US20200386137A1 - Smart def injector for low temperature reductant delivery - Google Patents
Smart def injector for low temperature reductant delivery Download PDFInfo
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- US20200386137A1 US20200386137A1 US16/803,217 US202016803217A US2020386137A1 US 20200386137 A1 US20200386137 A1 US 20200386137A1 US 202016803217 A US202016803217 A US 202016803217A US 2020386137 A1 US2020386137 A1 US 2020386137A1
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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]
- F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
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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
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/07—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas flow rate or velocity meter or sensor, intake flow meters only when exclusively used to determine exhaust gas parameters
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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
- F01N2610/14—Arrangements for the supply of substances, e.g. conduits
- F01N2610/1406—Storage means for substances, e.g. tanks or reservoirs
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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
- F01N2610/14—Arrangements for the supply of substances, e.g. conduits
- F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
- F01N2610/146—Control thereof, e.g. control of injectors or injection valves
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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
- F01N2900/1404—Exhaust gas temperature
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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
- F01N2900/1411—Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate
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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
- F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
- F01N2900/1806—Properties of reducing agent or dosing system
- F01N2900/1811—Temperature
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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
- F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
- F01N2900/1806—Properties of reducing agent or dosing system
- F01N2900/1812—Flow rate
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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
- F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
- F01N2900/1806—Properties of reducing agent or dosing system
- F01N2900/1821—Injector parameters
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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
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
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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
- This disclosure relates to a Smart DEF Injector for Low Temperature Reductant Delivery and its method of use. Particularly, this disclosure relates to an arrangement and method for calculating a maximum mass flow rate of DEF that may be injected for a sensed exhaust temperature and exhaust mass flow rate when the exhaust temperatures are below the normal temperature thresholds for DEF dosing.
- Diesel engines commonly operate with a lean air to fuel ratio, so that only part of the available oxygen is used in the fuel combustion reaction. While this helps to make diesel engines efficient, it also results in the formation of nitrogen oxides (NOx), an undesirable pollutant, during the combustion process.
- NOx nitrogen oxides
- EPA Environmental Protection Agency regulates the amount of NOx that may be emitted in vehicle exhaust, so that vehicle and engine manufacturers employ various techniques to reduce NOx emissions.
- SCR Selective Catalytic Reduction
- SCR works by injecting a solution of urea, a reductant that is sometimes referred to as Diesel Exhaust Fluid (DEF), into the flow of vehicle engine exhaust, often referred to as “dosing.”
- DEF Diesel Exhaust Fluid
- AdBlue Diesel Exhaust Fluid
- urea solution then evaporates and thermally decomposes due to the heat of the exhaust.
- Ammonia liberated from the urea then reacts with the NOx in the presence of a catalyst to form diatomic nitrogen (N2), water (H2O), and carbon dioxide (CO2).
- N2 diatomic nitrogen
- H2O water
- CO2 carbon dioxide
- the catalyst is provided in the form of a structure, often a honeycomb shape or similar arrangement, with a coating such as a metal oxide or metal exchanged zeolites, located downstream in the exhaust flow from the location of urea injection.
- a coating such as a metal oxide or metal exchanged zeolites
- the SCR urea injector and catalytic device, together with a filter for removing particulates from the exhaust flow, generally located upstream in the exhaust flow from the SCR urea injector and catalytic device, are often collectively referred to as exhaust aftertreatment.
- DEF injection components are normally dependent on an external control module that may be an Engine Control Unit (ECU) or Diesel Control Unit (DCU), which control the quantity and timing of the DEF injection according to one or more algorithms.
- ECU Engine Control Unit
- DCU Diesel Control Unit
- EGR Exhaust Gas Recirculation
- EGR recirculates a percentage of exhaust gases back into the intake of the engine, in order to lower the amount of free oxygen in the intake air and to reduce the peak in-cylinder combustion temperatures. This, in turn, reduces the amount of NOx formation that takes place within the cylinders, while also reducing overall engine efficiency.
- Most modern diesel engines utilize both EGR and SCR, sometimes in combination with some form of combustion optimization.
- EONOx Engine Out Nitrogen Oxide
- sensors are often provided in order to detect the NOx emissions within the flow of exhaust and to provide this information by way of J1939 data bus to a controller such as the ECU or DCU.
- injection of DEF into the flow of the vehicle engine exhaust is normally limited to when the exhaust gas temperature and the catalytic device are above a minimum threshold temperature. Limiting injection of DEF into the flow of the vehicle engine exhaust to when the exhaust gas temperature and the catalytic device are above a minimum threshold temperature is further done to prevent the growth of urea or other deposits in the exhaust and aftertreatment system. Normally, DEF dosing is not initiated until the exhaust gas temperature and the catalytic device are above 190 degrees Celsius for standard DEF injectors, or 150 degrees Celsius for flash-boil DEF injectors.
- a vehicle has an engine, an ECU or DCU connected to the engine and configured to control the engine, an exhaust system connected to the engine, and an SCR catalyst connected to the exhaust system.
- a DEF injector is connected to the exhaust system upstream of the SCR catalyst, and further connected to the ECU or DCU.
- An exhaust temperature sensor is connected to the ECU or DCU, and further connected to the DEF injector.
- An exhaust mass flow rate sensor is connected to the ECU or DCU, and further connected to the DEF injector.
- the ECU or DCU is further configured with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor.
- the DEF injector is configured with control logic and is configured to override and/or supplement the control logic located within the ECU or DCU.
- the control logic of the DEF injector uses exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU.
- a Smart DEF Injection Arrangement for a vehicle having an engine, an ECU or DCU connected to the engine and configured to control the engine, an exhaust system connected to the engine, and an SCR catalyst connected to the exhaust system.
- the Smart DEF Injection Arrangement includes a DEF injector connected to the exhaust system upstream of the SCR catalyst, and further connected to the ECU or DCU.
- An exhaust temperature sensor is connected to the ECU or DCU, and further connected to the DEF injector.
- An exhaust mass flow rate sensor connected to the ECU or DCU, and further connected to the DEF injector.
- the ECU or DCU is further configured with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor.
- the DEF injector is configured with control logic and is configured to override and/or supplement the control logic located within the ECU or DCU.
- the control logic of the DEF injector uses exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU.
- a method of reducing vehicle emissions in a vehicle having an engine includes several steps.
- the first step is connecting an ECU or DCU to the engine and configuring the ECU or DCU to control the engine.
- the second step is connecting an exhaust system to the engine.
- the third step is connecting an SCR catalyst to the exhaust system.
- the fourth step is connecting a DEF injector to the exhaust system upstream of the SCR catalyst, and further connecting the DEF injector to the ECU or DCU.
- the fifth step is connecting an exhaust temperature sensor to the ECU or DCU, and to the DEF injector.
- the sixth step is connecting an exhaust mass flow rate sensor to the ECU or DCU, and to the DEF injector.
- the seventh step is configuring the ECU or DCU with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor.
- the eighth step is configuring the DEF injector with control logic for overriding and/or supplementing the control logic configured within the ECU or DCU.
- the ninth step is controlling the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU, using the control logic of the DEF injector, exhaust temperature information provided by the exhaust temperature sensor, and exhaust mass flow rate information provided by the exhaust mass flow rate sensor.
- FIG. 1 is a side view of a vehicle having an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery according to the present disclosure, as described herein;
- FIG. 2 is a diagram of an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery and its method of use according to the present disclosure, as described herein;
- FIG. 3 is a graph of an exemplary DEF dosing rate as a percentage of fuel rate as a function of exhaust temperature for a given mass flow rate of exhaust according to an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery according to the present disclosure, as described herein.
- Embodiments described herein relate to a Smart DEF Injector for Low Temperature Reductant Delivery, and to a method for the use thereof.
- Embodiments of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may be applied to various types of passenger vehicles, recreational vehicles, and commercial vehicles, such as highway or semi-tractors with and without auxiliary power units (APUs), straight trucks with and without APUs, buses, fire trucks, agricultural vehicles, construction vehicles, campers, motorhomes, motorcycles, scooters, rail travelling vehicles, and trailers with APUs or refrigeration units. It is further contemplated that embodiments of the arrangement and method may be applied to vehicles having hybrid electric drive.
- APUs auxiliary power units
- embodiments of the arrangement and method may be applied to vehicles having engines configured for various fuels, such as, for non-limiting example, gasoline, diesel, propane, natural gas, and hydrogen, and particularly with respect to such engines being configured for lean-burn that use SCR.
- fuels such as, for non-limiting example, gasoline, diesel, propane, natural gas, and hydrogen
- Embodiments of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use utilize control logic that may be located partially or entirely within a DEF injector hardware itself, or in a dedicated DEF injector controller, rather than being located within the ECU or DCU. Alternately, embodiments of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may continue to utilize control logic that is located within the ECU or DCU, but may override and/or supplement the control logic located within the ECU or DCU with its own control logic located partially or entirely within the DEF injector hardware itself, or in a dedicated DEF injector controller. Specifically, the DEF injector and/or its dedicated DEF injector controller uses sensed and/or calculated exhaust flow and temperature as inlet conditions to determine if DEF injection can be enabled at reduced rates at temperatures below the normal thresholds.
- EER Excess Energy Ratio
- EER m . exhaust ⁇ c pair ⁇ ( T exhaust - 100 ) m . DEF ⁇ c pwater ⁇ ( 100 - 70 ) + m . DEF ⁇ h fgwater .
- the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use therefore, provides a DEF injector that doses a reduced amount of DEF that does not result in deposit formation at reduced exhaust temperatures below the normal temperature thresholds for DEF dosing of 190 degrees Celsius for standard DEF injectors and/or 150 degrees Celsius for flash-boil DEF injectors, by calculating the amount of DEF dosing that may occur without exceeding the threshold EER.
- the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use utilize input signals for exhaust flow and exhaust temperature.
- the reduced dosing may again occur independently of, or in addition to, any control algorithm located in the ECU or DCU, using logic contained within the DEF injector and/or in its dedicated DEF injector controller.
- another embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use utilizes logic located within the ECU or DCU that is supplemental to the normal DEF dosing logic normally located therein.
- FIG. 1 a side view of a vehicle 10 having an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery and its method of use is shown.
- the vehicle 10 includes a chassis 12 having a frame 14 , to which is attached a front axle 30 having front wheels 32 , and a rear axle 40 having rear wheels 42 .
- An engine 16 provides power for propulsion by way of a transmission (not shown) and a driveshaft (not shown), which is connected to the rear drive axle 40 .
- the engine 16 may also be provided with an EGR system 18 .
- the engine 16 may be controlled by an ECU or DCU 22 , which may also be connected to other vehicle subsystems by way of a data bus 20 , which may be embodied as a J1939 data bus.
- the vehicle 10 of FIG. 1 is further provided with an exhaust system 50 which is connected to and receives exhaust from the engine 16 , and which is provided with an exhaust aftertreatment system 52 , in order to remove certain unwanted particulates and nitrogen oxides from the exhaust gases.
- the exhaust aftertreatment system 52 may include a Diesel Oxidation Catalyst (DOC) 56 , a Diesel Particulate Filter (DPF) 58 , a Smart DEF Injector for Low Temperature Reductant Delivery 60 , and an SCR catalyst 62 .
- DOC Diesel Oxidation Catalyst
- DPF Diesel Particulate Filter
- Smart DEF Injector for Low Temperature Reductant Delivery 60
- SCR catalyst 62 SCR catalyst
- an EONOx sensor 54 an exhaust temperature sensor 64 , and an exhaust flow sensor 66 are situated at the upstream end of the exhaust aftertreatment system 52 , and are connected to the ECU or DCU 22 by way of the data bus 20 . It is also contemplated that the exhaust temperature sensor 64 and/or the exhaust flow sensor 66 may be located downstream of the DOC 56 and DPF 58 , just upstream of the Smart DEF Injector for Low Temperature Reductant Delivery 60 and the SCR catalyst 62 . It is further contemplated that the Smart DEF Injector for Low Temperature Reductant Delivery 60 and the SCR catalyst 62 may be located upstream of the DOC 56 and DPF 58 .
- the EONOx sensor 54 , the exhaust temperature sensor 64 , and the exhaust flow sensor 66 provide information concerning the nitrogen oxide content of the exhaust flow, the temperature of the exhaust flow, and the rate of flow of the exhaust in the way of sensor signals to the ECU or DCU 22 via the data bus 20 .
- the ECU or DCU 22 uses the information concerning the nitrogen oxide content of the exhaust flow, the temperature of the exhaust flow, and the rate of flow of the exhaust to control, for non-limiting example, operating parameters of the engine 16 , the EGR system 18 , and the Smart DEF Injector for Low Temperature Reductant Delivery 60 .
- FIG. 2 a graphic representation is shown of an exhaust system 50 having an exhaust aftertreatment system 52 and implementing an embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery 60 .
- the exhaust aftertreatment system 52 again includes a DOC catalyst 56 , a DPF 58 , and an SCR catalyst 62 .
- FIG. 2 shows the DOC catalyst 56 and DPF 58 upstream of the Smart DEF Injector for Low Temperature Reductant Delivery 60 and the SCR catalyst 62 .
- the Smart DEF Injector for Low Temperature Reductant Delivery 60 and the SCR catalyst 62 may be located upstream of the DOC catalyst 56 and DPF 58 .
- an EONOx sensor 54 may be provided upstream of the DOC catalyst 56 and DPF 58 .
- the Smart DEF Injector for Low Temperature Reductant Delivery 60 is located upstream of the SCR catalyst 62 , and is used to dose DEF from a DEF tank 70 into the flow of exhaust prior to the SCR catalyst 62 , so that the DEF urea solution evaporates and thermally decomposes due to the heat of the exhaust.
- ammonia liberated from the urea then reacts with the NOx in the presence of the SCR catalyst 62 to form diatomic nitrogen (N2), water (H2O), and carbon dioxide (CO2).
- the exhaust temperature sensor 64 and the exhaust flow sensor 66 provide information concerning the temperature of the exhaust flow and the rate of flow of the exhaust in the way of sensor signals to the ECU or DCU 22 .
- the ECU or DCU 22 uses the information concerning the temperature of the exhaust flow and the rate of flow of the exhaust to control the Smart DEF Injector for Low Temperature Reductant Delivery 60 when the temperature of the exhaust is above 190 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 embodied as a standard DEF injector, or when the temperature of the exhaust is above 150 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 embodied as a flash-boil DEF injector.
- the exhaust temperature sensor 64 and the exhaust flow sensor 66 also provide information concerning the temperature of the exhaust flow and the rate of flow of the exhaust in the way of sensor signals to the Smart DEF Injector for Low Temperature Reductant Delivery 60 itself.
- the Smart DEF Injector for Low Temperature Reductant Delivery 60 uses the information concerning the temperature of the exhaust flow and the rate of flow of the exhaust to take over and control DEF dosing at reduced rates when the temperature of the exhaust is below 190 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 embodied as a standard DEF injector, or when the temperature of the exhaust is below 150 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 embodied as a flash-boil DEF injector.
- the exhaust temperature sensor 64 and the exhaust flow sensor 66 may provide information concerning the temperature of the exhaust flow and the rate of flow of the exhaust in the way of sensor signals to a dedicated Smart DEF Injector controller 68 , which may be connected between the ECU or DCU 22 and the Smart DEF Injector for Low Temperature Reductant Delivery 60 , or may be connected independently to the Smart DEF Injector for Low Temperature Reductant Delivery 60 without being interposed between the ECU or DCU 22 and the Smart DEF Injector for Low Temperature Reductant Delivery 60 .
- the dedicated Smart DEF Injector controller 68 uses the information concerning the temperature of the exhaust flow and the rate of flow of the exhaust to take over and control DEF dosing at reduced rates when the temperature of the exhaust is below 190 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 embodied as a standard DEF injector, or when the temperature of the exhaust is below 150 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 embodied as a flash-boil DEF injector, similar to the embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery 60 wherein such control is exercised by the Smart DEF Injector for Low Temperature Reductant Delivery 60 itself.
- FIG. 3 shows a DEF dosing rate graph 100 that gives an exemplary DEF dosing rate 102 as a percentage of fuel rate as a function of exhaust temperature 104 for a given mass flow rate of exhaust.
- the exemplary DEF dosing rate graph 100 is presented for illustration purposes, and may not represent actual DEF dosing rates. What is illustrated by FIG. 3 , however, is that when the temperature of the exhaust is above 190 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a standard DEF injector, the ECU or DCU 22 controls the Smart DEF Injector for Low Temperature Reductant Delivery 60 according to an ECU/DCU controlled standard type Smart DEF Injection function or algorithm 106 .
- Smart DEF Injector for Low Temperature Reductant Delivery 60 When the temperature of the exhaust is below 190 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a standard DEF injector, the Smart DEF Injector for Low Temperature Reductant Delivery 60 itself, or in an alternate embodiment the dedicated Smart DEF Injector controller 68 , controls the Smart DEF Injector for Low Temperature Reductant Delivery 60 according to a Smart DEF Injector or dedicated Smart DEF Injector controller controlled standard type Smart DEF Injection function or algorithm 110 .
- a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a flash-boil type DEF injector
- the ECU or DCU 22 controls the Smart DEF Injector for Low Temperature Reductant Delivery 60 according to an ECU/DCU controlled flash-boil type Smart DEF Injection function or algorithm 108 .
- a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a flash-boil type DEF injector
- the Smart DEF Injector for Low Temperature Reductant Delivery 60 itself, or in an alternate embodiment the dedicated Smart DEF Injector controller 68 , controls the Smart DEF Injector for Low Temperature Reductant Delivery 60 according to a Smart DEF Injector or dedicated Smart DEF Injector controller controlled flash-boil type Smart DEF Injection function or algorithm 112 .
- the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use is able to lower unwanted exhaust NOx emissions in a region of exhaust temperature and exhaust mass flow rate below the capability of normal DEF injector control systems. Further, the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use is able to accomplish this without altering the programming of normal ECU/DCU controlled DEF injection, which allows the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use to be implemented on existing vehicles without extensive modification.
- the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may further be able to enable higher Engine-Out (EO) NOx levels, so that engines may be designed to operate at greater fuel economy, while still lowering overall tailpipe emissions.
- the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may be able to enable ultra-low tailpipe NOx levels and meet tailpipe NOx and greenhouse gas (GHG) requirements for low load cycles (LLC), which may be included in future regulatory rulings.
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Abstract
Description
- The present application claims priority to U.S. Provisional No. 62/859,372, filed Jun. 10, 2019, the entire contents of all of which are herein incorporated by reference.
- This disclosure relates to a Smart DEF Injector for Low Temperature Reductant Delivery and its method of use. Particularly, this disclosure relates to an arrangement and method for calculating a maximum mass flow rate of DEF that may be injected for a sensed exhaust temperature and exhaust mass flow rate when the exhaust temperatures are below the normal temperature thresholds for DEF dosing.
- Diesel engines commonly operate with a lean air to fuel ratio, so that only part of the available oxygen is used in the fuel combustion reaction. While this helps to make diesel engines efficient, it also results in the formation of nitrogen oxides (NOx), an undesirable pollutant, during the combustion process. Presently, the Environmental Protection Agency (EPA) regulates the amount of NOx that may be emitted in vehicle exhaust, so that vehicle and engine manufacturers employ various techniques to reduce NOx emissions.
- A common technique to reduce NOx tailpipe emissions involves the use of Selective Catalytic Reduction (SCR). SCR works by injecting a solution of urea, a reductant that is sometimes referred to as Diesel Exhaust Fluid (DEF), into the flow of vehicle engine exhaust, often referred to as “dosing.” Such DEF is commonly sold under the trademark AdBlue, or as ISO 22241 AUS325. The urea solution then evaporates and thermally decomposes due to the heat of the exhaust. Ammonia liberated from the urea then reacts with the NOx in the presence of a catalyst to form diatomic nitrogen (N2), water (H2O), and carbon dioxide (CO2). The catalyst is provided in the form of a structure, often a honeycomb shape or similar arrangement, with a coating such as a metal oxide or metal exchanged zeolites, located downstream in the exhaust flow from the location of urea injection. In order to maximize the effectiveness of the catalytic device, the evaporated urea and its thermal decomposition products, including the ammonia, must be properly mixed with the vehicle engine exhaust before entering the catalytic device. The SCR urea injector and catalytic device, together with a filter for removing particulates from the exhaust flow, generally located upstream in the exhaust flow from the SCR urea injector and catalytic device, are often collectively referred to as exhaust aftertreatment. DEF injection components are normally dependent on an external control module that may be an Engine Control Unit (ECU) or Diesel Control Unit (DCU), which control the quantity and timing of the DEF injection according to one or more algorithms.
- Another technique to reduce NOx tailpipe emissions involves the use of Exhaust Gas Recirculation (EGR). EGR recirculates a percentage of exhaust gases back into the intake of the engine, in order to lower the amount of free oxygen in the intake air and to reduce the peak in-cylinder combustion temperatures. This, in turn, reduces the amount of NOx formation that takes place within the cylinders, while also reducing overall engine efficiency. Most modern diesel engines utilize both EGR and SCR, sometimes in combination with some form of combustion optimization. In order to control such factors as boost pressure, fuel injection timing and profile, EGR valve setting, and SCR injection, it is necessary to detect NOx emissions within the flow of exhaust, and to adjust the controls accordingly. Therefore, Engine Out Nitrogen Oxide (EONOx) sensors are often provided in order to detect the NOx emissions within the flow of exhaust and to provide this information by way of J1939 data bus to a controller such as the ECU or DCU.
- In order to ensure complete evaporation and thermal decomposition of the urea solution, injection of DEF into the flow of the vehicle engine exhaust is normally limited to when the exhaust gas temperature and the catalytic device are above a minimum threshold temperature. Limiting injection of DEF into the flow of the vehicle engine exhaust to when the exhaust gas temperature and the catalytic device are above a minimum threshold temperature is further done to prevent the growth of urea or other deposits in the exhaust and aftertreatment system. Normally, DEF dosing is not initiated until the exhaust gas temperature and the catalytic device are above 190 degrees Celsius for standard DEF injectors, or 150 degrees Celsius for flash-boil DEF injectors.
- As a result, SCR catalytic conversion of NOx does not occur below the aforementioned threshold temperatures, with the result that tailpipe emissions are higher under these conditions. Accordingly, there is an unmet need for an arrangement and method for reducing NOx and other greenhouse gas emissions under low exhaust temperature operating conditions.
- According to one embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery, a vehicle has an engine, an ECU or DCU connected to the engine and configured to control the engine, an exhaust system connected to the engine, and an SCR catalyst connected to the exhaust system. A DEF injector is connected to the exhaust system upstream of the SCR catalyst, and further connected to the ECU or DCU. An exhaust temperature sensor is connected to the ECU or DCU, and further connected to the DEF injector. An exhaust mass flow rate sensor is connected to the ECU or DCU, and further connected to the DEF injector. The ECU or DCU is further configured with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor. The DEF injector is configured with control logic and is configured to override and/or supplement the control logic located within the ECU or DCU. The control logic of the DEF injector uses exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU.
- According to another embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery, A Smart DEF Injection Arrangement is provided for a vehicle having an engine, an ECU or DCU connected to the engine and configured to control the engine, an exhaust system connected to the engine, and an SCR catalyst connected to the exhaust system. The Smart DEF Injection Arrangement includes a DEF injector connected to the exhaust system upstream of the SCR catalyst, and further connected to the ECU or DCU. An exhaust temperature sensor is connected to the ECU or DCU, and further connected to the DEF injector. An exhaust mass flow rate sensor connected to the ECU or DCU, and further connected to the DEF injector. The ECU or DCU is further configured with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor. The DEF injector is configured with control logic and is configured to override and/or supplement the control logic located within the ECU or DCU. The control logic of the DEF injector uses exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor to control the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU.
- According to another embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery, a method of reducing vehicle emissions in a vehicle having an engine includes several steps. The first step is connecting an ECU or DCU to the engine and configuring the ECU or DCU to control the engine. The second step is connecting an exhaust system to the engine. The third step is connecting an SCR catalyst to the exhaust system. The fourth step is connecting a DEF injector to the exhaust system upstream of the SCR catalyst, and further connecting the DEF injector to the ECU or DCU. The fifth step is connecting an exhaust temperature sensor to the ECU or DCU, and to the DEF injector. The sixth step is connecting an exhaust mass flow rate sensor to the ECU or DCU, and to the DEF injector. The seventh step is configuring the ECU or DCU with control logic for controlling the DEF injector based on exhaust temperature information provided by the exhaust temperature sensor and exhaust mass flow rate information provided by the exhaust mass flow rate sensor. The eighth step is configuring the DEF injector with control logic for overriding and/or supplementing the control logic configured within the ECU or DCU. The ninth step is controlling the DEF injector to inject DEF at reduced rates when the exhaust temperature and/or the exhaust mass flow rate are lower than a threshold for DEF injection set by the ECU or DCU, using the control logic of the DEF injector, exhaust temperature information provided by the exhaust temperature sensor, and exhaust mass flow rate information provided by the exhaust mass flow rate sensor.
-
FIG. 1 is a side view of a vehicle having an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery according to the present disclosure, as described herein; -
FIG. 2 is a diagram of an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery and its method of use according to the present disclosure, as described herein; and -
FIG. 3 is a graph of an exemplary DEF dosing rate as a percentage of fuel rate as a function of exhaust temperature for a given mass flow rate of exhaust according to an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery according to the present disclosure, as described herein. - Embodiments described herein relate to a Smart DEF Injector for Low Temperature Reductant Delivery, and to a method for the use thereof. Embodiments of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may be applied to various types of passenger vehicles, recreational vehicles, and commercial vehicles, such as highway or semi-tractors with and without auxiliary power units (APUs), straight trucks with and without APUs, buses, fire trucks, agricultural vehicles, construction vehicles, campers, motorhomes, motorcycles, scooters, rail travelling vehicles, and trailers with APUs or refrigeration units. It is further contemplated that embodiments of the arrangement and method may be applied to vehicles having hybrid electric drive. It is further contemplated that, while presented herein as being used with diesel engines, embodiments of the arrangement and method may be applied to vehicles having engines configured for various fuels, such as, for non-limiting example, gasoline, diesel, propane, natural gas, and hydrogen, and particularly with respect to such engines being configured for lean-burn that use SCR.
- Embodiments of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use utilize control logic that may be located partially or entirely within a DEF injector hardware itself, or in a dedicated DEF injector controller, rather than being located within the ECU or DCU. Alternately, embodiments of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may continue to utilize control logic that is located within the ECU or DCU, but may override and/or supplement the control logic located within the ECU or DCU with its own control logic located partially or entirely within the DEF injector hardware itself, or in a dedicated DEF injector controller. Specifically, the DEF injector and/or its dedicated DEF injector controller uses sensed and/or calculated exhaust flow and temperature as inlet conditions to determine if DEF injection can be enabled at reduced rates at temperatures below the normal thresholds.
- As noted previously, the normal temperature thresholds for DEF dosing are 190 degrees Celsius for standard DEF injectors and 150 degrees Celsius for flash-boil DEF injectors. Nevertheless, exhaust at temperatures below these thresholds are capable of evaporating and thermally decomposing urea at reduced rates without forming urea deposits, depending on exhaust temperatures, mass flow rates of exhaust, mass flow rate of fuel, and mass flow rates of DEF. Specifically, a non-dimensional number referred to as Excess Energy Ratio (EER) may be used to identify operating conditions that are unlikely to produce urea deposits. One method for calculating EER is according to the equation published in SAE 2015-01-0989, which is incorporated herein in its entirety. EER is calculated as the ratio of energy available in the exhaust to the energy required to evaporate water from an initial temperature of 70 degrees Celsius, as follows:
-
-
- Where:
- mexhaust=mass flow rate of exhaust
- cpair=heat capacity of exhaust
- Texhaust=exhaust temperature
- mDEF=mass flow rate of DEF
- cpwater=heat capacity of water
- hfgwater=heat of vaporization of water
If the EER is above a certain threshold, typically about 20, DEF dosing at reduced rates is possible without resulting in urea deposits. Therefore, an exemplary algorithm of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use sets the EER to a certain threshold, for non-limiting example 20, and calculates a maximum mass flow rate of DEF that may be injected for the sensed exhaust temperature and flow rate when the exhaust temperatures are below the normal temperature thresholds for DEF dosing of 190 degrees Celsius for standard DEF injectors and/or 150 degrees Celsius for flash-boil DEF injectors.
- The Smart DEF Injector for Low Temperature Reductant Delivery and its method of use, therefore, provides a DEF injector that doses a reduced amount of DEF that does not result in deposit formation at reduced exhaust temperatures below the normal temperature thresholds for DEF dosing of 190 degrees Celsius for standard DEF injectors and/or 150 degrees Celsius for flash-boil DEF injectors, by calculating the amount of DEF dosing that may occur without exceeding the threshold EER. In order to do so, the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use utilize input signals for exhaust flow and exhaust temperature. The reduced dosing may again occur independently of, or in addition to, any control algorithm located in the ECU or DCU, using logic contained within the DEF injector and/or in its dedicated DEF injector controller. Alternately, another embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use utilizes logic located within the ECU or DCU that is supplemental to the normal DEF dosing logic normally located therein.
- Referring now to
FIG. 1 , a side view of avehicle 10 having an embodiment of a Smart DEF Injector for Low Temperature Reductant Delivery and its method of use is shown. Thevehicle 10 includes achassis 12 having aframe 14, to which is attached afront axle 30 havingfront wheels 32, and arear axle 40 havingrear wheels 42. Anengine 16 provides power for propulsion by way of a transmission (not shown) and a driveshaft (not shown), which is connected to therear drive axle 40. Theengine 16 may also be provided with anEGR system 18. Theengine 16 may be controlled by an ECU orDCU 22, which may also be connected to other vehicle subsystems by way of adata bus 20, which may be embodied as a J1939 data bus. - The
vehicle 10 ofFIG. 1 is further provided with anexhaust system 50 which is connected to and receives exhaust from theengine 16, and which is provided with anexhaust aftertreatment system 52, in order to remove certain unwanted particulates and nitrogen oxides from the exhaust gases. In a non-limiting exemplary arrangement, theexhaust aftertreatment system 52 may include a Diesel Oxidation Catalyst (DOC) 56, a Diesel Particulate Filter (DPF) 58, a Smart DEF Injector for LowTemperature Reductant Delivery 60, and anSCR catalyst 62. In the embodiment of the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use shown inFIG. 1 , anEONOx sensor 54, anexhaust temperature sensor 64, and anexhaust flow sensor 66 are situated at the upstream end of theexhaust aftertreatment system 52, and are connected to the ECU orDCU 22 by way of thedata bus 20. It is also contemplated that theexhaust temperature sensor 64 and/or theexhaust flow sensor 66 may be located downstream of theDOC 56 andDPF 58, just upstream of the Smart DEF Injector for LowTemperature Reductant Delivery 60 and theSCR catalyst 62. It is further contemplated that the Smart DEF Injector for LowTemperature Reductant Delivery 60 and theSCR catalyst 62 may be located upstream of theDOC 56 andDPF 58. In this way, theEONOx sensor 54, theexhaust temperature sensor 64, and theexhaust flow sensor 66 provide information concerning the nitrogen oxide content of the exhaust flow, the temperature of the exhaust flow, and the rate of flow of the exhaust in the way of sensor signals to the ECU orDCU 22 via thedata bus 20. The ECU orDCU 22 uses the information concerning the nitrogen oxide content of the exhaust flow, the temperature of the exhaust flow, and the rate of flow of the exhaust to control, for non-limiting example, operating parameters of theengine 16, theEGR system 18, and the Smart DEF Injector for LowTemperature Reductant Delivery 60. - Turning now to
FIG. 2 , a graphic representation is shown of anexhaust system 50 having anexhaust aftertreatment system 52 and implementing an embodiment of the Smart DEF Injector for LowTemperature Reductant Delivery 60. Theexhaust aftertreatment system 52 again includes aDOC catalyst 56, aDPF 58, and anSCR catalyst 62. It is noted thatFIG. 2 shows theDOC catalyst 56 andDPF 58 upstream of the Smart DEF Injector for LowTemperature Reductant Delivery 60 and theSCR catalyst 62. However, it is also contemplated that the Smart DEF Injector for LowTemperature Reductant Delivery 60 and theSCR catalyst 62 may be located upstream of theDOC catalyst 56 andDPF 58. In any case, an EONOx sensor 54 (not shown) may be provided upstream of theDOC catalyst 56 andDPF 58. The Smart DEF Injector for LowTemperature Reductant Delivery 60 is located upstream of theSCR catalyst 62, and is used to dose DEF from aDEF tank 70 into the flow of exhaust prior to theSCR catalyst 62, so that the DEF urea solution evaporates and thermally decomposes due to the heat of the exhaust. As noted previously, ammonia liberated from the urea then reacts with the NOx in the presence of theSCR catalyst 62 to form diatomic nitrogen (N2), water (H2O), and carbon dioxide (CO2). - The
exhaust temperature sensor 64 and theexhaust flow sensor 66 provide information concerning the temperature of the exhaust flow and the rate of flow of the exhaust in the way of sensor signals to the ECU orDCU 22. The ECU orDCU 22 uses the information concerning the temperature of the exhaust flow and the rate of flow of the exhaust to control the Smart DEF Injector for LowTemperature Reductant Delivery 60 when the temperature of the exhaust is above 190 degrees Celsius for a Smart DEF Injector for LowTemperature Reductant Delivery 60 embodied as a standard DEF injector, or when the temperature of the exhaust is above 150 degrees Celsius for a Smart DEF Injector for LowTemperature Reductant Delivery 60 embodied as a flash-boil DEF injector. Theexhaust temperature sensor 64 and theexhaust flow sensor 66 also provide information concerning the temperature of the exhaust flow and the rate of flow of the exhaust in the way of sensor signals to the Smart DEF Injector for LowTemperature Reductant Delivery 60 itself. The Smart DEF Injector for LowTemperature Reductant Delivery 60 uses the information concerning the temperature of the exhaust flow and the rate of flow of the exhaust to take over and control DEF dosing at reduced rates when the temperature of the exhaust is below 190 degrees Celsius for a Smart DEF Injector for LowTemperature Reductant Delivery 60 embodied as a standard DEF injector, or when the temperature of the exhaust is below 150 degrees Celsius for a Smart DEF Injector for LowTemperature Reductant Delivery 60 embodied as a flash-boil DEF injector. - Alternately, the
exhaust temperature sensor 64 and theexhaust flow sensor 66 may provide information concerning the temperature of the exhaust flow and the rate of flow of the exhaust in the way of sensor signals to a dedicated SmartDEF Injector controller 68, which may be connected between the ECU orDCU 22 and the Smart DEF Injector for LowTemperature Reductant Delivery 60, or may be connected independently to the Smart DEF Injector for LowTemperature Reductant Delivery 60 without being interposed between the ECU orDCU 22 and the Smart DEF Injector for LowTemperature Reductant Delivery 60. In either case, the dedicated SmartDEF Injector controller 68 uses the information concerning the temperature of the exhaust flow and the rate of flow of the exhaust to take over and control DEF dosing at reduced rates when the temperature of the exhaust is below 190 degrees Celsius for a Smart DEF Injector for LowTemperature Reductant Delivery 60 embodied as a standard DEF injector, or when the temperature of the exhaust is below 150 degrees Celsius for a Smart DEF Injector for LowTemperature Reductant Delivery 60 embodied as a flash-boil DEF injector, similar to the embodiment of the Smart DEF Injector for LowTemperature Reductant Delivery 60 wherein such control is exercised by the Smart DEF Injector for LowTemperature Reductant Delivery 60 itself. -
FIG. 3 shows a DEFdosing rate graph 100 that gives an exemplaryDEF dosing rate 102 as a percentage of fuel rate as a function ofexhaust temperature 104 for a given mass flow rate of exhaust. The exemplary DEFdosing rate graph 100 is presented for illustration purposes, and may not represent actual DEF dosing rates. What is illustrated byFIG. 3 , however, is that when the temperature of the exhaust is above 190 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a standard DEF injector, the ECU orDCU 22 controls the Smart DEF Injector for LowTemperature Reductant Delivery 60 according to an ECU/DCU controlled standard type Smart DEF Injection function oralgorithm 106. When the temperature of the exhaust is below 190 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a standard DEF injector, the Smart DEF Injector for LowTemperature Reductant Delivery 60 itself, or in an alternate embodiment the dedicated SmartDEF Injector controller 68, controls the Smart DEF Injector for LowTemperature Reductant Delivery 60 according to a Smart DEF Injector or dedicated Smart DEF Injector controller controlled standard type Smart DEF Injection function oralgorithm 110. - When the temperature of the exhaust is above 150 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a flash-boil type DEF injector, the ECU or
DCU 22 controls the Smart DEF Injector for LowTemperature Reductant Delivery 60 according to an ECU/DCU controlled flash-boil type Smart DEF Injection function oralgorithm 108. When the temperature of the exhaust is below 150 degrees Celsius for a Smart DEF Injector for Low Temperature Reductant Delivery 60 (not shown) embodied as a flash-boil type DEF injector, the Smart DEF Injector for LowTemperature Reductant Delivery 60 itself, or in an alternate embodiment the dedicated SmartDEF Injector controller 68, controls the Smart DEF Injector for LowTemperature Reductant Delivery 60 according to a Smart DEF Injector or dedicated Smart DEF Injector controller controlled flash-boil type Smart DEF Injection function oralgorithm 112. - In this way, the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use is able to lower unwanted exhaust NOx emissions in a region of exhaust temperature and exhaust mass flow rate below the capability of normal DEF injector control systems. Further, the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use is able to accomplish this without altering the programming of normal ECU/DCU controlled DEF injection, which allows the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use to be implemented on existing vehicles without extensive modification. That being said, the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may further be able to enable higher Engine-Out (EO) NOx levels, so that engines may be designed to operate at greater fuel economy, while still lowering overall tailpipe emissions. Conversely, the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use may be able to enable ultra-low tailpipe NOx levels and meet tailpipe NOx and greenhouse gas (GHG) requirements for low load cycles (LLC), which may be included in future regulatory rulings.
- While the Smart DEF Injector for Low Temperature Reductant Delivery and its method of use has been described with respect to at least one embodiment, the arrangement and method can be further modified within the spirit and scope of this disclosure, as demonstrated previously. This application is therefore intended to cover any variations, uses, or adaptations of the system and method using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which the disclosure pertains and which fall within the limits of the appended claims.
Claims (20)
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Cited By (2)
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US11415068B2 (en) * | 2019-08-13 | 2022-08-16 | GM Global Technology Operations LLC | System and method for controlling engine operating parameters during engine warm-up to reduce emissions |
US11555432B2 (en) * | 2020-12-04 | 2023-01-17 | Faurecia Systemes D'echappement | Exhaust gas post-treatment device |
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2020
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Cited By (2)
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US11415068B2 (en) * | 2019-08-13 | 2022-08-16 | GM Global Technology Operations LLC | System and method for controlling engine operating parameters during engine warm-up to reduce emissions |
US11555432B2 (en) * | 2020-12-04 | 2023-01-17 | Faurecia Systemes D'echappement | Exhaust gas post-treatment device |
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