WO2017108615A1

WO2017108615A1 - Gas pipe unit with particulate filter assembly, method of manufacturing same and heat exchanger for gas, particularly for the exhaust gases of an engine

Info

Publication number: WO2017108615A1
Application number: PCT/EP2016/081454
Authority: WO
Inventors: Carmen LARROSA LACUEY; Jésus JIMENEZ; Ruben LALAGUNA; Serafin URZAY
Original assignee: Valeo Termico, S.A.
Priority date: 2015-12-21
Filing date: 2016-12-16
Publication date: 2017-06-29
Also published as: ES2618883A1; ES2618883B1; EP3394416A1

Abstract

The assembly comprises a gas pipe unit (2) able to be fixed to one end of a heat exchanger block so that the one remains in fluidic communication with the other so that the gases pass through it, and a particulate filter (3), which is fixed non-removably to the gas pipe unit (2) by means of a completely fluidtight assembly achieved by laser welding. The method of manufacture comprises the operation that involves fixing the particulate filter to the gas pipe unit by laser welding. The heat exchanger comprises a heat exchanger block and the gas pipe unit with particulate filter assembly according to the invention.

Description

DESCRIPTION

GAS PIPING UNIT WITH PARTICLE FILTER, MANUFACTURING METHOD THEREFOR, AND THERMAL EXCHANGER FOR GAS,

ESPECIALLY FOR ENGINE EXHAUST GASES Technical field

The present invention generally relates, at a first point, to a gas-filter unit unit with a particulate filter, in particular for the exhaust gases of an engine, and more particularly to an assembly where the junction of the particulate filter with the gas piping unit is such as to ensure sealing. A second aspect of the invention relates to a method of manufacturing the entire first point.

On a third point, the present invention relates to a gas heat exchanger which comprises the entire first point.

The invention is particularly applicable in the exhaust gas recirculation exchangers of an engine ("Exhaust Gas Recirculation Coolers" or EGRC).

Prior art

The main function of the EGR exchangers is the heat exchange between the exhaust gas and the coolant, in order to cool the gases.

Currently, EGR heat exchangers are widely used for diesel applications to reduce emissions and also serve in gasoline applications to reduce fuel consumption.

The market tends to reduce engine size and to apply EGR heat exchangers not only in high pressure (HP) applications but also in low pressure (LP) applications; both have an impact on the design of the EGR heat exchangers. Vehicle manufacturers are demanding EGR heat exchangers with higher efficiencies and at the same time the space available for placing the exchanger and its components is getting smaller and smaller, making them more and more difficult to integrate.

In addition, in many applications the flow of heat transfer fluid available to cool the exhaust gas tends to be reduced, although the exchanger yields have gone up. The current configuration of RGE exchangers on the market is a metal heat exchanger typically made of stainless steel or aluminum.

Basically, there are two types of EGR heat exchangers: a first type consists of a housing inside which there is a bundle of parallel tubes for the passage of gases, the refrigerant circulating in the housing, outside the tubes, and the second type consists of a series of parallel plates which constitute the heat exchange surfaces, so that the exhaust gases and the refrigerant circulate between two plates, in alternating layers, with the possibility of including fins to improve the heat exchange.

In the case of heat exchangers tube bundle, the assembly between the tubes and the housing can be of different types. Generally, the tubes are fixed at their ends between two support plates connected to each end of the housing, the two support plates having a plurality of orifices for the installation of the respective tubes.

Said support plates are in turn fastened to connection means with the recirculation circuit, which may consist of a V-shaped connection or of a peripheral connecting flange or a flange, depending on the design of the recirculation circuit in the recirculation circuit. which is connected the exchanger. The peripheral collar can be assembled with a gas tank, so that the gas tank is an intermediate piece between the housing and the collar, or the collar can be assembled directly to the housing. In some EGR exchangers, mainly in low pressure (LP) applications, the cleanliness conditions are demanding, whereby the use of a particulate filter (not a soot filter) integrated in the exhaust line is more and more asked. Said filter is generally constituted by an independent component or, in some cases, by a component integrated with the RGE exchanger. The following patent documents propose heat exchangers with particle filters attached or integrated in different parts of the heat exchanger. The patent EP2273095B1 relates to a heat exchanger comprising a fluid filter integrated in said exchanger, which comprises a filter zone protruding from a flat surface. This filter is configured as a gasket and is mounted between the connection flange and the gas tank by means of hardware. EP2194351 B1 relates to a heat exchanger comprising a particulate filter for filtering exhaust gas, structurally integrated inside the gas inlet tube of the heat exchanger.

The patent FR2938051 B1 relates to a heat exchanger which comprises a filter housed in a selected position so that the filter is disposed near an extreme side of the tubular bundle.

However, these filters have the disadvantage of requiring a difficult and slow assembly process since additional seals and fastening by means of the fasteners are used. In addition, their volume increases the dimensions of the exchanger, with the resulting problems for mounting in the engine compartment. The patent ES2421 185B1, the holder of which is the present application, describes a heat exchanger which comprises a gas reservoir provided with an inlet port connectable to one end of the housing and an outlet connected to the line recirculating gas and a particulate filter assembled at the inlet port of the gas tank, preferably by arc or spot welding and, in addition, optionally by brazing.

Thermal exchangers are known which comprise a gas tank and a collar or a connecting flange, integrated to form a single piece, so that the end of the gas tank can be coupled to the gas outlet of the housing, as well as a particle filter internally coupled to the connecting collar or, as proposed in the Spanish application with the publication number 2531 124, also from the same holder as the present application, directly to the gas tank.

In particular, said Spanish application 2531 124 proposes a heat exchanger with a particle filter for filtering the exhaust gases associated with the outlet orifice of the gas reservoir and a seal disposed on an outer surface of the collar or the connecting flange, in which the filter is assembled by brazing between the gas tank and the collar or the connection flange, said filter thus being integrated into the gas tank forming a single piece which can be dismounted and can be coupled to the housing of the exchanger. The particle filter assemblies with the connection flange or with the gas reservoir proposed in said antecedents, carried out by electrical welding and / or brazing, do not succeed in guaranteeing a sealing around the whole assembly since they run on the risk of deforming the peripheral frame of the filter on which the welding is carried out, whereby with them there is a risk that unwelded material enters the engine circuit.

This is why it appears necessary to offer an alternative to the state of the art that fills the gaps found there, by providing a solution to the objective technical problem of preventing entry into the engine circuit. , through the filter, undesirable particles, in particular through the connections between it and the connecting flange or the gas tank.

Description of the invention

The object of the present invention is to provide a solution to the aforementioned objective technical problem. To this end, the present invention relates, at a first point, to a gas filter unit unit with particulate filter, for a gas heat exchanger, especially for the exhaust gases of an engine, in which, so known per se, the gas pipe unit is adapted to be attached to the end of a heat exchanger block so that it remains in fluid communication with it for the gases to pass through and the filter is attached to the gas pipeline unit to filter the exhaust gases therethrough.

Unlike the known proposals, in the assembly proposed by the first aspect of the present invention, typically, the particulate filter is attached to the gas conduit unit by means of a fully sealed assembly made by welding laser, thus ensuring a sealing all along the assembly or weld bead against the passage of even particles of a size of a few microns.

According to one embodiment, the gas conduit unit comprises a gas reservoir with a first portion including a first opening, connectable to an end of said heat exchanger block, and a second portion, including a second opening, be connected to a gas recirculation line, generally through a connection opening, the particulate filter being attached to said gas reservoir. According to a preferred variant of said embodiment, the particle filter of the assembly proposed by the first aspect of the invention comprises a peripheral frame having a first face in contact with a peripheral zone of the second part of the surrounding gas reservoir. said second aperture, said peripheral frame being joined to said peripheral area by means of a continuous weld seam which delimits a closed circuit, which is produced by laser welding and which completely traverses the thickness of the peripheral frame and partially penetrates, controlled manner, in said second part of the gas tank.

For an alternative embodiment, the gas conduit unit includes a connection flange connectable at a first end to a gas recirculation line and attached, at a second end opposite to said first end, to a reservoir. of the gas pipeline unit or integrated therewith, the particulate filter being attached to said connecting flange and arranged to filter the gases therethrough and pass through a through opening of the flange of connection. According to a preferred variant of said alternative embodiment, the particle filter of the assembly proposed by the first aspect of the invention comprises a peripheral frame having a first face in contact with a peripheral surface of said connecting flange surrounding said through aperture, said peripheral frame being joined to said peripheral surface by means of a continuous weld seam which delimits a closed circuit, which is produced by laser welding, which completely traverses the thickness of the peripheral frame and which partially penetrates, controlled way in the connection flange.

The aforementioned control of weld bead penetration results from the fact that the laser welding used allows a very precise control of the energy supplied by the laser beam and its position during the entire welding operation.

This very precise control makes it possible to obtain a very good weld, reliable and robust, which guarantees the tightness, even if the peripheral frame of the filter is not in perfect contact with the surface of the workpiece of the driving unit. gas on which it must be welded, that is to say even if any of the elements mentioned above, first face of the peripheral frame, peripheral surface of the connecting flange or peripheral zone of the second part of the gas tank, is not perfectly flat, so that there are depressions between the first face of the peripheral frame and the surface of the part on which it must be welded. These hollows are unacceptable for state-of-the-art proposals, which require that the surfaces to be welded be perfectly flat and, therefore, must use more expensive components.

Preferably, the assembly proposed by the first aspect of the invention comprises, as variants of any of the alternative embodiments described above, a reinforcing ring fixed to the second face of said peripheral frame opposite said first face to the average of the aforementioned continuous weld seam.

Advantageously, said reinforcing ring is made of metal, preferably of stainless steel, and said peripheral frame is made of metal or of thermoplastic material.

One of the advantages of using the reinforcement ring is that it allows to weld a filter whose peripheral frame is not perfectly concentric with the opening around which it must be welded (whether of connecting flange or gas tank).

The particulate filter is configured to block the passage of larger particles than the soot particles.

A second aspect of the present invention relates to a method of manufacturing a gas filter unit unit with particle filter, for gas heat exchanger, especially for the exhaust of an engine, the driving unit. of gas being adapted to attach to one end of a heat exchanger block so that it remains in fluid communication therewith for the gases to pass therethrough, wherein the method comprises the operation of securing immovable the particulate filter at the gas line unit to filter the exhaust gases passing through it.

Unlike the known manufacturing processes, the one proposed by the second aspect of the present invention comprises performing the attachment of the particle filter to the laser welding gas pipe unit, which provides a completely watertight assembly. passage of even particles of a size of a few microns. Finally, a third aspect of the present invention relates to a gas heat exchanger, in particular for the exhaust gases of an engine, which comprises:

- A heat exchanger block for the circulation of gases with heat exchange with a refrigerant fluid; and

a particulate filter gas line unit assembly according to the first aspect of the present invention, wherein the gas line unit is attached to the end of said heat exchanger block so that it remains in communication fluidic with it for the gases to pass through it. Brief description of the drawings

The foregoing and other advantages and features will be more fully understood from the following detailed description of some embodiments which refers to the accompanying drawings, which are to be taken by way of illustration and not by way of illustration. FIG. 1 is an exploded perspective view of the assembly proposed by the first aspect of the invention, for one embodiment in which the particle filter is arranged to attach to an integrated connection flange. to a gas tank; FIG. 2 is a perspective view of part of the assembly illustrated in FIG. 1, for the sake of clarity only a portion of the connection flange and the gas reservoir have been shown through a section following a transverse plane (vertical to the position shown); Figure 3 shows a view similar to that of Figure 2 but where the particle filter is also shown in section along the above-mentioned transverse plane, and an enlargement of a detail of said view; Figure 4 shows views similar to those of Figure 3, but for another embodiment slightly different from that of Figure 3, since the particle filter frame does not include a peripheral flange; Figure 5 shows views similar to those of Figure 3, for the same embodiment, but once the filter has been attached to the laser welding connection flange; Figure 6 shows an elevation and enlargement of a detail thereof, which correspond to those of Figure 5, for the same embodiment; Figure 7 shows a perspective view of the assembly proposed by the first aspect of the invention, for one embodiment in which the particulate filter is arranged to attach to a gas reservoir, as well as an enlargement of a detail of this view; for the sake of clarity only a part of the gas reservoir resulting from a section along a transverse plane is shown; and Figure 8 shows an elevational view, which corresponds to the perspective view of Figure 7, for the same embodiment.

Detailed description of some embodiments

In the accompanying figures are shown various embodiments of the assembly proposed by the first aspect of the present invention, which comprises a gas conduit unit 2 and a particle filter 3, wherein the driving unit of gas 2 is adapted to be attached to one end of a heat exchanger block (not shown) so that it remains in fluid communication therewith for the gases to pass through and the particulate filter 3 is attached to the gas pipe unit 2 by a completely sealed assembly made by laser welding.

As can be seen in the attached figures, the particle filter 3 comprises a central portion 3b or concave configuration screen as a tray and a wing or peripheral frame 3a by which to fix the filter 3 to the driving unit of gas 2.

In particular, in the embodiment of Figures 1 to 6, the gas pipe unit 2 comprises a connecting flange 4 connectable at a first end to a gas recirculation line and integrated with a gas tank 5 of the gas pipe unit, forming a single piece, the particle filter 3 being attached to said connecting flange 4 through the peripheral frame 3a and arranged to filter the gases that pass through and pass through an opening 4 of the connecting flange 4. The gas reservoir 5 comprises a first portion 5a, which comprises a first opening 01, connectable to one end of a heat exchanger block (not shown) and a second part 5b, which comprises a second opening 02 which can be connected to a gas recirculation line.

In another embodiment, not shown, the connecting flange 4 and the gas tank 5 are two independent parts attached to one another.

Figures 1, 2, 3 and 4 show a situation prior to the welding of the filter 3 to the connection flange 4, while in Figures 5 and 6 the filter 3 has already been welded to the connection flange 4.

In said embodiment, the peripheral frame 3a of the filter 3 has a first face (bottom face according to the illustrated position) in contact with a peripheral surface 4b the connecting flange 4 which surrounds the through opening 4a, defining a contact plane P1 (see FIG. 6), and which, in the embodiment shown, constitutes the lap of a step defined in the outer face of FIG. the connection flange 4.

The peripheral frame 3a is thus assembled to the peripheral surface 4r by means of a continuous weld seam C delimiting a closed circuit, which is produced by the laser welding, which completely traverses the thickness of the peripheral frame 3a and which penetrates partially in a controlled manner in the peripheral surface 4b of the connecting flange 4, as seen in Figures 5 and 6, in particular in the enlargements of details thereof. In the illustrated embodiment, the assembly proposed by the first aspect of the invention comprises a reinforcing ring 7 (see FIGS. 1 to 6) attached to a second face of the peripheral frame 3a, opposite to the first face, to the means of said continuous weld seam C, which traverses the entire thickness of the reinforcing ring 7, as is seen in Figures 5 and 6, in particular in their corresponding detail enlargements. Figure 4 shows a variant slightly different from that illustrated in Figures 1, 2, 3, 5 and 6, since on these, unlike Figure 4, the peripheral frame 3a comprises an annular flange R which extends from the peripheral frame 3a in the direction illustrated, such that the reinforcing ring 7 has a width smaller than that of the ring of FIG. 4 and one of its edges abuts against said annular flange R and preferably nestle there.

Figures 7 and 8 show another embodiment in which the filter 3 is attached to a gas reservoir 5 of the gas pipe unit 2, which has a first portion 5a, which comprises a first opening 01 , connectable to one end of a heat exchanger block (not shown) and a second portion 5b, which includes a second opening 02, connectable to a gas recirculation line, the particle filter 3 being attached to the reservoir of gas 5 through the peripheral frame 3a.

In particular, in said embodiment, the peripheral frame 3a has a first face (bottom face according to the illustrated position) in contact with a peripheral zone of the second part 5b of the gas reservoir 5 which surrounds the second opening O2, the frame 3a device being assembled to said peripheral zone by means of a continuous weld seam C (not shown in this example) which delimits a closed circuit, which is produced by laser welding and which completely traverses the thickness of the peripheral frame 3a and penetrates partially, in a controlled manner, in the second part 5b of the gas tank 5.

In the embodiment illustrated in FIGS. 7 and 8, the assembly proposed by the first aspect of the invention also comprises a reinforcing ring 7 fixed to a second face of the peripheral frame 3a, opposite to the first face, by means of said continuous weld seam C, which traverses the entire thickness of the reinforcing ring 7, in a manner similar to that of the embodiment shown in FIGS. 5 and 6, but to attach to the gas reservoir 5, in particular on the peripheral zone of the second part 5b thereof.

Although in the example of FIGS. 7 and 8 the peripheral zone of the second part 5b of the gas reservoir 5 is disposed on an internal face thereof, in another embodiment (not shown), it is arranged on an outer face thereof, surrounding the opening 02.

Those skilled in the art could introduce changes and modifications in the embodiments described without departing from the scope of the invention as defined in the appended claims, such as for example welding the particulate filter to other areas or components of the control unit or have more than one filter in the control unit.

Claims

1 .- Gas line unit assembly (2) with particulate filter (3), for a gas heat exchanger, in particular for exhaust gases from an engine, the gas line unit (2) being adapted to be attached to one end of a heat exchanger block so that it remains in fluid communication with the latter so that the gases pass through it and the particulate filter (3) being fixed irremovable to the unit of gas duct (2) for filtering the exhaust gases therethrough, characterized in that said particulate filter (3) is attached to the gas duct unit (2) by means of a completely sealed assembly by laser welding.

2. An assembly according to claim 1, characterized in that said gas conduit unit (2) comprises a gas reservoir (5) with a first portion (5a), comprising a first opening (01), connectable to one end of said heat exchanger block, and a second portion (5b), including a second opening (02), connectable to a gas recirculation line, the particulate filter (3) being attached to said gas reservoir (5) .

3. - The assembly of claim 2, characterized in that the gas pipe unit (2) further comprises a connecting flange (4) connectable at a first end to said gas recirculation line and fixed, by a second end opposite said first end, said second portion (5b) of the gas reservoir (5) or integrated therewith, the gas reservoir (5) being connectable to the gas recirculation line by the intermediate of said connecting flange (4).

4. - The assembly of claim 1, characterized in that said gas pipe unit (2) comprises a connecting flange (4) connectable by a first end to a gas recirculation line and fixed by a second end opposite said first end, to a gas reservoir (5) of the gas pipeline unit or integrated therewith, the particulate filter (3) being attached to said connecting flange (4) and disposed of in order to filter the gases passing through it and pass through a through opening (4a) of the connection flange (4).

5. - assembly according to claim 2 or 3, characterized in that the particle filter (3) comprises a peripheral frame (3a) having a first face in contact with a peripheral zone of said second portion (5b) of the gas tank (5) surrounding said second opening (02), said peripheral frame (3a) being joined to said peripheral area by means of a continuous weld seam (C) which delimits a closed circuit, which is produced by said laser welding and which completely traverses the thickness of said peripheral frame (3a) and partially penetrates, in a controlled manner, into said second portion (5b) of the gas tank (5).

6. - assembly according to claim 4, characterized in that the particle filter (3) comprises a peripheral frame (3a) having a first face in contact with a peripheral surface (4b) of said connecting flange (4) which surrounds said through opening (4a), said peripheral frame (3a) being joined to said peripheral surface by means of a continuous weld seam (C) which delimits a closed circuit, which is produced by said laser welding, which passes completely through the thickness of said peripheral frame (3a) and which partially penetrates, in a controlled manner, into said peripheral surface (4b) of said connecting flange (4).

7. - assembly according to claim 5 or 6, characterized in that it comprises a reinforcing ring (7) attached to a second face of said peripheral frame (3a), opposite said first face, by means of said continuous weld seam (VS).

8. An assembly according to claim 7, characterized in that said reinforcing ring (7) is metallic.

9. - assembly according to claim 8, characterized in that said reinforcing ring (7) is made of stainless steel.

10. - assembly according to any one of claims 5, 6 or 7, characterized in that said peripheral frame (3a) is metallic or thermoplastic material.

1 1. - An assembly according to any one of the preceding claims, characterized in that the particulate filter (3) is configured to block the passage of particles of larger size than the soot particles.

12. - Method of manufacturing a unit gas pipeline unit (2) with particle filter (3), for heat exchanger for gas, in particular for exhaust gases of an engine, the driving unit of gas (2) being adapted to attach to one end of a heat exchanger block so that it remains in fluid communication therewith for the gases to pass therethrough, wherein the process comprises the operation of to fix the particulate filter (3) to the gas pipeline unit (2) for filtering the exhaust gases therethrough, the method being characterized in that it comprises carrying out said filter attachment particles (3) to the gas pipeline unit (2) by laser welding.

13.- Heat exchanger for gas, in particular for the exhaust gases of an engine, which comprises:

- A gas pipe unit assembly (2) with particle filter (3) according to any one of claims 1 to 1 1, wherein the gas pipe unit (2) is attached to one end of said heat exchanger block thermal, so that it remains in fluid communication with it for the gases to pass through.