst can only operate once the engine has reached a temperature of about 120° C. to 180° C. but this can take several minutes in cold start-up conditions or at low engine load. Temperatures of around 180° C. are required when the reducing agent is a liquid urea solution such as AdBlue® and temperatures of approximately 120° C. are needed when the reducing agent is gaseous ammonia.
- Lean NOx Traps are NOx absorbers which chemically bind NOx during lean operation of a vehicle engine.
- Lean NOx Traps comprise ceramic cordierite honeycomb structures coated with fine-grained oxides such as aluminum oxide (Al 2 O 3 ), catalytically active materials (namely the platinum group metals platinum (Pt), palladium (Pd) and rhodium (Rh)), alkaline oxides or carbonates (for example, of barium (Ba) or sodium (Na)), and oxygen storage components (typically ceria-zirconia solid solutions).
- Al 2 O 3 aluminum oxide
- catalytically active materials namely the platinum group metals platinum (Pt), palladium (Pd) and rhodium (Rh)
- alkaline oxides or carbonates for example, of barium (Ba) or sodium (Na)
- oxygen storage components typically ceria-zirconia solid solutions.
- NOx trap During lean operation of an engine, fuel is burned with an excess of air. This means that during lean operation of the engine, the NOx trap is provided with oxygen which is used to oxidise NO to NO 2 .
- the NOx (NO and NO 2 ) can be absorbed onto the surface of the NOx trap by the alkaline oxides or carbonates. However, the absorption sites on the NOx trap will eventually become saturated and the NOx trap will not be able to bind with any more NOx.
- the vehicle engine When the absorber capacity of the NOx trap is saturated, the vehicle engine needs to be switched to rich mode. In contrast to lean engine operation, during rich engine operation an air/fuel ratio which provides exactly enough air to burn all of the fuel is used. This means that the oxygen in the NOx trap is replaced by reducing species (such as H 2 , CO and hydrocarbons). This results in the NOx absorbed by the NOx Trap being reduced to N 2 over a reduction catalyst. The N 2 is then released from the trap.
- reducing species such as H 2 , CO and hydrocarbons
- solid components and deposits are formed in the exhaust pipe.
- solid deposits are formed when AdBlue® is injected into a SCR at temperatures below 180° C. Such deposits may cause fouling or clogging of components of the system.
- the object of the present invention is to provide an improved NOx reduction system.
- the present invention therefore, provides a system for reducing nitrogen oxides of an exhaust gas produced by an engine of a vehicle, the system comprising a NOx trap, and a first adding means for adding a reducing agent to the exhaust gas, wherein the first adding means is positioned downstream of the engine and either upstream of or within the NOx trap.
- the added reducing agent can be used to purge the NOx trap.
- the purge of the NOx trap can also be activated by a combination of ammonia injection and reduced rich engine operation, also resulting in a saving of fuel.
- the first adding means is positioned upstream of the NOx trap.
- the NOx trap is a lean NOx trap (LNT).
- LNT lean NOx trap
- Suitable materials for use in the LNTs of the present invention are disclosed by U.S. Pat. No. 8,853,123, US patent application US 2002/0076373, and the article entitled “Novel low temperature NOx storage-reduction catalysts for diesel light-duty engine emissions based on hydrotalcite compounds” published in Catalysis Today (Volume 75, issues 1 to 4, 3 Jul. 2002, pages 421-429), for example.
- U.S. Pat. No. 8,853,123 describes a LNT catalyst with enhanced Nitrogen Oxide storage capacity at low temperature and significantly inhibited thermal desorption.
- This LNT catalyst is said to be prepared by coating a washcoat on a honeycomb-type carrier and drying and baking the same.
- the washcoat contains a first catalyst powder in which barium (Ba) and a precious metal are supported on a ceria support, and a second catalyst powder in which a precious metal is supported on a magnesium (Mg) substituted alumina support.
- the first adding means may comprise a nozzle for spraying or squirting the reducing agent into the exhaust gas.
- the reducing agent is ammonia.
- the ammonia is preferably provided in liquid or gaseous form.
- NOx reduction systems of the present invention may be connected to a tank for storing an ammonia precursor such as, for example, urea or a concentrated urea solution of at least 10% urea up to 35 wt % urea in water.
- This tank for storing an ammonia precursor is connected to an ammonia precursor decomposition unit for generation of ammonia, wherein the urea decomposition unit is in fluid communication with the adding means.
- the ammonia precursor may be a liquid ammonia precursor; in particular, it can be a solution.
- the ammonia precursor may be a solid.
- a tank for storing the products resulting from the decomposition of the ammonia precursor.
- the system further comprises a first Selective Catalytic Reduction unit, wherein this first Selective Catalytic Reduction unit is located downstream of the NOx trap.
- this first Selective Catalytic Reduction unit is located downstream of the NOx trap.
- the NOx trap and the first Selective Catalytic Reduction unit may be located within the same canning or casing.
- a combined unit has the advantages of being more compact and avoiding heat loss between the NOx trap and the first Selective Catalytic Reduction unit.
- the system further comprises a second Selective Catalytic Reduction unit, wherein the second Selective Catalytic Reduction unit is located downstream of the first Selective Catalytic Reduction unit.
- the system may also further comprise a second adding means for adding a reducing agent to the exhaust gas, wherein this second adding means is located upstream of at least one Selective Catalytic Reduction unit. Therefore, in embodiments with a single Selective Catalytic Reduction unit, the second adding means can be located upstream of this first Selective Catalytic Reduction unit. In embodiments with a first and second Selective Catalytic Reduction unit, the second adding means can be located upstream of both the first and second Selective Catalytic Reduction units or only the second Selective Catalytic Reduction unit.
- the second adding means is also adapted to add a reducing agent to the exhaust gas, for example, by squirting or spraying the reducing agent into the exhaust line.
- the second adding means may comprise a nozzle for spraying or squirting the reducing agent into the exhaust gas.
- the reducing agent is preferably ammonia, preferably in liquid or gaseous form.
- the system for reducing nitrogen oxides of an exhaust gas produced by an engine of a vehicle of the present invention further comprises at least one sensor and a controller, wherein the controller is configured to receive sensed data from the at least one sensor and to control at least one of the adding means based on the sensed data from the at least one sensor.
- a controller configured to receive sensed data from the at least one sensor can control the first adding means based on the sensed data.
- the controller may be configured to control only one of the first or second adding means, or the controller may control both the first and second adding means based on the sensed data. If there are further adding means, the controller may also control these.
- the system may comprise a NOx sensor located downstream of the NOx trap and a controller is configured to receive sensed data from the NOx sensor and to control at least one of the adding means based on the data received from the NOx sensor. Therefore, the controller may be configured to control at least the first and/or the second adding means based on the data received from the NOx sensor. For example, in embodiments with only a first adding means, this first adding means can be controlled based on the data received from the NOx sensor.
- Embodiments of the invention may comprise multiple NOx sensors, for example, two NOx sensors, wherein one of these NOx sensors is located downstream of the NOx trap and upstream of a SCR unit and the other NOx sensor is located downstream of this SCR unit.
- the controller is configured to receive sensed data from the multiple NOx sensors and control the adding of the reducing agent based on at least the sensed NOx data.
- the system may comprise a temperature sensor, wherein the controller is configured to control at least one of the adding means based on the temperature sensed by the temperature sensor.
- the controller may be configured to control at least the first and/or the second adding means based on the temperature sensed by the temperature sensor.
- the system may be provided with multiple temperature sensors.
- the system may have a first temperature sensor in or in close proximity to the NOx trap, and a second temperature sensor in or in close proximity to a SCR unit.
- the controller is configured to receive data from the multiple temperature sensors and to control one or more of the adding means based on at least this sensed temperature data.
- the system may comprise multiple NOx and/or temperature sensors.
- the controller is configured to receive sensed data from the multiple sensors and to control one or more of the adding means based on the data received from the sensors.
- the at least one of the adding means is configured to inject the reducing agent in the gas phase. Therefore, the first and/or second adding means may be configured to add the reducing agent in the gas phase.
- the first adding means are arranged to spray reducing agent in an exhaust line of the vehicle between the engine and the NOx trap.
- the system of the present invention is located within an exhaust line of the vehicle.
- Embodiments of the system of the invention may also be provided with a diesel oxidation catalyst (DOC) unit downstream of the engine and upstream of both the NOx trap and the first adding means.
- DOC unit diesel oxidation catalyst
- a controller configured to receive data indicative of a measured parameter in an exhaust system and control adding a reducing agent upstream of a NOx trap or within a NOx trap and downstream of an engine based on the received data.
- the controller may be configured to receive data indicative of a NOx content in an exhaust gas and control the adding of a reducing agent upstream of a NOx trap or within a NOx trap (and downstream of an engine) based on the received NOx content data.
- the controller may additionally or alternatively be configured to receive data indicative of the temperature of the exhaust system and control the adding of a reducing agent upstream of a NOx trap or within a NOx trap (and downstream of an engine) based on the received temperature data.
- an assembly for use in reducing nitrogen oxides of exhaust gas produced by an engine of a vehicle comprising a NOx trap, a first adding means for adding a reducing agent to the exhaust gas, and a controller configured to receive data indicative of a measured parameter, wherein the first adding means is positioned downstream of the engine and either upstream or within the NOx trap, and the controller is configured to control adding a reducing agent upstream of a NOx trap or within a NOx trap based on the received data.
- a method for reducing nitrogen oxides of an exhaust gas produced by an engine comprising: storing nitrogen oxides produced by an engine in a NOx trap positioned downstream of the engine; adding a reducing agent into the exhaust gas upstream of or within the NOx trap and downstream of the engine; and using this reducing agent to reduce the NOx absorbed in the NOx trap and purge the NOx trap.
- the reducing agent is ammonia.
- the method preferably further comprises using the reducing agent to reduce NOx in a Selective Catalytic Reduction (SCR) unit positioned downstream of the NOx trap.
- SCR Selective Catalytic Reduction
- the method comprises measuring a parameter and using this parameter to control the addition of the reducing agent, wherein the measured parameter may be a NOx content of the exhaust gas or a temperature.
- the temperature may be the temperature of the exhaust gas coming from the engine.
- the reducing agent is added once a required temperature is reached.
- the required temperature may be around 120 to 180° C., preferably, 120 to 140° C.
- the NOx content of the exhaust gas may be measured downstream of the NOx trap and/or downstream of a SCR unit
- FIG. 1 is a diagram illustrating a first embodiment of a system for reducing NOx
- FIG. 2 is a diagram illustrating a second embodiment of a system for reducing NOx
- FIG. 3 is a diagram illustrating a third embodiment of a system for reducing NOx
- FIG. 4 is a diagram illustrating a fourth embodiment of a system for reducing NOx
- FIG. 5 is a diagram illustrating a fifth embodiment of a system for reducing NOx
- FIG. 6 is a diagram illustrating a sixth embodiment of a system for reducing NOx
- FIG. 7 is a diagram illustrating a seventh embodiment of a system for reducing NOx
- FIG. 8 is a diagram illustrating an eighth embodiment of a system for reducing NOx
- FIG. 9 is a diagram illustrating a ninth embodiment of a system for reducing NOx
- FIG. 10 is a diagram illustrating a tenth embodiment of a system for reducing NOx.
- FIG. 11 is a diagram illustrating an eleventh embodiment of a system for reducing NOx.
- the figures show embodiments of a system for reducing nitrogen oxides found in the exhaust gas produced by an engine 1 of a vehicle.
- the systems comprise a NOx trap 3 and a first adding means 5 for adding a reducing agent to the exhaust gas, wherein the first adding means 5 is located downstream of the vehicle engine 1 and upstream of the NOx trap 3 .
- the first adding means 5 may be located within the NOx trap 3 .
- the arrow D shows the movement of the exhaust gas in the downstream direction.
- the systems are all located within an exhaust line 2 .
- the first adding means 5 comprises some form of outlet connected to the exhaust line.
- the means may comprise an injector or a spray with an outlet nozzle adapted to inject or spray the reducing agent in liquid or gaseous form into the exhaust line 2 .
- the reducing agent is liquid or gaseous ammonia.
- the reducing agent is supplied from the store 4 of reducing agent.
- This store 4 may be a store of ammonia.
- the store 4 may hold urea and the reducing agent store 4 further comprises a urea decomposition section configured to convert urea solution into ammonia for supply to the first adding means 5 .
- exhaust gases comprising nitrogen oxides are generated by the engine 1 . These exhaust gases move down the exhaust line 2 in direction D and pass through a NOx trap 3 positioned downstream of the engine 1 .
- the NOx generated by the engine is stored in the NOx trap 3 .
- reducing agent is injected into the exhaust gases upstream of the NOx trap 3 by the first adding means 5 .
- the system just comprises a NOx trap 3 .
- reducing agent is injected or sprayed into the exhaust line 2 upstream of the NOx trap 3 .
- the injected/sprayed reducing agent is then used by the NOx trap to reduce the absorbed NOx to diatomic nitrogen (N 2 ).
- the system also comprises at least one first Selective Catalytic Reduction (SCR) unit.
- SCR Selective Catalytic Reduction
- the systems comprise a NOx trap 3 , a first adding means 5 and a first Selective Catalytic Reduction (SCR) unit 6 , wherein this SCR unit 6 is located downstream of both the engine 1 and the NOx trap 3 . Therefore, the first adding means 5 is located downstream of the vehicle engine 1 and upstream of both the NOx trap 3 and the SCR unit 6 .
- SCR Selective Catalytic Reduction
- exhaust gases comprising nitrogen oxides are generated by the engine 1 . These exhaust gases move down the exhaust line 2 in direction D. The exhaust gases firstly pass through a NOx trap 3 positioned downstream of the engine 1 , before then passing through a first SCR unit 6 located downstream of the NOx trap 3 .
- the NOx generated by the engine 1 is stored in the NOx trap 3 positioned upstream of the SCR unit 6 .
- the system is warm enough (for example, around 120° C. to 180° C. or warmer) for the SCR unit 6 to function properly and reduce the NOx to diatomic nitrogen (N 2 ) and water (H 2 O)
- reducing agent can be injected upstream of the NOx trap 3 , resulting in both a purge of the NOx trap and reduction of NOx in the SCR unit 6 .
- the injected reducing agent is thus used to both purge the NOx trap 3 and reduce the NOx in the SCR unit 6 .
- FIGS. 2, 3 and 4 illustrate embodiments of the invention with only a single SCR unit 6 .
- the NOx trap 3 and the SCR 6 unit are spaced apart within the exhaust line 2 .
- the distance between the engine 1 and the NOx trap 3 is around 10 to 50 cm.
- the NOx trap 3 and SCR unit 6 are located within the same canning. This combined NOx trap 3 and SCR unit 6 is also positioned around 10 to 50 cm along the exhaust line 2 from the engine. The combined unit has the advantage of avoiding heat loss between the NOx trap 3 and the SCR unit 6 . The combined NOx trap 3 and SCR unit 6 is also more compact.
- the systems comprise a second SCR unit 7 in addition to the first SCR unit 6 .
- This second SCR unit 7 is located downstream of all of the engine 1 , the NOx trap 3 and the first SCR unit 6 .
- a second SCR unit 7 may be useful if the space for the first SCR unit 6 near the engine 1 is too small to host the full volume of the SCR catalyst.
- the exhaust gas will pass through the NOx trap 3 , the first SCR unit 6 and then the second SCR unit 7 . If there is any NOx remaining in the exhaust gas after it has passed through the NOx trap 3 and the first SCR unit 6 , this should be reduced to into diatomic nitrogen (N 2 ) and water (H 2 O) by the second SCR unit 7 . Therefore, providing a second SCR unit 7 can help ensure that the NOx content of the exhaust gas leaving the vehicle is zero or very low.
- the system is additionally provided with an additional adding means 8 (for example, an injector/spray with an outlet nozzle) positioned upstream of at least one SCR unit 6 , 7 .
- an additional adding means 8 for example, an injector/spray with an outlet nozzle
- the system is provided with a device 9 to distribute the reducing agent between the first adding means 5 and the second adding means 8 .
- This device 9 could be a three-way valve, for example.
- the reducing agent moves in direction A from the reducing agent store 4 .
- the NOx generated by the engine 1 is stored in the NOx trap 3 .
- NOx trap 3 becomes saturated, NOx will no longer be absorbed by the NOx trap 3 and will instead pass through the NOx trap 3 (i.e. “NOx slip” will occur).
- reducing agent can be injected upstream of the relevant SCR unit 6 , 7 by the second adding means 8 . Injection of reducing agent upstream of this SCR unit 6 , 7 allows the NOx that has passed through the NOx trap 3 to be reduced by the SCR unit 6 , 7 that has reached its operating temperature without purging the NOx trap 3 .
- the system is sufficiently warm (i.e.
- reducing agent when the NOx trap has reached its operating temperature), reducing agent will then be injected upstream of the NOx trap 3 by the first adding means 5 resulting in a purge of the NOx trap 3 in addition to reduction of the NOx by the reducing agent in one or more SCR units 6 , 7 .
- An SCR unit 6 , 7 may have a lower operating temperature than that of the NOx trap 3 if gaseous ammonia is used as the reducing agent, for example. If the reducing agent is gaseous ammonia, the operating temperature of the SCR units 6 , 7 may be around 120° C.
- the NOx trap may reach its operating temperature before at least one of the SCR units 6 , 7 reaches its operating temperature.
- reducing agent will be injected upstream of the NOx trap 3 by the first adding means 5 resulting in a purge of the NOx trap 3 .
- Reducing agent will only be injected by the second adding means 8 when the system is sufficiently warm for the SCR unit 6 , 7 downstream of the second adding means 8 to operate.
- the first SCR unit 6 is likely to reach its required operating temperature before the second SCR unit 7 as it is positioned closer to the engine 1 .
- the embodiment shown in FIG. 6 is a combination of the embodiments of FIGS. 4 and 5 , i.e. the embodiment of FIG. 6 has both a second SCR unit 7 and a second adding means 8 .
- the NOx generated by the engine 1 will be stored by the NOx trap 3 when the system is at low temperature (for example, just after start-up or at low engine load). If the NOx trap 3 was to eventually become saturated with NOx, no further NOx will be absorbed by the NOx trap 3 and the NOx will instead pass through the NOx trap 3 (the “NOx slip”).
- reducing agent can be injected by the second adding means 8 at an injection point positioned upstream of the second SCR unit 7 , allowing the second SCR unit 7 to reduce the non-absorbed NOx without purging the NOx. Subsequently, when the SCR units 6 , 7 are sufficiently warm, reducing agent is injected by a first adding means 5 , i.e. reducing agent is injected upstream of the NOx trap 3 , resulting in the purge of the NOx trap 3 and a reduction of the NOx in the first and second SCR units 6 , 7 .
- the second adding means 8 is positioned upstream of the first SCR unit 6 instead of downstream of this unit as shown in FIG. 6 .
- the NOx trap 3 When the system of FIG. 7 is in use, the NOx trap 3 will trap the NOx generated by the engine 1 when the system is at low temperature.
- the reducing agent can be injected upstream of a SCR unit 6 , 7 by the second adding means 8 when the NOx trap 3 has become saturated and is no longer absorbing any NOx (i.e. “NOx slip” is occurring) provided that at least one of the SCR units 6 , 7 has reached its operating temperature.
- SCR unit 6 Normally, SCR unit 6 will reach its operating temperature before SCR unit 7 as it is closer to the engine 1 . This allows the NOx escaping from the NOx trap 3 to be reduced by an SCR unit 6 , 7 without purging the NOx trap 3 .
- the added reducing agent is used by the second SCR unit 7 .
- the added reducing agent is used by both the first SCR unit 6 and the second SCR unit 7 .
- the first SCR unit 6 is closer to the engine 1 and so will generally become warmer faster than the second SCR unit 7 .
- an optional third adding means 11 has been added to the system of FIG. 7 .
- This third adding means 11 (for example, an injector or a spray comprising a nozzle) is positioned downstream of the first SCR unit 6 and upstream of the second SCR unit 7 .
- the system is provided with a second device 10 for distributing the reducing agent between the third adding means 11 and the first and second adding means 5 , 8 .
- This second device 10 could be a three-way valve, for example.
- the system additionally comprises two NOx sensors 20 , 21 . Apart from the sensors, the general set-up of the system is substantially identical to that shown in FIG. 2 .
- the first NOx sensor 20 is positioned downstream of the NOx trap 3 and upstream of the SCR unit 6 .
- the second NOx sensor is positioned downstream of the SCR unit 6 .
- the NOx trap 3 When the system of FIG. 9 is in use, the NOx trap 3 will accumulate NOx when the system is cold. At this point, no reducing agent has been injected.
- the temperature of the system can either be measured by a temperature sensor (not shown) or the temperature of the system can be estimated (for example, by assuming that the system will remain cold for x minutes after the engine has been started up, or by using a more sophisticated algorithm that takes into account the engine loads and associated durations).
- the NOx trap 3 When the first NOx sensor 20 detects NOx, this means that the NOx trap 3 is saturated and it is no longer absorbing NOx. Under these circumstances, the reducing agent is sprayed into the system by the first adding means 5 and the NOx trap 3 is purged. The NOx trap 3 can then proceed to absorb more NOx.
- reducing agent is injected into the system again so that there is reducing agent available to reduce the NOx in the SCR unit 6 . Furthermore, the injected reducing agent will also purge the NOx trap 3 . This will ensure that the NOx trap 3 maintains NOx absorption ability which is desirable if the engine is then turned off and later restarted.
- the system of FIG. 9 is also provided with a second NOx sensor 21 .
- This NOx sensor 21 is used to monitor the operation of the SCR unit 6 to check that it is working properly.
- the system shown in FIG. 10 also comprises two NOx sensors 20 , 21 . Apart from the sensors 20 , 21 , the general set-up of this embodiment is the same as that shown in FIG. 4 . This embodiment differs from the embodiment of FIG. 9 in that the system comprises two adding means: a first and a second adding means 5 , 8 .
- the NOx trap 3 When the system of FIG. 10 is in use, the NOx trap 3 accumulates the NOx when the system is cold. No reducing agent is injected at this point. Again, the temperature can be measured by a temperature sensor (not shown) or the temperature of the system can be estimated (for example, by assuming that the system will remain cold for x minutes after the engine has been started up, or by using a more sophisticated algorithm that takes into account the engine loads and associated durations).
- the NOx trap 3 may operate at a lower temperature than the SCR unit 6 or vice versa.
- the NOx trap operates at a lower temperature, when the temperature of the system is determined to be too low (for example, less than 140° C.) for the SRC unit 6 to operate, and when the first NOx sensor 20 detects the presence of any NOx, reducing agent is injected into the exhaust line 2 by the first adding means 5 to purge the NOx trap 3 . In the presence of reducing agent, the NOx trapped on the NOx trap will be reduced to N 2 .
- the reducing agent will be injected by the second adding means 8 when the system becomes sufficiently warm (detected, for example, by a temperature sensor) to ensure that there is reducing agent available to reduce the NOx in the SCR unit 6 .
- further injection of reducing agent by the first adding means 5 also ensures that the NOx trap has a low NOx content meaning that it would still have absorption ability if the engine is turned off and then restarted.
- the system will reach a temperature at which the SCR unit 6 can operate before the NOx trap 3 can work. This can occur if ammonia gas is being used as the reducing agent, for example.
- reducing agent can be injected upstream of the SCR unit 6 by the second adding means 8 . Injection of reducing agent upstream of the SCR unit 6 allows the NOx that has passed through the NOx trap 3 to be reduced by the SCR unit 6 without purging the NOx trap 3 . When the system is sufficiently warm, reducing agent will then be injected upstream of the NOx trap 3 by the first adding means 5 resulting in a purge of the NOx trap 3 in addition to reduction of the NOx by the reducing agent in the SCR unit 6 .
- the system of FIG. 10 is provided with a second NOx sensor 21 positioned downstream of the SCR unit 6 .
- This NOx sensor 21 is used to monitor the operation of the SCR unit 6 to check that it is working properly.
- a system may be provided with only a single NOx sensor, for example, with either the first or second sensor 20 , 21 .
- FIG. 11 the substantially identical to the system shown in FIG. 9 except that the system further comprises a controller 40 configured to receive data from the NOx sensors 20 , 21 .
- the controller is also configured to control the first adding means 5 based on the data received from the sensors 20 , 21 .
- the data transmitted to the controller 40 from sensor 20 is shown by line 30
- the data transmitted to the controller from the sensor 21 is shown by line 31
- the control instruction sent to the first adding means 5 is shown by line 33 .
- the system may be provided with a temperature sensor in addition to or instead of a NOx sensor.
- the data recorded by the temperature sensor can then be transmitted to the control means 40 , and the control means 40 can use this temperature data to control the first adding means 5 .
- the controller 40 can control multiple adding means, for example, first and second 5 , 8 adding means using the data receiving from the NOx and/or temperature sensor(s).
- reducing agent in addition to spraying reducing agent upstream of the NOx trap 3 to purge the trap when it is saturated, reducing agent may also be sprayed upstream of the NOx trap 3 when it is not saturated to keep the NOx trap 3 ready to absorb NOx at all times. This is advantageous as it means that the NOx trap 3 will be ready to absorb NOx should the engine 1 be restarted.
- Reducing agent such as ammonia may be sprayed upstream of the NOx trap 3 at regular time intervals, for example.
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Abstract
A system and method for reducing the nitrogen oxides found in the exhaust produced by a vehicle engine, the system comprising a NOx trap and a first adding means for adding a reducing agent to the exhaust gas. The first adding means is positioned downstream of the engine and either upstream of or within the NOx trap.
Description
- The invention relates to a system and method for reducing the nitrogen oxides found in the exhaust gas produced by a vehicle engine.
- Emissions from vehicle engines are of increasing concern to governments and organisations around the world. There, therefore, exists the need for emission control technologies.
- Known emission control technologies include systems for reducing the nitrogen oxides (i.e. NO, NO2) of exhaust gas produced by a vehicle engine. Such technologies include Selective Catalytic Reduction (SCR) and Lean NOx Traps (LNT). The SCR and LNT systems are provided in the exhaust line of a vehicle.
- Selective Catalytic Reduction is a process used for converting the nitrogen oxides (NOx) produced by a vehicle engine into diatomic nitrogen (N2) and water (H2O). Suitable catalysts for use in Selective Catalytic Reduction include base metal catalysts such as vanadium and tungsten. In a Selective Catalytic Reduction unit, the reduction of the NOx generally takes place in a catalytic chamber. Before the NOx gases pass into this chamber they are mixed with a reducing agent. Suitable reducing agents include liquid urea solution (for example, AdBlue®) and gaseous ammonia.
- A SCR catalyst can only operate once the engine has reached a temperature of about 120° C. to 180° C. but this can take several minutes in cold start-up conditions or at low engine load. Temperatures of around 180° C. are required when the reducing agent is a liquid urea solution such as AdBlue® and temperatures of approximately 120° C. are needed when the reducing agent is gaseous ammonia.
- Lean NOx Traps are NOx absorbers which chemically bind NOx during lean operation of a vehicle engine. Lean NOx Traps comprise ceramic cordierite honeycomb structures coated with fine-grained oxides such as aluminum oxide (Al2O3), catalytically active materials (namely the platinum group metals platinum (Pt), palladium (Pd) and rhodium (Rh)), alkaline oxides or carbonates (for example, of barium (Ba) or sodium (Na)), and oxygen storage components (typically ceria-zirconia solid solutions).
- During lean operation of an engine, fuel is burned with an excess of air. This means that during lean operation of the engine, the NOx trap is provided with oxygen which is used to oxidise NO to NO2. The NOx (NO and NO2) can be absorbed onto the surface of the NOx trap by the alkaline oxides or carbonates. However, the absorption sites on the NOx trap will eventually become saturated and the NOx trap will not be able to bind with any more NOx.
- When the absorber capacity of the NOx trap is saturated, the vehicle engine needs to be switched to rich mode. In contrast to lean engine operation, during rich engine operation an air/fuel ratio which provides exactly enough air to burn all of the fuel is used. This means that the oxygen in the NOx trap is replaced by reducing species (such as H2, CO and hydrocarbons). This results in the NOx absorbed by the NOx Trap being reduced to N2 over a reduction catalyst. The N2 is then released from the trap.
- However, when a vehicle engine is operated in rich mode, there is increased fuel consumption.
- Additionally, when exhaust gases are being produced by the engine but the exhaust line is not warm enough for the SCR catalyst to operate properly, solid components and deposits are formed in the exhaust pipe. For example, solid deposits are formed when AdBlue® is injected into a SCR at temperatures below 180° C. Such deposits may cause fouling or clogging of components of the system.
- The object of the present invention is to provide an improved NOx reduction system. The present invention, therefore, provides a system for reducing nitrogen oxides of an exhaust gas produced by an engine of a vehicle, the system comprising a NOx trap, and a first adding means for adding a reducing agent to the exhaust gas, wherein the first adding means is positioned downstream of the engine and either upstream of or within the NOx trap.
- In positioning the first adding means for adding a reducing agent to the exhaust gas upstream or within the NOx trap, the added reducing agent can be used to purge the NOx trap. As explained above, it has previously been necessary to switch the engine to rich mode to purge a NOx trap. The present invention, therefore, removes the need to switch to engine rich mode and resulting a fuel saving. The purge of the NOx trap can also be activated by a combination of ammonia injection and reduced rich engine operation, also resulting in a saving of fuel.
- Preferably, the first adding means is positioned upstream of the NOx trap.
- Preferably, the NOx trap is a lean NOx trap (LNT). Suitable materials for use in the LNTs of the present invention are disclosed by U.S. Pat. No. 8,853,123, US patent application US 2002/0076373, and the article entitled “Novel low temperature NOx storage-reduction catalysts for diesel light-duty engine emissions based on hydrotalcite compounds” published in Catalysis Today (Volume 75,
issues 1 to 4, 3 Jul. 2002, pages 421-429), for example. - U.S. Pat. No. 8,853,123 describes a LNT catalyst with enhanced Nitrogen Oxide storage capacity at low temperature and significantly inhibited thermal desorption. This LNT catalyst is said to be prepared by coating a washcoat on a honeycomb-type carrier and drying and baking the same. The washcoat contains a first catalyst powder in which barium (Ba) and a precious metal are supported on a ceria support, and a second catalyst powder in which a precious metal is supported on a magnesium (Mg) substituted alumina support.
- US 2002/0076373 describes the use of lithium in NOx adsorbers for improved low temperature performance. In this patent application, a combination of lithium and alkali material and/or alkaline earth material are said to enable the low temperature reduction of NOx to molecular nitrogen.
- In the paper published in Catalysis Today, the presence of dispersed Mg(Al)O oxide is said to promote the low temperature storage of NOx.
- In some embodiments of the invention, the first adding means may comprise a nozzle for spraying or squirting the reducing agent into the exhaust gas.
- Preferably, the reducing agent is ammonia. The ammonia is preferably provided in liquid or gaseous form.
- NOx reduction systems of the present invention may be connected to a tank for storing an ammonia precursor such as, for example, urea or a concentrated urea solution of at least 10% urea up to 35 wt % urea in water. This tank for storing an ammonia precursor is connected to an ammonia precursor decomposition unit for generation of ammonia, wherein the urea decomposition unit is in fluid communication with the adding means. In one particular embodiment the ammonia precursor may be a liquid ammonia precursor; in particular, it can be a solution. In another embodiment, the ammonia precursor may be a solid.
- In an embodiment of the invention, there is a provided a tank for storing the products resulting from the decomposition of the ammonia precursor.
- Preferably, the system further comprises a first Selective Catalytic Reduction unit, wherein this first Selective Catalytic Reduction unit is located downstream of the NOx trap. In some embodiments of the invention, the NOx trap and the first Selective Catalytic Reduction unit may be located within the same canning or casing. A combined unit has the advantages of being more compact and avoiding heat loss between the NOx trap and the first Selective Catalytic Reduction unit.
- More preferably, the system further comprises a second Selective Catalytic Reduction unit, wherein the second Selective Catalytic Reduction unit is located downstream of the first Selective Catalytic Reduction unit.
- The system may also further comprise a second adding means for adding a reducing agent to the exhaust gas, wherein this second adding means is located upstream of at least one Selective Catalytic Reduction unit. Therefore, in embodiments with a single Selective Catalytic Reduction unit, the second adding means can be located upstream of this first Selective Catalytic Reduction unit. In embodiments with a first and second Selective Catalytic Reduction unit, the second adding means can be located upstream of both the first and second Selective Catalytic Reduction units or only the second Selective Catalytic Reduction unit.
- The second adding means is also adapted to add a reducing agent to the exhaust gas, for example, by squirting or spraying the reducing agent into the exhaust line. In embodiments of the invention, the second adding means may comprise a nozzle for spraying or squirting the reducing agent into the exhaust gas. The reducing agent is preferably ammonia, preferably in liquid or gaseous form.
- Preferably, the system for reducing nitrogen oxides of an exhaust gas produced by an engine of a vehicle of the present invention further comprises at least one sensor and a controller, wherein the controller is configured to receive sensed data from the at least one sensor and to control at least one of the adding means based on the sensed data from the at least one sensor.
- Therefore, in embodiments of the invention with only a first adding means, a controller configured to receive sensed data from the at least one sensor can control the first adding means based on the sensed data.
- In embodiments with a first and second adding means, the controller may be configured to control only one of the first or second adding means, or the controller may control both the first and second adding means based on the sensed data. If there are further adding means, the controller may also control these.
- In some embodiments, the system may comprise a NOx sensor located downstream of the NOx trap and a controller is configured to receive sensed data from the NOx sensor and to control at least one of the adding means based on the data received from the NOx sensor. Therefore, the controller may be configured to control at least the first and/or the second adding means based on the data received from the NOx sensor. For example, in embodiments with only a first adding means, this first adding means can be controlled based on the data received from the NOx sensor.
- Embodiments of the invention may comprise multiple NOx sensors, for example, two NOx sensors, wherein one of these NOx sensors is located downstream of the NOx trap and upstream of a SCR unit and the other NOx sensor is located downstream of this SCR unit. In such embodiments, the controller is configured to receive sensed data from the multiple NOx sensors and control the adding of the reducing agent based on at least the sensed NOx data.
- Additionally or alternatively, the system may comprise a temperature sensor, wherein the controller is configured to control at least one of the adding means based on the temperature sensed by the temperature sensor. The controller may be configured to control at least the first and/or the second adding means based on the temperature sensed by the temperature sensor.
- In some embodiments, the system may be provided with multiple temperature sensors. For example, the system may have a first temperature sensor in or in close proximity to the NOx trap, and a second temperature sensor in or in close proximity to a SCR unit. In such embodiments, the controller is configured to receive data from the multiple temperature sensors and to control one or more of the adding means based on at least this sensed temperature data.
- In some embodiments, the system may comprise multiple NOx and/or temperature sensors. In these embodiments, the controller is configured to receive sensed data from the multiple sensors and to control one or more of the adding means based on the data received from the sensors.
- Preferably, the at least one of the adding means is configured to inject the reducing agent in the gas phase. Therefore, the first and/or second adding means may be configured to add the reducing agent in the gas phase.
- In some embodiments, the first adding means are arranged to spray reducing agent in an exhaust line of the vehicle between the engine and the NOx trap.
- Preferably, the system of the present invention is located within an exhaust line of the vehicle.
- Embodiments of the system of the invention may also be provided with a diesel oxidation catalyst (DOC) unit downstream of the engine and upstream of both the NOx trap and the first adding means. As DOC unit is configured to promote oxidation of exhaust gas components by oxygen it should be located upstream of the first adding means or the reducing agent may be oxidized by the DOC.
- In a further aspect of the invention there is provided a controller configured to receive data indicative of a measured parameter in an exhaust system and control adding a reducing agent upstream of a NOx trap or within a NOx trap and downstream of an engine based on the received data.
- In embodiments of this further aspect of the invention, the controller may be configured to receive data indicative of a NOx content in an exhaust gas and control the adding of a reducing agent upstream of a NOx trap or within a NOx trap (and downstream of an engine) based on the received NOx content data.
- In other embodiments, the controller may additionally or alternatively be configured to receive data indicative of the temperature of the exhaust system and control the adding of a reducing agent upstream of a NOx trap or within a NOx trap (and downstream of an engine) based on the received temperature data.
- In another aspect of the invention there is provided an assembly for use in reducing nitrogen oxides of exhaust gas produced by an engine of a vehicle, the assembly comprising a NOx trap, a first adding means for adding a reducing agent to the exhaust gas, and a controller configured to receive data indicative of a measured parameter, wherein the first adding means is positioned downstream of the engine and either upstream or within the NOx trap, and the controller is configured to control adding a reducing agent upstream of a NOx trap or within a NOx trap based on the received data.
- The optional further features of the other aspects of the invention described above also apply to this assembly.
- In a further aspect of the invention there is a method for reducing nitrogen oxides of an exhaust gas produced by an engine, the method comprising: storing nitrogen oxides produced by an engine in a NOx trap positioned downstream of the engine; adding a reducing agent into the exhaust gas upstream of or within the NOx trap and downstream of the engine; and using this reducing agent to reduce the NOx absorbed in the NOx trap and purge the NOx trap.
- Preferably, the reducing agent is ammonia.
- The method preferably further comprises using the reducing agent to reduce NOx in a Selective Catalytic Reduction (SCR) unit positioned downstream of the NOx trap.
- Preferably, the method comprises measuring a parameter and using this parameter to control the addition of the reducing agent, wherein the measured parameter may be a NOx content of the exhaust gas or a temperature.
- The temperature may be the temperature of the exhaust gas coming from the engine. Preferably, the reducing agent is added once a required temperature is reached. The required temperature may be around 120 to 180° C., preferably, 120 to 140° C.
- The NOx content of the exhaust gas may be measured downstream of the NOx trap and/or downstream of a SCR unit
- The accompanying drawings are used to illustrate presently preferred non-limiting exemplary embodiments of the present invention. The above and other advantages of the features and objects of the invention will become more apparent and the invention will be better understood from the following detailed description when read in conjunction with the accompanying drawings, in which:
-
FIG. 1 is a diagram illustrating a first embodiment of a system for reducing NOx; -
FIG. 2 is a diagram illustrating a second embodiment of a system for reducing NOx; -
FIG. 3 is a diagram illustrating a third embodiment of a system for reducing NOx; -
FIG. 4 is a diagram illustrating a fourth embodiment of a system for reducing NOx; -
FIG. 5 is a diagram illustrating a fifth embodiment of a system for reducing NOx; -
FIG. 6 is a diagram illustrating a sixth embodiment of a system for reducing NOx; -
FIG. 7 is a diagram illustrating a seventh embodiment of a system for reducing NOx; -
FIG. 8 is a diagram illustrating an eighth embodiment of a system for reducing NOx; -
FIG. 9 is a diagram illustrating a ninth embodiment of a system for reducing NOx; -
FIG. 10 is a diagram illustrating a tenth embodiment of a system for reducing NOx; and -
FIG. 11 is a diagram illustrating an eleventh embodiment of a system for reducing NOx. - The figures show embodiments of a system for reducing nitrogen oxides found in the exhaust gas produced by an
engine 1 of a vehicle. In all of the embodiments, the systems comprise aNOx trap 3 and a first adding means 5 for adding a reducing agent to the exhaust gas, wherein the first addingmeans 5 is located downstream of thevehicle engine 1 and upstream of theNOx trap 3. - In alternative embodiments of the invention, the first adding means 5 may be located within the
NOx trap 3. - In all of
FIGS. 1 to 11 , the arrow D shows the movement of the exhaust gas in the downstream direction. In addition, the systems are all located within anexhaust line 2. - In the embodiments of all of the figures, the first adding
means 5 comprises some form of outlet connected to the exhaust line. For example, the means may comprise an injector or a spray with an outlet nozzle adapted to inject or spray the reducing agent in liquid or gaseous form into theexhaust line 2. Preferably, the reducing agent is liquid or gaseous ammonia. - The reducing agent is supplied from the
store 4 of reducing agent. Thisstore 4 may be a store of ammonia. Alternatively, in some embodiments of the invention, thestore 4 may hold urea and the reducingagent store 4 further comprises a urea decomposition section configured to convert urea solution into ammonia for supply to the first addingmeans 5. - When the systems of all of the embodiments of
FIGS. 1 to 11 are in use, exhaust gases comprising nitrogen oxides are generated by theengine 1. These exhaust gases move down theexhaust line 2 in direction D and pass through aNOx trap 3 positioned downstream of theengine 1. - Preferably, when the exhaust system is at low temperature (for example, just after the engine has been started-up or when the engine is operating at low engine load), the NOx generated by the engine is stored in the
NOx trap 3. In order to purge theNOx trap 3, reducing agent is injected into the exhaust gases upstream of theNOx trap 3 by the first addingmeans 5. - In the embodiment of
FIG. 1 , the system just comprises aNOx trap 3. When the system ofFIG. 1 is in use, reducing agent is injected or sprayed into theexhaust line 2 upstream of theNOx trap 3. The injected/sprayed reducing agent is then used by the NOx trap to reduce the absorbed NOx to diatomic nitrogen (N2). - Preferably, the system also comprises at least one first Selective Catalytic Reduction (SCR) unit. Such preferred embodiments of the invention are illustrated by
FIGS. 2 to 11 . - In all of the embodiments of
FIGS. 2 to 11 , the systems comprise aNOx trap 3, a first addingmeans 5 and a first Selective Catalytic Reduction (SCR)unit 6, wherein thisSCR unit 6 is located downstream of both theengine 1 and theNOx trap 3. Therefore, the first addingmeans 5 is located downstream of thevehicle engine 1 and upstream of both theNOx trap 3 and theSCR unit 6. - When the systems of the embodiments of
FIGS. 2 to 11 are in use, exhaust gases comprising nitrogen oxides are generated by theengine 1. These exhaust gases move down theexhaust line 2 in direction D. The exhaust gases firstly pass through aNOx trap 3 positioned downstream of theengine 1, before then passing through afirst SCR unit 6 located downstream of theNOx trap 3. - Preferably, when the system is at low temperature, the NOx generated by the
engine 1 is stored in theNOx trap 3 positioned upstream of theSCR unit 6. When the system is warm enough (for example, around 120° C. to 180° C. or warmer) for theSCR unit 6 to function properly and reduce the NOx to diatomic nitrogen (N2) and water (H2O), reducing agent can be injected upstream of theNOx trap 3, resulting in both a purge of the NOx trap and reduction of NOx in theSCR unit 6. The injected reducing agent is thus used to both purge theNOx trap 3 and reduce the NOx in theSCR unit 6. -
FIGS. 2, 3 and 4 illustrate embodiments of the invention with only asingle SCR unit 6. InFIGS. 2 and 4 , theNOx trap 3 and theSCR 6 unit are spaced apart within theexhaust line 2. In the embodiments ofFIGS. 2 and 4 , the distance between theengine 1 and theNOx trap 3 is around 10 to 50 cm. - In the embodiment of
FIG. 3 , theNOx trap 3 andSCR unit 6 are located within the same canning. Thiscombined NOx trap 3 andSCR unit 6 is also positioned around 10 to 50 cm along theexhaust line 2 from the engine. The combined unit has the advantage of avoiding heat loss between theNOx trap 3 and theSCR unit 6. The combinedNOx trap 3 andSCR unit 6 is also more compact. - In the embodiments of
FIGS. 5 to 8 , the systems comprise asecond SCR unit 7 in addition to thefirst SCR unit 6. Thissecond SCR unit 7 is located downstream of all of theengine 1, theNOx trap 3 and thefirst SCR unit 6. Asecond SCR unit 7 may be useful if the space for thefirst SCR unit 6 near theengine 1 is too small to host the full volume of the SCR catalyst. - When the embodiments of
FIGS. 5 to 8 are in use, the exhaust gas will pass through theNOx trap 3, thefirst SCR unit 6 and then thesecond SCR unit 7. If there is any NOx remaining in the exhaust gas after it has passed through theNOx trap 3 and thefirst SCR unit 6, this should be reduced to into diatomic nitrogen (N2) and water (H2O) by thesecond SCR unit 7. Therefore, providing asecond SCR unit 7 can help ensure that the NOx content of the exhaust gas leaving the vehicle is zero or very low. - In the embodiments of
FIGS. 4, 6, 7, 8 and 10 , the system is additionally provided with an additional adding means 8 (for example, an injector/spray with an outlet nozzle) positioned upstream of at least oneSCR unit device 9 to distribute the reducing agent between the first addingmeans 5 and the second addingmeans 8. Thisdevice 9 could be a three-way valve, for example. In the embodiments shown in these figures, the reducing agent moves in direction A from the reducingagent store 4. - When the embodiments of
FIGS. 4, 6, 7, 8 and 10 are in use and the exhaust system is at low temperature (for example, just after start-up or at low engine load), the NOx generated by theengine 1 is stored in theNOx trap 3. When theNOx trap 3 becomes saturated, NOx will no longer be absorbed by theNOx trap 3 and will instead pass through the NOx trap 3 (i.e. “NOx slip” will occur). - In these circumstances, if at least one of the
SCR units relevant SCR unit means 8. Injection of reducing agent upstream of thisSCR unit NOx trap 3 to be reduced by theSCR unit NOx trap 3. When the system is sufficiently warm (i.e. when the NOx trap has reached its operating temperature), reducing agent will then be injected upstream of theNOx trap 3 by the first adding means 5 resulting in a purge of theNOx trap 3 in addition to reduction of the NOx by the reducing agent in one ormore SCR units - An
SCR unit NOx trap 3 if gaseous ammonia is used as the reducing agent, for example. If the reducing agent is gaseous ammonia, the operating temperature of theSCR units - In an alternative mode of operation, the NOx trap may reach its operating temperature before at least one of the
SCR units NOx trap 3 by the first adding means 5 resulting in a purge of theNOx trap 3. Reducing agent will only be injected by the second adding means 8 when the system is sufficiently warm for theSCR unit - In the embodiments with two SCR units (shown
FIGS. 6, 7 and 8 ), thefirst SCR unit 6 is likely to reach its required operating temperature before thesecond SCR unit 7 as it is positioned closer to theengine 1. - The embodiment shown in
FIG. 6 is a combination of the embodiments ofFIGS. 4 and 5 , i.e. the embodiment ofFIG. 6 has both asecond SCR unit 7 and a second addingmeans 8. When the system ofFIG. 6 is in use, the NOx generated by theengine 1 will be stored by theNOx trap 3 when the system is at low temperature (for example, just after start-up or at low engine load). If theNOx trap 3 was to eventually become saturated with NOx, no further NOx will be absorbed by theNOx trap 3 and the NOx will instead pass through the NOx trap 3 (the “NOx slip”). Once theSCR unit 7 has reached its operating temperature, reducing agent can be injected by the second adding means 8 at an injection point positioned upstream of thesecond SCR unit 7, allowing thesecond SCR unit 7 to reduce the non-absorbed NOx without purging the NOx. Subsequently, when theSCR units means 5, i.e. reducing agent is injected upstream of theNOx trap 3, resulting in the purge of theNOx trap 3 and a reduction of the NOx in the first andsecond SCR units - In the system illustrated by
FIG. 7 , the second adding means 8 is positioned upstream of thefirst SCR unit 6 instead of downstream of this unit as shown inFIG. 6 . - When the system of
FIG. 7 is in use, theNOx trap 3 will trap the NOx generated by theengine 1 when the system is at low temperature. As with the embodiments ofFIGS. 4 and 6 , the reducing agent can be injected upstream of aSCR unit NOx trap 3 has become saturated and is no longer absorbing any NOx (i.e. “NOx slip” is occurring) provided that at least one of theSCR units SCR unit 6 will reach its operating temperature beforeSCR unit 7 as it is closer to theengine 1. This allows the NOx escaping from theNOx trap 3 to be reduced by anSCR unit NOx trap 3. Then, when theNOx trap 3 is sufficiently warm, reducing agent is sprayed upstream of theNOx trap 3 by the first adding means 5 to purge theNOx trap 3. The NOx will then be reduced by the NOx trap as well as the first andsecond SCR units - It may be advantageous to use the embodiment of
FIG. 7 as opposed to the embodiment ofFIG. 6 . In the system shown inFIG. 6 , the added reducing agent is used by thesecond SCR unit 7. However, in the embodiment ofFIG. 7 , the added reducing agent is used by both thefirst SCR unit 6 and thesecond SCR unit 7. Thefirst SCR unit 6 is closer to theengine 1 and so will generally become warmer faster than thesecond SCR unit 7. - In the embodiment of
FIG. 8 , an optional third adding means 11 has been added to the system ofFIG. 7 . This third adding means 11 (for example, an injector or a spray comprising a nozzle) is positioned downstream of thefirst SCR unit 6 and upstream of thesecond SCR unit 7. The system is provided with asecond device 10 for distributing the reducing agent between the third adding means 11 and the first and second adding means 5, 8. Thissecond device 10 could be a three-way valve, for example. - In the embodiment of the system illustrated by
FIG. 9 , the system additionally comprises twoNOx sensors FIG. 2 . - The
first NOx sensor 20 is positioned downstream of theNOx trap 3 and upstream of theSCR unit 6. The second NOx sensor is positioned downstream of theSCR unit 6. - When the system of
FIG. 9 is in use, theNOx trap 3 will accumulate NOx when the system is cold. At this point, no reducing agent has been injected. The temperature of the system can either be measured by a temperature sensor (not shown) or the temperature of the system can be estimated (for example, by assuming that the system will remain cold for x minutes after the engine has been started up, or by using a more sophisticated algorithm that takes into account the engine loads and associated durations). - When the
first NOx sensor 20 detects NOx, this means that theNOx trap 3 is saturated and it is no longer absorbing NOx. Under these circumstances, the reducing agent is sprayed into the system by the first addingmeans 5 and theNOx trap 3 is purged. TheNOx trap 3 can then proceed to absorb more NOx. - When the system becomes sufficiently warm (detected, for example, by a temperature sensor), reducing agent is injected into the system again so that there is reducing agent available to reduce the NOx in the
SCR unit 6. Furthermore, the injected reducing agent will also purge theNOx trap 3. This will ensure that theNOx trap 3 maintains NOx absorption ability which is desirable if the engine is then turned off and later restarted. - The system of
FIG. 9 is also provided with asecond NOx sensor 21. ThisNOx sensor 21 is used to monitor the operation of theSCR unit 6 to check that it is working properly. - The system shown in
FIG. 10 also comprises twoNOx sensors sensors FIG. 4 . This embodiment differs from the embodiment ofFIG. 9 in that the system comprises two adding means: a first and a second adding means 5, 8. - When the system of
FIG. 10 is in use, theNOx trap 3 accumulates the NOx when the system is cold. No reducing agent is injected at this point. Again, the temperature can be measured by a temperature sensor (not shown) or the temperature of the system can be estimated (for example, by assuming that the system will remain cold for x minutes after the engine has been started up, or by using a more sophisticated algorithm that takes into account the engine loads and associated durations). - In the system of
FIG. 10 , theNOx trap 3 may operate at a lower temperature than theSCR unit 6 or vice versa. - If the NOx trap operates at a lower temperature, when the temperature of the system is determined to be too low (for example, less than 140° C.) for the
SRC unit 6 to operate, and when thefirst NOx sensor 20 detects the presence of any NOx, reducing agent is injected into theexhaust line 2 by the first adding means 5 to purge theNOx trap 3. In the presence of reducing agent, the NOx trapped on the NOx trap will be reduced to N2. - In this situation, the reducing agent will be injected by the second adding means 8 when the system becomes sufficiently warm (detected, for example, by a temperature sensor) to ensure that there is reducing agent available to reduce the NOx in the
SCR unit 6. - As with the system of
FIG. 9 , further injection of reducing agent by the first adding means 5 also ensures that the NOx trap has a low NOx content meaning that it would still have absorption ability if the engine is turned off and then restarted. - Alternatively, if the
SCR unit 6 can operate at a lower temperature than theNOx trap 3, the system will reach a temperature at which theSCR unit 6 can operate before theNOx trap 3 can work. This can occur if ammonia gas is being used as the reducing agent, for example. - In these circumstances, when the
first NOx sensor 20 detects the presence of any NOx, if theSCR unit 6 has reached its operating temperature, reducing agent can be injected upstream of theSCR unit 6 by the second addingmeans 8. Injection of reducing agent upstream of theSCR unit 6 allows the NOx that has passed through theNOx trap 3 to be reduced by theSCR unit 6 without purging theNOx trap 3. When the system is sufficiently warm, reducing agent will then be injected upstream of theNOx trap 3 by the first adding means 5 resulting in a purge of theNOx trap 3 in addition to reduction of the NOx by the reducing agent in theSCR unit 6. - Again, further injection of reducing agent by the first adding
means 5 ensures that the NOx trap has a low NOx content meaning that it would still have absorption ability if the engine is turned off and then restarted. - As with the embodiment of
FIG. 9 , the system ofFIG. 10 is provided with asecond NOx sensor 21 positioned downstream of theSCR unit 6. ThisNOx sensor 21 is used to monitor the operation of theSCR unit 6 to check that it is working properly. - In alternative embodiments of the invention, a system may be provided with only a single NOx sensor, for example, with either the first or
second sensor - In the final figure,
FIG. 11 , the substantially identical to the system shown inFIG. 9 except that the system further comprises acontroller 40 configured to receive data from theNOx sensors sensors FIG. 11 , the data transmitted to thecontroller 40 fromsensor 20 is shown byline 30, the data transmitted to the controller from thesensor 21 is shown byline 31, and the control instruction sent to the first addingmeans 5 is shown byline 33. - In an alternative embodiment of the system of
FIG. 11 , the system may be provided with a temperature sensor in addition to or instead of a NOx sensor. The data recorded by the temperature sensor can then be transmitted to the control means 40, and the control means 40 can use this temperature data to control the first addingmeans 5. - In further alternative embodiments, the
controller 40 can control multiple adding means, for example, first and second 5, 8 adding means using the data receiving from the NOx and/or temperature sensor(s). - In all of the above described embodiments, in addition to spraying reducing agent upstream of the
NOx trap 3 to purge the trap when it is saturated, reducing agent may also be sprayed upstream of theNOx trap 3 when it is not saturated to keep theNOx trap 3 ready to absorb NOx at all times. This is advantageous as it means that theNOx trap 3 will be ready to absorb NOx should theengine 1 be restarted. Reducing agent such as ammonia may be sprayed upstream of theNOx trap 3 at regular time intervals, for example.
Claims (15)
1. A system for reducing nitrogen oxides of an exhaust gas produced by an engine of a vehicle, the system comprising:
a NOx trap;
a first adding means for adding a reducing agent to the exhaust gas, the first adding means being positioned downstream of the engine and either upstream of or within the NOx trap;
a first Selective Catalytic Reduction unit, the first Selective Catalytic Reduction unit being located downstream of the NOx trap;
wherein the reducing agent is ammonia.
2. The system of claim 1 , wherein the NOx trap and the first Selective Catalytic Reduction unit are located within a same canning.
3. The system of claim 1 , wherein the system further comprises a second Selective Catalytic Reduction unit; wherein the second Selective Catalytic Reduction unit is located downstream of the first Selective Catalytic Reduction unit.
4. The system of claim 2 , wherein the system further comprises a second adding means for adding a reducing agent to the exhaust gas; wherein the second adding means is located upstream of at least one Selective Catalytic Reduction unit.
5. The system of claim 1 , wherein the system further comprises:
at least one sensor; and
a controller configured to receive sensed data from the at least one sensor and to control at least one of the adding means based on the sensed data from the at least one sensor.
6. The system of claim 5 , wherein the system comprises:
a NOx sensor located downstream of the NOx trap; and
the controller is configured to receive sensed data from the NOx sensor and to control at least one of the adding means based on the sensed data from the NOx sensor.
7. The system of claim 5 , wherein the system comprises:
a second adding means for adding a reducing agent to the exhaust gas; wherein the second adding means is located upstream of at least one Selective Catalytic Reduction unit;
a temperature sensor; and
the controller is configured to control at least one of the adding means based on the temperature sensed by the temperature sensor.
8. The system of claim 4 , wherein at least one of the adding means is configured to inject the reducing agent in the gas phase.
9. The system of claim 1 , wherein the first adding means are arranged to spray the reducing agent in an exhaust line extending between the engine and the NOx trap.
10. The system of claim 1 , wherein the system is located within an exhaust line of the vehicle.
11. A controller configured to:
receive data indicative of a measured parameter in an exhaust system; and
control adding a reducing agent upstream of a NOx trap or within a NOx trap and downstream of an engine based on the received data.
12. The controller of claim 11 , wherein the controller is configured to:
receive data indicative of a NOx content in an exhaust gas; and
control the adding of a reducing agent upstream of a NOx trap or within a NOx trap, based on the received NOx content data.
13. The controller of claim 11 , wherein the controller is configured to:
receive data indicative of the temperature of the exhaust system; and
control the adding of a reducing agent upstream of a NOx trap or within a NOx trap, based on the received temperature data.
14. A method for reducing nitrogen oxides of an exhaust gas produced by an engine, the method comprising:
storing nitrogen oxides produced by an engine in a NOx trap positioned downstream of the engine;
adding a reducing agent into the exhaust gas upstream of or within the NOx trap and downstream of the engine; and
using this reducing agent to reduce the NOx absorbed in the NOx trap and purge the NOx trap.
15. The controller of claim 12 , wherein the controller is configured to:
receive data indicative of the temperature of the exhaust system; and
control the adding of a reducing agent upstream of a NOx trap or within a NOx trap, based on the received temperature data.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP15150829.8 | 2015-01-12 | ||
EP15150829.8A EP3043038A1 (en) | 2015-01-12 | 2015-01-12 | NOx reduction system |
PCT/EP2016/050479 WO2016113260A1 (en) | 2015-01-12 | 2016-01-12 | Nox reduction system |
Publications (1)
Publication Number | Publication Date |
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US20170370259A1 true US20170370259A1 (en) | 2017-12-28 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US15/542,839 Abandoned US20170370259A1 (en) | 2015-01-12 | 2016-01-12 | NOx REDUCTION SYSTEM |
Country Status (4)
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US (1) | US20170370259A1 (en) |
EP (1) | EP3043038A1 (en) |
CN (1) | CN107109984A (en) |
WO (1) | WO2016113260A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102018222571A1 (en) | 2018-12-20 | 2020-06-25 | Ford Global Technologies, Llc | Method for operating an exhaust gas aftertreatment device of a motor vehicle |
DE102019203061A1 (en) * | 2019-03-06 | 2020-09-10 | Ford Global Technologies, Llc | Method for regenerating a NOx storage catalytic converter of an exhaust gas aftertreatment device |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20200131961A1 (en) * | 2018-10-29 | 2020-04-30 | GM Global Technology Operations LLC | Exhaust gas treatment systems and methods for diagnosing the same |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100236224A1 (en) * | 2009-03-20 | 2010-09-23 | Basf Catalysts Llc | Emissions Treatment System With Lean NOx Trap |
US20100319320A1 (en) * | 2009-06-17 | 2010-12-23 | Gm Global Technology Operations, Inc. | Exhaust gas treatment system including a lean nox trap and two-way catalyst and method of using the same |
US8037674B2 (en) * | 2003-02-12 | 2011-10-18 | Delphi Technologies, Inc. | System and method of NOx abatement |
US8661790B2 (en) * | 2011-11-07 | 2014-03-04 | GM Global Technology Operations LLC | Electronically heated NOx adsorber catalyst |
US20150275730A1 (en) * | 2014-03-27 | 2015-10-01 | Cummins Inc. | Systems and methods to reduce reductant consumption in exhaust aftertreament systems |
US9221017B2 (en) * | 2011-07-04 | 2015-12-29 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas control apparatus for internal combustion engine |
US9790830B2 (en) * | 2015-12-17 | 2017-10-17 | Tenneco Automotive Operating Company Inc. | Exhaust after-treatment system including electrolysis generated H2 and NH3 |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62117620A (en) * | 1985-11-19 | 1987-05-29 | Nippon Shokubai Kagaku Kogyo Co Ltd | Method for removing nitrogen oxide contained in exhaust gas of gasoline engine |
JP4034375B2 (en) * | 1997-04-03 | 2008-01-16 | トヨタ自動車株式会社 | Exhaust gas purification device for internal combustion engine |
US20020076373A1 (en) | 2000-12-19 | 2002-06-20 | Michel Molinier | Use of lithium in NOx adsorbers for improved low temperature performance |
US7861516B2 (en) * | 2003-06-18 | 2011-01-04 | Johnson Matthey Public Limited Company | Methods of controlling reductant addition |
US7213395B2 (en) * | 2004-07-14 | 2007-05-08 | Eaton Corporation | Hybrid catalyst system for exhaust emissions reduction |
US7062904B1 (en) * | 2005-02-16 | 2006-06-20 | Eaton Corporation | Integrated NOx and PM reduction devices for the treatment of emissions from internal combustion engines |
US7257941B1 (en) * | 2006-03-14 | 2007-08-21 | Eaton Corporation | Model based diagnostics of an aftertreatment fuel dosing system |
GB2460825A (en) * | 2008-06-06 | 2009-12-16 | Delphi Tech Inc | Reagent dosing system |
DE102011078326A1 (en) * | 2011-06-29 | 2013-01-03 | Ford Global Technologies, Llc | Adsorption device i.e. lean nitrogen oxide trap, for use in diesel engine of e.g. passenger car, has adsorption layer connected with carrier, where device does not comprises elements made from copper, ruthenium, rhodium, palladium or gold |
KR101438953B1 (en) | 2012-12-18 | 2014-09-11 | 현대자동차주식회사 | LNT Catalysts with Enhanced Storage Capacities of Nitrogen Oxide at Low Temperature |
WO2014115303A1 (en) * | 2013-01-25 | 2014-07-31 | トヨタ自動車株式会社 | Exhaust purification device for internal combustion engine |
-
2015
- 2015-01-12 EP EP15150829.8A patent/EP3043038A1/en not_active Withdrawn
-
2016
- 2016-01-12 CN CN201680004947.7A patent/CN107109984A/en active Pending
- 2016-01-12 US US15/542,839 patent/US20170370259A1/en not_active Abandoned
- 2016-01-12 WO PCT/EP2016/050479 patent/WO2016113260A1/en active Application Filing
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8037674B2 (en) * | 2003-02-12 | 2011-10-18 | Delphi Technologies, Inc. | System and method of NOx abatement |
US20100236224A1 (en) * | 2009-03-20 | 2010-09-23 | Basf Catalysts Llc | Emissions Treatment System With Lean NOx Trap |
US20100319320A1 (en) * | 2009-06-17 | 2010-12-23 | Gm Global Technology Operations, Inc. | Exhaust gas treatment system including a lean nox trap and two-way catalyst and method of using the same |
US9221017B2 (en) * | 2011-07-04 | 2015-12-29 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas control apparatus for internal combustion engine |
US8661790B2 (en) * | 2011-11-07 | 2014-03-04 | GM Global Technology Operations LLC | Electronically heated NOx adsorber catalyst |
US20150275730A1 (en) * | 2014-03-27 | 2015-10-01 | Cummins Inc. | Systems and methods to reduce reductant consumption in exhaust aftertreament systems |
US9790830B2 (en) * | 2015-12-17 | 2017-10-17 | Tenneco Automotive Operating Company Inc. | Exhaust after-treatment system including electrolysis generated H2 and NH3 |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102018222571A1 (en) | 2018-12-20 | 2020-06-25 | Ford Global Technologies, Llc | Method for operating an exhaust gas aftertreatment device of a motor vehicle |
DE102019203061A1 (en) * | 2019-03-06 | 2020-09-10 | Ford Global Technologies, Llc | Method for regenerating a NOx storage catalytic converter of an exhaust gas aftertreatment device |
US11220941B2 (en) | 2019-03-06 | 2022-01-11 | Ford Global Technologies, Llc | Methods and systems for an aftertreatment system |
Also Published As
Publication number | Publication date |
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WO2016113260A1 (en) | 2016-07-21 |
EP3043038A1 (en) | 2016-07-13 |
CN107109984A (en) | 2017-08-29 |
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