EP2469210B1 - Heat exchanger with stacked plates - Google Patents

Description

The present invention relates to a stacked plate heat exchanger.

The invention is particularly applicable to any type of heat exchanger mounted in the compartment of an engine, in particular to the exhaust gas recirculation exchangers of an engine (Exhaust Gas Recirculation Coolers or EGRC).

BACKGROUND OF THE INVENTION

The current configuration of EGR exchangers on the market is a metal heat exchanger typically made of stainless steel or aluminum.

There are essentially two types of EGR heat exchanger: a first type is composed of a carcass inside which is arranged a bundle of tubes for the passage of gases, the refrigerant flowing in the carcass outside the tubes, and the second type has a series of parallel plates forming the heat exchange surfaces, the exhaust gas and the refrigerant circulating between two plates, in alternating layers, fins that can be provided to improve the exchange of heat. heat.

The loop of the recirculation system further comprises an EGR valve regulating the passage of exhaust gases through the heat exchanger.

Stacked plate heat exchangers are known in which each plate has a longitudinal closing side wall, each pair of plates being mounted with its respective lateral walls arranged at the longitudinal ends to ensure the separation and closure of the gas and fluid circuits. refrigerant.

Each circuit may also be of the "I" shaped linear type, where the fluid inlet and the fluid outlet are disposed at opposite ends; or it may be of the U-shaped type, where the fluid inlet and the fluid outlet occupy adjacent positions at the same open end, the opposite end being closed, and defining a forward passage and a passage back through the channels of the plates. In the latter case, the closed end for the return of the fluid is generally constituted by a closed reservoir.

1. a) Une configuration en "U" verticale : le flux de gaz est dirigé à travers la totalité des canaux du circuit de gaz de la moitié des plaques, et revient par d'autres canaux du circuit de gaz appartenant au reste des plaques complètement distinctes.
2. b) Une configuration en "U" horizontale : le flux de gaz est dirigé à travers la moitié des canaux de la totalité des plaques, et revient par l'autre moitié des canaux du circuit de gaz appartenant aux mêmes plaques.

Stacked plate EGR heat exchangers can have two possible "U" configurations:

1. a) A vertical "U" configuration: the gas flow is directed through all channels of the gas circuit of half of the plates, and returns through other channels of the gas circuit belonging to the remainder of the completely separate plates .
2. b) A horizontal "U" configuration: the gas flow is directed through half of the channels of all the plates, and returns through the other half of the channels of the gas circuit belonging to the same plates.

The majority of the EGR exchanger components are metallic so that the exchangers are assembled by mechanical means before being welded or arc or laser welded to provide an adequate level of sealing for the intended application.

In some cases, the EGR exchanger may also include components made of plastic, which may perform a single function or several functions as a single part.

The main function of EGR exchangers is the exchange of heat between the exhaust gas and the refrigerant for the purpose of cooling the gases. The EGR exchangers must also fulfill other secondary functions, including assembly with the engine block, connection with the refrigerant or connection with the exhaust gas circuit.

In all these cases, the manufacturing process requires a large number of oven-welding seams or arc or laser welding, resulting in a complex and expensive operation.

In stacked plate heat exchangers, it is necessary to close two separate circuits: the hot fluid and the cold fluid. This type of heat exchanger is usually made by baking.

In order to avoid significant pressure drops, the fluids enter the heat exchanger directly. The use of piping being impossible, the usual solutions are to use tanks or accessories to introduce the fluid into the heat exchanger.

The assembly and the baking of this type of interfaces with the stacked plates can cause problems of quality, in other words leaks, the two circuits - refrigerant and gas - must therefore be adequately closed to prevent possible leakage.

From the overall point of view of efficiency, it is very important, in "U" configurations, that the flow of hot gas does not mix with the flow of cold gas. It is therefore obvious that the gas inlet flow should never directly reach the gas outlet flow.

Because of the market trend of reduced engine size and the use of EGR heat exchangers not only in high pressure (HP) applications but also in low pressure (LP) applications, the Available space for the exchanger and its components continues to decrease. The environments in which the EGR exchanger must be integrated are becoming more complex. It is therefore important to develop compact EGR exchangers with integrated parts that can be accommodated in the available space

JP-A-2010112201 discloses a stacked plate heat exchanger according to the preamble of claim 1.

DESCRIPTION OF THE INVENTION

The subject of the present invention is a stacked plate heat exchanger designed to overcome the drawbacks of heat exchangers known in the art, making it possible to reduce or even eliminate the proportion of the inlet flow of the fluid to be cooled which does not enter the heat exchanger. exchanger and is introduced directly into the output stream of the fluid to be cooled in the "U" configuration exchangers.

The stacked plate heat exchanger, object of the present invention, comprises the features of claim 1.

In this way, the separation means make it possible to integrate the closure function between the inlet flow and the outlet flow of the fluid to be cooled, if although they act as a separation barrier between the inlet flow and the outlet flow of the fluid to be cooled and furthermore avoid, as far as possible, the risk of diverting the flow between said inlet and said outlet.

The separation means comprise a barrier wall coupled to the outer face of the fixing flange, said wall being capable of dividing the inlet and outlet zone of the fluid to be cooled at said open end of the plate assembly. stacked. Said wall must be adapted to the design of the plates in each configuration.

Advantageously also, said separating wall is capable of coming into direct contact with a shutter or valve of an EGR valve to close the inlet flow and the outlet flow of the fluid to be cooled through the exchanger.

Said wall being integrated in the outer part of the flange, it also plays the role of interface between the exchanger and the valve or the EGR pipe.

Preferably, said wall may be an independent piece coupled to the flange or is manufactured as a single piece integrated into the flange. The configuration of the flange can also vary depending on the configuration of the EGR exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 est une vue en perspective de l'ensemble de plaques empilées montrant la paroi séparatrice intégrée à la bride, pour un échangeur de chaleur EGR de configuration en "U" verticale, selon un premier mode de réalisation de l'invention ;
• la figure 2 est une vue en perspective de l'ensemble de plaques empilées selon la figure 1, montrant le flux d'entrée et le flux de sortie de gaz et le détournement éventuel entre lesdits flux ;
• la figure 3 est une vue en perspective de l'échangeur de chaleur monté, selon la figure 1 ;
• la figure 4 est une vue de face de l'échangeur de chaleur monté, selon la figure 1 ;
• la figure 5 est une vue en perspective de l'ensemble de plaques empilées montrant la paroi séparatrice intégrée à la bride, pour un échangeur de chaleur EGR de configuration en "U" horizontale, selon un deuxième mode de réalisation de l'invention ;
• la figure 6 est une vue en perspective de l'ensemble de plaques empilées selon la figure 5, montrant le flux d'entrée et le flux de sortie de gaz, et le détournement éventuel entre lesdits flux ;
• la figure 7 est une vue agrandie de la paroi séparatrice montrant les emboîtements de jonction avec les plaques, selon l'échangeur de la figure 5 ;
• la figure 8 est une vue en perspective de l'échangeur de chaleur monté, selon la figure 5 ; et
• la figure 9 est une vue de face de l'échangeur de chaleur monté, selon la figure 5.

In order to facilitate the description of what has been explained above, drawings are enclosed in which are shown, in schematic form and by way of non-limiting example, only two practical examples of embodiment of the plate heat exchanger. stacked of the invention. In these drawings:

• the figure 1 is a perspective view of the set of stacked plates showing the separating wall integrated in the flange, for a vertical U-shaped "E" shaped heat exchanger, according to a first embodiment of the invention;
• the figure 2 is a perspective view of the set of plates stacked according to the figure 1 , showing the input flow and the gas output flow and the eventual diversion between said flows;
• the figure 3 is a perspective view of the mounted heat exchanger, according to the figure 1 ;
• the figure 4 is a front view of the mounted heat exchanger, according to the figure 1 ;
• the figure 5 is a perspective view of the set of stacked plates showing the separating wall integrated in the flange, for a horizontal "U" configuration EGR heat exchanger, according to a second embodiment of the invention;
• the figure 6 is a perspective view of the set of plates stacked according to the figure 5 , showing the inlet flow and the gas outlet flow, and the possible diversion between said flows;
• the figure 7 is an enlarged view of the dividing wall showing the interlocking junctions with the plates, according to the exchanger of the figure 5 ;
• the figure 8 is a perspective view of the mounted heat exchanger, according to the figure 5 ; and
• the figure 9 is a front view of the mounted heat exchanger, according to the figure 5 .

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Figures 1 to 4 , the heat exchanger 1 EGR comprises a plurality of stacked plates 2 between which the gas to be cooled and the refrigerant fluid circulate between two independent circuits defined by said plates 2, in alternating layers.

Each plate 2 has a longitudinal longitudinal closing wall 3, as shown by the Figures 1 and 2 each pair of plates 2 being mounted with their respective side walls 3 disposed in the longitudinal ends for separation and closure of the circuits.

The exchanger 1 also comprises a carcass 4 intended to receive the set of stacked plates 2, as shown by the Figures 3 and 4 as well as a fastening flange 5 coupled in said open end and a gas reservoir 6 in said closed end. The configuration of the flange 5 may also vary depending on the configuration of the exchanger 1.

In this case, the circuit of the gas to be cooled has a configuration in "U" where the inlet and the outlet of the gases occupy adjacent positions at the same open end of the set of stacked plates 2, the end opposite being closed, and said plates defining forward channels and return channels.

The exchanger 1 also comprises a wall 7 forming a barrier for separating the inlet flow and the gas outlet stream, said wall 7 being integrated with the fixing flange 5. Said wall 7 can also be an independent part coupled to the flange 5 or be manufactured as a single piece integrated flange 5.

The stacked plate EGR exchangers may have two possible "U" configurations, namely horizontal or vertical, as will be explained later.

The Figures 1 to 4 show a first embodiment of the invention in which the exchanger 1 is of the type of "U" vertical configuration, that is, the gas flow is directed through all the channels of the gas circuit of the half of the plates 2, and returns through other channels of the gas circuit belonging to the rest of the plates 2 completely separate.

In this case, the separating wall 7 is integrated in the flange 5 in a substantially horizontal position and welded in the oven to an intermediate plate 2a for separating the inlet flow and the gas outlet flow.

In this way, the separating wall 7 makes it possible to integrate the closure function between the inlet flow and the gas outlet flow, so that it acts as a separating barrier between the inlet flow and the flow the gas outlet and further avoids as far as possible the risk of diverting the flow between said inlet and said outlet.

To the figure 2 , white arrows illustrate the direction of the input flow and the gas output flow and a black arrow illustrates the possible diversion between said flows.

Said separating wall 7 is coupled to the external face of the fastening flange 5, said wall 7 being capable of dividing the inlet and outlet gas zone at said open end of the set of stacked plates 2. Said wall 7 must be adapted to the design of the plates 2 in each configuration.

Said separating wall 7 is also capable of coming into direct contact with a shutter or valve of an EGR valve (not shown) to close the inlet flow and the gas outlet flow through the exchanger 1.

Said wall 7 being integrated in the outer part of the flange 5, it also plays the role of interface between the exchanger 1 and the valve or the EGR pipe.

The Figures 5 to 9 illustrate a second embodiment of the invention in which the exchanger 1 'is of the type of horizontal "U" configuration, in other words the flow of the gases is directed through half of the channels of all the plates 2, and returns through the other half of the channels of the gas circuit belonging to the same plates 2.

In this case, the partition wall 7 is integrated in a substantially vertical position and welded in the oven to the plates 2 in an intermediate position for separating the inlet flow and the gas outlet flow.

In the same way, at figure 6 , white arrows illustrate the direction of the input flow and the gas output flow and a black arrow illustrates the possible diversion between said flows.

Furthermore, in this embodiment of the horizontal "U" configuration, the separating wall 7 comprises housings 8 that can be nested in the ends of the plates 2, as illustrated by FIG. figure 7 .

In this way, this interlocking junction makes it possible to reduce as much as possible the risk of possible internal diversion, and thus to improve the heat efficiency of the exchanger 1. The wall 7 is also in direct contact with the plates 2 due to its welding in the oven with said plates 2, and provided with fins or disruptive elements (not shown) to reduce the risk of diversion possible.

In both embodiments, the carcass 4 furthermore comprises two lateral reservoirs 4a joined to each other, intended to receive the lateral flow of entry and exit of refrigerant into the set of stacked plates 2, as illustrated by FIGS. figures 3 and 8 .

The exchanger 1 also comprises an inlet well 9 and a refrigerant outlet well 10 disposed on opposite sides of the carcass 4, as illustrated by FIGS. figures 4 and 9 .

This design of side plates 2 can allow the lateral connection of the coolant wells 9, 10 so as to ensure a distribution of the side coolant in the exchanger 1, which offers many advantages for the integration of a heat exchanger Stacked plate EGR 2 in a small or complex space of the engine block environment.

Claims (3)

1. Heat exchanger (1) with stacked plates, comprising a plurality of stacked plates (2) between which the fluid to be cooled and the coolant fluid circulate between two independent circuits defined by said plates (2), in alternating layers, the circuit of the fluid to be cooled having a "U" configuration, whereby the inlet and the outlet of said fluid to be cooled occupy adjacent positions at one and the same open end of the assembly of stacked plates, the opposite end being closed, and said plates (2) defining outward channels and return channels, and comprising a fastening flange (5) coupled to said open end, said exchanger comprising means (7) of separation of the inlet flow and of the outlet flow of the fluid to be cooled, said separation means (7) being integrated with said fastening flange (5), characterized in that said exchanger is of the type with a horizontal "U" configuration in which the flow of fluid to be cooled is directed via one half of the channels of the totality of the plates (2) and returns via the other half of the channels of the circuit of fluid to be cooled belonging to the same plates (2), in that said separation means comprise a wall (7) forming a barrier coupled to the external face of the fastening flange (5), said wall (7) being capable of dividing the inlet and outlet zone of the fluid to be cooled at said open end of the assembly of stacked plates (2), in that the separating wall (7) is integrated in a substantially vertical position and brazed to the plates (2) in an intermediate position that makes it possible to separate the inlet flow and the outlet flow of the fluid to be cooled, and in that the separating wall (7) comprises slots (8) capable of being engaged with the ends of the plates (2).
2. Exchanger (1) according to Claim 1, wherein said separating wall (7) is capable of entering into direct contact with a shutter or flap of an EGR valve in order to close off the inlet flow and the outlet flow of the fluid to be cooled via the exchanger (1).
3. Exchanger (1) according to Claim 1 or 2, wherein said wall (7) is an independent component coupled to the flange (5) or, alternatively, is manufactured in the form of a single piece integrated with the flange (5).

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