Title of Invention	" AN EXHAUST AFTER-TREATMENT SYSTEM OF A VEHICLE AND A METHOD OF EXTENDING EMISSIONS PERFORMANCE OF AN EXHAUST AFTER-TERATMENT SYSTEM"
Abstract	TITLE "An exhaust after-treatment system of a vehicle and a method of extending emissions performance of an exhaust after-treatment system" The invention relates to an exhaust after-treatment system (14) for a vehicle (10) having a dosing agent (38) that is selectively injected into an exhaust from a dosing agent source (44), comprising : a first module (50) that determines a level of said dosing agent (DALEVEL) within said dosing source (44); wherein said dosing agent (38) comprises ammonia; a second module (46) that selectively generates a signal when said vehicle is at a predetermined location and an engine (10) is started; and a third module (39) that reduces vehicle performance when said level (DALEVEL) is less than a first predetermined level (DALow), said level (DALEVEL) is greater than a second predetermined level (DAEMPTY), and said signal is not generated, that regulates operation of said engine (10) to increase a selective catalytic reduction (SCR) catalyst temperature (TCAT) when said SCR catalyst temperature (TCAT) is less than a predetermined temperature (TTHR) while said vehicle performance is reduced, and that disables said engine (10) when said level (DALEVEL) is less than said second level (DLow) and said signal is generated.

Title of Invention

" AN EXHAUST AFTER-TREATMENT SYSTEM OF A VEHICLE AND A METHOD OF EXTENDING EMISSIONS PERFORMANCE OF AN EXHAUST AFTER-TERATMENT SYSTEM"

Abstract

TITLE "An exhaust after-treatment system of a vehicle and a method of extending emissions performance of an exhaust after-treatment system" The invention relates to an exhaust after-treatment system (14) for a vehicle (10) having a dosing agent (38) that is selectively injected into an exhaust from a dosing agent source (44), comprising : a first module (50) that determines a level of said dosing agent (DALEVEL) within said dosing source (44); wherein said dosing agent (38) comprises ammonia; a second module (46) that selectively generates a signal when said vehicle is at a predetermined location and an engine (10) is started; and a third module (39) that reduces vehicle performance when said level (DALEVEL) is less than a first predetermined level (DALow), said level (DALEVEL) is greater than a second predetermined level (DAEMPTY), and said signal is not generated, that regulates operation of said engine (10) to increase a selective catalytic reduction (SCR) catalyst temperature (TCAT) when said SCR catalyst temperature (TCAT) is less than a predetermined temperature (TTHR) while said vehicle performance is reduced, and that disables said engine (10) when said level (DALEVEL) is less than said second level (DLow) and said signal is generated.

Full Text	This application is related to U.S. Serial No. (To be assigned), filed on December 14, 2006 (GP-307049), entitled, "Method of Monitoring A Dosing Agent Supply For Treating Exhaust" and U.S. Serial No. (To be assigned), filed on December 14, 2006 (GP-308075-PTE-CD), entitled, "Emissions Conformance For An Exhaust After-Treatment System Having A Dosing Agent Supply". The disclosures of the above applications are incorporated herein by reference. FIELD The present invention relates to vehicle exhaust systems, and more particularly to a diesel exhaust control during a limp-home mode. BACKGROUND Internal combustion engines combust to an air and fuel mixture to generate drive torque. The combustion process generates exhaust that is exhausted from the engine to atmosphere. The exhaust contains nitrogen oxides (NOx), carbon dioxide (C02) and carbon monoxide (CO) particulates. An exhaust after-treatment system treats the exhaust to reduce emissions prior to being released to atmosphere. In an exemplary exhaust after-treatment system, a dosing system injects a dosing agent (e.g., urea) into the exhaust upstream of a catalyst. The exhaust and dosing agent mixture reacts over the catalyst to reduce the level of emissions. The dosing system includes a dosing agent supply and an injector. The amount of dosing agent injected is based on the level of emissions in the exhaust. If the dosing agent supply is empty or at a low level, insufficient dosing agent is injected into the exhaust stream, and emissions are not reduced as desired. It is a concern that vehicle operators may not replenish the required dosing agent. As disclosed in commonly assigned U.S. Patent Application No. (To be assigned), filed on December 14, 2006, and entitled, Emissions Conformance For An Exhaust After Treatment System Having A Dosing Agent Supply', the disclosure of which is incorporated herein by reference, vehicle operation can enter a limp-home that limits the vehicle drivability to encourage the vehicle operator to replenish the dosing agent. SUMMARY Accordingly, the present disclosure provides a method of extending emissions performance of an exhaust after-treatment system of a vehicle that includes a dosing agent. The method includes determining a level of a dosing agent source, selectively entering a limp-home mode based on the level and monitoring a catalyst temperature during said limp-home mode. Operation of an engine is regulate to increase the catalyst temperature when the catalyst temperature is less than a threshold catalyst temperature during the limp-home mode. In one feature, the regulating includes throttling the engine. In another feature, the regulating includes adjusting an air flow of the engine. In another feature, the regulating includes adjusting a fueling rate of the engine. In other features, the method further includes post-injecting fuel into exhaust upstream of the catalyst. The post-injecting occurs when the catalyst temperature is greater than the threshold catalyst temperature. In still another feature, the catalyst temperature is monitored based on a catalyst temperature sensor signal. In yet another feature, the catalyst temperature is monitored based on a catalyst temperature model. Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE ACCONMPANYING DRAWINGS The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: Figure 1 is a functional block diagram of an exemplary vehicle system including an exhaust after-treatment system according to the present disclosure. Figure 2 is a flowchart illustrating exemplary steps executed by the diesel exhaust control of the present disclosure; Figure 3 is a flowchart illustrating steps executed by the diesel exhaust control to determine whether the vehicle stopped at a convenient location; and Figure 4 is a flowchart illustrating exemplary steps executed by the diesel exhaust control during the limp-home mode; and Figure 5 is a functional block diagram illustrating exemplary modules that execute the extended emissions conformance control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the term module refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, or other suitable components that provide the described functionality. Referring now to Figure 1, an exemplary vehicle system 10 is schematically illustrated. The vehicle system 10 includes an engine system 12, an exhaust after-treatment system 14. The engine system 12 includes an engine 16 having a cylinder 18, an intake manifold 20 and an exhaust manifold 22. Air flows into the intake manifold 20 through a throttle 24. The air is mixed with fuel and the air and fuel mixture is combusted within the cylinder 18 to drive a piston (not shown). Although a single cylinder 16 is illustrated, it is appreciated that the engine 12 may include additional cylinders 18. For example, engines having 2, 3, 4, 5, 6, 8, 10, 12 and 16 cylinders are anticipated. The fuel is provided from a fuel source 26 and is injected into the air stream using an injector 28. A fuel level sensor 30 is responsive to the amount of fuel within the fuel source 26. Exhaust is produced through the combustion process and is exhausted from the cylinder 18 into the exhaust manifold 22. The exhaust after- treatment system 14 treats the exhaust flowing therethrough to reduce emissions before being released to the atmosphere. The exhaust after-treatment system 14 includes a dosing system 32, a diesel oxidation catalyst (DOC) 34, an emissions sensor 36 and a catalyst 38 that is preferably provided as a selective catalytic (SCR) catalyst. The DOC 34 reacts with the exhaust to reduce emission levels of the exhaust. The emissions sensor 36 is responsive to an emissions (e.g., NOx) level of the exhaust. It is also anticipated that a diesel particulate filter (DPF) 40 may be located downstream from the catalyst 30 that filters diesel particulates to further reduce emissions. The exhaust after-treatment system 14 can optionally include a catalyst temperature sensor 39 that is responsive to a temperature of the catalyst 38 (TCAT) and that generates a temperature signal based thereon. The diesel exhaust control of the present disclosure can be implemented using the temperature sensor signal, as described in further detail below. The dosing system 32 includes a dosing agent injector 42, a dosing agent storage tank 44 and a dosing agent supply sensor 46. The dosing system 32 selectively injects a dosing agent (e.g., urea) into the exhaust stream to further reduce emissions. More specifically, the amount of the dosing agent is determined based on the signal generated by the exhaust sensor. The exhaust and dosing agent mixture reacts within the catalyst 38 to further reduce exhaust emissions. A control module 50 regulates operation of the vehicle system 10 based on the extended emissions conformance control of the present invention. More specifically, the control module 50 determines a dosing agent level (DALEVEL) based on the signal generated by the dosing agent supply sensor 46. The control module can calculate a vehicle range (RANGEDA) based on the amount of dosing agent remaining. More specifically, RANGEDA indicates the remaining drivable distance before the entire dosing agent is consumed. RANGEDA can be displayed on a display (not shown) to alert the vehicle operator. If DALEVEL is below a first predetermined or low dosing agent threshold value (DALOW), the control module 50 sets a low dosing agent flag (FLAGDALOW) (e.g., equal to 1 or TRUE) indicating that the dosing agent level is low and should be refilled. Additionally, the control module 50 activates an indicator 52 that alerts the vehicle operator that the dosing agent supply is low and should be refilled. The indicator 52 can be a visual and/or audible indication that alerts the vehicle operator to the low condition. If DALEVEL is below a second predetermined or empty dosing agent threshold value (DAEMPTY), the control module 50 sets an empty dosing agent flag (FLAGDAEMPTY) (e.g., equal to 1 or TRUE). Further, the control module 50 activates the indicator 52 to indicate that the dosing agent source 44 is empty. When the dosing agent source 44 is refilled and DALEVEL exceeds DAEMPTY and/or DALOW, FLAGDAEMPTY and/or FLAGDALOW is/are cleared and the indicator 52 is also cleared. The extended emissions conformance control selectively impedes vehicle operation based on the dosing agent level. More specifically, if the dosing agent monitoring control determines that the vehicle is at a convenient location, a convenient location flag (FLAGCL) is set (e.g., equal to 1 or TRUE). A convenient location can include, but is not limited to, a fuel station, a maintenance workshop and/or an oil change workshop. If FLAGDALOW is set and the vehicle is stopped at a convenient location (i.e., a location where additional dosing agent is available) the extended emissions conformance control disables operation of the vehicle by setting a disable flag (FLAGDIS) until the dosing agent is replenished. It is also anticipated, however, that the vehicle operation need not be disabled even though the vehicle is at a convenient location, but can be impeded. More specifically, the vehicle operation can enter a limp-home mode, as described in further detail below. The diesel exhaust control selectively impedes operation of the vehicle during the limp-home mode while meeting emissions requirements even in the absence of dosing agent. More specifically, TCAT is monitored during the operation in the limp-home mode. If TCAT is less than a threshold temperature (TTHR)/ engine operation is regulated to increase the exhaust gas temperatures, thereby increasing TCAT- TTHR corresponds to a temperature at which the catalyst 38 is considered active. The exhaust gas temperature can be increased by engine throttling and air flow control. More specifically, the intake throttle can be placed in closed position in order to reduce engine air flow and air-to-fuel ratio. The turbocharger settings can also be modified to reduce air flow through the engine and to increase exhaust temperatures. Additionally and/or alternatively, the fuel injection timing can be retarded to further increase the exhaust gas temperatures. In one feature, TCAT can be directly measured using the temperature sensor 39. In an alternative feature, TCAT can be determined based on a catalyst temperature model that is processed by the control module 50. More specifically, engine speed, air flow and fuel quantity can be used as inputs for a catalyst temperature model. Once TCAT exceeds TTHR, small amounts of fuel can be post-injected (i.e. injected into a cylinder just after a combustion event), such that the fuel is expelled from the cylinder with the exhaust and flows to the exhaust after- treatment system 14. The heat energy of the catalyst 38 includes combustion of the fuel, thereby maintaining TCAT above TTHR or increasing TCAT- The diesel exhaust control continues to operate the engine in this manner to maintain acceptable catalyst temperatures (i.e whereby the catalyst is active) and emissions control. Once the dosing agent is replenished and the limp-home mode is exited, the engine system 12 can be operated using normal control strategies. In accordance with other features of the present disclosure when FLAGDAEMPTY is set and FLAGa is not set (i.e., when the vehicle is not deemed to be at a convenient location), the limp-home mode is entered, whereby vehicle operation is impeded. Vehicle operation can be impeded by relaxing the drivability and fuel economy constraints, and employing more aggressive modes of combustion that reduce emissions. In one feature, pre-mixed charge compression ignition (PCCI) combustion is extensively used. PCCI combustion is known to significantly reduce NOx and particulate emissions, however, it may decrease fuel economy and increase engine noise. In an alternative feature, fueling levels are reduced. By lowering the fueling levels, engine power levels, N0X and particulate emissions are correspondingly reduced. At the same time, TCAT is monitored and controlled in accordance with the diesel exhaust control described above. In an alternative feature, vehicle operation is impeded when FLAGDALOW is set. In this manner, the remaining dosing agent can be utilized in hand with the above-described engine operating modes, to maximize emissions performance while extending the dosing agent range. At the same time, TCAT is monitored and controlled in accordance with the diesel exhaust control described above. For example, the fueling levels can be reduced based on DALEVEL to reduce emissions, and at the same time, the remaining dosing agent can be used to further reduce emissions below the desired level. By combining fueling level reduction and dosing agent emissions reduction, the drivability and fuel economy are not as adversely affected as would be by reducing fueling levels alone to achieve the desired emissions performance. However, if TCAT does not exceed TTHR, the engine system 12 is operated as described above to increase TCAT- Referring now to Figure 2, exemplary steps will be described in detail. In step 202, control monitors DALEVEL- Control calculates and displays RANGEDA in step 204 based on DALEVEL In step 206, control determines whether DALEVEL is less that DALow- If DALEVEL is not less that DALow , control clears all dosing agent related flags in step 208 and control ends. If DALEVEL is less thanl DALOW , control determines whether DALEVEL is less than DAEMPTY in step 210. If DALEVEL is not less that DAEMPTY , control sets FLAGDALOW in step 212 and control continues in step 213. If DALEVEL is less than DAEMPTY, control sets FLAGDAEMPTY in step 216 and control continues in step 218. in step 218, control determines whether FLAGCa is set. If FLAGa is not set, control continues in step 213. If FLAGa is set, control sets FLAGDS in step 220. Control disables vehicle operation in step 222 and continues in step 214. In step 213, control impedes vehicle operation by implementing one of or a combination of the strategies discussed in detail above. In step 214, control displays the dosing agent status based on the dosing agent related flags and control ends. For example, 'Dosing Agent Low', "Dosing Agent Empty" or "Vehicle Disable Due To Empty Dosing Agent" messages can be displayed. Referring now to Figure 2, exemplary steps to determine whether the vehicle is stopped at a convenient location will be described in detail. In step 300, control determines whether an engine start just occurred. If an engine start occurred, control continues in step 302. If an engine start did not occur, control continues in step 304. In step 302, control determines FUELLEVEL. In step 306, control determines AFUEUEVEL as the difference between FUELLEVEL and the fuel level that was stored in memory immediately prior to the last engine shut - off event. In step 308, control determines whether ΔFUELLEVEL is greater than a threshold difference (ΔTHR). If AFUEUEVEL is greater than ΔTHR, control determines that the vehicle was refueled during the most recent shut-down and continues in step 310. If ΔFUELLEVEL is not greater than ΔTHR, control determines that the vehicle was not refueled during the most recent shut-down and continues in step 312. In step 304, control continuously monitors FUEUEVEL- In step 314, control determines whether FUEUEVEL is increasing at a rate (e.g. dFL/dft) greater than a threshold rate (e.g. dFL/dtTHR)- If dFL/dt is greater than dFL/dtmR, control determines that the vehicle is being refueled and continues in step 310. If dFLydt is not greater than dFL/dtrHR, control determines that the vehicle is not being refueled and continues in step 312. In step 310, control sets FLAGa. In step 312, control stores the new or most recent FUEUEVEL into memory and control ends. Although the diesel exhaust control is described in detail above using the fuel station scenario as an example. It is appreciated that the diesel exhaust control can monitor other scenarios including, but not limited to, maintenance and/or oil change to determine whether the vehicle is located in a convenient location. For example, the diesel exhaust control can monitor vehicle maintenance flags stored in memory and determine that the vehicle is at a convenient location if one or more maintenance related flags are set or reset. Alternatively, the diesel exhaust control can monitor an oil level or an oil characteristic. For example, if the oil level (OIUEVEL) increases or an oil parameter (OILPAR) (e.g., including, but not limited to, electrical impedance) indicates that an oil change has just occurred, the diesel exhaust control can determine that the vehicle is at a convenient location to refill the dosing agent. It is further anticipated that another input can be implemented to determine whether the vehicle is at a convenient location. For example, a global positioning system (GPS) may be implemented, such as that provided with a vehicle equipped with an OnStar™ system. The GPS can generate a signal indicating that the vehicle is at a convenient location. Referring now to Figure 4, exemplary steps that we are executed by the diesel exhaust control during the limp-home mode will be described in detail. In step 400, control determines whether the vehicle is being operated in the limp-home mode. If the vehicle is not being operated in the limp-home mode, control ends. If the vehicle is being operated in the limp-home mode, control determines TCAT in step 402. In step 404, control determines whether TCAT is greater than TTHR. If TCAT is not greater than TTHR, control regulates engine operation to increase TCAT in step 406 and loops back to step 402. If TCAT is greater than TTHR, control regulates engine operation per a limp-home mode strategy and to maintain TCAT and control ends. Referring now to Figure 5, exemplary modules that execute the extended emissions conformance control of the present invention will be described in detail. The exemplary module include a FLAGDALOW module 500, a a FLAGEMPTY module 502, a RANGEDA module 504, a FLAGa module 506, a display module 508, an AND module 510, an indicator module 512, a disable module 514, a limp-home module 516 and a TCAT module 517. The FLAGDALOW module 500, the FLAGEMPTY module 502 and the RANGEDA module 504 can be individual modules or can be sub-modules within a larger module 518. The FLAGDALOW module 500 selectively sets FLAGDALOW based on DALEVEL and DALOW- Similarly, the FLAGDAEMPTY module 502 selectively sets FLAGDAEMPTY based on DALEVEL and DAEMPTY. The RANGEDA module 504 calculates RANGEDA based on DALEVEL- The FLAGCL module 506 selectively sets FLAGo. based on FUELLEVEL, OILLEVEL and/or OILPAR. It is also anticipated that FLAGa based on FUEUEVEL/ OIUEVEL and/or OILPAR. It is also anticipated that FLAGa can be selectively set based on maintenance flags or any other factor that would indicate the vehicle is at a convenient location. Furthermore, FLAGa can be set based on another input, such as a signal generated by a GPS, as described above. The display module 508 graphically displays RANGEDA to alert the vehicle operator to the remaining distance the vehicle can travel before the dosing agent source is empty or below a desired level. The AND module 510 generates a signal based on FLAGDAEMPTY and FLAGa- For example, if both FLAGDAEMPTY and FLAGa are set. (e.g. equal to 1) the AND module 510 outputs a signal indicating that the dosing agent is empty and the vehicle is located at a convenient location. The indicator module 512 generates an indication an indication signal (e.g., audible and/or visual) based on FLAGDAEMPTY or FLAGDALOW to alert the vehicle operator to the status of the dosing agent source. The disable module 514 selectively disables vehicle operation based on the output of the AND module 510. More specifically, the disable module 514 generates control signal that disable vehicle operation until the dosing agent source is replenished. The limp-home module 516 selectively regulates the vehicle operation based on TCAT, FLAGDAEMPTY/ the output of the AND module 510, FLAGDALOW and/or DALEVEL. More specifically, the limp-home module 516 implements one of or a combination of the strategies described in detail above, and generates corresponding control signals. The TCAT module 517 determines TCAT module 517 determines TCAT and provides it to the limp-home module 516. Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims. WE CLAIM : 1. An exhaust after-treatment system (14) for a vehicle (10) having a dosing agent (38) that is selectively injected into an exhaust from a dosing agent source (44), comprising : a first module (50) that determines a level of said dosing agent (DALEVEL) within said dosing source (44); wherein said dosing agent (38) comprises ammonia; a second module (46) that selectively generates a signal when said vehicle is at a predetermined location and an engine (10) is started; and a third module (39) that reduces vehicle performance when said level (DALEVEL) is less than a first predetermined level (DALow), said level (DALEVEL) is greater than a second predetermined level (DAEMPTY), and said signal is not generated, that regulates operation of said engine (10) to increase a selective catalytic reduction (SCR) catalyst temperature (TCAT) when said SCR catalyst temperature (TCAT) is less than a predetermined temperature (TTHR) while said vehicle performance is reduced, and that disables said engine (10) when said level (DALEVEL) is less than said second level (DLow) and said signal is generated. 2. The exhaust after-treatment system as claimed in claim 1 wherein said third module operates said engine in a pre-mixed charge combustion ignition (PCCI) mode when said level is less than said first predetermined level, said level is greater than said second predetermined level, and said signal is not generated. 3. The exhaust after-treatment system as claimed in claim 1 wherein said third module transitions operation of said engine from a first mode to a second mode when said level is less than said first predetermined level, said level is greater than said second predetermined level, and said signal is not generated, and wherein output nitrogen oxides (NOx) and particulate matter amounts are less during operation in said second mode than during operation in said first mod00e. 4. The exhaust after-treatment system as claimed in claim 1 wherein said second module generates said signal when a difference between first and second fuel levels is greater than a predetermined amount, wherein said first fuel level is before said engine is started, and wherein said second fuel level is one of when and after said engine is started. 5. The exhaust after-treatment system as claimed in claim 1 wherein said second module generate said signal when a difference between first and second oil levels is greater than a predetermined amount. wherein said first oil level is before said engine is started, and wherein said second oil level is one of when and after said engine is started. 6. The exhaust after-treatment system as claimed in claim 1 wherein said second module selectively generates said signal based on a change in an oil parameter. 7. The exhaust after-treatment system as claimed in claim 6 wherein said oil parameter is electrical impedance of said oil. 8. The exhaust after-treatment system as claimed in claim 1 wherein said second module generates said signal based on a second signal from a global positioning system (GPS). 9. A method of extending emissions performance of an exhaust after- treatment system of a vehicle having a dosing agent, comprising: determining a level of said dosing agent within a dosing agent source, wherein said dosing agent comprises ammonia; selectively generating a signal when said vehicle is at a predetermined location and an engine is started; reducing vehicle performance when said level is less than a first predetermined level, said level is greater than a second predetermined level, and said signal is not generated; regulating operation of an engine to increase a selective catalytic reduction (SCR) catalyst temperature when said SCR catalyst temperature is less than a predetermined temperature while said vehicle performance is reduced; and disabling said engine when said level is less than said second level and said signal is generated. 10. The method as claimed in claim 9 wherein said regulating comprises operating said engine in a pre-mixed charge combustion ignition (PCCI) mode when said level is less than said first predetermined level, said level is greater than said second predetermined level, and said signal is not generated. 11. The method as claimed in claim 9 wherein said regulating comprises transitioning operation of said engine from a first mode to a second mode when said level is less than said first predetermined level, said level is greater than said second predetermined level, and said signal is not generated, and wherein output nitrogen oxides (NOx) and particulate matter amounts are less during operation in said second mode than during operation in said first mode. 12. The method as claimed in claim 9 wherein said generating comprises generating said signal when a difference between first and second fuel levels is greater than a predetermined amount. wherein said first fuel level is before said engine is started, and wherein said second fuel level is one of when and after said engine is started. 13. The method as claimed in claim 9 wherein said generating comprises generating said signal when a difference between first and second oil levels is greater than a predetermined amount. wherein said first oil level is from before said engine is started, and wherein said second oil level is from one of when and after said engine is started. 14. The method as claimed in claim 9 wherein said generating comprises generating said signal based on a change in an oil parameter. 15. The method as claimed in claim 14 wherein said oil parameter is an electrical impedance of said oil. 16. The method as claimed in claim 9 wherein said generating comprises generating said signal based on a second signal from a global positioning system (GPS). ABSTRACT TITLE "An exhaust after-treatment system of a vehicle and a method of extending emissions performance of an exhaust after-treatment system" The invention relates to an exhaust after-treatment system (14) for a vehicle (10) having a dosing agent (38) that is selectively injected into an exhaust from a dosing agent source (44), comprising : a first module (50) that determines a level of said dosing agent (DALEVEL) within said dosing source (44); wherein said dosing agent (38) comprises ammonia; a second module (46) that selectively generates a signal when said vehicle is at a predetermined location and an engine (10) is started; and a third module (39) that reduces vehicle performance when said level (DALEVEL) is less than a first predetermined level (DALow), said level (DALEVEL) is greater than a second predetermined level (DAEMPTY), and said signal is not generated, that regulates operation of said engine (10) to increase a selective catalytic reduction (SCR) catalyst temperature (TCAT) when said SCR catalyst temperature (TCAT) is less than a predetermined temperature (TTHR) while said vehicle performance is reduced, and that disables said engine (10) when said level (DALEVEL) is less than said second level (DLow) and said signal is generated.

Full Text

This application is related to U.S. Serial No. (To be assigned), filed
on December 14, 2006 (GP-307049), entitled, "Method of Monitoring A Dosing
Agent Supply For Treating Exhaust" and U.S. Serial No. (To be assigned), filed
on December 14, 2006 (GP-308075-PTE-CD), entitled, "Emissions Conformance
For An Exhaust After-Treatment System Having A Dosing Agent Supply". The
disclosures of the above applications are incorporated herein by reference.
FIELD
The present invention relates to vehicle exhaust systems, and
more particularly to a diesel exhaust control during a limp-home mode.
BACKGROUND
Internal combustion engines combust to an air and fuel mixture to
generate drive torque. The combustion process generates exhaust that is
exhausted from the engine to atmosphere. The exhaust contains nitrogen oxides
(NOx), carbon dioxide (C02) and carbon monoxide (CO) particulates. An exhaust
after-treatment system treats the exhaust to reduce emissions prior to being
released to atmosphere.

In an exemplary exhaust after-treatment system, a dosing system
injects a dosing agent (e.g., urea) into the exhaust upstream of a catalyst. The
exhaust and dosing agent mixture reacts over the catalyst to reduce the level of
emissions. The dosing system includes a dosing agent supply and an injector.
The amount of dosing agent injected is based on the level of emissions in the
exhaust. If the dosing agent supply is empty or at a low level, insufficient dosing
agent is injected into the exhaust stream, and emissions are not reduced as
desired.
It is a concern that vehicle operators may not replenish the
required dosing agent. As disclosed in commonly assigned U.S. Patent
Application No. (To be assigned), filed on December 14, 2006, and entitled, Emissions Conformance For An Exhaust After Treatment System Having A
Dosing Agent Supply', the disclosure of which is incorporated herein by
reference, vehicle operation can enter a limp-home that limits the vehicle
drivability to encourage the vehicle operator to replenish the dosing agent.
SUMMARY
Accordingly, the present disclosure provides a method of extending
emissions performance of an exhaust after-treatment system of a vehicle that
includes a dosing agent. The method includes determining a level of a dosing
agent source, selectively entering a limp-home mode based on the level and
monitoring a catalyst temperature during said limp-home mode. Operation of an

engine is regulate to increase the catalyst temperature when the catalyst
temperature is less than a threshold catalyst temperature during the limp-home
mode.
In one feature, the regulating includes throttling the engine.
In another feature, the regulating includes adjusting an air flow of
the engine.
In another feature, the regulating includes adjusting a fueling rate
of the engine.
In other features, the method further includes post-injecting fuel
into exhaust upstream of the catalyst. The post-injecting occurs when the
catalyst temperature is greater than the threshold catalyst temperature.
In still another feature, the catalyst temperature is monitored
based on a catalyst temperature sensor signal.
In yet another feature, the catalyst temperature is monitored
based on a catalyst temperature model.
Further areas of applicability will become apparent from the
description provided herein. It should be understood that the description and
specific examples are intended for purposes of illustration only and are not
intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE ACCONMPANYING DRAWINGS
The present invention will become more fully understood from the
detailed description and the accompanying drawings, wherein:
Figure 1 is a functional block diagram of an exemplary vehicle
system including an exhaust after-treatment system according to the present
disclosure.
Figure 2 is a flowchart illustrating exemplary steps executed by the
diesel exhaust control of the present disclosure;
Figure 3 is a flowchart illustrating steps executed by the diesel
exhaust control to determine whether the vehicle stopped at a convenient
location; and
Figure 4 is a flowchart illustrating exemplary steps executed by the
diesel exhaust control during the limp-home mode; and
Figure 5 is a functional block diagram illustrating exemplary
modules that execute the extended emissions conformance control.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description of the preferred embodiment is merely

exemplary in nature and is in no way intended to limit the invention, its
application or uses. For purposes of clarity, the same reference numbers will be
used in the drawings to identify similar elements. As used herein, the term
module refers to an application specific integrated circuit (ASIC), an electronic
circuit, a processor (shared, dedicated or group) and memory that execute one
or more software or firmware programs, a combinational logic circuit, or other
suitable components that provide the described functionality.
Referring now to Figure 1, an exemplary vehicle system 10 is
schematically illustrated. The vehicle system 10 includes an engine system 12, an
exhaust after-treatment system 14. The engine system 12 includes an engine 16
having a cylinder 18, an intake manifold 20 and an exhaust manifold 22. Air
flows into the intake manifold 20 through a throttle 24. The air is mixed with fuel
and the air and fuel mixture is combusted within the cylinder 18 to drive a piston
(not shown). Although a single cylinder 16 is illustrated, it is appreciated that the
engine 12 may include additional cylinders 18. For example, engines having 2, 3,
4, 5, 6, 8, 10, 12 and 16 cylinders are anticipated. The fuel is provided from a
fuel source 26 and is injected into the air stream using an injector 28. A fuel level
sensor 30 is responsive to the amount of fuel within the fuel source 26.
Exhaust is produced through the combustion process and is
exhausted from the cylinder 18 into the exhaust manifold 22. The exhaust after-
treatment system 14 treats the exhaust flowing therethrough to reduce
emissions before being released to the atmosphere. The exhaust after-treatment
system 14 includes a dosing system 32, a diesel oxidation catalyst (DOC) 34, an

emissions sensor 36 and a catalyst 38 that is preferably provided as a selective
catalytic (SCR) catalyst. The DOC 34 reacts with the exhaust to reduce emission
levels of the exhaust. The emissions sensor 36 is responsive to an emissions
(e.g., NOx) level of the exhaust. It is also anticipated that a diesel particulate
filter (DPF) 40 may be located downstream from the catalyst 30 that filters diesel
particulates to further reduce emissions.
The exhaust after-treatment system 14 can optionally include a
catalyst temperature sensor 39 that is responsive to a temperature of the
catalyst 38 (TCAT) and that generates a temperature signal based thereon. The
diesel exhaust control of the present disclosure can be implemented using the
temperature sensor signal, as described in further detail below.
The dosing system 32 includes a dosing agent injector 42, a dosing
agent storage tank 44 and a dosing agent supply sensor 46. The dosing system
32 selectively injects a dosing agent (e.g., urea) into the exhaust stream to
further reduce emissions. More specifically, the amount of the dosing agent is
determined based on the signal generated by the exhaust sensor. The exhaust
and dosing agent mixture reacts within the catalyst 38 to further reduce exhaust
emissions.
A control module 50 regulates operation of the vehicle system 10
based on the extended emissions conformance control of the present invention.
More specifically, the control module 50 determines a dosing agent level
(DALEVEL) based on the signal generated by the dosing agent supply sensor 46.

The control module can calculate a vehicle range (RANGEDA) based on the
amount of dosing agent remaining. More specifically, RANGEDA indicates the
remaining drivable distance before the entire dosing agent is consumed.
RANGEDA can be displayed on a display (not shown) to alert the vehicle
operator.
If DALEVEL is below a first predetermined or low dosing agent threshold
value (DALOW), the control module 50 sets a low dosing agent flag (FLAGDALOW)
(e.g., equal to 1 or TRUE) indicating that the dosing agent level is low and
should be refilled. Additionally, the control module 50 activates an indicator 52
that alerts the vehicle operator that the dosing agent supply is low and should be
refilled. The indicator 52 can be a visual and/or audible indication that alerts the
vehicle operator to the low condition. If DALEVEL is below a second predetermined
or empty dosing agent threshold value (DAEMPTY), the control module 50 sets an
empty dosing agent flag (FLAGDAEMPTY) (e.g., equal to 1 or TRUE). Further, the
control module 50 activates the indicator 52 to indicate that the dosing agent
source 44 is empty. When the dosing agent source 44 is refilled and DALEVEL
exceeds DAEMPTY and/or DALOW, FLAGDAEMPTY and/or FLAGDALOW is/are cleared and
the indicator 52 is also cleared.
The extended emissions conformance control selectively impedes vehicle
operation based on the dosing agent level. More specifically, if the dosing agent
monitoring control determines that the vehicle is at a convenient location, a
convenient location flag (FLAGCL) is set (e.g., equal to 1 or TRUE). A convenient
location can include, but is not limited to, a fuel station, a maintenance workshop

and/or an oil change workshop. If FLAGDALOW is set and the vehicle is stopped at
a convenient location (i.e., a location where additional dosing agent is available)
the extended emissions conformance control disables operation of the vehicle by
setting a disable flag (FLAGDIS) until the dosing agent is replenished. It is also
anticipated, however, that the vehicle operation need not be disabled even
though the vehicle is at a convenient location, but can be impeded. More
specifically, the vehicle operation can enter a limp-home mode, as described in
further detail below.
The diesel exhaust control selectively impedes operation of the
vehicle during the limp-home mode while meeting emissions requirements even
in the absence of dosing agent. More specifically, TCAT is monitored during the
operation in the limp-home mode. If TCAT is less than a threshold temperature
(TTHR)/ engine operation is regulated to increase the exhaust gas temperatures,
thereby increasing TCAT- TTHR corresponds to a temperature at which the catalyst
38 is considered active. The exhaust gas temperature can be increased by
engine throttling and air flow control. More specifically, the intake throttle can be
placed in closed position in order to reduce engine air flow and air-to-fuel ratio.
The turbocharger settings can also be modified to reduce air flow through the
engine and to increase exhaust temperatures. Additionally and/or alternatively,
the fuel injection timing can be retarded to further increase the exhaust gas
temperatures.
In one feature, TCAT can be directly measured using the
temperature sensor 39. In an alternative feature, TCAT can be determined based

on a catalyst temperature model that is processed by the control module 50.
More specifically, engine speed, air flow and fuel quantity can be used as inputs
for a catalyst temperature model.
Once TCAT exceeds TTHR, small amounts of fuel can be post-injected
(i.e. injected into a cylinder just after a combustion event), such that the fuel is
expelled from the cylinder with the exhaust and flows to the exhaust after-
treatment system 14. The heat energy of the catalyst 38 includes combustion of
the fuel, thereby maintaining TCAT above TTHR or increasing TCAT- The diesel
exhaust control continues to operate the engine in this manner to maintain
acceptable catalyst temperatures (i.e whereby the catalyst is active) and
emissions control. Once the dosing agent is replenished and the limp-home
mode is exited, the engine system 12 can be operated using normal control
strategies.
In accordance with other features of the present disclosure when
FLAGDAEMPTY is set and FLAGa is not set (i.e., when the vehicle is not deemed to
be at a convenient location), the limp-home mode is entered, whereby vehicle
operation is impeded. Vehicle operation can be impeded by relaxing the
drivability and fuel economy constraints, and employing more aggressive modes
of combustion that reduce emissions. In one feature, pre-mixed charge
compression ignition (PCCI) combustion is extensively used. PCCI combustion is
known to significantly reduce NOx and particulate emissions, however, it may
decrease fuel economy and increase engine noise. In an alternative feature,
fueling levels are reduced. By lowering the fueling levels, engine power levels,

N0X and particulate emissions are correspondingly reduced. At the same time,
TCAT is monitored and controlled in accordance with the diesel exhaust control
described above.
In an alternative feature, vehicle operation is impeded when
FLAGDALOW is set. In this manner, the remaining dosing agent can be utilized in
hand with the above-described engine operating modes, to maximize emissions
performance while extending the dosing agent range. At the same time, TCAT is
monitored and controlled in accordance with the diesel exhaust control described
above. For example, the fueling levels can be reduced based on DALEVEL to
reduce emissions, and at the same time, the remaining dosing agent can be
used to further reduce emissions below the desired level. By combining fueling
level reduction and dosing agent emissions reduction, the drivability and fuel
economy are not as adversely affected as would be by reducing fueling levels
alone to achieve the desired emissions performance. However, if TCAT does not
exceed TTHR, the engine system 12 is operated as described above to increase
TCAT-
Referring now to Figure 2, exemplary steps will be described in
detail. In step 202, control monitors DALEVEL- Control calculates and displays
RANGEDA in step 204 based on DALEVEL In step 206, control determines whether
DALEVEL is less that DALow- If DALEVEL is not less that DALow , control clears all
dosing agent related flags in step 208 and control ends. If DALEVEL is less thanl
DALOW , control determines whether DALEVEL is less than DAEMPTY in step 210. If
DALEVEL is not less that DAEMPTY , control sets FLAGDALOW in step 212 and control

continues in step 213. If DALEVEL is less than DAEMPTY, control sets FLAGDAEMPTY in
step 216 and control continues in step 218.
in step 218, control determines whether FLAGCa is set. If FLAGa
is not set, control continues in step 213. If FLAGa is set, control sets FLAGDS in
step 220. Control disables vehicle operation in step 222 and continues in step
214. In step 213, control impedes vehicle operation by implementing one of or a
combination of the strategies discussed in detail above. In step 214, control
displays the dosing agent status based on the dosing agent related flags and
control ends. For example, 'Dosing Agent Low', "Dosing Agent Empty" or "Vehicle
Disable Due To Empty Dosing Agent" messages can be displayed.
Referring now to Figure 2, exemplary steps to determine whether the
vehicle is stopped at a convenient location will be described in detail. In step
300, control determines whether an engine start just occurred. If an engine start
occurred, control continues in step 302. If an engine start did not occur, control
continues in step 304.
In step 302, control determines FUELLEVEL. In step 306, control
determines AFUEUEVEL as the difference between FUELLEVEL and the fuel level
that was stored in memory immediately prior to the last engine shut - off event.
In step 308, control determines whether ΔFUELLEVEL is greater than a threshold
difference (ΔTHR). If AFUEUEVEL is greater than ΔTHR, control determines that the
vehicle was refueled during the most recent shut-down and continues in step

310. If ΔFUELLEVEL is not greater than ΔTHR, control determines that the vehicle
was not refueled during the most recent shut-down and continues in step 312.
In step 304, control continuously monitors FUEUEVEL- In step 314,
control determines whether FUEUEVEL is increasing at a rate (e.g. dFL/dft)
greater than a threshold rate (e.g. dFL/dtTHR)- If dFL/dt is greater than dFL/dtmR,
control determines that the vehicle is being refueled and continues in step 310.
If dFLydt is not greater than dFL/dtrHR, control determines that the vehicle is not
being refueled and continues in step 312. In step 310, control sets FLAGa. In
step 312, control stores the new or most recent FUEUEVEL into memory and
control ends.
Although the diesel exhaust control is described in detail above
using the fuel station scenario as an example. It is appreciated that the diesel
exhaust control can monitor other scenarios including, but not limited to,
maintenance and/or oil change to determine whether the vehicle is located in a
convenient location. For example, the diesel exhaust control can monitor vehicle
maintenance flags stored in memory and determine that the vehicle is at a
convenient location if one or more maintenance related flags are set or reset.
Alternatively, the diesel exhaust control can monitor an oil level or an oil
characteristic. For example, if the oil level (OIUEVEL) increases or an oil
parameter (OILPAR) (e.g., including, but not limited to, electrical impedance)

indicates that an oil change has just occurred, the diesel exhaust control can
determine that the vehicle is at a convenient location to refill the dosing agent.
It is further anticipated that another input can be implemented to
determine whether the vehicle is at a convenient location. For example, a global
positioning system (GPS) may be implemented, such as that provided with a
vehicle equipped with an OnStar™ system. The GPS can generate a signal
indicating that the vehicle is at a convenient location.
Referring now to Figure 4, exemplary steps that we are executed
by the diesel exhaust control during the limp-home mode will be described in
detail. In step 400, control determines whether the vehicle is being operated in
the limp-home mode. If the vehicle is not being operated in the limp-home
mode, control ends. If the vehicle is being operated in the limp-home mode,
control determines TCAT in step 402.
In step 404, control determines whether TCAT is greater than TTHR.
If TCAT is not greater than TTHR, control regulates engine operation to increase
TCAT in step 406 and loops back to step 402. If TCAT is greater than TTHR, control
regulates engine operation per a limp-home mode strategy and to maintain TCAT
and control ends.
Referring now to Figure 5, exemplary modules that execute the
extended emissions conformance control of the present invention will be
described in detail. The exemplary module include a FLAGDALOW module 500, a

a FLAGEMPTY module 502, a RANGEDA module 504, a FLAGa module 506, a display
module 508, an AND module 510, an indicator module 512, a disable module
514, a limp-home module 516 and a TCAT module 517. The FLAGDALOW module
500, the FLAGEMPTY module 502 and the RANGEDA module 504 can be individual
modules or can be sub-modules within a larger module 518.
The FLAGDALOW module 500 selectively sets FLAGDALOW based on
DALEVEL and DALOW- Similarly, the FLAGDAEMPTY module 502 selectively sets
FLAGDAEMPTY based on DALEVEL and DAEMPTY. The RANGEDA module 504 calculates
RANGEDA based on DALEVEL- The FLAGCL module 506 selectively sets FLAGo. based
on FUELLEVEL, OILLEVEL and/or OILPAR. It is also anticipated that FLAGa based on
FUEUEVEL/ OIUEVEL and/or OILPAR. It is also anticipated that FLAGa can be
selectively set based on maintenance flags or any other factor that would
indicate the vehicle is at a convenient location. Furthermore, FLAGa can be set
based on another input, such as a signal generated by a GPS, as described
above. The display module 508 graphically displays RANGEDA to alert the vehicle
operator to the remaining distance the vehicle can travel before the dosing agent
source is empty or below a desired level.
The AND module 510 generates a signal based on FLAGDAEMPTY and
FLAGa- For example, if both FLAGDAEMPTY and FLAGa are set. (e.g. equal to 1)
the AND module 510 outputs a signal indicating that the dosing agent is empty
and the vehicle is located at a convenient location. The indicator module 512
generates an indication an indication signal (e.g., audible and/or visual) based on
FLAGDAEMPTY or FLAGDALOW to alert the vehicle operator to the status of the dosing

agent source. The disable module 514 selectively disables vehicle operation
based on the output of the AND module 510. More specifically, the disable
module 514 generates control signal that disable vehicle operation until the
dosing agent source is replenished.
The limp-home module 516 selectively regulates the vehicle
operation based on TCAT, FLAGDAEMPTY/ the output of the AND module 510,
FLAGDALOW and/or DALEVEL. More specifically, the limp-home module 516
implements one of or a combination of the strategies described in detail above,
and generates corresponding control signals. The TCAT module 517
determines TCAT module 517 determines TCAT and provides it to the limp-home
module 516.
Those skilled in the art can now appreciate from the foregoing description
that the broad teachings of the present invention can be implemented in a
variety of forms. Therefore, while this invention has been described in
connection with particular examples thereof, the true scope of the invention
should not be so limited since other modifications will become apparent to the
skilled practitioner upon a study of the drawings, the specification and the
following claims.

WE CLAIM :
1. An exhaust after-treatment system (14) for a vehicle (10) having a dosing
agent (38) that is selectively injected into an exhaust from a dosing agent
source (44), comprising :
a first module (50) that determines a level of said dosing agent (DALEVEL)
within said dosing source (44);
wherein said dosing agent (38) comprises ammonia;
a second module (46) that selectively generates a signal when said vehicle
is at a predetermined location and an engine (10) is started; and
a third module (39) that reduces vehicle performance when said level
(DALEVEL) is less than a first predetermined level (DALow), said level
(DALEVEL) is greater than a second predetermined level (DAEMPTY), and said
signal is not generated, that regulates operation of said engine (10) to
increase a selective catalytic reduction (SCR) catalyst temperature (TCAT)
when said SCR catalyst temperature (TCAT) is less than a predetermined
temperature (TTHR) while said vehicle performance is reduced, and that
disables said engine (10) when said level (DALEVEL) is less than said
second level (DLow) and said signal is generated.
2. The exhaust after-treatment system as claimed in claim 1 wherein said
third module operates said engine in a pre-mixed charge combustion
ignition (PCCI) mode when said level is less than said first predetermined

level, said level is greater than said second predetermined level, and said
signal is not generated.
3. The exhaust after-treatment system as claimed in claim 1 wherein said
third module transitions operation of said engine from a first mode to a
second mode when said level is less than said first predetermined level,
said level is greater than said second predetermined level, and said signal
is not generated, and
wherein output nitrogen oxides (NOx) and particulate matter amounts are
less during operation in said second mode than during operation in said
first mod00e.
4. The exhaust after-treatment system as claimed in claim 1 wherein said
second module generates said signal when a difference between first and
second fuel levels is greater than a predetermined amount,
wherein said first fuel level is before said engine is started, and
wherein said second fuel level is one of when and after said engine is
started.
5. The exhaust after-treatment system as claimed in claim 1 wherein said
second module generate said signal when a difference between first and
second oil levels is greater than a predetermined amount.
wherein said first oil level is before said engine is started, and wherein
said second oil level is one of when and after said engine is started.

6. The exhaust after-treatment system as claimed in claim 1 wherein said
second module selectively generates said signal based on a change in an
oil parameter.
7. The exhaust after-treatment system as claimed in claim 6 wherein said oil
parameter is electrical impedance of said oil.
8. The exhaust after-treatment system as claimed in claim 1 wherein said
second module generates said signal based on a second signal from a
global positioning system (GPS).
9. A method of extending emissions performance of an exhaust after-
treatment system of a vehicle having a dosing agent, comprising:
determining a level of said dosing agent within a dosing agent source,
wherein said dosing agent comprises ammonia;
selectively generating a signal when said vehicle is at a predetermined
location and an engine is started;
reducing vehicle performance when said level is less than a first
predetermined level, said level is greater than a second predetermined
level, and said signal is not generated;
regulating operation of an engine to increase a selective catalytic
reduction (SCR) catalyst temperature when said SCR catalyst temperature
is less than a predetermined temperature while said vehicle performance
is reduced; and
disabling said engine when said level is less than said second level and
said signal is generated.

10. The method as claimed in claim 9 wherein said regulating comprises
operating said engine in a pre-mixed charge combustion ignition (PCCI)
mode when said level is less than said first predetermined level, said level
is greater than said second predetermined level, and said signal is not
generated.
11. The method as claimed in claim 9 wherein said regulating comprises
transitioning operation of said engine from a first mode to a second mode
when said level is less than said first predetermined level, said level is
greater than said second predetermined level, and said signal is not
generated, and
wherein output nitrogen oxides (NOx) and particulate matter amounts are
less during operation in said second mode than during operation in said
first mode.
12. The method as claimed in claim 9 wherein said generating comprises
generating said signal when a difference between first and second fuel
levels is greater than a predetermined amount.
wherein said first fuel level is before said engine is started, and
wherein said second fuel level is one of when and after said engine is
started.
13. The method as claimed in claim 9 wherein said generating comprises
generating said signal when a difference between first and second oil
levels is greater than a predetermined amount.
wherein said first oil level is from before said engine is started, and

wherein said second oil level is from one of when and after said engine is
started.
14. The method as claimed in claim 9 wherein said generating comprises
generating said signal based on a change in an oil parameter.
15. The method as claimed in claim 14 wherein said oil parameter is an
electrical impedance of said oil.
16. The method as claimed in claim 9 wherein said generating comprises
generating said signal based on a second signal from a global positioning
system (GPS).

ABSTRACT
TITLE "An exhaust after-treatment system of a vehicle
and a method of extending emissions performance
of an exhaust after-treatment system"
The invention relates to an exhaust after-treatment system (14) for a
vehicle (10) having a dosing agent (38) that is selectively injected into an
exhaust from a dosing agent source (44), comprising : a first module (50)
that determines a level of said dosing agent (DALEVEL) within said dosing
source (44); wherein said dosing agent (38) comprises ammonia; a
second module (46) that selectively generates a signal when said vehicle
is at a predetermined location and an engine (10) is started; and a third
module (39) that reduces vehicle performance when said level (DALEVEL) is
less than a first predetermined level (DALow), said level (DALEVEL) is greater
than a second predetermined level (DAEMPTY), and said signal is not
generated, that regulates operation of said engine (10) to increase a
selective catalytic reduction (SCR) catalyst temperature (TCAT) when said
SCR catalyst temperature (TCAT) is less than a predetermined temperature
(TTHR) while said vehicle performance is reduced, and that disables said
engine (10) when said level (DALEVEL) is less than said second level (DLow)
and said signal is generated.

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Patent Number

259315

Indian Patent Application Number

1496/KOL/2007

PG Journal Number

11/2014

Publication Date

14-Mar-2014

Grant Date

07-Mar-2014

Date of Filing

01-Nov-2007

Name of Patentee

GM GLOBAL TECHNOLOGY OPERATIONS, INC.

Applicant Address

300 GM RENAISSANCE CENTER, DETROIT, MICHIGAN

Inventors:

#	Inventor's Name	Inventor's Address
1	DAVID B. BROWN	3681 OLDE DOMINION, BRIGHTON, MICHIGAN 48114

PCT International Classification Number

F01N9/00; F01N3/18; F02D41/14

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	11/639370	2006-12-14	U.S.A.