WO2018162783A1

WO2018162783A1 - Heat exchanger for gases, particularly engine exhaust gases, and method for manufacturing said exchanger

Info

Publication number: WO2018162783A1
Application number: PCT/ES2018/070182
Authority: WO
Inventors: José Antonio De La Fuente Romero; Darío Jorge PEÑA SÁNCHEZ; Carlos Rodrigo Marco
Original assignee: Valeo Térmico, S. A.
Priority date: 2017-03-10
Filing date: 2018-03-12
Publication date: 2018-09-13
Also published as: ES2681129A1; ES2681129B1

Abstract

The invention relates to an exchanger comprising a first circuit of exhaust gas fluid, a heat-exchange case (1), and an inlet port (2) and an outlet port (3) for coolant, the exchanger being characterised in that a portion of a wall of the heat-exchange case (1) is defined by a surface of a part (5) for connecting to the engine, the connection part (5) including the inlet port (2) and the outlet port (3) for the coolant from the engine. The method comprises the steps of: connecting the connection part (5) to a structure of the case (1); fitting into recesses (7) of the structure of the case (1) plates (8) for assembly with the connection part (5); and applying solder to the edge of the connection part (5).

Description

DESCRIPTION

HEAT EXCHANGES FOR GASES, ESPECIALLY FOR EXHAUST GASES OF AN ENGINE, AND MANUFACTURING METHOD OF SUCH EXCHANGER

The present invention generally concerns, in a first aspect, a heat exchanger for gases, especially for exhaust gases of an engine, which includes a plurality of gas circulation ducts and a housing for heat exchange between said gases and a cooling fluid that surrounds the gas circulation ducts housed inside the housing.

A second aspect of the present invention concerns a method of manufacturing said heat exchanger of the first aspect.

The invention is especially applied in exhaust recirculation exchangers of an engine ("Exhaust Gas Recirculation Coolers" or EGRC). Background of the invention

The main function of the EGRC exchangers is the exchange of heat between the exhaust gases and a cooling fluid, in order to cool these gases. Currently, EGRC heat exchangers are widely used for diesel applications to reduce emissions, and are also used in gasoline applications to reduce fuel consumption.

The current configuration of the EGRC exchangers on the market corresponds to a heat exchanger that includes a heat exchange housing generally made of stainless steel or aluminum. Basically, there are two types of EGR heat exchangers: a first type consists of a housing in whose interior there is a parallel conduit beam for the passage of gases, the refrigerant circulating through the housing, externally to the conduits, and the second type consists of a series of parallel plates that constitute the heat exchange surfaces, so that the exhaust gases and the refrigerant circulate between two plates, in alternating layers.

In the case of duct beam heat exchangers, the connection between the ducts and the housing can be of different types. Generally, the ducts are fixed at their ends between two structural parts coupled at each end of the housing, both structural parts having a plurality of holes for receiving the ends of the respective ducts. The cooling fluid inlet and outlet inside the heat exchange housing is carried out by means of cooling fluid inlet and outlet ducts that are both tightly coupled to the housing. In the state of the art, heat exchangers for gases are known in which, due to certain technical requirements, the flow of coolant fluid from the engine is conducted directly into the exchanger housing regardless of ducts specifically designed for this purpose. In these exchangers, the flow of coolant fluid is conducted directly into the heat exchange housing, through fluid inlet and outlet ports provided in the housing itself and in a joint flange with the motor that joins to the wall of the housing. Brazing between the flange and the housing wall is carried out by interposing a nickel sheet between the two components. The process of assembling the heat exchangers described in the previous paragraph has the disadvantage that it requires an operation to align the coolant fluid inlet and outlet holes of the housing and the connection flange with the engine, as well as the correct placement of the Nickel sheet to ensure a tight seal by welding between both components completely.

Description of the invention

In order to solve the aforementioned drawbacks, according to a first aspect, the present invention provides a heat exchanger for gases, especially for exhaust gases of an engine, comprising; - a first fluid circuit for the circulation of said exhaust gases,

a heat exchange housing intended to delimit a second fluid circuit for the circulation of a refrigerant fluid that exchanges heat with the gases of the first circuit inside said housing, and

an inlet port and an outlet port for said refrigerant fluid inside said housing.

The exchanger is characterized by the fact that at least a wall portion of said heat exchange housing is defined by a surface of a connecting piece with the motor, said same joining piece including the inlet port and the port of output for the flow of coolant from the engine or engine block. In the claimed exchanger the flow of coolant fluid enters and exits the housing through the connecting piece with the engine, which is configured in this case so that it defines a portion of the wall of the heat exchange housing that enters in contact with the cooling fluid. In this way, a lighter exchanger is obtained that is easier to assemble, since it has fewer components.

Preferably, the heat exchange housing comprises a structure provided with an opening capable of being closed by said connecting piece with the motor, at least a portion of the surface of said connecting part defining a wall of the housing arranged in correspondence with The opening. For example, this structure may be a tubular structure devoid of a wall portion on one of its sides or an open structure substantially "U" shaped, with a lateral opening.

The exchanger claimed makes it possible to dispense with the Nickel sheet used in the state of the art to weld the joint with the wall of the heat exchange housing. In fact, in the present invention, the connecting piece with the motor is welded together in the contour of the heat exchange housing opening using Nickel paste.

Advantageously, the coolant fluid inlet and outlet ports include at least two holes in the surface of said connecting piece with the engine configured to be directly connected to the coolant fluid flow from the engine. In the present invention, the flow of the cooling fluid from the engine block passes through these holes to directly contact the gas circulation ducts of the first circuit. A light and low cost device is thus obtained.

According to a preferred embodiment, the connecting piece with the motor is configured as a flange, a surface of said connecting flange defining the portion of the wall of the heat exchange housing intended to be arranged in correspondence with the opening of the structure of said housing.

According to the same preferred embodiment, the exchanger comprises two plates for assembling, at the ends of the housing, the flange or connecting piece with two structural parts intended to receive the plurality of exhaust gas circulation ducts of the first fluid circuit .

These assembly plates facilitate obtaining a watertight wall in the structure of the heat exchange housing.

Advantageously, the open structure of the heat exchange housing includes a recess adapted to receive one of said assembly plates at each of the respective ends of said housing. In this way, said assembly plates are substantially flush with the outer surface of the housing structure and serve as a support and welding base for the flange or connecting piece.

Again advantageously, the inner face of the flange or connecting piece defines a projection adapted to fit between two mounting plates in the opening of the structure of the heat exchange housing.

This projection is located substantially in the same plane as the assembly plates, once the flange or connecting piece is assembled, determining together with them a wall of the exchange housing that comes into contact with the cooling fluid.

According to one embodiment, said assembly plates of the engine connection piece are joined in solidarity with the edges of each of the structural parts of the ends of the heat exchange housing, forming together with each of said parts Structural a single piece of assembly at the ends of the housing.

This results in a more compact and easy to assemble design.

According to the same embodiment, said structural parts are provided with a plurality of holes arranged to receive the ends of each of the base circulation ducts on both sides of the heat exchange housing, defining extensions of the lateral edges of each said structural parts joining the assembly plates of the connection piece with the motor.

According to a second aspect, the present invention provides a method of manufacturing the claimed exchanger comprising performing the steps of; to. joining said connecting piece or flange to an open structure of the heat exchange housing to form at least a wall portion of said heat exchange housing, b. fit, in some recesses of the structure of said housing, assembly plates with the piece or joint flange, said assembly plates being at least partially overlapped by said piece or joint flange at the ends of the housing, c. apply welding to the contour of said part or joint flange with the assembly plates at the ends of the housing and with the structure of the housing. According to a preferred embodiment, step b) is carried out by assembling structural pieces at the ends of the housing, the edges of said structural parts including extensions that form the assembly plates with the flange or joint piece with the block of engine.

Advantageously, the solder joint of step c) is carried out using Nickel paste which is distributed along the contour of the joint piece or flange assembly, carcass structure and assembly plates.

According to the same preferred embodiment, in a step d), the end of each gas circulation duct is inserted into a hole of the structural parts of the ends of the heat exchange housing, said ducts being exposed to the flow of cooling fluid from the motor that circulates between an input port and an output port of the part or flange of union with the motor.

As mentioned, the exchanger claimed is light, easy to assemble and cheaper than those of the prior art. Brief description of the figures

To better understand how much has been exposed, some drawings are attached in which, schematically and only by way of non-limiting example, a practical case of realization is represented.

Figure 1 shows a partially exploded perspective view of a state of the art gas heat exchanger.

Figure 2 shows an exploded perspective view of an open structure of a heat exchange housing of the exchanger of the present invention, and a flange or connecting piece of said housing with a motor or engine block.

Figure 3 shows a perspective view of a flange or connecting piece welded to the open housing structure.

Figure 4 shows a partially exploded perspective view of the assembly of housing and flange or connecting piece of figure 3, and of a structural part provided with assembly plates with the flange or connecting piece.

Figure 5 shows a partially exploded perspective view of a heat exchange housing that includes at its respective ends two structural parts provided with assembly plates with the part or flange connecting with the motor.

Figure 6 shows a detail of an assembly plate inserted in a shoulder of the open structure of the heat exchange housing.

Figure 7 shows a perspective view of a connecting piece or flange with the motor assembled in the structure of the heat exchange housing on corresponding assembly plates. Figures 8 and 9 show a front view of the inner face of the connecting piece or flange that includes the shoulder to fit between assembly plates, as well as a section of said same piece or joining flange.

Description of a preferred embodiment

A preferred embodiment of a gas heat exchanger of the present invention is described below, with reference to Figures 2 to 9. Figure 1 represents a state of the art gas heat exchanger. The gas exchanger of the present invention comprises;

a first fluid circuit (not shown) for the circulation of the exhaust gases of an engine,

a heat exchange housing 1 that delimits a second fluid circuit (not shown) for the circulation of a cooling fluid that exchanges heat with the exhaust gases of the first circuit inside the housing 1, and

an inlet port 2 and an outlet port 3 for said cooling fluid.

As can be seen in Figure 2, the heat exchange housing 1 comprises an open structure provided with an opening 4 capable of being closed by a piece 5 connecting with the motor or motor block, so that a portion of the surface of said connecting piece 5 defines a wall of the housing 1 arranged in correspondence with said opening 4. This wall is in contact with the cooling fluid that bathes a beam of gas circulation ducts (not shown).

In the described embodiment, the connection piece 5 is configured as a connection flange with the motor, and is provided with holes defining the coolant fluid inlet and outlet ports 2, 3, which can be connected directly to the flow of coolant from the engine. The same flange includes a plurality of holes 6 for the passage of fasteners.

Returning to the open structure of the housing 1, Figure 2 shows an outline of the opening

4 provided with a recess 7 adapted to receive assembly plates 8 at each of the ends 1 a, 1 b of this housing 1. As can be seen in Figure 4, in the embodiment described, the plates 8 of assembly are joined in solidarity with the lateral edges of structural pieces 9 provided at the ends 1a, 1b of the housing 1 to receive conduits (not shown) for circulation of the first fluid circuit. In fact, these assembly plates 8 are configured as extensions on the sides of said structural parts 9, being able to be inserted in the recess 7 of the contour of the opening 4 of the structure of the housing 1, flush with the outermost surface of the same heat exchange housing 1 (see detail in Figure 6).

Figures 8 and 9 show a front view and a section of the flange or connecting piece 5 with the motor in which there is a projection 10 adapted to fit in the opening 4 of the housing between the assembly plates 8. Thus, once assembled the flange or piece

5 in connection with the structure of the housing 1, the projection 10 is located substantially in the same plane as the assembly plates 8, determining a wall portion of the exchange housing 1 that comes into contact with the cooling fluid.

As mentioned in the description of the invention, the exchanger claimed is lighter and easier to assemble, since it has fewer components. In addition, it has the advantage that it makes it possible to dispense with the Nickel sheet 11 which is used in the state of the art to weld the connection piece 5 'with the wall of the heat exchange housing 1'. As can be seen in Figure 1 of the prior art, the wall of the housing 1 'comprises holes 12 that must be aligned with the inlet ports 2' and outlet 3 'of cooling fluid.

Next, the steps of the manufacturing method of the claimed heat exchanger are described with reference to the figures.

In a first stage, the flange or connecting piece 5 with the motor or motor block is joined by electric welding with the open structure of the heat exchange housing 1 to form a portion of the wall of the housing 1 arranged in correspondence with the opening 4. In a second stage, the structural parts 9 are assembled at the ends 1a, 1 b of the housing 1 by fitting the assembly plates 8 into the recess 7 of these ends 1 a, 1 b, so that the sides of the part 5 or union flange with the motor overlap the outer surface of the assembly plates 8 (see figure 7). Then, in a third stage, brazing is applied to the contour of the piece 5 or union flange with the assembly plates 8 and with the structure of the housing 1, distributing Nickel paste along the entire contour.

At a later stage, the end of each duct (not shown) of the first gas circulation circuit is inserted into an orifice of the structural parts 9 of the ends 1 a, 1 b of the heat exchange housing 1, these being left conduits exposed to the flow of coolant from the engine that circulates directly between an inlet port and an outlet port of the part 5 or flange of connection with the engine. The tests have made it possible to verify that the proposed assembly solution guarantees an optimum degree of tightness of the refrigerant fluid circuit inside the housing 1.

Although reference has been made to a specific embodiment of the invention, it is apparent to one skilled in the art that the heat exchanger, and the described method are susceptible of numerous variations and modifications, and that all the mentioned details may be replaced by other technically equivalent ones, without departing from the scope of protection defined by the appended claims.

Claims

1. Heat exchanger for gases, especially for exhaust gases of an engine, comprising;

a first fluid circuit for the circulation of said exhaust gases,

a heat exchange housing (1) intended to delimit a second fluid circuit for the circulation of a refrigerant fluid that exchanges heat with the gases of the first circuit inside said housing (1), and

an inlet port (2) and an outlet port (3) for said coolant inside said casing (1),

characterized by the fact that;

at least a portion of a wall of said heat exchange housing (1) is defined by a surface of a connecting piece (5) with the motor, said same connecting piece (5) including the inlet port (2) and the outlet port (3) for the flow of cooling fluid from the engine.

2. Heat exchanger according to claim 1, wherein said heat exchange casing (1) comprises a structure provided with an opening (4) capable of being at least partially closed by said connecting piece (5) with the motor , a portion of the surface of said connecting piece (5) defining a housing wall (1) arranged in correspondence with said opening (4) intended to come into contact with the cooling fluid.

3. Exchanger according to any of the preceding claims, wherein said coolant fluid inlet and outlet ports (2,3) comprise holes in the surface of said connecting piece (5) configured to be directly connected to the fluid flow coolant from the engine.

4. Exchanger according to claim 2, wherein said connecting piece (5) with the motor is configured as a flange, a surface of said connecting flange defining the wall portion of the housing for exchange (1) heat intended to be arranged in correspondence with the opening (4) of the structure of said housing (1).

5. Heat exchanger according to any of the preceding claims, comprising plates (8) for assembling said connecting piece (5) with parts (9) structural intended to receive a plurality of exhaust ducts of the first fluid circuit at the respective ends of the housing (1).

6. Heat exchanger according to claims 2 and 3, wherein the open structure of said housing (1) includes a recess (7) adapted to receive one of said plates

(8) assembly at each of the respective ends (1 a, 1 b) of said housing (1).

7. Exchanger according to claims 4 and 5, wherein the inner face of said connecting flange defines a shoulder (10) adapted to fit between two mounting plates (8) in the opening (4) of the housing structure (1) heat exchange.

8. Exchanger according to claim 5, wherein said assembly plates (8) with the connecting piece (5) are joined in solidarity with the edges of each of the structural parts (9) of the ends (1a, 1 b) of the heat exchange housing (1), forming together with each of said structural parts (9) a single assembly piece.

9. Exchanger according to any of claims 5 or 8, wherein said parts

(9) structural are provided with a plurality of holes that are arranged to receive the ends of each of said circulation ducts on both sides of the heat exchange housing (1), defining extensions of the edges of each of said structural parts (9) the plates (8) for assembling the part (5) connecting with the motor.

10. Method of manufacturing the exchanger according to claim 1, comprising performing the steps of;

to. joining said connecting piece (5) to a structure of the heat exchange housing (1) to form at least a portion of a wall of said housing (1) capable of coming into contact with the cooling fluid,

b. fit mounting plates (8) with said connecting piece (5) into recesses (7) of the structure of the heat exchange housing (1), said assembly plates (8) being overlapped by said part (5) ) of connection with the motor,

C. apply welding to the contour of said connecting piece (5) with the plates (8) of assembly of the ends (1 a, 1 b) of the housing (1), and with the structure of the housing (1).

1. Method according to claim 10, wherein step b) is carried out by assembling structural parts (9) at the ends of the housing (1), including the edges of said structural parts (9) the plates (8) of assembly with the part (1) of union with the motor.

12. Method according to any of claims 10 to 1, wherein step c) is carried out using Nickel paste distributed along the contour of the connecting piece (5).

13. Method according to claim 11, comprising a step d) in which the ends of gas circulation ducts are inserted into holes of the structural parts (9) of the ends (1 a, 1 b) of the heat exchange casing (1), said ducts being exposed to the flow of coolant fluid from the engine that circulates between an inlet port (2) and an outlet port (3) of the connecting piece (5) with the engine .