FR3062417A1 - DEVICE FOR TREATING AN EXHAUST GAS. - Google Patents

Abstract

The invention relates to a device (1) for treating an exhaust gas of a motor vehicle comprising: - at least a first treatment element (4), and - at least a second treatment element (7) , the device (1) being configured to allow a circulation of the gas in contact successively with the first and second treatment elements (4, 7).

Description

@ Holder (s): VALEO THERMAL SYSTEMS Simplified joint-stock company.

O Extension request (s):

® Agent (s): VALEO THERMAL SYSTEMS.

® DEVICE FOR THE TREATMENT OF AN EXHAUST GAS.

(57) The invention relates to a device (1) for treating an exhaust gas from a motor vehicle comprising:

- at least a first processing element (4), and

- at least a second treatment element (7), the device (1) being configured to allow a circulation of the gas in contact successively with the first and second treatment elements (4, 7).

FR 3 062 417 - A1

DEVICE FOR THE TREATMENT OF AN EXHAUST GAS

The invention relates to a device for the treatment of a motor vehicle exhaust gas.

Diesel or petrol engines emit pollutants from the combustion of fuel, which are released into the exhaust gases of motor vehicles.

The pollutants from the combustion of a diesel or petrol engine are usually unburnt hydrocarbons, nitrogen oxides or carbon oxides, and in the case of diesel engines, carbonaceous particles also called soot.

In order to comply with increasingly stringent environmental standards, it is necessary to control the exhaust gas emissions released by a motor vehicle.

For this purpose, it is known to use a catalytic converter in the engine exhaust line.

A catalytic converter includes a catalyst that initiates or enhances certain chemical reactions to transform the toxic constituents of the exhaust gas into less toxic elements.

It is also known to carry out the treatment of in particular carbonaceous particles contained in the exhaust gas by the introduction of a particle filter in the exhaust line.

A particle filter used in the automotive field most often comprises a porous ceramic matrix. During engine operation, the gas passes through the ceramic matrix so that the particles contained in the exhaust gas settle and accumulate in the particulate filter. Following the deposition of the particles, the filter can be subjected to a regeneration phase during which the particles are eliminated by self-ignition.

In order to maximize the treatment of exhaust gas, car manufacturers are encouraged to use both a catalytic converter and a particle filter in the same motor vehicle.

However, this requires significant available space in the engine exhaust line, and can therefore be difficult to implement.

The object of the invention is to at least partially remedy this drawback.

To this end, the invention relates to a device for treating an exhaust gas from a motor vehicle comprising:

- at least a first processing element, and

- At least a second treatment element, the device being configured to allow a circulation of the gas in contact successively with the first and second treatment elements.

Such a device is sufficiently compact while combining the roles of both a catalytic converter and a particulate filter.

According to one embodiment, the first treatment element is made from a material that is porous to the exhaust gas, the first treatment element being configured to retain particles contained in the exhaust gas.

The first treatment element thus makes it possible to carry out the function of a particle filter by retaining the carbonaceous particles of the exhaust gas.

According to another embodiment, the second treatment element is covered by a catalyst, the catalyst being configured to allow a chemical reaction of the exhaust gas coming into contact with the second treatment element.

The second processing element thus makes it possible to carry out the function of a catalytic converter by reducing the harmfulness of the exhaust gas discharged downstream of the device.

According to another embodiment, the first and second processing elements are arranged opposite one another.

According to another embodiment, the second treatment element is arranged on one face of the first treatment element between a first and a second opening of the treatment element.

According to another embodiment, the first and second treatment elements have a substantially flattened shape and extend respectively in a direction of elongation.

The first and second processing elements being stacked on top of each other, the device comprises a small total thickness depending on the stacking direction, and can therefore be easily accommodated in the exhaust line of the engine.

According to another embodiment, the second treatment element comprises a plurality of orifices, the orifices being configured to allow the passage of gas in contact with the second treatment element.

According to another embodiment, a surface of the second treatment element comprises a plurality of arches offset axially with respect to each other so as to form the orifices.

According to another embodiment, each arch has a general shape of an inverted U.

According to another embodiment, the device comprises at least one spacer, the spacer being configured to channel the circulation of the exhaust gas in the device in contact successively with the first and second treatment elements.

According to another embodiment, the spacing element comprises a gas passage orifice, the gas passage orifice being configured to receive the second treatment element.

According to another embodiment, the spacer comprises a flange protruding from one face of the spacer, the flange being configured to allow the circulation of gas through the first treatment element.

The invention also relates to a system comprising a plurality of devices according to the invention, the devices being superimposed on each other in a stacking direction.

Such a system makes it possible to treat a larger quantity of gas simultaneously.

Other characteristics and advantages of the invention will become apparent on reading the description which follows. This is purely illustrative and should be read in conjunction with the accompanying drawings in which:

- Figure 1 illustrates an exploded view of a device for the treatment of an exhaust gas according to an embodiment of the invention;

- Figure 2 illustrates a section along the section plane II-II of the device of Figure 1 once assembled;

- Figure 3 illustrates a perspective view of a first processing element of Figure 1;

- Figure 4 illustrates a perspective view of a second processing element of Figure 1;

- Figure 5 illustrates an enlarged view of the second processing element of Figure 4;

- Figure 6 illustrates a perspective view of a spacer of Figure 1;

- Figure 7 illustrates a top view of the spacer of Figure 6, in which the edges are shown in bold lines; and

- Figure 8 illustrates a schematic sectional view of a system for the treatment of an exhaust gas according to another embodiment of the invention.

Device for treating an exhaust gas

The subject of the invention is a device 1 for the treatment of a motor vehicle exhaust gas.

The invention finds an advantageous application for the exhaust gas of a thermal engine of a motor vehicle of the diesel or petrol type.

In the embodiment illustrated in Figures 1 and 2, the device 1 comprises an inlet 2 for gases and an outlet 3 for gases. The inlet 2 is intended to be connected to an upstream part of an exhaust line of the motor vehicle, while the outlet 3 is intended to be connected to a downstream part of the exhaust line.

As illustrated more particularly in FIGS. 1 and 3, the device 1 comprises at least a first processing element 4.

The first processing element 4 extends in a direction of elongation A.

The first processing element 4 has a substantially flattened shape, that is to say, having two opposite parallel flat faces 4a, 4b.

In the illustrated embodiment, the first processing element 4 has a general ovoid shape. Of course, the invention is not limited to this embodiment, and the first processing element 4 can also take any other form.

The first processing element 4 comprises a first opening 5 and a second opening 6. It will be noted that the openings 5 and 6 are for example macroscopic. The first and second openings 5, 6 are located respectively at each end of the first treatment element 4 in the direction of elongation A.

Advantageously, the first and second openings 5, 6 of the first treatment element 4 are identical to one another.

The first processing element 4 between the first and the second opening 5, 6 has an advantageously constant thickness in a stacking direction E perpendicular to the direction of elongation A.

The first treatment element 4 is composed in particular of a material which is porous to the exhaust gas.

By porous is meant that the exhaust gas can pass on either side of the material of the first treatment element 4. In other words, the material comprises pores or holes, for example of microscopic size, through which gas can pass right through.

The first treatment element 4 is advantageously composed in particular of a ceramic material.

The first treatment element 4 is configured to collect particles of the exhaust gas, in particular carbonaceous, when it is crossed by the exhaust gas.

As illustrated more precisely in FIGS. 1, 4 and 5, the device 1 also comprises at least one second processing element 7.

The second processing element 7 is composed in particular of a metal material, for example stainless steel.

The second processing element 7 also has a substantially flattened shape and extends in an elongation direction A.

In the illustrated embodiments, the second processing element 7 has a generally rectangular shape. Of course, the invention is not limited to this embodiment, and the second processing element 7 can also take any other form.

The second treatment element 7 comprises a surface configured to maximize contact with the exhaust gas during its circulation in the device 1.

The second processing element 7 can be made of a corrugated material, in a corrugated form for example.

In the embodiment illustrated in FIGS. 4 and 5, the surface of the second treatment element 7 comprises a plurality of arches 8 in the shape of an inverted U. The arches 8 are offset axially with respect to each other so as to form orifices 9 distributed, preferably uniformly, on the second treatment element 7. An exhaust gas can circulate in contact with the surface of the second treatment element 7, in particular along the direction of elongation A, passing through the orifices 9.

As particularly visible in FIG. 5, the second treatment element 7 has a generally rectangular surface 50.

The surface 50 includes an alternation of so-called lower portions 51 and of so-called upper portions 52.

Each of the upper 51 and lower 52 portions extends longitudinally parallel to a long edge 53 of the surface 50.

The upper portions 51 are arranged at a height different from the lower portions 52 so that a short edge 54 of the surface 50 comprises a succession of inverted U's and U's.

The upper portions 51 are preferably identical to each other.

Likewise, the lower portions 52 are preferably identical to each other.

Each arch 8 joins by two arms 55 in L between an upper portion 51 and an adjacent lower portion 52.

The two L 55 arms delimit the associated opening 9.

Preferably, the arms 55 of the arches 8 extend parallel to each other.

The surface of the second treatment element 7 is covered in whole or in part by at least one catalyst. The catalyst is in particular a redox catalyst intended to react with the exhaust gas.

The second treatment element 7 is configured to transform the harmful constituents of the exhaust gas into less harmful constituents when it comes into contact with the catalyst.

As illustrated in FIG. 2, the first treatment element 4 and the second treatment element 7 are superimposed one on the other in the stacking direction E perpendicular to the direction of elongation A. More particularly, the second treatment element 7 is arranged on a face 4a of the first treatment element 4, between the first and second openings 5, 6.

The device 1 also includes at least one spacer 10, more particularly illustrated in FIGS. 6 and 7.

In the embodiment shown in Figures 1 and 2, the device 1 comprises a first spacer 10 and a second spacer 11. The two spacers 10, 11 are identical one of the other.

The spacer 10, 11a also has a substantially flattened shape and extends in the direction of elongation A and has two opposite parallel faces 10a, 10b.

The spacing element 10, 11 preferably has a general shape identical to the first treatment element 4, in particular an ovoid.

Similarly to the first treatment element 4, the spacer 10, 11 comprises a first opening 12 and a second opening 13. The first and second openings 12, 13 are located respectively at each end of the element d 'spacing 10, in the direction of elongation A.

The spacer 10, 11 also includes a gas passage orifice 14 in the stacking direction E, located between the first and second openings 12, 13. The passage orifice 14 is advantageously located in the center of the spacer 10, 11. The passage orifice 14 has a shape corresponding to the general shape of the second treatment element 7, so that the recess is configured to receive the second treatment element 7.

At least one of the faces 10a of the spacer 10, 11 includes a flange projecting in the stacking direction E.

As illustrated diagrammatically in FIGS. 6 and 7, the spacer 10, 11 includes a first flange 15 arranged in a peripheral manner, along the entire periphery of the spacer 10, 11.

The spacer 10, 11 also includes a second flange 16 arranged around the second opening 13 and the passage orifice 14 of the spacer 10, 11. The first opening 12 of the spacer d spacing 10, 11 has no peripheral rim.

The first and second flanges 15, 16 have a height at least equal to the height of the second processing element 7 in the stacking direction E.

The spacer 10, 11 is made of a material impermeable to exhaust gas.

The spacer 10, 11 is configured to allow gas to flow and be channeled into device 1, as will be described below. In particular, the flanges 15, 16 are configured to allow the circulation of all of the gas through the first treatment element 4 between the inlet 2 and the outlet 3 of the device 1.

The first spacer 10 is arranged in contact with the face

4a of the first treatment element 4. In particular, the first and second openings 12, 13 of the first spacer 10 coincide with the first and second openings 5, 6 of the first treatment element 4, respectively.

The second treatment element 7 is arranged in the passage orifice 14 of the first spacer 10, advantageously in contact with the first treatment element 4.

However, as a variant, the first processing element 4 and the first spacing element 10 can form a single element.

According to this variant, the second treatment element 7 is arranged in contact with the first treatment element 4, which further comprises at least one or more flanges 15, 16 as described above.

The second spacer 11 is arranged in contact with the face 4b of the first treatment element 4. In particular, the first and second openings 12, 13 of the second spacer 11 coincide with the second and first openings 6 respectively, 5 of the first processing element 4.

Furthermore, as visible in FIG. 1, the first and second spacing elements 10, 11 are oriented in an opposite direction relative to each other in the direction of elongation A, so that the first opening 12 of a spacer 10, 11 coincides with the second opening 13 of the other spacer 11, 10, and vice versa.

Two closure plates 17, 18, advantageously impermeable to the exhaust gas, are placed respectively on each side of the device 1 in the stacking direction E, in particular in contact with the spacing elements 10, 11.

Each closure plate 17, 18 comprises an opening corresponding respectively to the inlet 2 and to the outlet 3 of the device 1, and coinciding with the second openings 13 of the first and second spacer elements 10, 11.

The device 1 is configured to allow circulation of the exhaust gas between the inlet 2 and the outlet 3 passing through the first treatment element 4 and the second treatment element 7.

It is noted that, according to a variant not illustrated, the porous element 4 is not necessarily provided with orifices 5 and 6. It can be shorter, which corresponds to its rectangular part, and be integrated into the elements 10 and 11, preferably stainless steel, in the passage orifice 14.

Device operation

The operation of the device 1 according to the embodiment illustrated in FIGS. 1 and 2 is described below.

The exhaust gas passes through the inlet 2 of the device and then through the second opening 13 of the first spacer element. The gas then circulates in the second treatment element 7. The gas passes in particular in contact with the surface of the second treatment element 7 in the orifices

9.

Due to the second flange 16 of the first spacer 10, the gas cannot flow directly to the outlet 3 of the device 1. The gas is forced to pass through the first treatment element 4 passing through the passage orifice 14 of the first spacer 10, as illustrated by the arrows 19 in FIG. 2.

Due to the second rim 16 of the second spacer 10, the gas cannot subsequently flow directly to the inlet 2 of the device 1. The gas circulates in the passage orifice 14 of the second spacer 11 before being evacuated by outlet 3 of device 1.

Passing the gas successively in contact with the second treatment element 7 and through the first treatment element 4 makes it possible to treat the gas by combining the known effects of a catalytic converter and a particle filter.

Of course, the embodiment described above is not limiting and other configurations are possible. In particular, the gas can come into contact with the first treatment element 4 before circulating in contact with the second treatment element 7.

Furthermore, the embodiment illustrated in FIGS. 1 and 2 comprises a single first element and a single second treatment element 4, 7. However, a device 1 according to the invention can also comprise a plurality of first treatment elements 4 and / or second treatment elements 7, advantageously superimposed in the stacking direction E. For example, a second additional treatment element can also be housed in the passage orifice 14 of the second spacer element 11 .

It is thus possible to circulate the exhaust gas in several treatment elements 4, 7 one after the other in order to maximize the treatment of the gas.

As schematically illustrated in FIG. 8, the invention also relates to a system 21 comprising a plurality of devices 1 as described above.

The system 21 consists of a stack of first and second processing elements 4, 7, as well as of spacing elements 10, 11 as described above.

A gas flowing from the inlet 2 of the system 21 can circulate as illustrated by the arrows 20, and come into contact successively with at least a first and at least a second treatment element 4, 7 before being evacuated by the exit 3.

Obviously, the invention is not limited to the embodiments described above and provided only by way of example. It includes various modifications, alternative forms and other variants that a person skilled in the art may envisage within the framework of the present invention and in particular any combination of the different operating modes described above, which can be taken separately or in combination.

In particular, although the invention is described in connection with the treatment of exhaust gases from a motor vehicle, the invention can also be advantageous in any type of application requiring a combined treatment of a gas.

Claims (12)

1. Device (1) for treating an exhaust gas from a motor vehicle comprising: - at least a first processing element (4), and - at least a second treatment element (7), the device (1) being configured to allow a circulation of the gas in contact successively with the first and second treatment elements (4, 7). 2. Device (1) according to claim 1, wherein the first treatment element (4) is made from a material porous to the exhaust gas, the first treatment element (4) being configured to retain particles contained in the exhaust gas. 3. Device (1) according to any one of the preceding claims, in which the second treatment element (7) is covered by a catalyst. 4. Device (1) according to any one of the preceding claims, wherein the first and second treatment elements (4, 7) are arranged opposite one another. 5. Device (1) according to the preceding claim, wherein the second treatment element (7) is arranged on a face (4a) of the first treatment element (4) between a first and a second opening (5, 6) of the processing element. 5. Device (1) according to any one of the preceding claims, wherein the first and second elements (4, 7) have a substantially flattened shape and extend respectively in a direction of elongation (A). 6. Device (1) according to any one of the preceding claims, in which the second treatment element (7) comprises a plurality of orifices (9), the orifices (9) being configured to allow the passage of the gas in contact of the second processing element (7). 7. Device (1) according to the preceding claim, wherein a surface of the second treatment element (7) comprises a plurality of arches (8) offset axially relative to each other so as to form the orifices (9). 8. Device (1) according to the preceding claim, wherein each arch has a general shape of inverted U. 9. Device according to any one of the preceding claims, comprising at least one spacer (10, 11), the spacer (10, 11) being configured to channel the circulation of the exhaust gas in the device (1) in contact successively with the first and second processing elements (4, 7). 10. Device (1) according to the preceding claim, wherein the spacer element (10, 11) comprises a gas passage orifice (14), the gas passage orifice (14) being configured to receive the second processing element (7). 11. Device (1) according to claims 9 or 10, wherein the spacer (10) comprises at least one flange (16) projecting from one face (10a) of the spacer (10) , the flange (16) being configured to allow gas to flow through the first treatment element (4). 12. System (21) comprising a plurality of devices (1) according to any one of the preceding claims, the devices (1) being superimposed on each other in a stacking direction (E). 1/5