DE102019206109A1 - Exhaust gas aftertreatment device with turbocharger between nitrogen oxide storage catalytic converter and particle filter - Google Patents

Abstract

An exhaust gas aftertreatment device (2) for an internal combustion engine (1) is described, which comprises an inlet, a nitrogen oxide storage catalyst (4) being arranged downstream of the inlet and a turbocharger (3) being arranged downstream of the nitrogen oxide storage catalyst (4) , a particulate filter (5) is arranged downstream of the turbocharger (3), an SCR catalytic converter (6, 7) downstream of the particulate filter (5) and a device downstream of the particulate filter (5) and upstream of the SCR catalytic converter (6, 7) is arranged for injecting urea (14).

Description

The present invention relates to an exhaust gas aftertreatment device, an internal combustion engine arrangement, a motor vehicle, a method for operating an exhaust gas aftertreatment device and a computer program m product.

In connection with motor vehicles that are driven by internal combustion engines, exhaust gas aftertreatment is of essential importance. In particular, the increasing emission requirements require constant improvement in the quality of exhaust gas aftertreatment. Exhaust gas aftertreatment during the cold start phase is a particular challenge, since many catalytic converters usually have not yet reached their operating temperature during a cold start. This applies in particular to the typically used diesel oxidation catalytic converters (DOC) and catalytic converters for selective catalytic reduction (SCR catalytic converters). As a rule, optimal operation of the exhaust gas aftertreatment components is only possible within a narrow temperature range. Overall, it is desirable to further reduce harmful emissions, such as in particular the emission of nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbons (HC).

In the documents US 8250866 B2 , US 9003781 and DE 10 2014 213070 A1 For example, catalytic converters are arranged upstream of the turbine of a turbocharger.

Against this background, the object of the present invention is to provide a further improved exhaust gas aftertreatment device and a method for operating such an exhaust gas aftertreatment device, wherein in particular the exhaust gas aftertreatment is improved under cold start conditions. Further tasks are to provide an advantageous computer program product, an advantageous internal combustion engine arrangement and a motor vehicle.

These objects are achieved by an exhaust gas aftertreatment device for an internal combustion engine according to claim 1, an internal combustion engine arrangement according to claim 6, a motor vehicle according to claim 8, a method for operating an exhaust gas aftertreatment device according to claim 9 and a computer program product according to claim 11. The dependent claims contain further advantageous developments of the present invention.

The exhaust gas aftertreatment device according to the invention for an internal combustion engine comprises an inlet. A nitrogen oxide storage catalytic converter is arranged downstream of the inlet. A turbocharger is arranged downstream of the nitrogen oxide storage catalytic converter. A particle filter, for example a catalytically coated particle filter, is arranged downstream of the turbocharger. An SCR catalytic converter is arranged downstream of the particle filter. A device for injecting urea is arranged downstream of the particulate filter and upstream of the SCR catalytic converter.

By arranging a nitrogen oxide storage catalytic converter upstream of the turbocharger, the removal of emissions that are harmful to health and the environment from the exhaust gas is improved overall and in particular under cold start conditions. In addition, the high temperatures of the exhaust gas upstream of the turbocharger and the high pressure increase the amount of nitrogen oxide which is stored in the catalytic converter. Due to the arrangement of the particle filter and the SCR catalytic converter directly downstream of the turbocharger, the SCR catalytic converter quickly reaches its operating temperature, which is particularly advantageous under cold start conditions. The upstream connection of the particle filter prevents soot and fine dust from being deposited in the downstream exhaust gas aftertreatment components.

Overall, the present invention on the one hand covers a wide exhaust gas temperature range with optimal exhaust gas aftertreatment, for example also under cold start conditions. At the same time, the nitrogen oxide storage catalytic converter can be regenerated regularly under optimal conditions.

A first lambda sensor or a lambda probe and / or a first temperature sensor are preferably arranged upstream of the nitrogen oxide storage catalytic converter. A second lambda sensor or a lambda probe can be arranged downstream of the nitrogen oxide storage catalytic converter. A second temperature sensor can be arranged downstream of the particle filter, in particular upstream of the SCR catalytic converter. Said sensors are preferably connected to a control device, for example an electronic control unit (ECU), and enable the exhaust gas aftertreatment device or the individual exhaust gas aftertreatment components to be controlled depending on the temperature and / or the composition of the exhaust gas. The device for injecting urea can also be connected to the control device.

In an advantageous variant, the exhaust gas aftertreatment device is designed in such a way that the inlet comprises an exhaust manifold and the nitrogen oxide storage catalytic converter is integrated into the exhaust manifold. This is the one below On the other hand, the high exhaust gas temperature and the high pressure of the exhaust gas can increase the NOx storage amount in the nitrogen oxide storage catalytic converter. The particle filter can be arranged, for example, directly downstream of the turbocharger.

The particle filter and / or the SCR catalytic converter can be arranged downstream of the nitrogen oxide storage catalytic converter, for example in the underbody area of a motor vehicle. This arrangement results in areas with different operating temperatures for the individual exhaust gas aftertreatment components and the nitrogen oxide conversion is improved.

The internal combustion engine arrangement according to the invention comprises an internal combustion engine and an exhaust gas aftertreatment device according to the invention arranged downstream of the internal combustion engine. It has the advantages already mentioned. In an advantageous variant, the particle filter and / or the SCR catalyst are arranged below the internal combustion engine and / or below the turbocharger and / or below the nitrogen oxide storage catalyst, that is, for example, in the underbody area. With this arrangement, the particle filter and / or the SCR catalytic converter can be operated under high load at lower operating temperatures and thus with improved nitrogen oxide conversion. In addition, an optimal operating temperature is made possible and nitrogen dioxide (NO2) production is increased, which improves the soot particle combustion in the particle filter. Furthermore, an arrangement in the underbody area is advantageous with regard to an optimal use of the installation space. The arrangement described within the scope of the present invention also reduces the emission of carbon monoxide and the emission of unburned hydrocarbons in the second nitrogen oxide storage catalytic converter.

The motor vehicle according to the invention comprises a previously described internal combustion engine arrangement according to the invention. The internal combustion engine arrangement according to the invention and the motor vehicle according to the invention have the advantages already mentioned in connection with the exhaust gas aftertreatment device according to the invention. The motor vehicle according to the invention can be a passenger car, a truck, a motorcycle, a moped, a bus or a minibus.

The method according to the invention for operating an exhaust gas aftertreatment device for an internal combustion engine relates to an exhaust gas aftertreatment device which comprises an inlet.

A nitrogen oxide storage catalytic converter is arranged downstream of the inlet. A turbocharger is arranged downstream of the nitrogen oxide storage catalytic converter. A particle filter, for example a catalytically coated particle filter, is arranged downstream of the turbocharger. An SCR catalytic converter is arranged downstream of the particle filter. A device for injecting urea, in particular an aqueous urea solution, is arranged downstream of the particle filter and upstream of the SCR catalytic converter.

The method comprises the following steps: A first temperature of the exhaust gas upstream of the nitrogen oxide storage catalytic converter is determined, for example measured. A second temperature of the exhaust gas downstream of the particulate filter is determined, for example measured. If the second temperature is higher than a second temperature threshold value, urea, preferably in the form of an aqueous urea solution, is injected upstream of the SCR catalytic converter. If the first temperature is higher than a first temperature threshold value, the nitrogen oxide storage catalytic converter is regenerated.

In a preferred variant, the first temperature threshold value is at least 200 degrees Celsius (200 ° C.) and / or the second temperature threshold value is at least 180 degrees Celsius (180 ° C.). These threshold values ensure optimal regeneration of the nitrogen oxide storage catalytic converter and, at the same time, optimal operation of the SCR catalytic converter.

The exhaust gas aftertreatment device according to the invention can comprise, for example, a control device which is designed to carry out a method according to the invention as described above. The method according to the invention has the advantages described in connection with the exhaust gas aftertreatment device according to the invention.

The computer program product according to the invention comprises commands which, when the program is executed by a computer, cause the computer to execute a previously described method according to the invention. It is particularly suitable for retrofitting existing exhaust gas aftertreatment systems designed accordingly.

• 1 zeigt schematisch einen Verbrennungsmotor mit einer erfindungsgemäßen Abgasnachbehandlungsvorrichtung.
• 2 zeigt schematisch ein erfindungsgemäßes Verfahren in Form eines Flussdiagramms.
• 3 zeigt schematisch ein erfindungsgemäßes Kraftfahrzeug.

The figures show:

• 1 shows schematically an internal combustion engine with an exhaust gas aftertreatment device according to the invention.
• 2 shows schematically a method according to the invention in the form of a flow chart.
• 3 shows schematically a motor vehicle according to the invention.

In the 1 is an internal combustion engine 1 shown, which fluidically with an exhaust gas aftertreatment device according to the invention 2 connected is. With the internal combustion engine 1 it can be a diesel engine, for example.

The exhaust gas aftertreatment device according to the invention 2 includes a turbocharger 3 . Upstream of the turbocharger 3 is a nitrogen oxide storage catalytic converter 4th arranged. Downstream of the turbocharger 3 is a particle filter 5 , for example a catalytically coated particle filter, arranged. Downstream of the particulate filter 5 is an SCR catalytic converter 6 and / or further exhaust gas aftertreatment devices 7th , which may include at least one further SCR catalyst, for example, arranged.

Upstream of the nitrogen oxide storage catalytic converter 4th are a first lambda sensor 10 and a first temperature sensor 9 arranged. A second lambda sensor 12 is immediately downstream of the nitrogen oxide storage catalytic converter 4th , in the present variant upstream of the turbocharger 3 , arranged. A second temperature sensor 11 and a device for injecting urea 14th are downstream of the particulate filter 5 and upstream of the SCR catalyst 6 arranged.

The lambda sensors 10 and 12 who have favourited temperature sensors 9 and 11 and the device for injecting urea 14th are each with a control device 13 connected. The internal combustion engine 1 is also with the control device 13 connected. This is in the 1 indicated by dashed lines. By means of the control device 13 the exhaust gas aftertreatment devices can be controlled individually depending on the composition of the exhaust gas, as well as depending on the temperatures determined by means of the temperature sensors. The control of the exhaust gas aftertreatment devices mentioned can in particular regenerate and desulfurize the nitrogen oxide storage catalytic converter 4th , the regeneration of the soot filter or particle filter, as well as the dosing of the injection of urea 14th include.

As part of the 2 The procedure shown is in a first step 15th a first temperature of the exhaust gas upstream of the nitrogen oxide storage catalytic converter 4th certainly. This can be done, for example, by means of the first temperature sensor 9 respectively. In addition, in step 15th a second temperature of the exhaust gas downstream of the particulate filter 5 certainly. This can be done, for example, by means of the second temperature sensor 11 respectively.

In step 16 it is checked whether the second temperature is higher than a second temperature threshold value. If this is the case, step 17th Urea upstream of the SCR catalyst 6 by means of the device for injecting urea 14th injected. The second temperature threshold value is preferably at least 180 ° C. If the second temperature is not higher than the second temperature threshold value, then in step 18th checked whether the first temperature is higher than a first temperature threshold. If this is the case, step 19th the nitrogen oxide storage catalytic converter 4th regenerated. The first temperature threshold is preferably at least 200 ° C. If the first temperature is not higher than the first temperature threshold value, the method jumps to step 15th back. The steps 16 and 18th can also be carried out simultaneously or in reverse order. Following the steps 17th and 19th the procedure also jumps to step 15th back.

That in the 3 shown motor vehicle 20th includes an internal combustion engine 1 , for example a diesel engine, and an exhaust gas aftertreatment device according to the invention 2 .

List of reference symbols

1

Internal combustion engine

2

Exhaust aftertreatment device

3

turbocharger

4th

Nitrogen oxide storage catalytic converter

5

Particle filter

6th

SCR catalytic converter

7th

Exhaust aftertreatment device

9

first temperature sensor

10

first lambda sensor

11

second temperature sensor

12

second lambda sensor

13th

Control device

14th

Device for injecting urea

15th

Determining a first temperature of the exhaust gas upstream of the nitrogen oxide storage catalytic converter and a second temperature of the exhaust gas downstream of the particulate filter

16

Is the second temperature higher than a second temperature threshold?

17th

Injecting urea upstream of the SCR catalyst

18th

Is the first temperature higher than a first temperature threshold?

19th

Regeneration of the nitrogen oxide storage catalytic converter

20th

Motor vehicle

J

Yes

N

No

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 8250866 B2 [0003]
• US 9003781 [0003]
• DE 102014213070 A1 [0003]

Claims (12)

Exhaust gas aftertreatment device (2) for an internal combustion engine (1), which comprises an inlet, characterized in that a nitrogen oxide storage catalyst (4) is arranged downstream of the inlet, a turbocharger (3) is arranged downstream of the nitrogen oxide storage catalyst (4), and downstream of the turbocharger (3) a particle filter (5) is arranged, downstream of the particle filter (5) an SCR catalytic converter (6, 7) and downstream of the particle filter (5) and upstream of the SCR catalytic converter (6, 7) an injection device of urea (14) is arranged. The exhaust gas aftertreatment device (2) according to the preceding claim, characterized in that a first lambda sensor (10) and / or a first temperature sensor (9) is arranged upstream of the nitrogen oxide storage catalyst (4) and a first lambda sensor (9) is arranged downstream of the nitrogen oxide storage catalyst (4) second lambda sensor (12) is arranged and / or a second temperature sensor (11) is arranged downstream of the particle filter (5). Exhaust gas aftertreatment device (2) according to one of the preceding claims, characterized in that the particle filter (5) is designed as a catalytically coated particle filter (5). Exhaust gas aftertreatment device (2) according to one of the preceding claims, characterized in that the inlet comprises an exhaust manifold and the first nitrogen oxide storage catalytic converter (4) is integrated in the exhaust manifold. Exhaust gas aftertreatment device (2) according to one of the preceding claims, characterized in that the particle filter (5) is arranged directly downstream of the turbocharger (3). Internal combustion engine arrangement, which comprises an internal combustion engine (1) and an exhaust gas aftertreatment device (2) arranged downstream of the internal combustion engine (1) according to one of the Claims 1 to 5 includes. Internal combustion engine arrangement according to the preceding claim, characterized in that the particle filter (5) and / or the SCR catalyst (6, 7) below the internal combustion engine (1) and / or below the turbocharger (3) and / or below the nitrogen oxide storage catalyst (4) are arranged. A motor vehicle (20) comprising an internal combustion engine assembly according to any preceding claim. A method for operating an exhaust gas aftertreatment device (2) for an internal combustion engine (1), which comprises an inlet, a nitrogen oxide storage catalyst (4) being arranged downstream of the inlet, a turbocharger (3) being arranged downstream of the nitrogen oxide storage catalyst (4), a particulate filter (5) is arranged downstream of the turbocharger (3), an SCR catalytic converter (6, 7) is arranged downstream of the particulate filter (5), an SCR catalytic converter (6, 7) is arranged downstream of the particle filter (5) and upstream of the SCR catalytic converter (6, 7) Device for injecting urea (14) is arranged, characterized in that the method comprises the following steps: - determining a first temperature (15) of the exhaust gas upstream of the nitrogen oxide storage catalyst (4), - determining a second temperature (15) of the exhaust gas downstream of the particle filter (5), if the second temperature is higher than a second temperature threshold value (16), injecting urea (17) upstream towards the SCR catalytic converter (6, 7), - if the first temperature is higher than a first temperature threshold value (18), regeneration (19) of the nitrogen oxide storage catalytic converter (4). Method according to the preceding claim, characterized in that the first temperature threshold value is at least 200 degrees Celsius (200 ° C) and / or the second temperature threshold value is at least 180 degrees Celsius (180 ° C). Computer program product comprising instructions which, when the program is executed by a computer, cause the latter to carry out a method according to one of the preceding claims. Exhaust aftertreatment device (2) according to one of the Claims 1 to 5 , characterized in that the exhaust gas aftertreatment device (2) comprises a control device (13) which is designed to implement a method according to one of the Claims 9 or 10 execute.

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