DE102012009355B4 - Exhaust gas cleaning device and internal combustion engine arrangement - Google Patents

Abstract

Exhaust gas cleaning device (3) for cleaning exhaust gas from an internal combustion engine (2), which has a plurality of combustion chambers (5), each connected to an exhaust pipe (10) of an exhaust manifold (12), with a secondary air supply device (14) which is used to supply fresh air into the exhaust gas lines (10) and has a plurality of secondary air lines (15), which are each connected to at least one of the exhaust gas lines (10) and open into a common supply line (16) on their sides facing away from the exhaust gas lines (10), each of the secondary air lines (15 ) a cross-section adjustment device (18) for interrupting the flow connection between the supply line (16) and the at least one connected exhaust pipe (10) is assigned, characterized in that the cross-section adjustment devices (18) are present as a common cross-section adjustment device (21) in the form of a rotary actuator (22) or sliding plate (26) and a rotatable or displaceable closing element (23) mounted in the exhaust manifold (12), by means of which a flow opening (20) of the secondary air line (15) facing away from the respective exhaust line (10) can be closed.

Description

The invention relates to an exhaust gas cleaning device for cleaning exhaust gas from an internal combustion engine, which has several combustion chambers each connected to an exhaust pipe of an exhaust manifold, with a secondary air supply device which serves to supply fresh air into the exhaust pipes and has several secondary air pipes, each connected to at least one of the exhaust pipes connected and open on their sides facing away from the exhaust lines into a common supply line, each of the secondary air lines being assigned a cross-section adjustment device for interrupting the flow connection between the supply line and the at least one connected exhaust line. The invention also relates to an internal combustion engine arrangement.

Exhaust gas cleaning devices of the type mentioned at the beginning are assigned to internal combustion engines which each have a plurality of combustion chambers, which are present, for example, in cylinders of the internal combustion engine. Fresh air and fuel or a fuel-air mixture, which is then ignited and burned, is fed to the combustion chambers. The resulting exhaust gases are discharged from the combustion chambers through the exhaust pipes. The exhaust lines are, for example, in an exhaust manifold, by means of which the exhaust lines are combined into a common exhaust line, which is connected on its side facing away from the exhaust lines, for example to an exhaust gas aftertreatment device of the exhaust gas cleaning device, in particular a catalytic converter. The exhaust gas of the combustion chambers of the exhaust gas aftertreatment device is thus fed through the exhaust gas lines and subsequently the common exhaust gas line. This is provided, for example, to at least partially remove or convert certain exhaust gas components such as hydrocarbons and / or nitrogen oxides.

For this purpose, the exhaust gas aftertreatment device must be brought to a certain operating temperature. If the exhaust gas aftertreatment device has a temperature below the specific operating temperature, the undesired exhaust gas constituents cannot or only incompletely be converted. In order to heat the exhaust gas aftertreatment device, which is arranged downstream of the combustion chambers with respect to the exhaust gas, more quickly, the secondary air supply device is provided. By means of this, fresh air can be introduced into the exhaust gas lines, which subsequently reacts exothermically with unburned fuel still contained in the exhaust gas. This process is known as thermal post-combustion.

In this way, additional heat is introduced into the exhaust gas, which heats the exhaust gas aftertreatment device and thus brings it to the specific operating temperature more quickly.

To supply the fresh air, the secondary air supply device has several secondary air lines. Each secondary air line is connected to at least one of the exhaust lines. On the side of the corresponding secondary air line facing away from the respective exhaust gas line, the latter opens into the common supply line. With the aid of the secondary air supply device, fresh air can therefore first be introduced through the common supply line into the secondary air lines and then through these into the exhaust gas lines. A secondary air valve is often provided in the common supply line, by means of which the supply of fresh air is interrupted by the exhaust gas aftertreatment device after the specific operating temperature has been reached. The fresh air is therefore only supplied to the internal combustion engine during a cold start, as long as the exhaust gas aftertreatment device has a temperature which is lower than the specific operating temperature. By providing the secondary air supply device, however, the torque achievable by means of the internal combustion engine is reduced because the achievable combustion chamber filling of the combustion chambers is reduced.

From the prior art, for example, is the document DE 44 45 971 A1 known. This describes a method for controlling the supply of secondary air in internal combustion engines, in which secondary air can be supplied downstream of each exhaust valve of the internal combustion engine into the individual exhaust duct assigned to each exhaust valve by means of a secondary air pump via a secondary air line and supply lines. It is provided that the supply of secondary air into one of the individual outlet channels only takes place when the associated outlet valve is open.

The document also discloses EP 2 075 445 A1 a secondary air supply system that supplies secondary air to an exhaust passage of an engine, comprising: a supply source of the secondary air; a supply duct through which the secondary air is supplied from the supply source to the exhaust duct; determining means that determines a state of the engine; a memory that stores a target air-fuel ratio previously set depending on the state of the engine; and adjustment means based on the condition of the engine determined by the determination Direction is determined, and the target air-fuel ratio stored in the memory, an amount of the secondary air to be supplied from the supply duct to the exhaust duct, so that an air-fuel ratio in the exhaust duct is the target air -Fuel ratio is.

The publication also describes DE 195 47 285 A1 a device for reducing the pollutant emissions of vehicles, the publication EP 0 224 732 A1 a device on a supercharged internal combustion engine and the publication DE 41 40 986 A1 an arrangement for exhaust gas purification, in particular of internal combustion engines for motor vehicles.

It is the object of the invention to propose an exhaust gas purification device which does not have the disadvantage mentioned at the beginning, but in particular, despite the secondary air supply device, enables a high combustion chamber filling and thus the provision of a torque that could be achieved without the secondary air supply device.

According to the invention, this is achieved with an exhaust gas cleaning device having the features of claim 1. It is provided that the cross-section adjustment devices are present as a common cross-section adjustment device, which is in the form of a rotary actuator or sliding plate and has a rotatable or displaceable closing element mounted in the exhaust manifold, by means of which a flow opening of the secondary air line facing away from the respective exhaust gas line can be closed.

Basically, it is provided that each of the secondary air lines is assigned a cross-section adjustment device for interrupting the flow connection between the supply line and the at least one connected exhaust gas lines. The reduction in the torque that can be provided by the internal combustion engine occurs as a result of the connection of the individual exhaust lines to one another via the secondary air lines and the common supply line. This means that due to the ignition sequence of the internal combustion engine and the resulting pressure pulsations in the exhaust pipes or the exhaust manifold, exhaust gas can flow over between the individual combustion chambers of the cylinders through the exhaust pipes. This requires a reduced filling of the combustion chamber with fresh air. The torque that can be achieved with the internal combustion engine is correspondingly reduced. This reduction is counteracted by the interruption of the flow connection between the supply line and the exhaust lines. When the flow connection is interrupted, there is no connection between all areas of the supply line and the at least one exhaust gas line connected to the respective secondary air line, and in particular no connection between the connected exhaust gas lines and another one of the exhaust gas lines.

For this purpose, the cross-section adjustment device can be provided in the at least one of the secondary air lines and / or the supply line. In particular, it is advantageous if the opening of the respective secondary air line into the supply line is closed by the cross-section adjustment device. In this way, exhaust gas from the exhaust gas line cannot pass through the respective secondary air line into another one of the secondary air lines and thus another one of the exhaust gas lines. The overflow of exhaust gas between the exhaust pipes or the combustion chambers and thus the occurrence of the torque reduction are thus prevented. Nevertheless, until the specific operating temperature is reached, secondary air can be introduced into the exhaust gas lines by the exhaust gas aftertreatment device by means of the secondary air supply device. The invention also enables the secondary air lines to be enlarged in terms of their cross section, because the overflow effect no longer has to be taken into account. The flow resistance of the secondary air lines can be reduced accordingly. The enlargement of the cross-section of the secondary air lines ultimately also has a positive effect on possible coking phenomena in the secondary air lines.

According to the invention it is provided that a cross-section adjustment device is assigned to each secondary air line. It is of course particularly advantageous if all secondary air lines can be closed or released with the aid of cross-section adjustment devices. In this way, the overflow from each of the exhaust pipes into another one of the exhaust pipes can be prevented. Accordingly, the occurrence of the torque reduction can be completely prevented after the exhaust gas aftertreatment device has reached the operating temperature.

The invention provides that the cross-section adjustment devices for at least some of the secondary air lines are present as a common cross-section adjustment device. By providing the common cross-section adjustment device, the interruption of the flow connection between the supply line and the exhaust lines for a plurality of secondary air lines can be achieved at the same time with little effort. In particular, there is only one setting device for the common cross-section adjustment device is provided, which is used for the joint and simultaneous adjustment of the cross-section adjustment devices of the corresponding secondary air lines. It is therefore not necessary to provide a plurality of actuating devices that can in particular be actuated independently of one another, although this is of course nevertheless possible.

According to the invention it is provided that the cross-section adjustment device is in the form of a rotary actuator or a sliding plate. The actuation of the cross-section adjustment device can therefore take place by turning the rotary actuator or moving the sliding plate. The rotary actuator or sliding plate has a rotatable (rotary actuator) or displaceable or displaceable (sliding plate) closing element. The closing element can, for example, be designed as a plug, that is to say have the shape of a truncated cone. Alternatively, of course, a ball, a cylinder piston or a cylinder, each with a passage opening, can also be provided as the closing element.

It is further provided according to the invention that the cross-section adjustment device has a rotatable or displaceable closing element, by means of which a flow opening of the secondary air line facing away from the respective exhaust gas line can be closed. As already stated above, the closing element can be present as part of a rotary actuator or sliding actuator and can be rotated or displaced accordingly. By rotating or shifting, the closing element can be brought into at least two positions, one of the positions being a release position and another of the positions being a closed position. In the release position, the flow connection between the supply line and the exhaust line assigned to the respective secondary air line is released, so that fresh air can get from the supply line via the secondary air line into the exhaust line connected to it.

In the closed position, on the other hand, the closing element is arranged in such a way that the flow connection is interrupted. Correspondingly, neither fresh air can get through the secondary air line into the exhaust gas line, nor can the exhaust gas line enter another of the secondary air lines via the secondary air line. In the closed position, the closing element is arranged in such a way that the flow opening of the secondary air line is covered and thus closed. Each secondary air line has only one flow opening facing away from the exhaust gas line, which, for example, represents the opening into the supply line. When the flow opening is released, fresh air can get from the supply line through the flow opening into the secondary air line and further into the exhaust gas line.

The invention further relates to an internal combustion engine arrangement with an internal combustion engine and an exhaust gas purification device for cleaning exhaust gas from the internal combustion engine, namely according to the above statements, the internal combustion engine having a plurality of combustion chambers each connected to an exhaust pipe of an exhaust manifold and the exhaust gas purification device having a secondary air supply device for the supply of fresh air in the exhaust lines and has several secondary air lines, each connected to at least one of the exhaust lines and opening into a common supply line on their sides facing away from the exhaust lines, each of the secondary air lines having a cross-section adjustment device for interrupting the flow connection between the supply line and the at least one connected Exhaust pipe is assigned. It is provided that the cross-section adjustment devices are present as a common cross-section adjustment device, which is in the form of a rotary actuator or sliding plate and has a rotatable or displaceable closing element mounted in the exhaust manifold, by means of which a flow opening of the secondary air line facing away from the respective exhaust gas line can be closed. The exhaust gas cleaning device can be developed in accordance with the above explanations.

• 1 eine schematische Darstellung einer Brennkraftmaschinenanordnung mit einer Brennkraftmaschine und einer Abgasreinigungseinrichtung,
• 2 eine schematische Darstellung eines Krümmers der Brennkraftmaschine mit einer Querschnittsverstelleinrichtung und einem Sekundärluftventil,
• 3 ein Querschnitt durch eine erste Ausführungsform der Querschnittsverstelleinrichtung, und
• 4 eine zweite Ausführungsform der Querschnittsverstelleinrichtung.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing, without restricting the invention. Show:

• 1 a schematic representation of an internal combustion engine arrangement with an internal combustion engine and an exhaust gas purification device,
• 2 a schematic representation of a manifold of the internal combustion engine with a cross-section adjustment device and a secondary air valve,
• 3 a cross section through a first embodiment of the cross section adjustment device, and
• 4th a second embodiment of the cross-section adjustment device.

the 1 shows a schematic representation of an internal combustion engine arrangement 1 with an internal combustion engine 2 and an exhaust gas purification device 3. The internal combustion engine 2 has several cylinders 4, each of which has a combustion chamber 5. The cylinder 4 refer The combustion chambers 5 can be supplied with fresh air by means of a fresh air supply device 6, which has a main supply line 7 and a plurality of connecting lines 8. One of the connecting lines 8 is assigned to each of the combustion chambers 5. One end of the connecting lines 8 is assigned to the combustion chamber and the other end is connected to the main supply line 7. On the side of the main supply line 7 facing away from the connecting lines 8, an air filter 9 is provided.

When the internal combustion engine 2 is in operation, fresh air is sucked in through the air filter 9 and supplied to the combustion chambers 5 of the cylinders 4 through the main supply line 7 and the connecting lines 8. In addition to the fresh air, fuel is also supplied to the combustion chambers 5, for example in the form of a fuel-air mixture or by direct injection. The fuel burns together with the air, producing exhaust gas which is discharged from the combustion chambers 5 through exhaust pipes 10. An exhaust pipe 10 is preferably assigned to each of the combustion chambers 5. The exhaust lines 10 open into a collecting line 11 on their sides facing away from the combustion chambers 5. The exhaust lines 10 and / or at least a region of the collecting line 11 can be part of an exhaust manifold 12 of the internal combustion engine 2. The exhaust gas produced by the internal combustion engine 2 is fed through the collecting line 11 to an exhaust gas aftertreatment device 13, for example a catalytic converter. It is then discharged into the surroundings of the internal combustion engine arrangement 1, for example through an exhaust pipe of a motor vehicle.

During a cold start of the internal combustion engine 2, the temperature of the exhaust gas aftertreatment device 13 is lower than a certain operating temperature. Only once this operating temperature has been reached, however, can the exhaust gas fed to the exhaust gas aftertreatment device 13 be cleaned by the latter with sufficient efficiency, that is to say, for example, the pollutants contained therein can be converted. For this reason, the exhaust gas cleaning device 3 has a secondary air supply device 14 which has several secondary air lines 15. The secondary air lines 15 are each connected to at least one of the exhaust gas lines 10 or open into it. With their sides facing away from the respective exhaust gas line 10, they open into a common supply line 16, which in turn is connected to a further air filter 17 on its side facing away from the secondary air lines 15. The air filter 17 can also be formed together with the air filter 9 or the feed line 16 can be connected to the main feed line 7. It is now provided that at least one of the secondary air lines 15, preferably all of the secondary air lines 15, have a cross-section adjustment device 18 (not shown here), by means of which the flow connection between the supply line 16 and the at least one exhaust gas line 10 can be interrupted.

This is based on the 2 made clear. This shows a schematic representation of a longitudinal section through the exhaust manifold 12 in which the exhaust lines 10 are formed. The secondary air line 15 and the supply line 16 can also be seen. A secondary air valve 19 is also shown. In terms of flow, this is provided between the air filter 17 and all secondary air lines 15. It is clear that a cross-section adjustment device 18 is assigned to each secondary air line 15, whereby a flow opening 20, with which the respective secondary air line 15 opens into the supply line 16, can be closed by means of this. The cross-section adjustment devices 18 are present as a common cross-section adjustment device 21, this being designed as a rotary actuator 22 in the present example. For this purpose it has a closing element 23 which is designed as a hollow tube with outlet openings 24. One of the outlet openings 24 is assigned to each of the secondary air lines 15. The supply line 16 is connected to an interior space of the closing element 23 or is present therein.

The closing element 23 can be brought into at least one release position and at least one closed position by rotation. In the closed position shown here, the outlet openings 24 do not correspond to the secondary air lines 15, so that the flow connection between the supply line 16 or the interior of the closing element 23 and the secondary air lines 15 is interrupted. Correspondingly, the flow connection between the supply line 16 and the exhaust lines 10 is also not released. In the release position, on the other hand, the outlet openings 24 are at least partially arranged in congruence with the flow openings 24, so that fresh air can flow from the supply line 16 into the secondary air lines 15 and thus into the exhaust lines 10, provided that the secondary air valve 19 has released the flow connection from the air filter 17. Of course, the secondary air valve 19 can also be dispensed with and the interruption or release of the flow connection between the air filter 17 and the secondary air lines 15 can be implemented solely with the aid of the cross-section adjustment devices 18 or the common cross-section adjustment devices 21.

the 3 FIG. 4 shows a longitudinal section through a region of FIG 2 exhaust manifold 12 shown, wherein the common cross-section adjustment device 21 is present in a first embodiment. In accordance with the above explanations, the common cross-section adjustment device 21 is present as a rotary actuator 22 which has the closing element 23 with the outlet openings 24. To interrupt or release the flow connection between the supply line 16 and the exhaust lines 10, the outlet openings 24, as in FIG 3 shown, at least partially brought into congruence with the flow openings 20. This is done by a rotary movement in the direction of arrow 25. The rotary actuator 22 is rotatably mounted in the exhaust manifold 12 or a housing of the exhaust gas cleaning device 3.

the 4th shows a further embodiment of the common cross-section adjustment device 21. The above statements essentially retain their validity, so that reference is made to them in this respect. The difference is that the common cross-section adjustment device 21 is not designed as a rotary adjuster 22, but as a sliding adjuster 26. To this extent, the closing element 23 is not rotatable, but rather displaceable in the direction of the arrow 27 in order to interrupt or release the flow connection between the supply line 16 and the exhaust lines 10.

List of reference symbols

1

Internal combustion engine assembly

2

Internal combustion engine

3

Exhaust gas cleaning device

4th

cylinder

5

Combustion chamber

6th

Fresh air supply device

7th

Main feeder

8th

Connecting line

9

Air filter

10

Exhaust pipe

11th

Manifold

12th

Exhaust manifold

13th

Exhaust aftertreatment device

14th

Secondary air supply device

15th

Secondary air duct

16

Feed line

17th

Air filter

18th

Cross-section adjustment device

19th

Secondary air valve

20th

Flow opening

21

according to cross-section adjustment device

22nd

Turntable

23

Closing element

24

Outlet opening

25th

arrow

26th

Sliding plate

27

arrow

Claims (2)

Exhaust gas cleaning device (3) for cleaning exhaust gas from an internal combustion engine (2), which has a plurality of combustion chambers (5) each connected to an exhaust gas line (10) of an exhaust manifold (12), with a secondary air supply device (14) which is used to supply fresh air into the Exhaust gas lines (10) is used and has several secondary air lines (15) which are each connected to at least one of the exhaust gas lines (10) and open on their sides facing away from the exhaust gas lines (10) into a common supply line (16), each of the secondary air lines (15 ) a cross-section adjustment device (18) for interrupting the flow connection between the supply line (16) and the at least one connected exhaust pipe (10) is assigned, characterized in that the cross-section adjustment devices (18) are present as a common cross-section adjustment device (21), which is in the form of a rotary actuator (22) or sliding plate (26) is present and a rotatable ode r has a sliding closing element (23) mounted in the exhaust manifold (12), by means of which a flow opening (20) of the secondary air line (15) facing away from the respective exhaust line (10) can be closed. Internal combustion engine arrangement (1) with an internal combustion engine (2) and an exhaust gas cleaning device (3) for cleaning exhaust gas from the internal combustion engine (2) Claim 1 , wherein the internal combustion engine (2) has several combustion chambers (5) each connected to an exhaust pipe (10) of an exhaust manifold (12) and the exhaust gas cleaning device (3) has a secondary air supply device (14) which is used to supply fresh air into the exhaust pipes ( 10) and has several secondary air lines (15) which are each connected to at least one of the exhaust gas lines (10) and open on their sides facing away from the exhaust gas lines (10) into a common supply line (16), each of the secondary air lines (15) having one Cross-section adj l device (18) for interrupting the flow connection between the supply line (16) and the at least one connected exhaust gas line (10) is assigned, characterized in that the cross-section adjustment devices (18) are present as a common cross-section adjustment device (21) which is in the form of a rotary actuator (22 ) or sliding plate (26) is present and has a rotatable or displaceable closing element (23) mounted in the exhaust manifold (12), by means of which a flow opening (20) of the secondary air line (15) facing away from the respective exhaust line (10) can be closed.

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