WO2012038072A1

WO2012038072A1 - Counterflow apparatus for recuperation in particle filter systems

Info

Publication number: WO2012038072A1
Application number: PCT/EP2011/004714
Authority: WO
Inventors: Horst Wagner
Original assignee: Emico Gmbh
Priority date: 2010-09-21
Filing date: 2011-09-20
Publication date: 2012-03-29
Also published as: WO2012038072A4; DE202010012800U1

Abstract

The invention relates to a counterflow apparatus for recuperation in diesel particle filters, comprising a housing (10) with an inner casing (14), a front end surface (26) and a rear end surface (25), a front inlet (11) for cold exhaust gas (16) and a rear inlet (12) for warm exhaust gas (17). Also provided are at least two counterflow chambers (21, 23) which are arranged adjacent to one another and in which the exhaust gases (16, 17) are conducted past one another, wherein the counterflow chambers (21, 23) are separated from one another by partitions (13) and each counterflow chamber (21, 23) has at least one passage opening (18, 20) for guiding the exhaust gases (16, 17) from one portion into a further portion. Furthermore, an intermediate wall (15) is provided for separating the front exhaust-gas chamber (27) from the rear exhaust-gas chamber (22) in a gas-tight manner, and at least one outlet opening (24) for the cold exhaust gas and at least one outlet opening (19) for the warm exhaust gas (17) are provided on the housing (10).

Description

Description:

Countercurrent device for recuperation in particle filter systems Technical field:

The present invention relates to a counterflow device for recuperation in particulate filter systems. Furthermore, the invention relates to a particulate filter system comprising the countercurrent device according to the invention.

State of the art:

Particulate filter systems or particulate filter arrangements serve for filtering exhaust gases of an internal combustion engine, for example a diesel engine, and have an inlet and an outlet with at least one particle filter arranged in the flow path. In diesel engines, the particulate filter has the task of removing the soot particles present in the exhaust gases. Especially at low temperatures, it tends to clog up quickly. Therefore, it is endeavored to operate the particle filter at the highest possible temperatures to a regeneration of the soot particles stored in the filter

perform. For this it is necessary that the necessary for the regeneration

Ignition temperature of the soot particles is as high as possible, even if the diesel engine is operated with only low load proportions. If the diesel engine is operated only at low load, the exhaust gas temperature remains correspondingly low in this operating state, so that the filter can not regenerate and the soot particles remain in the filter. The heavy loading of the filter and the gas-carrying ducts with soot leads to malfunction of the system and the engine (for example, loss of power, increased fuel consumption) and also increases the risk of fire. After some time, the motor vehicle is no longer ready for use and the filter must be replaced or cleaned consuming.

Systems are therefore known in the prior art which attempt to ensure the minimum temperature required for the operability and regeneration of the particulate filter. For example, catalytic coatings are known before or in the filter region in order to lower the ignition temperature required for soot combustion.

CONFIRMATION COPY In most cases, however, these measures are not sufficient to initiate the ignition process and, in addition, such passive systems are less effective.

For this reason, active systems are often used which provide thermal energy for particle combustion by targeted combustion of diesel fuel (burners) injected in front of or in the filter system. Of the

Energy consumption of such systems is correspondingly high.

In addition to the said active systems, it is also possible to generate the ignition temperature required for the regeneration by means of a heating element which is arranged in a pre-filter (oxidation catalyst) upstream of the diesel particulate filter, thereby triggering a chain reaction of ignition events, which cause the ignition Soot particles are burned in the particle filter

(see DE 10 2009 014 371 A1).

Both the former passive and the active systems with their

additional external heat input is based on the same problem: the existing heat energy is not sufficient to reliably Rußabbrand

(Filter regeneration). Furthermore, the process is active systems

Energy-consuming, because the energy through the electrical system or via the

Combustion of fuel must be supplied. In particular, when removing electrical energy from the electrical system is only a short time quota available to perform the regeneration. From technical applications are known heat exchangers, the waste heat from the

Incorporate combustion process in the supply air for combustion, for example, to preheat the intake air of an engine.

In the closest prior art for the present invention, EP 1 801 372 A1, the passive system described is a particle filter arrangement in which the ignition temperature required for the regeneration is reduced by means of heat exchange. Here, use is made of a temperature gradient between the exhaust gas streams, for which purpose three sections are provided in the device described therein, through which the exhaust gases flow. Initially, the exhaust gases are directed essentially towards the outlet, later towards the inlet and thus into Returned the opposite direction, and finally led back towards the outlet. The exhaust system therefore takes place essentially in the manner of a degenerate "Z". The diesel particulate filter is arranged in one of the sections and is flowed around. For the heat exchange, a distribution and deflection element is provided in EP 1 801 372 A1, which leads a first exhaust gas flow coming from the inlet to the first section of the line, and deflects a second exhaust gas flow arriving from the second section of the line to the third section of the line. It is preferred to realize a star-shaped deflection, in which the various exhaust gas streams cross over without them mixing. The crossing or crossing

Exhaust gas routing causes the distribution and diverting element to heat up and deliver heat to the colder exhaust gas.

A disadvantage of this arrangement is that the various exhaust gas streams only cross several times without selectively flow past contact surfaces and to use their lengths for heat transfer, whereby the proposed heat exchange is less effective. Furthermore, the design effort for the desired star-shaped deflection is disproportionately high. Presentation of the invention:

Against this background, it is an object of the present invention to provide a device to improve the heat exchange at the same time manageable design effort for particulate filter systems and in which the disadvantages of the aforementioned prior art are avoided.

This object is achieved by a counterflow device having the features of claim 1. Preferred embodiments can be found in the subclaims again. The inventive countercurrent device for recuperation in diesel particulate filters comprises a housing with an inner jacket and a front and a rear end face. The jacket can preferably be formed by a pipe or a piece of pipe (eg support tube). Further, the apparatus has a front inlet for cold exhaust gas and a rear inlet for warm exhaust gas and at least two juxtaposed countercurrent chambers, in which the exhaust gases via a Contact surface without mixing be passed to each other, creating a

Heat exchange for heating the cold exhaust gas flow over the warm

Exhaust gas flow is achieved. For this purpose, the countercurrent chambers are separated by partitions. Each countercurrent chamber has at least one

Through opening for the exhaust gas of the exhaust gases from a section of

Exhaust system in another section. For gas-tight separation of the front exhaust gas chamber, which receives the cold exhaust gas via the front inlet, from the rear exhaust chamber into which flows the warm exhaust gas of the rear inlet, a gas-tight partition wall is provided. Furthermore, the device has an outlet opening for the cold exhaust gas and at least one outlet opening for the warm exhaust gas at the housing.

In a preferred embodiment, the countercurrent chambers are arranged axially around the housing. This results in several countercurrent chambers, which have contact surfaces for the heat exchange of the exhaust gas streams passing one another, whereby a maximum heat exchange can take place in a space that is less available. By the flowing past exhaust gas streams of the combustion gases from the main filter and the still cold exhaust gases of the engine heat exchange over the partitions is achieved by heat energy is transferred to the cold incoming exhaust gases. Thus, a heat flow from the hot exhaust gas stream of

Main filter to the incoming exhaust gas of the front exhaust chamber.

The invention leaves open the choice to design the chamber lengths and the chamber heights depending on the application profile to the contact surfaces for the

Countercurrent heat transfer optimally adapted for the particular application. Furthermore, the efficiency can be increased by increasing the number of countercurrent chambers by creating additional contact surfaces for the heat exchange by further partitions. The axial arrangement of the countercurrent chambers around the housing allows a symmetrical structure, whereby the production is facilitated. Furthermore, the preferably circular cross section of the countercurrent device can be easily combined with the geometry of the main filter. In one embodiment, it is provided that the extended core tube of the countercurrent device as a support tube for a prefilter arranged there (eg stainless steel wire mesh, oxidation catalyst) serves. As a result, the prefilter is not only held, but is also heated for improved ignition by the hot exhaust gas inside the tube.

The countercurrent chamber according to the invention can be constructed either in one piece or from several components. Preferably, the structure is chosen so that the individual countercurrent chambers and sections are formed by the respective components themselves. For example, the jacket bottom of the housing of the central

Support tube or a part thereof are formed. According to the invention, it is provided that first the cold exhaust gas from the front

Inlet flows via the passage opening into the first countercurrent chamber and leaves it again via the outlet opening. The warm exhaust gas is passed via the rear inlet via the passage opening in the second countercurrent chamber to the outlet opening. Since the two countercurrent chambers are adjacent to each other, a heat transfer can take place via the partition wall. The partition wall preferably has metallic contact surfaces in order to allow the most efficient possible heat exchange.

The cold exhaust gas first flows from the first countercurrent chamber over the

Diesel particulate filter and allows by the preheating easier ignition of the soot particles stored in the filter. In the particulate filter itself, the exhaust gas stream is heated and, as described above, returned to the counterflow direction.

The passage openings for the exhaust gas streams are preferably formed on the inner jacket, the outlet openings for the cold exhaust gas and the warm exhaust gas are expediently formed on end faces of the housing. The

Countercurrent chambers are preferably formed by the jacket bottom, the end faces and the partitions. Preferably located in the region of the rear inlet is an oxidation catalyst which contributes to the recuperation. For heating the exhaust gas flow and thus raising the ignition temperature, a heating element is preferably arranged in or on the oxidation catalytic converter. The invention further comprises a particulate filter system comprising an inlet and an outlet for exhaust gases and at least one particulate filter, wherein the particulate filter system comprises a countercurrent device according to the invention. Preferably, an oxidation catalyst with a heating element is arranged in front of the particle filter. Preferably, the warm exhaust stream flowing out of the countercurrent chamber of the counterflow device is directed to the outlet via an outer chamber along the particulate filter.

Brief description of the drawings: The invention will be explained in more detail in the following drawings. Show it

Fig. 1 is an isometric view of the counterflow device according to the invention, Fig. 2 is a particulate filter system consisting of a particulate filter and a

counterflow device according to the invention,

Fig. 3 is a schematic representation of an embodiment of a

Particulate filter system. Ways to carry out the invention and commercial usability:

In Fig. 1, an embodiment of a countercurrent device 1 according to the invention is shown. This consists of a housing 10 with a front end face 26 and a rear end face 25. The cold exhaust gas 16 is passed through an inlet 11 into a front exhaust chamber 27. For the heat exchange, a plurality of countercurrent chambers 21, 23 separated from each other by partition walls 13 are arranged axially around the central support tube. The cold exhaust gas stream 16 is first conducted from the front exhaust chamber 27 via an opening 18, which is located in the jacket 14, upwards into the first countercurrent chamber 21. This has at the rear end face 25 a further outlet opening 24 for the passed exhaust gas flow. This one is about the

subsequent particulate filter 33 (not shown) passed and thereby warmed up. The warm exhaust gas flow 17 passing through the particulate filter 33 passes back into the countercurrent device 1 via the inlet 12. The inlet 12 initially leads into a rear exhaust chamber 22, via which the warm exhaust gas flow 17 via passage openings 20, which are likewise formed on the jacket 14, up in the other, parallel to adjacent countercurrent chamber 21 arranged countercurrent chamber 23 is passed. It thus finds an exhaust system from an outer section to an inner one

Section instead, and finally back into an outer section, which is, however, separated gas-tight from the first section, whereby an efficient heat exchange in countercurrent over the partitions 13 can take place. From the countercurrent chamber 23, the exhaust gas flow leaves the countercurrent device 1 via the outlet opening 19. The front exhaust chamber 27 and the rear exhaust chamber 22 are through a

Partition wall 15 separated from each other. In Fig. 2, an inventive particulate filter system is shown, in which in the front section, the countercurrent device 1 according to the invention before a

Oxidation catalyst 30 and a diesel particulate filter 33 is arranged. The cold exhaust gas stream 16 is first conducted via the inlet 11 into the front exhaust chamber 27 of the countercurrent device 1 and reaches there via the passage opening 18 upwards into the first countercurrent chamber 21, which leaves the exhaust gas flow via the outlet opening 24 again. The exhaust stream is then passed through the oxidation catalyst 30 to the diesel particulate filter 33. In the embodiment shown is in the

Oxidation catalyst 30, a heating element 32 arranged to increase the temperature of the effluent from the first countercurrent chamber 21 exhaust gas stream for regeneration. The warm exhaust gas flow 17 passes via the rear exhaust chamber 22 from the inner portion via the passage opening 20 upwards in the other

Countercurrent chamber 23. The countercurrent chamber 21 for the cold exhaust gas stream 16 and the countercurrent chamber 23 for the warm exhaust gas stream 17 are separated from each other via the partition wall 13. About the partition 13, the heat exchange takes place in

Counterflow principle. The symmetrical circular arrangement of the countercurrent chambers 21, 23 around the support tube enables a space-saving and at the same time efficient construction of the inventive countercurrent device 1. Depending on the number of

Countercurrent chambers 21, 23, the efficiency of the heat exchanger can be further increased by additional contact surfaces for energy transfer are created.

The warm exhaust gas stream 17, after having flowed from the inside to the outside into the further countercurrent chamber 23, passes via the outlet opening 19 into an outer chamber 39, which passes the exhaust gas flow past the particle filter 33, wherein a further

Maintaining warming is achieved. Finally, the exhaust gas flow to Outlet 34 to the exhaust system. The whole particulate filter system is located in a housing 31.

FIG. 3 shows a schematic representation of the particle filter system according to the invention. From a motor 40, the exhaust gas 16 passes through the inlet 11 to the first countercurrent chamber 21 and leaves it via outlet openings 24 to

Oxidation catalyst 30, in which a heating element 32 is located for additional heating. The exhaust gas flow is purified via the particle filter 33 and passes as a hot exhaust gas flow 17 via the inlet 12 into the countercurrent chamber 23, in which it is then led via the outlet openings 19 to the outside in the outer chamber 39 on the particle filter 33 to the outlet 34.

Claims

claims:

1. Countercurrent device for recuperation in diesel particulate filters, comprising

- A housing (10) with

an inner jacket (14),

a front end face (26) and

a rear end face (25),

a front inlet (1 1) for cold exhaust gas (16) and a rear inlet (12) for warm exhaust gas (17),

- At least two juxtaposed Gegenstromkammem (21, 23) in which the exhaust gases (16, 17) are guided past each other, the Gegenstromkammem (21, 23) by partitions (13) are separated from each other and each countercurrent chamber (21, 23) at least one Passage opening (18, 20) for the exhaust gas routing of the exhaust gases (16, 17) from one section to another section,

an intermediate wall (15) for gas-tight separation of the front exhaust chamber (27) from the rear exhaust chamber (22),

- At least one outlet opening (24) for the cold exhaust gas and at least one outlet opening (19) for the warm exhaust gas (17) on the housing (10).

2. Countercurrent device according to claim 1, characterized in that the

Gegenstromkammem (21, 23) axially on the housing (10) are arranged.

3. Counterflow device according to claim 1 or 2, characterized in that the cold exhaust gas (16) flows from the front inlet (11) via the passage opening (18) into the first counterflow chamber (21) and leaves it via the outlet opening (24), and the warm exhaust gas (17) via the rear inlet (12) over the

Passage opening (20) in the second counterflow chamber (23) to the outlet opening (19) flows.

4. Countercurrent device according to one of claims 1 to 3, characterized in that the passage openings (18, 20) on the jacket (14) are formed and the jacket bottom (14) is formed by a pipe or pipe section. Countercurrent device according to one of claims 1 to 4, characterized in that the outlet opening (24) for the cold exhaust gas at the front end side (26) of the housing (10) and the outlet opening (19) for the warm exhaust gas (17) at the rear End face (25) of the housing (10) are formed.

Countercurrent device according to one of claims 1 to 5, characterized in that the Gegenstromkammem (21, 23) of the shell (14), the end faces (25, 26) and the partitions (13) are formed.

Countercurrent device according to one of claims 1 to 6, characterized in that the exhaust gas from the outlet opening (19) in an outer chamber (39) of a particulate filter system (30) is guided.

Countercurrent device according to one of claims 1 to 3, characterized in that in the region of the rear inlet (8), an oxidation catalyst (30) is arranged.

Countercurrent device according to claim 8, characterized in that in or on the oxidation catalyst (30) a heating element (32) is arranged.

Particulate filter system comprising

an inlet (11) and an outlet (34) for exhaust gases,

- At least one particulate filter (33), characterized in that the

Particulate filter system comprises a countercurrent device (1) according to one of claims 1 to 9.

11. A particulate filter system according to claim 10, characterized in that before the

Particle filter (33) an oxidation catalyst (30) with a heating element (32) is arranged.

12. A particulate filter system according to claim 10 or 11, characterized in that from the countercurrent chamber (23) of the countercurrent device (1) flowing out warm exhaust gas flow (17) via an outer chamber (39) along the particulate filter (33) to the outlet (34) becomes.