DE102018206355B3 - Motor vehicle and operating method - Google Patents

Abstract

It is a motor vehicle (10) having an internal combustion engine (11), an exhaust line (12) for discharging an exhaust gas of the internal combustion engine (11), in the exhaust line (12) arranged first Stickstoffoxidadsorber (13) and in the exhaust line (12) downstream of first nitrogen oxide adsorber (13) arranged second nitrogen oxide adsorber (15) provided. According to the invention, the motor vehicle (10) comprises an oxygen introduction device (21) for introducing oxygen into the exhaust line (12) downstream of the first nitrogen oxide adsorber (13) and upstream of the second nitrogen oxide adsorber (15) and a fuel introduction device (22) for introducing fuel into the exhaust gas line (12) downstream of the first nitrogen oxide adsorber (13) and upstream of the second nitrogen oxide adsorber (15). In addition, an operating method (30) for the motor vehicle (10) is provided.

Description

The present invention relates to a motor vehicle having an internal combustion engine, an exhaust gas system for discharging an exhaust gas of the internal combustion engine, a first nitrogen oxide adsorber arranged in the exhaust gas system and a second nitrogen oxide adsorber arranged downstream of the first nitrogen oxide adsorber in the exhaust gas system. In addition, the present invention relates to an operating method for operating the motor vehicle.

From the DE 10 2010 038 175 A1 For example, a method for adjusting a lean NOx trap (LNT, also known as a nitrogen oxide adsorber) in an exhaust system of a motor vehicle is known. The method includes determining the amount of nitrogen oxides (NOx) upstream of the lean NOx trap, calculating the amount of nitrogen oxides stored in the lean NOx trap, and estimating an estimated NOx concentration downstream of the lean NOx trap by means of a kinetic model of the lean NOx trap, calculating a limit function based on the measured NOx concentration downstream and a mass flow rate of nitrogen oxides in the exhaust gas, calculating an adjustment signal by subtracting the estimated NOx concentration downstream of the limit function, adjusting the amount of stored nitrogen oxides by means of the adaptation signal and / or adjusting the NOx release by means of the remaining adjustment signal and / or adjusting the total rate of NOx storage by means of a storage adjustment rate generated by subtracting the NOx release from the adjustment signal, conversion from a concentration to a mass flow rate , Division by the maximum storage capacity and sign inversion and / or improving the estimation of the mass of stored nitrogen oxides by means of a memory adaptation generated by integration of the memory adjustment rate, generation of a factor therefrom and multiplication by the nominal total storage capacity.

In the DE 60 2004 003 354 T2 there is shown an exhaust system including a particulate filter and NOx absorber. The exhaust system comprises a first nitrogen oxide absorber and a second nitrogen oxide absorber downstream of the first one, with ports arranged to supply fuel upstream of the first nitrogen oxide absorber, the soot filter and before the second nitrogen oxide absorber, and downstream of the first, depending on the operating situation and to inject air into the exhaust stream prior to the second nitrogen oxide absorber.

In the EP 1 321 643 A1 an arrangement for the aftertreatment of exhaust gases is shown. In this case, in an exhaust line a close-coupled nitrogen oxide storage catalyst and a second nitrogen oxide storage catalyst and between an oxidation catalyst and a particulate filter provided, between the near-engine nitrogen oxide storage catalyst and the oxidation catalyst via a fuel supply unit fuel can be introduced into the exhaust stream and between the Oxidation catalyst and the particle filter secondary air can be introduced into a connecting line.

In the DE 10 2014 206 455 A1 there is shown a regeneration method for an exhaust aftertreatment system having in the exhaust stream a three-way catalyst, a near-engine nitrogen oxide storage catalyst, and an underbody nitrogen oxide storage catalyst, with a lambda sensor provided downstream of each catalyst.

In the DE 10 2016 118 810 A1 an exhaust system is shown in which downstream of a NOx absorber catalyst as the first nitrogen oxide and a lean NOx trap as a second nitrogen oxide nor an SCR catalyst is provided, wherein between the NOx absorber catalyst and the lean NOx trap an injector for Hydrocarbons and between the lean NOx trap and the SCR catalyst is provided an injector for a nitrogen-containing reducing agent.

The present invention has for its object to provide a motor vehicle with improved exhaust aftertreatment.

This object is achieved with a motor vehicle according to claim 1 and an operating method according to claim 2. Advantageous developments of the invention are specified in the dependent claims.

The motor vehicle according to the invention has an internal combustion engine, an exhaust system for discharging an exhaust gas of the internal combustion engine, a first nitrogen oxide adsorber arranged in the exhaust system and a second nitrogen oxide adsorber arranged downstream of the first nitrogen oxide adsorber in the exhaust system. According to the invention, the motor vehicle comprises an oxygen introduction device for introducing oxygen into the exhaust line downstream of the first nitrogen oxide adsorber and upstream of the second nitrogen oxide adsorber, and a fuel introduction device for introducing fuel into the exhaust line downstream of the first nitrogen oxide adsorber and upstream of the second nitrogen oxide adsorber.

This advantageously makes it possible to selectively influence the second nitrogen oxide adsorber and optionally further exhaust aftertreatment devices and to bring about a desired mode of operation of these.

The motor vehicle according to the invention also has a first lambda sensor, which is arranged in the exhaust gas line downstream of the first nitrogen oxide adsorber and upstream of the second nitrogen oxide adsorber.

Thus, a current lambda value (A) can be determined, which can then be changed by introducing oxygen and / or fuel.

The motor vehicle according to the invention has a second lambda sensor, which is arranged in the exhaust line downstream of the second nitrogen oxide adsorber.

This can be deduced on the operation of the second Nitric Oxide adsorber and he second nitrogen oxide adsorber thus be monitored.

The motor vehicle according to the invention has a first further exhaust gas aftertreatment device, which is arranged in the exhaust gas line between the first nitrogen oxide adsorber and the second nitrogen oxide adsorber.

This arrangement allows additional exhaust aftertreatment before the exhaust gas flows through the second nitrogen oxide adsorber.

The motor vehicle according to the invention has a second further exhaust gas aftertreatment device, which is arranged in the exhaust gas line downstream of the second nitrogen oxide adsorber. The second further exhaust aftertreatment device is, for example, an exhaust gas aftertreatment device designed to carry out a selective catalytic reduction.

Thus, the second further exhaust aftertreatment device benefits from the possibility of being able to influence the exhaust gas by adding oxygen. In particular, the lifetime of SCR catalysts can be extended by higher lambda values.

In the operating method according to the invention for a motor vehicle having an internal combustion engine, an exhaust line for discharging an exhaust gas of the internal combustion engine, a first arranged in the exhaust line and a nitrogen oxide arranged in the exhaust line downstream of the first Stickstoffoxidadsorbers second Stickstoffoxidadsorber according to the invention in a measure oxygen in the exhaust line downstream of the first Stickoxidadsorbers and introduced upstream of the second nitrogen oxide adsorber.

As a result, the lambda value (λ) of the exhaust gas can advantageously be increased. In addition, the exhaust gas can be cooled.

In the operating method according to the invention, in addition to oxygen, fuel is also introduced into the exhaust line downstream of the first nitrogen oxide adsorber and upstream of the second nitrogen oxide adsorber.

As a result, the exhaust gas can be cooled lambda-neutral or the lambda value can be increased or reduced.

In an advantageous embodiment of the operating method according to the invention, a state of the motor vehicle is determined in a state determination, and the determined state is compared with a desired state in an adjustment. The measure is carried out on condition that it is determined in the adjustment that the particular state deviates from the desired state. The state is a temperature, or a lambda value upstream of the second nitrogen oxide adsorber, or a hydrocarbon slip downstream of the second nitrogen oxide adsorber, or a carbon monoxide slip downstream of the second nitrogen oxide adsorber.

Thus, the measure can be carried out as needed.

• 1 ein erfindungsgemäßes Kraftfahrzeug in einer beispielhaften Ausgestaltung; und
• 2 ein erfindungsgemäßes Betriebsverfahren in einer beispielhaften Ausführung.

Further advantages of the present invention will become apparent from the detailed description and the drawings. The invention will be explained in more detail with reference to the figures and the description below. Show it:

• 1 an inventive motor vehicle in an exemplary embodiment; and
• 2 an inventive operating method in an exemplary embodiment.

In the 1 is the motor vehicle according to the invention 10 shown schematically in an exemplary embodiment. The car 10 includes an internal combustion engine 11 as well as an exhaust system 12 by the one in the operation of the internal combustion engine 11 derived exhaust gas is derived. In the exhaust system 12 are several exhaust aftertreatment devices 13 . 14 . 15 . 16 . 17 arranged. So has the motor vehicle 10 at least over a first nitrogen oxide adsorber 13 and a second nitrogen oxide adsorber 15 , The second nitrogen oxide adsorber is here 15 downstream of the first nitrogen oxide adsorber 13 in the exhaust system 12 arranged.

According to the invention, the motor vehicle 10 an oxygen introduction device 21 and a fuel introduction device 22 on. In this case, the oxygen introduction device 21 adapted to oxygen at an oxygen introduction site 23 in the exhaust system 12 downstream of the first nitrogen oxide adsorber 13 and upstream of the second nitrogen oxide adsorber 15 contribute. In particular, the oxygen introduction device 21 designed to introduce the oxygen as part of air. The fuel introduction device 22 is adapted to fuel at a fuel injection point 24 in the exhaust system 12 downstream of the first nitrogen oxide adsorber 13 and upstream of the second nitrogen oxide adsorber 15 contribute. In particular, the fuel injection point 24 downstream of the oxygen introduction site 23 arranged. Between the collection points 23 . 24 and the second nitrogen oxide adsorber 15 is preferably no further exhaust aftertreatment device arranged.

The motor vehicle preferably has a control unit 20 on. The oxygen introduction device 21 and the fuel introduction device 22 be from the control unit 20 controlled. The control unit 20 is formed, the operating method according to the invention 30 to control.

In addition to the two nitrogen oxide adsorbers 13 . 15 includes the motor vehicle 10 in particular further exhaust aftertreatment devices 14 . 16 . 17 , So has the motor vehicle 10 in particular a first further exhaust aftertreatment device 14 on. The first further exhaust aftertreatment device 14 is in the exhaust system 12 between the first nitrogen oxide adsorber 13 and the second nitrogen oxide adsorber 15 upstream of the points of introduction 23 . 24 arranged.

In addition, the motor vehicle includes 10 in particular a second further exhaust aftertreatment device 16 , The second further exhaust aftertreatment device 16 is in the exhaust system 12 downstream of the second nitrogen oxide adsorber 15 arranged. The second further exhaust aftertreatment device 16 is designed to perform a selective catalytic reduction. For example, the second further exhaust aftertreatment device 16 an SCR catalyst (SCR) or an SCR-coated particulate filter (SDPF). Downstream of the second further exhaust aftertreatment device 16 may be a third further exhaust aftertreatment device 17 be arranged. In this way it is in the 1 shown.

The car 10 has means that are suitable for a condition of the motor vehicle 10 to determine. So has the motor vehicle 10 in particular via a first lambda sensor 18 who is in the exhaust system 12 downstream of the first nitrogen oxide adsorber 13 and upstream of the second nitrogen oxide adsorber 15 is arranged. The first lambda sensor 18 is preferably directly downstream of the first nitrogen oxide adsorber 13 arranged, in such a way that between the first nitrogen oxide adsorber 13 and the first lambda probe 18 no further exhaust aftertreatment device is arranged. Furthermore, the motor vehicle includes 10 in particular a second lambda sensor 19 that in the exhaust system 12 downstream of the second nitrogen oxide adsorber 15 is arranged. The second lambda sensor 19 is preferably directly downstream of the second nitrogen oxide adsorber 15 arranged, that is, in such a way that between the second nitrogen oxide adsorber 15 and the second lambda probe 19 no further exhaust aftertreatment device is arranged. In addition, the motor vehicle 10 in particular at least one upstream of the second nitrogen oxide adsorber 15 arranged temperature sensor for determining the temperature of the exhaust gas.

The motor vehicle according to the invention 10 is formed, the operating method according to the invention 30 perform. The operating method according to the invention 30 is in the 2 in an exemplary embodiment schematically from a start 31 to an end 35 shown.

In the operating procedure 30 becomes a measure 34 carried out in the oxygen in the exhaust line upstream of the second Stickstoffoxidadsorbers 15 is introduced. The oxygen is in particular directly upstream of the second nitrogen oxide adsorber 15 introduced, so in such a way that between the oxygen introduction site 23 and the second nitrogen oxide adsorber 15 no further exhaust aftertreatment device is arranged. The oxygen is preferably introduced in the form of oxygen-containing air.

In the measure 34 In particular, in addition to the oxygen, fuel is also upstream of the second nitrogen oxide adsorber 15 is introduced. The fuel is, in particular, directly upstream of the second nitrogen oxide adsorber 15 introduced, so in the way that between the fuel injection point 24 and the second nitrogen oxide adsorber 15 no further exhaust aftertreatment device is arranged. The fuel is preferably of the type with which the internal combustion engine 11 is driven. It is also conceivable that a different fuel than that for the drive of the internal combustion engine 11 intended to be used.

Both the measure 34 as well as the design of the measure 34 in particular depending on a condition of the motor vehicle 10 carried out. This is done in the operating procedure 30 a condition determination 32 made at a current state of the motor vehicle 10 is determined. In a balance 33 becomes the in the state determination 32 determined state is compared with a desired state. The measure 34 will be after the adjustment 33 provided that in the reconciliation 33 it is determined that in the state determination 32 certain state deviates from the nominal state.

The condition of the motor vehicle 10 is for example defined by at least one temperature. The temperature is for example an exhaust gas temperature or an exhaust aftertreatment device temperature of one of the exhaust aftertreatment devices 15 . 16 . 17 downstream of the points of introduction 23 . 24 , The temperature is detected by the at least one temperature sensor. In addition to the at least one temperature or in addition to this, the condition of the motor vehicle 10 by a lambda value upstream of the second nitrogen oxide adsorber 15 , by means of the second lambda sensor 19 is measured, defined. In addition or in addition, the state of the motor vehicle 10 by a hydrocarbon slip downstream of the second nitrogen oxide adsorber 15 be defined. In addition or in addition, the state of the motor vehicle 10 by carbon monoxide slip downstream of the second nitrogen oxide adsorber 15 be defined.

That's the measure 34 especially in different modes.

In a first mode, the exhaust aftertreatment devices become 15 . 16 . 17 downstream of the points of introduction 23 . 24 heated. For this purpose, oxygen and fuel in the exhaust system 12 introduced if at least one of the exhaust aftertreatment devices 15 . 16 . 17 downstream of the points of introduction 23 . 24 has too low a temperature.

In a second mode, during a first phase of rich operation, nitrogen oxide desorption is reduced by the lambda value (λ) of the exhaust gas upstream of the second nitrogen oxide adsorber 15 is increased to> 1, so oxygen is introduced.

In a third mode, a rich operation of the internal combustion engine 11 monitors for hydrocarbon slip or carbon monoxide slip of the second nitrogen oxide adsorber 15 to prevent.

In a fourth mode, a nitrogen oxide conversion of the second further exhaust aftertreatment device configured to perform a selective catalytic reduction 16 increased by the introduction of oxygen.

In a fifth mode, exhaust aftertreatment performance is improved by aging of the second exhaust after-treatment device configured to perform a selective catalytic reduction 16 is slowed down by less frequently exposing it to a rich environment (λ <1) by increasing the oxygen content by introducing oxygen.

LIST OF REFERENCE NUMBERS

10

motor vehicle

11

internal combustion engine

12

exhaust gas line

13

First nitrogen oxide adsorber

14

First further exhaust aftertreatment device

15

Second nitrogen oxide adsorber

16

Second additional exhaust aftertreatment device

17

Third further exhaust aftertreatment device

18

First lambda sensor

19

Second lambda sensor

20

control unit

21

Oxygen delivery device

22

Fuel delivery device

23

Oxygen Collection Department

24

Fuel introduction point

30

operating procedures

31

begin

32

state determination

33

adjustment

34

measure

35

The End

Claims (4)

Motor vehicle (10) with an internal combustion engine (11), an exhaust line (12) for discharging an exhaust gas of the internal combustion engine (11), a first nitrogen oxide adsorber (13) arranged in the exhaust line (12) and one in the exhaust line (12) downstream of the first nitrogen oxide adsorber (12). 13) arranged second oxygenating device (15), wherein the motor vehicle (10) an oxygen introduction device (21) for introducing oxygen at an oxygen introduction point (23) in the exhaust line (12) downstream of the first Stickstoffoxidadsorbers (13) and upstream of the second Stickoxidadsorbers (15 ) and a fuel introduction device (22) for introducing fuel at a fuel introduction point (24) into the exhaust line (12) downstream of the first nitrogen oxide adsorber (13) and upstream of the second nitrogen oxide adsorber (15), characterized in that the motor vehicle (10) has a first lambda sensor (18) in the exhaust line (12) downstream of the first Stickstoffoxidadsorbers (13) and s on the second Wherein the motor vehicle (10) has a second lambda sensor (19) which is arranged in the exhaust line (12) downstream of the second nitrogen oxide adsorber (15), wherein the motor vehicle (10) has a first further exhaust gas aftertreatment device (14). which is arranged in the exhaust gas line (12) between the first nitrogen oxide adsorber (13) and the second nitrogen oxide adsorber (15), wherein the motor vehicle (10) comprises a second further exhaust gas aftertreatment device (16) in the exhaust gas line (12) downstream of the second nitrogen oxide adsorber (15), said second further exhaust aftertreatment means (16) being an exhaust aftertreatment means configured to perform a selective catalytic reduction, said fuel introduction site (24) being located downstream of said oxygen introduction site (23) and between said oxygen introduction site (23), said fuel introduction site (24) and the second nitrogen oxide adsorber r (15), no further exhaust gas aftertreatment device is arranged between the first nitrogen oxide adsorber (13) and the first lambda sensor (18) and between the second nitrogen oxide adsorber (15) and the second lambda sensor (19). Operating method (30) for a motor vehicle (10) according to Claim 1 with an internal combustion engine (11), an exhaust line (12) for discharging an exhaust gas of the internal combustion engine (11), a first nitrogen oxide adsorber (13) arranged in the exhaust gas line (12) and a second one arranged in the exhaust gas line (12) downstream of the first nitrogen oxide adsorber (13) Nitrogen adsorber (15), characterized in that in a measure (34) oxygen in the exhaust line (12) downstream of the first Stickstoffoxidadsorbers (13) and upstream of the second Stickstoffoxidadsorbers (15) is introduced and that in the measure (34) in addition to the oxygen Also, fuel is introduced into the exhaust line (12) downstream of the first nitrogen oxide adsorber (13) and upstream of the second nitrogen oxide adsorber (15), the oxygen being introduced upstream of the fuel into the exhaust line (12). Operating procedure (30) according to Claim 2 in which a state of the motor vehicle (10) is determined in a state determination (32) and in an adjustment (33) the determined state is compared with a desired state, wherein the measure (34) is carried out on condition that in the adjustment ( 33) is determined that the particular state deviates from the desired state. Operating procedure (30) according to Claim 3 wherein the condition is a temperature, or a lambda value upstream of the second nitrogen oxide adsorber (15), or a hydrocarbon slip downstream of the second nitrogen oxide adsorber (15), or a carbon monoxide slip downstream of the second nitrogen oxide adsorber (15).

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