DE102016109812A1 - Method for operating a vehicle - Google Patents

Abstract

A method for operating a motor vehicle is provided. The motor vehicle includes an engine and an exhaust aftertreatment device in an exhaust pipe of the engine, the exhaust aftertreatment device comprising a passive NOx adsorber (PNA) configured to capture nitrogen oxides from the exhaust gases at and below a first temperature and at or above a second temperature To release nitrogen oxides in the exhaust gases and to oxidize hydrocarbon and / or carbon monoxide with a catalyst. The method includes monitoring the engine air-fuel ratio, determining an aging parameter of the exhaust aftertreatment device by integrating the engine air-fuel ratio with respect to time, determining whether the exhaust aftertreatment device should be regenerated based on the aging parameter, and regenerating the exhaust aftertreatment device.

Description

Technical area

The present disclosure relates to a method of operating a vehicle, and particularly, although not exclusively, relates to a method of operating a vehicle including a passive NOx adsorber (PNA).

background

Motor vehicles are often equipped with exhaust aftertreatment devices such as Diesel Particulate Filters (DPFs), Selective Catalytic Reduction (SCR) devices, Lean NOx Trap (LNTs) and / or Passive NOx Adsorbers (PNAs). fitted. These devices remove contaminants from the exhaust gases by trapping, oxidizing or reducing the impurity species. Combinations of such devices may be implemented to ensure the best emission control over a variety of operating conditions.

Exhaust after-treatment devices may be periodically regenerated to continue to operate efficiently. The regeneration of exhaust aftertreatment devices is associated with a disadvantage in terms of fuel consumption and / or can lead to an increase in emissions during regeneration. Thus, it may be desirable to regenerate aftertreatment devices only when necessary to maintain their performance.

Some aftertreatment devices, such as PNAs, may be regenerated periodically or following events known to cause significant degradation, such as the regeneration of a DPF or a desulphurisation event of an LNT in the same exhaust line as the PNA. However, the aftertreatment devices may also be affected under other driving conditions and therefore may be inefficient until a regeneration event is triggered.

Presentation of the invention

According to a first aspect of the present disclosure, there is provided a method of operating a motor vehicle, the motor vehicle including an engine and an exhaust aftertreatment device in an exhaust pipe of the engine, the exhaust aftertreatment device comprising a passive NOx adsorber (PNA) configured to:
capture nitrogen oxides from exhaust gases at or below a first temperature and deliver nitrogen oxides into the exhaust gases at or above a second temperature; and
Hydrocarbon and / or carbon monoxide with a catalyst to oxidize. The method comprises: monitoring an engine air-fuel equivalence ratio, for example a lambda value of exhaust gases from the engine, determining an aging parameter of the exhaust aftertreatment device by integrating the engine air-fuel equivalence ratio with respect to time, determining whether the exhaust aftertreatment device is regenerating based on the aging parameter and regenerating the exhaust aftertreatment device.

In this specification, passive NOx adsorber (PNA) is intended to mean any device configured for installation in an exhaust conduit of a vehicle, such as a motor vehicle, configured to capture nitrogen oxides from the exhaust gases at or below a first temperature and at or above to release nitrogen oxides into the exhaust gases at a second temperature; and to oxidize hydrocarbon and / or carbon monoxide with a catalyst. Such a device may be known as a passive NOx adsorber or Nitrogen Storage Catalyst Lite (LNT-Lite).

The method may further include monitoring the temperature of exhaust gases from the engine, and the aging parameter of the exhaust after-treatment device may be determined by integrating a function of the temperature and the air-fuel equivalence ratio with respect to time.

Further, the method may include monitoring the engine operating time and / or fuel consumption, and the aging parameter of the exhaust after-treatment device may be determined at least in part from the monitored operating time and / or fuel consumption.

Further, the method may include determining a response temperature of the catalyst based on the aging parameter. Determining whether the exhaust aftertreatment device should be regenerated may be performed by comparing the response temperature to a threshold. The exhaust aftertreatment device may be regenerated by operating the engine under conditions of rich combustion. The regeneration of the exhaust aftertreatment device may be performed during an acceleration event of the vehicle.

The method may further comprise determining the effect of the regeneration of the exhaust aftertreatment device on the aging parameter. The effect of the regeneration of the exhaust aftertreatment device on the aging parameter may be determined by monitoring the engine air-fuel equivalence ratio during regeneration and integrating the engine air-fuel equivalence ratio with respect to time.

Additionally or alternatively, the effect of the regeneration of the exhaust aftertreatment device on the aging parameter may be determined by monitoring the temperature of engine exhaust gases and the engine's air-fuel equivalence ratio during regeneration and integrating a function of the temperature and air-fuel equivalence ratio Time to be determined.

The aging parameter may be related to anticipated oxidation of the exhaust aftertreatment device catalyst. The catalyst may comprise a platinum group metal.

The vehicle may further include a selective catalytic reduction (SCR) device, and the method may further comprise configuring the SCR device to reduce the nitrogen oxides released by the PNA at or above the second temperature. Additionally or alternatively, the method may include adjusting the amount of reductant introduced into the SCR device according to the aging parameter of the PNA.

Further, the vehicle may include an exhaust gas recirculation (EGR) system, and the method may further include adjusting the amount of exhaust gas recirculated by the EGR system according to the aging parameter of the PNA. Additionally or alternatively, the method may further include adjusting the amount of exhaust gas recirculated through the EGR system to reduce the temperature of the exhaust gases entering the PNA during regeneration of the PNA.

In accordance with another aspect of the present disclosure, there is provided a controller configured to perform the method according to an aforementioned aspect of the disclosure.

According to another aspect of the present disclosure, there is provided software that, when executed by a computing device, causes the computing device to perform the method according to the aforementioned aspect of the disclosure.

According to another aspect of the present disclosure, there is provided a motor vehicle including an engine, an exhaust aftertreatment device in an exhaust pipe of the engine, the exhaust aftertreatment device comprising a PNA configured to: capture nitrogen oxides from the exhaust gases at or below a first temperature; deliver nitrogen oxides into the exhaust gases above a second temperature; and
To oxidize hydrocarbons and / or carbon monoxide with a catalyst; and a controller configured to perform the method according to a previously mentioned aspect of the present disclosure.

To avoid unnecessary duplication of effort and text repetition in the description, certain features will be described in terms of only one or more aspects or embodiments of the invention. It should be understood, however, that features described with respect to any aspect or embodiment of the invention may be used in any other aspect or embodiment of the invention, if technically possible.

Brief description of the drawings

For a better understanding of the present disclosure and to illustrate its possible implementation, reference will now be made, by way of example, to the accompanying drawings, in which: show in it:

1 a schematic view of the flow of air and exhaust gases through a previously proposed engine system and exhaust aftertreatment system;

2 a method of operating a vehicle according to the present disclosure; and

3 12 is a schematic view of a controller configured to operate a vehicle in accordance with the present disclosure.

Detailed description

On 1 Referring to a vehicle 1 an engine 2 , an air intake 4 , an exhaust gas recirculation (EGR) system 6 and an exhaust system 8th include. The engine 2 may include a diesel engine, however, it is equally contemplated that the present disclosure could be applied to any other type of vehicle engine, such as a gasoline engine. Additionally or alternatively, the engine may be self-priming or include a turbocharger and / or a supercharger and / or provided with some other form of improved intake. The vehicle may include an additional engine, such as an electric motor, and the engine 2 can be part of a hybrid drive system.

As in 1 shown, the engine can 2 an intake manifold 2a and an exhaust manifold 2 B include. The intake manifold 2a can with intake air from inlet 4 be supplied via the intake manifold 2a in the engine 2 can be pulled. The intake air can be in the engine 2 be mixed with fuel and burned to provide power to drive the vehicle as well as any auxiliary systems, such as electrical systems, which are provided on the vehicle to drive. The combustion of the fuel and intake air produces exhaust gases that include water vapor, carbon dioxide (CO ₂ ), carbon monoxide (CO), nitrogen oxides (NO x), and other gases passing through the exhaust manifold 2 B can be dissipated.

As in 1 shown includes the EGR system 6 a high pressure EGR system. Additionally or alternatively, the EGR system 6 a low-pressure EGR system in which exhaust gases can be returned after being expanded by the turbine of a turbocharger. Alternatively, the vehicle may not include an EGR system. The EGR system 6 allows some of the exhaust gases to the inlet of the engine 2 is returned. Replacing a portion of the oxygen-rich air with burned exhaust gases reduces the proportion of content of each cylinder available for combustion. This results in reduced heat output and lower peak cylinder temperature, thereby reducing the formation of NOx.

Exhaust gases that do not have the EGR system 6 can be recycled, in the exhaust system 8th enter. As in 1 shown, the exhaust system 8th One or more exhaust aftertreatment devices, such as a passive NOx adsorber (PNA) 10 , include. The exhaust system 8th can also be a device 12 for selective catalytic reduction (SCR device). The exhaust aftertreatment devices may be upstream of an exhaust outlet 14 be provided. The SCR device 12 may be actively controlled as described below or may be a passive SCR device. Additionally or alternatively, the exhaust aftertreatment system may include a diesel particulate filter (DPF), a nitrogen oxide storage catalyst (LNT), a diesel oxidation catalyst (DOC), and / or any other exhaust aftertreatment device. Additionally or alternatively, the exhaust system may include a combined aftertreatment device, such as a combined SCR / DPF device. The exhaust aftertreatment systems may be provided in any order in the exhaust system.

The vehicle 1 may also exhaust outlet sensors 16 and / or engine sensors 18 include. The sensors may include one or more temperature sensors and / or one or more lambda sensors. The lambda sensors may include narrowband or broadband lambda probes. Additionally or alternatively, the lambda sensors may include any other sensor capable of measuring the amount of oxygen in the exhaust gases and / or the air-fuel ratio and / or the air-fuel equivalence ratio of combustion in the engine 2 to determine. The engine sensors 18 can be downstream of the exhaust manifold 2 B be provided. Additionally or alternatively, exhaust gas outlet temperature and / or lambda sensors may be used 16 at or near the outlet 14 be provided, which may be configured to measure the temperature and / or the oxygen content of the exhaust gases as soon as they have the exhaust aftertreatment devices 10 . 12 have flowed through. Additionally or alternatively, exhaust gas temperature and / or lambda sensors (not shown) may be located elsewhere in the exhaust system, for example, between the PNA 10 and the SCR device 12 , be provided.

The PNA 10 may comprise a wash-coated honeycomb structure which may comprise a Platinum Group Metal (PGM) catalyst, for example a platinum, palladium, osmium, iridium, ruthenium or rhodium catalyst , If the PNA 10 For example, by the exhaust gases having been heated to a temperature that is at or above a response temperature of the catalyst, the PGM catalyst may be in the PNA 10 begin to catalyze a reaction, adsorbed by the NOx compounds from the exhaust gases and in the PNA 10 can be captured. The response temperature of the catalyst may be so low that the PNA 10 NOx from the exhaust gases at lower temperatures than other aftertreatment devices configured to adsorb NOx, such as an LNT, can be effectively adsorbed. The PNA 10 can also start using NOx at lower temperatures than the SCR device 12 can be operated to adsorb as described below. The PNA 10 may be configured to deliver the stored NOx when it reaches higher operating temperatures. Unlike a LNT, the PNA 10 be configured to allow the delivery of stored NOx without specifically adjusting the operation of the engine, for example, by initiating a rich-combustion engine mode.

In addition to catalyzing the adsorption of NOx in the PNA 10 When the PGM catalyst in the PNA is at or above the response temperature, oxidation reactions of other exhaust gases, such as CO and / or unburned hydrocarbons (HC), can be catalyzed by the PGM catalyst. These gases can be oxidized in the PNA to form CO ₂ and water.

In the in 1 The exhaust system shown uses the SCR device 12 controlled injection of a reductant, for example from an SCR dosing system (not shown), to convert NOx compounds present in the exhaust gases to nitrogen gas and water through a chemical reduction process. In the in 1 As shown, urea is injected into the exhaust system and undergoes thermal decomposition and hydrolysis to produce ammonia. The generated ammonia may act as the reducing agent in the SCR device. The metered addition of urea may be controlled to affect the efficiency with which NOx is removed from the exhaust gases. Additionally or alternatively, another reductant may be introduced through the SCR dosing system. Again, in addition or as an alternative thereto, the reducing agent may pass through a reforming process of another upstream of the SCR device 12 installed exhaust aftertreatment device can be provided.

It may be necessary for the exhaust system to be 8th and / or the SCR device 12 heated / heated to a suitable temperature before the urea can thermally decompose and the SCR device can work effectively. The PNA 10 can therefore be at lower temperatures than the SCR device 12 work. The SCR device 12 however, it can continue at higher temperatures than those where the PNA 10 begins to work the NOx previously trapped by the device as described above. By providing the PNA 10 upstream of the SCR device 12 as in the exhaust system 8th from 1 shown, the exhaust system 8th operate effectively to NOx over a wider temperature range than any of the devices is individually able to remove from the exhaust gases.

As described above, impurity species such as HC and / or CO may be present in the PNA 10 be oxidized. The PGM catalyst can act as a catalyst in these oxidation reactions. During such reactions, the PGM catalyst itself can be oxidized. In addition, the PGM catalyst may be directly oxidized at higher temperatures by oxidizing species in the exhaust gases, for example, the PGM catalyst may be a reactant in the oxidation reaction. This effect can be exacerbated if the engine is operated under leaner combustion conditions which can lead to higher concentrations of oxidizing species within the exhaust gases. Oxidation of the PGM catalyst may cause an increase in the response temperature of the catalyst, which may increase the temperature at which the PNA begins to capture NOx efficiently from the exhaust gases and / or the oxidation of other impurity species, such as CO and HC. cause. An increase in the response temperature of the catalyst can therefore lead to aging of the PNA 10 to lead.

To reduce the response temperature of the catalyst and improve the efficiency of the PNA 10 the PNA can be regenerated. It can be a mode of the engine 2 with a rich combustion to increase the concentration of reducing species, such as HC and CO, in the exhaust gases. The oxidized PGM catalyst can be reduced by the reducing species, thereby reversing the PNA aging process and reducing the response temperature of the PGM catalyst. The reaction in which the oxidized PGM catalyst is reduced may proceed at a higher reaction rate with respect to the oxidation reaction of the PGM catalyst when the operating temperature of the PNA is reduced, and thus the operation of the engine and / or the EGR system may be controlled to reduce the temperature of the exhaust gases.

The operation of the engine to reduce the response temperature of the PGM catalyst in the PNA may be performed periodically, for example, after a certain engine run time or distance, or after a certain amount of fuel in the engine 2 has been burned. Additionally or alternatively, the engine may be operated to regenerate the PNA following, for example, regeneration of a DPF of the exhaust system or a desulfurization event of an exhaust system LNT following specific events known to adversely affect the performance of the PNA , These events can be a period of lean engine operation 2 at high temperature, leading to oxidation of the PGM catalyst and thus aging of the PNA 10 can lead. Additionally or alternatively, the aging of the PNA 10 be monitored directly, and the regeneration of the PNA can be performed based on the aging of the PNA.

With reference to 2 becomes a procedure 200 for operating a vehicle according to an example of the present disclosure. The procedure 200 can take a first step 202 in which the air-fuel equivalence ratio, for example the lambda value, of the engine is monitored. In a second step 204 For example, a function dependent on the air-fuel equivalence ratio with respect to time may be integrated to an aging parameter of an exhaust aftertreatment device, for example the PNA 10 to determine. In a third step 206 may be determined based on the aging parameter, whether the exhaust aftertreatment device should be regenerated. In a fourth step 208 For example, the exhaust aftertreatment device can be regenerated.

In addition to monitoring the air-fuel equivalence ratio in the first step 202 Also, the temperature of the exhaust gases from the engine can be monitored. If the temperature of the exhaust gases is monitored in the first step, the function shown in the second step 204 is integrated to determine an aging parameter of the exhaust aftertreatment device, moreover be dependent on the exhaust gas temperature.

As above with reference to 1 described aging of an exhaust aftertreatment device, for example, the PNA 10 which correspond to oxidation of a catalyst of the device. The rate of oxidation reaction of the catalyst may be dependent upon the temperature of exhaust gases and / or the concentration of oxidizing species in the exhaust gases. By monitoring the air-fuel equivalence ratio of the engine and / or the temperature of the exhaust gases in the first step 202 , for example, by using the engine temperature and / or the lambda sensors 18 and / or the outlet temperature and / or the lambda sensors 16 , the oxidation rate of the catalyst can be determined. For example, a function of temperature and / or air-fuel equivalence ratio may be used to calculate the oxidation rate of the catalyst or a parameter that represents the oxidation rate. Alternatively, a look-up table may be referenced and a value for the oxidation rate or the representative parameter may be determined according to the temperature and / or the air-fuel equivalence ratio. The value calculated or determined from the look-up table may be integrated with respect to time to determine an oxidation of the catalyst that may provide an aging parameter of the exhaust aftertreatment device.

The integration of the calculated or determined oxidation rate can be performed continuously while the vehicle is in operation. Alternatively, the integration may be performed by considering discrete values recorded at predetermined intervals. As another alternative, the integration may be performed only while the temperature and / or the air-fuel equivalence ratio are / are within predetermined ranges.

In addition or as an alternative to applying the monitored temperature and / or air-fuel equivalence ratio to determine an aging parameter of the exhaust aftertreatment device, an operating time, distance, and / or fuel consumption of the engine may be monitored and used to determine or adjust the engine Aging parameters of the exhaust aftertreatment device, for example, by reference to an alternative look-up table used.

For determining in the third step whether the exhaust aftertreatment device should be regenerated, a response temperature of a catalyst of the exhaust aftertreatment device can be determined. For example, a second look-up table may be referenced, and a response temperature may be determined according to the aging parameter of the exhaust aftertreatment device. The response temperature may be compared to a threshold, and if the determined response temperature is greater than or equal to the threshold, it may be determined that the exhaust aftertreatment device should be regenerated.

If the exhaust system 8th another exhaust aftertreatment device that may be controlled to affect the rate at which NOx compounds are removed from the exhaust gases, such as the SCR 12 , the method may include an additional step of controlling the other exhaust aftertreatment device to remove any additional NOx due to the aging of the PNA 10 has not been captured.

The other exhaust aftertreatment device may also be configured to remove any NOx compounds that are released as soon as the PNA 10 has reached a higher temperature at which it begins to release the stored NOx as described above.

When the vehicle is accelerating, the difference in fuel consumption and / or emissions of the vehicle between ideal engine operation and rich engine operation may be less than at other points in the vehicle drive cycle. The regeneration of the exhaust aftertreatment device in step 208 can therefore be performed when the vehicle accelerates.

During regeneration of the exhaust aftertreatment device, the rate of reduction of the oxidized PGM catalyst may be dependent upon the temperature of the exhaust gases and / or the concentration of reducing species in the exhaust gases. The effect of a regeneration period on the catalyst can therefore be determined from the exhaust gas temperature and / or air-fuel equivalent ratio measurements in a manner similar to the determination of the aging parameter. The function of the temperature and / or the air-fuel equivalence ratio or the look-up table described above may allow negative values to be integrated as described above to determine the reduction to the aging parameter.

The procedure 200 may further comprise an additional step of determining the effect of the regeneration of the exhaust aftertreatment device on the aging parameter. As described above, this may be accomplished by monitoring the temperature of exhaust gases from the engine and / or the air-fuel equivalence ratio of the engine during regeneration and integrating a function of the temperature and / or an air-fuel equivalence ratio with respect to time. In addition, or alternatively, the look-up table may be referenced, and a reduction rate of the catalyst may be determined from the look-up table.

Updating the aging parameter during regeneration as well as under normal operating conditions may permit control of the length of a regeneration event to provide the desired reduction in aging of the aftertreatment device and thus the desired reduction in response temperature. Monitoring the effect of the regeneration may further allow for sharing the regeneration between multiple regeneration events. This may be useful when the regeneration has to be stopped or abandoned, for example, when it is no longer possible to operate the engine under conditions of rich combustion. In addition, regeneration may be intentionally split into shorter regeneration events that may be performed during periods during which it is most efficient to operate the engine under conditions of rich combustion, for example, when the vehicle is accelerating.

Now on 3 Referring to, becomes a controller 300 for operating a vehicle according to an example of the present disclosure. The control 300 can be a first module 302 configured to monitor an air-fuel equivalence ratio of the engine and / or a temperature of exhaust gases from an engine of the vehicle. The control 300 can be a second module 304 configured to integrate a function of the air-fuel equivalence ratio and / or the temperature of exhaust gases to an aging parameter of an exhaust aftertreatment device, for example the PNA 10 to determine. The control 300 can be a third module 306 configured to determine, based on the aging parameter, whether the exhaust aftertreatment device should be regenerated. The control 300 can be a fourth module 308 include, which may control the vehicle for regenerating the exhaust aftertreatment device.

As described above, the second module 304 to determine the aging parameter of the exhaust aftertreatment device a memory 304a in which a look-up table is stored. The look-up table may allow the determination of an aging rate of the aftertreatment device, such as an oxidation rate of a catalyst of the aftertreatment device, based on exhaust temperature and / or engine air-fuel equivalence ratio values. The look-up table may also include negative values for the rate of aging that may correspond to exhaust temperature and / or engine air-fuel equivalence ratio values encountered in a regeneration event.

To determine whether the exhaust aftertreatment device should be regenerated based on the aging parameter, the third module 306 a second memory 306a in which a second look-up table is stored. The second look-up table may allow a determination of a response temperature of a catalyst of the aftertreatment device based on the aging parameter. The third module 306 may be configured to compare the determined response temperature value to a threshold to determine whether the exhaust aftertreatment device should be regenerated.

It will be understood by those skilled in the art that while the invention has been described by way of example with reference to one or more examples, it is not limited to the disclosed examples and alternative examples could be constructed without departing from the scope of the invention as defined in the appended claims departing.

Claims (21)

 A method of operating a motor vehicle, the motor vehicle comprising an engine and an exhaust aftertreatment device in an exhaust pipe of the engine, the exhaust aftertreatment device comprising a passive NOx adsorber (PNA) configured to: capture nitrogen oxides from exhaust gases at or below a first temperature and deliver nitrogen oxides into the exhaust gases at or above a second temperature; and To oxidize hydrocarbon and / or carbon monoxide with a catalyst; the method comprising: Monitoring an air-fuel equivalence ratio of the engine; Determining an aging parameter of the exhaust aftertreatment device by integrating the air-fuel equivalence ratio of the engine with respect to time; Determining whether the exhaust aftertreatment device should be regenerated based on the aging parameter; and Regenerating the exhaust aftertreatment device.  The method of claim 1, further comprising monitoring a temperature of exhaust gases from the engine, wherein the aging parameter of the exhaust after-treatment device is determined by integrating a function of the temperature and the air-fuel equivalence ratio with respect to time.  The method of claim 1 or 2, further comprising monitoring operating time and / or fuel consumption of the engine, wherein the aging parameter of the exhaust after-treatment device is determined at least in part from the monitored operating time and / or fuel consumption.  The method of any one of the preceding claims, further comprising determining a response temperature of the catalyst based on the aging parameter.  The method of claim 4, wherein determining whether the exhaust aftertreatment device should be regenerated is performed by comparing the response temperature to a threshold.  A method according to any one of the preceding claims, wherein the exhaust aftertreatment device is regenerated by operating the engine under conditions of rich combustion.  The method of any preceding claim, further comprising determining the effect of the regeneration of the exhaust aftertreatment device on the aging parameter.  The method of claim 7, wherein the effect of the regeneration of the exhaust aftertreatment device on the aging parameter is determined by: Monitoring the air-fuel equivalence ratio of the engine during regeneration; and Integrating the air-fuel equivalence ratio of the engine with respect to time.  The method of claim 7, wherein the effect of the regeneration of the exhaust aftertreatment device on the aging parameter is determined by: Monitoring the temperature of exhaust gases from the engine and the air-fuel equivalence ratio of the engine during regeneration; and Integrating a function of temperature and air-fuel equivalence ratio with respect to time.  Method according to one of the preceding claims, wherein the aging parameter with an anticipated oxidation of the catalyst of the exhaust aftertreatment device in relation.  A process according to any one of the following claims wherein the catalyst comprises a platinum group metal.  Method according to one of the preceding claims, wherein the vehicle further comprises a device for selective catalytic reduction (SCR device).  The method of claim 12, the method further comprising configuring the SCR device to reduce the nitrogen oxides emitted by the PNA at or above the second temperature.  The method of claim 12 or 13, wherein the method further comprises adjusting an amount of reductant introduced into the SCR device according to the aging parameter of the PNA.  Method according to one of the preceding claims, wherein the vehicle further comprises an exhaust gas recirculation (EGR) system. The method of claim 15, wherein the method further comprises adjusting an amount of exhaust gas recirculated through the EGR system according to the aging parameter of the PNA.  The method of claim 15 or 16, wherein the method further comprises adjusting an amount of exhaust gas recirculated through the EGR system to reduce the temperature of the exhaust gases entering the PNA during regeneration of the PNA.  Method according to one of the preceding claims, wherein the regeneration of the exhaust gas aftertreatment device during an acceleration event of the vehicle is performed.  A controller configured to perform the method of any one of the preceding claims.  Software that, when executed by a computing device, causes the computing device to perform the method of any one of claims 1 to 18.  Motor vehicle comprising: an engine; an exhaust aftertreatment device in an exhaust pipe of the engine, the exhaust after-treatment device comprising a PNA configured to capture nitrogen oxides from the exhaust gases at or below a first temperature, deliver nitrogen oxides into the exhaust gases at or above a second temperature, and hydrocarbons and / or carbon monoxide with a To oxidize the catalyst; and a controller configured to perform the method of any one of claims 1 to 18.

Images