Heat exchanger with an added-on collector

The present invention relates to a heat exchanger (1) comprising at least one heat exchange bundle (2), a box (4, 6) and a collector (8), the box (4, 6) being arranged at one end (24, 26) of the heat exchange bundle (2), the heat exchange bundle (2) comprising at least one peripheral wall (10) which delimits a housing (18) in which a plurality of tubes (12) extend, inside which tubes a first fluid circulates and around which a second fluid circulates, at least one opening (30) being provided in the peripheral wall (10) and a collector (8) comprising a peripheral edge (40) being arranged so as to cover the opening (30).

The present invention relates to the field of heat exchangers, and more particularly to rendering a collector which is added onto a heat-exchange bundle integral with a heat exchanger.

A heat exchanger, such as, for example, a charge air cooler, generally comprises a heat-exchange bundle comprising tubes inside which a first fluid circulates. The exchanger also comprises input or output boxes which are positioned on both sides of the heat-exchange bundle, making it possible to direct the first fluid into the plurality of tubes. The heat exchanger also comprises at least one collector which makes it possible to irrigate or discharge a second heat-bearing fluid from the heat-exchange bundle, the second fluid being designed to exchange calories with the first heat-bearing fluid.

During the process for production of the heat exchanger, the collectors are habitually derived from a deformation of a peripheral wall of the heat-exchange bundle, such that said collector and the peripheral wall of the heat-exchange bundle form a single part. However, the applicant observed that this formation of the collector on the peripheral wall gave rise to problems of sealing in the long term, because of the tube becoming fragile at the join with the collector. The sealing problems at the tube-collector join then have the effect of creating leakages of the second fluid towards the first fluid, thus giving rise to breakdown of the vehicle equipped with this heat exchanger.

The tube-collector joining area becomes fragile in particular because of the concentration of stress between the collector and the tubes of the bundle when the exchanger is subjected to mechanical stresses, in particular when thermal shocks are sustained. The concentrations of stress are derived mainly from the variation of thickness between the collector and the tubes, with the tubes being thinner than the collector. At this joining (or separation) area, a wedge or a notch will be formed, which creates concentrations of stress when the exchanger is subjected to mechanical stresses. The stresses can be purely of a mechanical type, or they can be thermal, or also thermo-mechanical.

The objective of the present invention is thus to eliminate the aforementioned disadvantages, by designing a collector, the sealing of which with the heat-exchange bundle is improved, and thus makes it possible to increase the reliability and service life of the heat exchanger.

The invention thus relates to a heat exchanger comprising at least one heat-exchange bundle, a box and a collector, the box being positioned at an end of the heat-exchange bundle, the heat-exchange bundle comprising at least one peripheral wall which delimits a receptacle in which there extends a plurality of tubes within which a first fluid circulates, and around which a second fluid circulates, at least one opening being provided in the peripheral wall, the heat exchanger being characterized in that the collector is added onto the peripheral wall, the collector delimiting a chamber at least partly, and comprising a peripheral edge which surrounds a window of the collector, the collector being positioned so as to cover the opening provided in the peripheral wall, such that the window is at least partly in line with the opening, and the peripheral edge is at least partly in contact with said peripheral wall.

The heat exchanger is a device allowing exchanges of calories between two fluids without the fluids mixing. In the context of the invention, this heat exchanger may in particular be a charge air cooler, the function of which is to cool the air coming from a turbocharger before it is input into an internal combustion engine.

The heat exchanger thus comprises an input box which makes it possible to direct the air output from the turbocharger, in this case the first fluid, to the heat-exchange bundle, and an output box making it possible to direct the air output from the heat-exchange bundle to the internal combustion engine. More specifically, the input box and the output box are connected to the plurality of tubes provided in the receptacle of the heat-exchange bundle, such that the input box and/or the output box and the plurality of tubes are in fluid communication with one another.

The function of the collector is to direct the second fluid in the receptacle of the heat-exchange bundle, between the plurality of tubes. Thus, the opening provided in the peripheral wall of the heat-exchange bundle is a through-opening, i.e. it is open on the receptacle of the heat-exchange bundle. Advantageously, the window of the collector is strictly in line with the opening, and it is thus understood that the collector, the chamber of which is positioned covering the opening, permits the circulation of the second fluid between the collector and the receptacle of the heat-exchange bundle. Advantage is thus derived from the peripheral edge which extends against the peripheral wall of the heat-exchange bundle, making it possible to ensure optimal sealing between the collector and the heat-exchange bundle.

It is also understood that the peripheral edge which is added onto the heat exchanger makes it possible to increase the thickness of said heat exchanger at the join between the collector and the heat-exchange bundle. This therefore reduces the risks of damage to this area caused by the thermal shocks between the first fluid and the second fluid.

According to a characteristic of the invention, the peripheral wall of the heat-exchange bundle comprises an inner face which faces towards the receptacle, and an outer face which faces towards the environment on the exterior of the heat-exchange bundle, the peripheral edge of the collector being in contact with the outer face of the peripheral wall.

According to a characteristic of the invention, the plurality of tubes extends longitudinally in the receptacle which is delimited by the peripheral wall, the opening being provided transversely to the plurality of tubes.

According to an example of the invention, the tubes are arranged in series in a transverse direction of the heat exchanger, perpendicularly to the longitudinal direction in which they extend. The opening is thus provided in the peripheral wall, perpendicularly to the plurality of tubes, in the receptacle of the heat-exchange bundle.

Advantage is derived from a configuration of this type in that it allows the opening to cover all of the tubes accommodated in the receptacle of the heat-exchange bundle, and thus to homogenize the circulation of the second fluid around the tubes.

According to a characteristic of the invention, the window of the collector and the opening provided in the peripheral wall are aligned on the same transverse axis, and a width of the window is larger than a width of the opening.

The width of the window and the width of the opening are measured along a straight line perpendicular to the transverse axis on which the opening and the window are aligned. It is understood from this particular structural characteristic that the peripheral edge does not encroach on the opening. In other words, during use of the heat exchanger, the peripheral edge of the collector is not interposed on the path of the second fluid when the fluid passes through the opening.

According to a characteristic of the invention, the chamber has a first end of the collector which extends over a first height measured along a plane of symmetry of the chamber, and a second end of the collector which extends over a second height measured along the plane of symmetry, the first height being greater than the second height. The first end is the one via which the second fluid enters into the chamber of the collector.

It is understood from this characteristic of the invention that the volume of the chamber is greater at the first end than the volume of the chamber at the second end of the collector.

During operation of the heat exchanger, the height of the chamber is adapted to the flow rate of the second fluid, according to its position along the second fluid second fluid chamber.

Thus, the decrease in the height of the chamber of the collector is for example proportional to the decrease in the flow rate of the second fluid in the chamber of the collector. Advantage is derived from this characteristic in that it makes it possible to obtain homogeneousness of supply of the heat-exchange bundle along its second fluid width. Thus, the distribution of the second fluid in the receptacle is balanced, and makes it possible to optimize the heat exchanges between the first fluid and the second fluid.

According to a characteristic of the invention, the opening comprises a first border which extends in the longitudinal direction of the heat-exchange bundle over a first distance, and a second border which extends in the longitudinal direction of the heat-exchange bundle over a second distance, the second distance being equal to the first distance.

According to an alternative of the invention, the opening comprises a first border which extends in the longitudinal direction of the heat-exchange bundle over a first distance, and a second border which extends in the longitudinal direction of the heat-exchange bundle over a second distance, the second distance being strictly shorter or also strictly longer than the first distance.

During the operation of the heat exchanger, when the second fluid is circulating in the chamber of the collector in a direction of circulation going from the second border of the opening towards the first border of the opening, it is understood that the flow rate of the second fluid in the chamber is greater at the second border than at the first border, with part of the second fluid having already passed through the opening. Thus, advantageously, the longitudinal distance along which the opening extends can be inversely proportional to the flow rate of the second fluid in the chamber of the collector.

Advantage is derived from this characteristic in that it makes it possible to homogenize he distribution of the second fluid in the receptacle of the heat-exchange bundle, and thus to optimize the heat exchanges between the first fluid and the second fluid.

According to a characteristic of the invention, at least one rib extends into the opening. A rib of this type is provided by the material of the peripheral wall of the heat-exchange bundle.

More specifically, the at least one rib extends in the opening in the longitudinal direction of the heat-exchange bundle.

According to a characteristic of the invention, the at least one rib is provided in line with at least one of the tubes of the plurality of tubes of the heat-exchange bundle.

The rib then has the function of protecting the tube during operation of the heat exchanger, in particular during the distribution of the second fluid from the collector to the receptacle of said heat-exchange bundle, as well as protecting it against thermal shocks. Advantageously, there are as many ribs provided in the opening as there are tubes in the heat-exchange bundle. There can therefore be a plurality of tubes and ribs.

According to a characteristic of the invention, a section of the rib has a form complementary to a portion of the tube

Advantage is derived from a characteristic of this type in that it reinforces the retention of the tube in the receptacle of the heat-exchange bundle, in particular during the passage of the second fluid through the opening. The tube is thus wedged by the rib.

According to a characteristic of the invention, the peripheral edge and the peripheral wall are rendered integral with one another by brazing. Rendering integral of this type of the peripheral edge on the peripheral wall ensures optimal sealing between the collector and the heat-exchange bundle. This therefore increases the service life of the heat exchanger by doubling increasing the thickness of wall in a location of the heat exchanger which is subjected to substantial stresses.

According to a characteristic of the heat exchanger, the heat-exchange bundle comprises a first longitudinal end and a second longitudinal end which are opposite one another in the longitudinal direction of the heat-exchange bundle, the input box being positioned at the first longitudinal end and the output box being positioned at the second longitudinal end, the heat-exchange bundle also comprising a first opening which is provided in a first longitudinal wall of the peripheral wall, and a second opening which is provided on a second longitudinal wall of the peripheral wall, a first collector being positioned such as to cover the first opening and a second collector being positioned such as to cover the second opening.

It should be considered that the first opening, the second opening, the first collector and the second collector are all in conformity with the invention as described above.

Each of the first collector and the second collector is thus connected to a circulation duct allowing one to distribute the second fluid and the other to discharge the second fluid, each from their chamber. It is thus understood that the second fluid is initially distributed in the chamber of the first collector by its circulation duct, and then passes through the first opening in order to circulate in the receptacle defined by the peripheral wall of the heat-exchange bundle, and then passes through the second opening, in order to be discharged from the chamber of the second collector by means of its circulation duct. This therefore permits the calorific exchanges between the first fluid circulating in the plurality of tubes, and the second fluid circulating around the tubes, between the first collector and the second collector.

It will be noted that the first fluid is a gaseous mixture, whereas the second fluid is a heat-bearing liquid, for example a glycoled water.

The characteristics, variants and different embodiments of the invention may be associated with one another, in various combinations, as long as they are not mutually incompatible or mutually exclusive. It will be possible, in particular, to conceive of variants of the invention that comprise only a selection of the characteristics described below, in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to distinguish the invention from the prior art.

In the figures, elements common to several figures keep the same reference sign.

FIG.1illustrates a heat exchanger1according to the invention. The heat exchanger1, for example a charge air cooler, is composed of at least one heat-exchange bundle2, an input box4, an output box6, and at least one collector8.

The heat-exchange bundle2extends in a main direction of extension, or longitudinal direction L, and comprises at least one peripheral wall10and a plurality of tubes12. The peripheral wall10is in the form of a quadrilateral defined by two longitudinal walls14and two lateral walls16. More specifically, the peripheral wall10comprises a first lateral wall16aand a second lateral wall16bwhich extend parallel to one another and opposite one another in a transverse direction T which is perpendicular to the longitudinal direction L of the heat-exchange bundle2, and a first longitudinal wall14aand a second longitudinal wall14bwhich extend parallel to one another and opposite one another in a vertical direction V perpendicular to the longitudinal direction L and transverse direction T of the heat-exchange bundle2, such that they connect the lateral walls16.

The peripheral wall10of the heat-exchange bundle2defines a receptacle18in which the plurality of tubes12extends. More specifically, the receptacle18is defined by an inner face20of the peripheral wall10, and an outer face22, opposite the inner face20of the peripheral wall10, and corresponds to the face of the peripheral wall10which faces opposite the space occupied by the heat-exchange bundle2.

The tubes12extend in the receptacle18of the heat-exchange bundle2in the longitudinal direction L thereof. More specifically, the tubes12of the plurality of tubes extend between a first longitudinal end24of the heat-exchange bundle2and a second longitudinal end26of the heat-exchange bundle2, opposite the first longitudinal end24in the longitudinal direction L of the heat-exchange bundle2. As can be seen partly inFIG.1, the plurality of tubes12is arranged in the receptacle18in rows of tubes12in the transverse direction T of the heat-exchange bundle2, while being spaced from one another, such that a space28is provided between each of the tubes12of the plurality of tubes12. The tubes12of the plurality of tubes12are tubes which are rolled or obtained from rendering two plates integral.

The input box4is positioned at the first longitudinal end24of the heat-exchange bundle2, whereas the output box6is positioned at the second longitudinal end26of the heat-exchange bundle2. The input box4and the output box6are thus each connected to one end of each of the tubes12of the plurality of tubes12, respectively at the first longitudinal end24and the second longitudinal end26of the heat-exchange bundle2. In other words, the plurality of tubes12is in fluid communication with the input box4and the output box6.

The input box4thus has the function of directing a first fluid towards the heat-exchange bundle2, and in particular in the plurality of tubes12. It is thus understood that the first fluid, for example a flow of charge air of an internal combustion engine, circulates between the input box4and the output box6, passing through each of the tubes12of the plurality of tubes12of the heat-exchange bundle2.

In the receptacle18, and more specifically in the space28provided between the tubes12, a second fluid circulates. The second fluid can in particular be a heat-bearing fluid designed to exchange calories with the first fluid which circulates in the plurality of tubes12. A first collector8aand a second collector8bare thus positioned respectively on the first longitudinal wall14aand the second longitudinal part14bof the peripheral wall10of the heat-exchange bundle2. More specifically, the first collector8aand the second collector8bare positioned such as to cover a first opening30aand a second opening30bshown inFIGS.2and4, in contact with the peripheral wall10. The openings30aand30bare wedging areas between the tubes12and the collectors8aand8b. These are areas of high mechanical stresses, in particular as far as thermal shock is concerned.

Hereinafter in the description, only the characteristics of the first collector8aand the first opening30awill be described in detail, but it is understood that these characteristics can apply mutatis mutandis to the second collector8band the second opening30b. Thus, hereinafter in the description, the first collector8aand the second collector8bwill be grouped together under the term “collector8”, when the characteristics apply to one or the other of the first collector8aand the second collector8b. Similarly, the first opening30aand the second opening30bwill be grouped together under the term “opening30”, when the characteristics apply to one or the other of the first opening30aor the second opening30b.FIG.2illustrates the opening30provided in one of the longitudinal walls14of the peripheral wall10of the heat-exchange bundle2. It is understood that the opening30is a through-opening, i.e. it is open in the receptacle18of the heat-exchange bundle2.

According to the invention, the opening30extends transversely in the longitudinal wall14of the peripheral wall10, relative to the plurality of tubes12which extend longitudinally in the receptacle18of the heat-exchange bundle2. In other words, the opening30extends in the longitudinal wall14of the peripheral wall10, perpendicularly to the plurality of tubes12.

As previously described, the plurality of tubes12is arranged in series and transversely in the receptacle18, and it is thus understood that, advantageously, the opening30extends transversely, such that it is facing each of the tubes12of the plurality of tubes12. Thus, homogeneous irrigation of the second fluid is ensured in the receptacle18, and more particularly in the space28formed between each of the tubes12.

The opening30is delimited by borders32of the longitudinal wall14. More specifically, a first border32aand a second border32bboth extend in the longitudinal direction L of the heat-exchange bundle2, whereas a third border32cand a fourth border32dextend in the transverse direction T of the heat exchanger2, and such that they connect the first border32aand the second border32b. A first distance D1is defined as the distance taken in the longitudinal direction L of the heat-exchange bundle2over which the first border32aextends, and a second distance D2is defined as the distance taken in the longitudinal direction L of the heat-exchange bundle2over which the second border32bextends. According to the first embodiment of the opening30, the first distance D1is equal to the second distance D2.

According to a characteristic of the invention, at least one rib34extends in the opening30. According to the example illustrated of the invention, a plurality of ribs34extends in the opening30in the longitudinal direction L of the heat-exchange bundle2. It is thus understood that each of the ribs34extends in the opening30, between the third border32cand the fourth border32dof said opening30. The rib(s)34is/are portions of the peripheral wall10, and form(s) strips which pass through the opening from one longitudinal edge to the other.

Each of the ribs34of the plurality of ribs34is thus spaced from an adjacent rib34, such that the particular arrangement of the ribs34in the opening30forms slots36. It is thus understood that the second fluid passes through the opening30at the slots36provided therein by the plurality of ribs34.

According to a characteristic of the invention, which can be seen in particular inFIG.3, showing a view in cross-section of the opening30according to a first vertical plane A-A shown inFIG.2, at least one rib34extends in the opening30, in line with one of the tubes12of the plurality of tubes12. In the example illustrated, each of the ribs34of the plurality of ribs34extends in line with one of the tubes12of the plurality of tubes12. The rib34athus has the function of protecting the tube12during use of the heat exchanger2, i.e. during circulation of the first fluid and in particular of the second fluid. It is thus understood that, advantageously, there are as many ribs34provided in the opening30as there are tubes12which extend in the receptacle18of the heat-exchange bundle2.

Again according to the invention, at least one section of rib34has a form which is complementary to a portion of one of the tubes12of the plurality of tubes12. In other words, the rib34is provided such that it can cooperate with a portion of the tube12. This therefore guarantees that the rib34remains in line with the tube12during use of the heat exchanger2, i.e. during the passage of the second fluid in the opening30.

According to a second embodiment of the opening30shown inFIG.4, the second distance D2of the second border32bis strictly shorter than the first distance D1of the first border32a. It is thus understood that the opening30provided in the longitudinal wall14extends from the first border32b, such that the third border32cand the fourth border32dare increasingly distant from one another as the first border32aapproaches the opening30. Thus, each of the ribs34provided in the opening30extends in the longitudinal direction L of the heat-exchange bundle2, over an increasing distance, as it approaches the first border32aof the opening30.

Advantage is derived from this characteristic during use of the heat exchanger, when the input of the second fluid into the receptacle18takes place at the second border32bof the opening30. In fact, it is understood that, during the distribution of the second fluid into the receptacle18, the flow rate of the second fluid in the chamber38of the collector8is greater at the second border32bcompared with the flow rate of the second fluid when it reaches the first border32a, with part of the fluid already having passed through the opening30. It is thus understood that the longitudinal distance over which the opening30extends is in inverse proportion to the flow rate of the second fluid in the chamber38of the collector8.

Thus, the enlargement of the opening30going from the second border32bto the first border32ahas the effect of distributing the second fluid better in the receptacle18of the heat-exchange bundle2, by decreasing the volume of a chamber38delimited by the collector8where the flow rate of the second fluid is greater, and by enlarging the volume of the chamber38of the collector8where the flow rate of the second fluid is lesser.

The collector8will now be described in cooperation withFIGS.1,5and6, withFIG.6illustrating a view in cross-section of the heat-exchange bundle2at the opening30, according to a second vertical plane B-B shown inFIG.5.

The collector8according to the invention comprises at least one chamber38and a peripheral edge40, and is positioned such as to cover the opening30previously described. The collector8thus has the function of distributing second fluid to receptacle18of the heat-exchange bundle2or discharging it therefrom. This therefore defines an input end42and an output end44of the collector8, opposite one another on the collector8, in the transverse direction T of the heat-exchange bundle2.

According to the example illustrated and shown inFIG.6, an input orifice46is provided at the first end42of the collector8, and a circulation duct48is rendered integral around the input orifice46. It is thus understood that the collector8and the circulation duct48are in fluid communication with one another.

Alternatively, an output orifice can be provided at the second end44of the collector8, in order for the circulation duct48to be rendered integral around said output orifice.

The chamber38of the collector8is delimited by a chamber wall50which has a curved form, and provides the chamber38with a cross-section with a concave form. The peripheral edge40thus extends from a free edge52of the chamber wall50, and such that the peripheral edge40surrounds a window54of the chamber38of the collector8. “Window”54means the fact that this opens the collector8onto an exterior volume, to the volume defined by the chamber38of said collector8.

According to the invention, the collector8is positioned such as to cover the opening30, so that the window54of the chamber38is in line with the opening30, and the peripheral edge40comes into contact with a part of the outer face22of the peripheral wall10of the heat-exchange bundle2. In other words, the window54is positioned facing the opening30, such that the chamber38and the receptacle18are in fluid communication with one another.

More specifically, an axis of alignment X1, shown inFIG.5is defined, on which the chamber38of the collector8and the opening30are aligned. A width of window L1is defined as the width of the window54taken along a straight line perpendicular to the axis of alignment X1and parallel to the longitudinal direction L of the heat-exchange bundle2, and a width of the opening L2is defined as the width of the opening30taken along a line perpendicular to the axis of alignment X1and parallel to the longitudinal direction L of the heat-exchange bundle2. The width of the window L1is thus strictly greater than the width of the opening L2. It is thus understood that the peripheral edge40does not extend facing the opening30provided in the peripheral wall10. In other words, during the operation of the heat exchanger, the peripheral edge40of the collector8is not in interaction with the second fluid circulating between the collector8and the receptacle18.

The peripheral edge10extends parallel to the longitudinal wall14of the peripheral wall10, such that it is in continuous contact therewith. This therefore ensures continuous sealing between the peripheral edge40and the peripheral wall10, and leakages of the second fluid from the collector8and the receptacle18are avoided. According to a non-limiting example of the invention, the peripheral edge40and the peripheral wall10are brazed to one another, such that securing and optimal sealing of the peripheral edge40with the peripheral wall10is ensured.

As can be seen in particular inFIG.1, the chamber38of the collector8has a plane of symmetry S. This therefore defines a first height H1of the collector8taken at the first end42of the collector8along the plane of symmetry S, and a second height H2of the collector8taken at the second end44of the collector8. According to the invention, the first height H1is greater than the second height H2.

Advantage is derived from a characteristic of this type, in that it makes it possible to direct the second fluid and concentrate it at the second end44of the collector8. More specifically, when the second fluid enters the chamber38of the collector8via the circulation duct48provided at the first end42, it is understood that its flow rate is greater at the first end42than at the second end44of the collector8. Thus, by reducing progressively the height of the collector8and thus of the chamber38from the first end42to the second end44, the volume of the chamber38is reduced, and a constant flow rate of second fluid is thus maintained in the entire said chamber38. This therefore permits homogeneous distribution of the second fluid in all of the receptacle18of the heat-exchange bundle2.

As previously described, the first opening30ais provided in the first longitudinal wall14a, and the second opening30bis provided in the second longitudinal wall14bof the peripheral wall10. More specifically, the first opening30ais provided at the first longitudinal end24, and the second opening30bis provided at the second longitudinal end26of the heat-exchange bundle2. The first collector30ais thus defined as the input collector of the second fluid in the heat-exchange bundle2, and the second collector30bis defined as the output collector of the second fluid from the heat-exchange bundle2.

When the heat exchanger1is functioning, the second fluid reaches the chamber38of the input collector30aby means of the circulation duct48, it then passes through the first opening30a, facing which the window54of the chamber38of the input collector30ais positioned, it then passes through the receptacle18, and in particular the space28provided between each of the tubes12, in order then to be collected in the chamber38of the output collector30b, and be discharged from the heat exchanger1by means of the circulation duct48of the output collector30b.

It is thus understood that the circulation of the second fluid as has just been described allows the fluid to exchange calories with the first fluid which circulates between the input box4and the output box6, in the plurality of tubes12of the heat-exchange bundle2.

The invention achieves well the objective which had been set out for it, by conceiving of a simple means for reducing the problems of breakages between the collector and the heat-exchange bundle, by proposing a collector which is added onto the heat-exchange bundle, comprising a peripheral edge which is rendered integral with said heat-exchange bundle.

However, the invention should not be limited to the means and configurations exclusively described and illustrated, and it also applies to all equivalent means or configurations, and to any combination of such means or configurations.