HEAT EXCHANGER, IN PARTICULAR OIL COOLER

Abstract

The present invention provides a heat exchanger including a flow duct for a coolant and a flow duct for a medium to be cooled, a cover on one side of the heat exchanger, and a thermostat valve operable to regulate temperature-dependent throughflow in one of the flow ducts, arranged on an inflow or outflow duct, and covered by the cover. A temperature sensor of the valve is arranged in a housing, which is fastened in proximity to the inflow or outflow duct so that one of the medium to be cooled and the coolant can flow around an outer side of the housing, with the temperature sensor on an inner side of the housing reacting to a local temperature and correspondingly regulating throughput of an other of the medium to be cooled and the coolant through the heat exchanger.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Priority is hereby claimed to German Patent Application No. DE 10 2007 010 393.1, filed Mar. 3, 2007, the entire contents of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a heat exchanger, such as an oil cooler.

SUMMARY

EP 0916816 B1 discloses a heat exchanger having several advantages. In the heat exchanger, a dome in the form of a cover, which, for example, serves for the introduction and distribution of the coolant, is situated on one side. The heat exchanger is provided with a thermostat valve whose temperature sensor extends into one of the inflow or outflow ducts, in particular into inflow or outflow ducts which conduct the medium to be cooled, in particular oil. The valve element which is controlled by the temperature sensor and which controls the throughflow with coolant is seated in the region of the coolant space closed off by the cover. The coolant space is sealed off by means of seals with respect to the one inflow or outflow duct for the other medium, with the seals being arranged between the thermostat valve and a holding connecting pipe for the latter. Such required seals are disadvantageous. They not only complicate the installation of the thermostat valve but can also be sources of faults, can degrade in terms of their sealing action or can lose the sealing action altogether. There is then the risk of the coolant being mixed with the other medium, which is to be cooled. This results in damage, in particular when using the heat exchanger in connection with internal combustion engines, in particular of vehicles.

The present invention provides a heat exchanger, in particular an oil cooler, of the abovementioned type, in which seals of the type mentioned in the introduction can be dispensed with and the associated susceptibility to faults is eliminated.

The heat exchanger of the present invention can include a temperature sensor of the thermostat valve that is not in direct contact with the medium to be cooled, and nevertheless can measure the temperature of the medium to be cooled by means of the housing which acts as a heat exchanger element, and as a function thereof, can control the throughflow of the other medium, in particular coolant, with the coolant being reliably separated from the medium to be cooled, in particular oil, without the need for seals. The heat exchanger also has the advantage of a very compact design. On account of seals not being necessary, costs are reduced. In addition, the thermostat valve can be easily and simply assembled. The compact installation height of the heat exchanger does not have an adverse effect.

Further details and advantages of the invention and embodiments of the heat exchanger can be gathered from the following description, claims, and figures.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic, partially sectioned side view of a part of a heat exchanger with a section in the region of an inflow or outflow duct for a coolant, as per a first exemplary embodiment.

FIG. 2 shows a section, similar to FIG. 1, of a part of a heat exchanger as per a second exemplary embodiment.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

The drawings show, as an example for a heat exchanger 1, a heat exchanger, in particular in the design of an oil cooler, which is embodied for example as a housingless plate-type heat exchanger which has individual heat exchanger plates 2 and 3 which are placed one above the other, run horizontally, are joined together and form separate horizontal flow ducts 10 and 11 which are delimited from one another. The flow ducts 10 are, for example, traversed by a coolant, in particular cooling water. The flow ducts 11 are provided for the other medium, for example oil, which is to be cooled. The relationships can however also be interchanged.

At the top and at the bottom in the drawings, the heat exchanger is closed off, for example, by a cover plate or base plate 18 or the like. The heat exchanger 1 has inflow or outflow ducts which are connected to the flow ducts 10, 11 and of which, in the drawings, only the inflow or outflow ducts 9, 13 are visible on account of the local illustration, with it being possible for the visible duct to serve either for the inflow or the outflow of the coolant, in particular cooling water. The inflow and outflow ducts 9, 13 extend through the plate stack and are connected to the horizontal flow ducts 10 for the coolant. In a corresponding way, the inflow and outflow ducts (not shown) for the other medium, in particular oil, also extend through the plate stack, with said ducts which serve for the inlet and outlet of oil being connected to the horizontal flow ducts 11. The flow ducts 10 and 11 are arranged in an alternating manner with one above the other.

Arranged in the region of the upper cover plate 18 is a connecting pipe 21 which can for example serve as an inlet for the coolant and which is, for example, assigned to the inflow duct 9. On account of the diagrammatic illustration, the outflow duct 13 for the coolant is not visible, nor its outlet connecting pipe.

With regard to the basic design, the heat exchanger I corresponds approximately to a design as can be seen from EP0916816 B1. In order to avoid unnecessary repetitions, reference is made to said disclosure, even to the extent that the heat exchanger can also be designed, instead of the housingless design shown, for example, in such a way that the heat exchanger is surrounded by a housing which for example contains inflow or outflow ducts for the coolant, while flow ducts 11 for the medium, in particular oil, which is to be cooled are contained in the interior of the housing. Heat exchangers of said type with an inner plate stack and an outer housing are also encompassed by the invention and can be gathered for example from the above-stated publication.

The heat exchanger 1 which is embodied, for example, as an oil cooler has, on the lower side in the drawing, a cover 4 which, in the example as per FIG. 1, is formed from an approximately pot-shaped or substantially convex dome 5. A thermostat valve 6 in the form of a regulating valve is also provided, which thermostat valve 6 is arranged at the inflow or outflow duct 9, 13 which is covered by the cover 4, for example, with the dome 5. The temperature-dependent flow through the heat exchanger in one of the flow ducts 10, 11 can be regulated by means of said thermostat valve 6. For example, the flow through the flow ducts 10 which conduct the coolant can be regulated in a temperature-dependent fashion, specifically as a function of the temperature of the other medium, in particular oil.

Arranged at the lower region of the heat exchanger 1 in the drawings is a housing 40 which is embodied as a heat exchanger element. The housing 40 is, for example, of pot-shaped design and is in direct contact with a facing plate, for example the base plate 18, of the heat exchanger 1 to which the housing 40 is fixedly and sealingly fastened, for example, by soldering, welding or the like. Here, the housing 40 overlaps the inflow or outflow duct 9, 13. A medium, in particular oil, can flow around the outside 41 of the housing 40, which medium is situated in the space 42 which is delimited by the cover 4, for example as per FIG. 1 with a dome 5, and the plate 18. The housing 40 can be formed from aluminum or copper, brass or the like.

The thermostat valve 6 is arranged in the lower region of the inflow or outflow duct 9, 13, and in such a way here that its temperature sensor 31 is situated within the housing 40 and, in this case on the inner side 43 of the housing 40, reacts to the local temperature which corresponds substantially or quite precisely to that of the one medium, in particular oil, and on account thereof, correspondingly regulates the throughput of the other medium, in particular coolant, through the heat exchanger 1. On account of this arrangement, the thermostat valve 6 is not in contact with the medium to be cooled, in particular oil, as a result of which there is no requirement for special seals for the medium to be cooled, in particular oil. The housing 40 which is embodied as a heat exchanger element conducts the temperature of the medium to be cooled, in particular oil, which is situated on the outer side to the inner side 43 and there, to the temperature sensor 31 of the thermostat valve 6.

The temperature sensor 31 of the thermostat valve 6 can be in direct heat-exchanging contact with the inner side 43 of the housing 40. In this case, the temperature of the medium to be cooled, in particular oil, in the space 42 is transmitted to the temperature sensor 31 by means of thermal conduction.

Instead or in addition, an intermediate space 44 can be formed between the temperature sensor 31 of the thermostat valve 6 and the inner side 43 of the housing 40. The intermediate space 42 can be connected to the inflow or outflow duct 9, 13 or, without a connection thereto, can be filled with the coolant or a heat transfer medium.

The housing 40 and/or the temperature sensor 31 of the thermostat valve 6 can be provided with elements 45, 46, for example in the form of projections, fins or the like, which enlarge the thermal contact face of the housing 40 or temperature sensor 31. In the case of the housing 40, said elements 45 can be provided on its inner side 43 and/or outer side 41. In this way, the thermal conduction from the medium to be cooled in the space 42 to the temperature sensor 31 is further improved.

As is for example known from EP 0916816 B1, the thermostat valve 6, in the case of the temperature sensor 31 being for example designed as an expansion element thermostat in the interior of the housing, has an expansion material which, in the event of a temperature increase, expands in terms of its volume and, in the event of a temperature reduction, contracts again so as to reduce in volume. Inserted into the interior of the housing and of the expansion material contained therein is an actuating element in the form of a piston 26 which projects out of the housing and, in the event of a temperature increase, is pushed out of the housing of the temperature sensor 31. The piston 26 is connected to a coaxial rod 32 which actuates a valve element 27, for example, in the form of a valve plate. The valve element 27, which can be actuated by the thermostat valve 6 and the passage 28 which is controlled by said valve element 27, are arranged in the interior of the inflow or outflow duct 9, 13 for the coolant. The housing 40 and the temperature sensor 31 of the thermostat valve 6 are situated on the opposite side of the heat exchanger 1 from the valve element 27. The thermostat valve 6 is held in the closed position illustrated in the drawing by means of a pressure spring 29 which acts on the valve element 27, and can be moved into an open position in the event of the temperature sensor 31 being heated when the other medium, in particular oil, in the space 42 has reached a corresponding temperature limit. This occurs in that the piston 26 is pushed out in the upward direction in the drawing, and as a result, the rod 32 with the valve element 27 is moved upward in the drawing counter to the action of the pressure spring 29 and so as to open the passage 28, so that a medium, in particular coolant, can flow into the inflow duct 9 or out of the outflow duct 13 and therefore the medium to be cooled which is conducted in the flow ducts 11 can be cooled by the coolant in the flow ducts 10. If the temperature of the medium to be cooled falls below the response threshold of the temperature sensor 31 of the thermostat valve 6, the expansion material in the housing of the part 31 contracts so as to reduce in volume to such an extent that the pressure spring 29 can move the valve element 27 with the rod 32 and the piston 26 in the downward direction in the drawing into the starting position and therefore into the closed position.

In the case of an intermediate space 44 being formed between the inner side 43 and the temperature sensor 31, said intermediate space 44 can be connected to the inflow or outflow duct 9, 13 for the coolant by means of small openings 47 which have only a small passage cross section.

The described design of the heat exchanger has the advantage of a compact and simple design. It is possible to control the flow through the heat exchanger for example with coolant as a function of the temperature of the other medium, for example oil, which is to be cooled, by means of a commercially available thermostat valve 6. Here, the thermostat valve 6 is not in contact with the medium to be cooled, for example oil. Any seals or sealing materials are therefore not necessary. The temperature-dependent regulation is possible on account of the housing 40 which is formed as a heat exchanger and which separates the two media, that is to say the medium to be cooled, in particular oil, on the one hand and the coolant, in particular cooling water, on the other hand from one another without the requirement for seals. The temperature sensor 31 can be in direct heat-exchanging contact with the housing 40, with the elements 45, 46 increasing the heat conduction from the medium, for example oil, situated in the space 42 to the temperature sensor 31. It is likewise possible to provide an intermediate space 44 for increasing the thermal conduction, which intermediate space 44 is filled for example with a heat-exchanging medium or with coolant or is fed with coolant via openings 47. Also advantageous is the simple design of the heat exchanger, which can in this way be of particularly compact design. The thermostat valve 6 can be inserted in a particularly simple manner into the heat exchanger 1.

While, in the first exemplary embodiment as per FIG. 1, the cover 4 has an approximately cap-shaped dome 5 into which the housing 40 and the temperature sensor 31 contained therein project at least predominantly, so that the one medium, for example oil, which is situated in the intermediate space 42 between the dome 5 and the housing 40, can flow around the housing 40 at the outer side 41 of the latter, in the second exemplary embodiment as per FIG. 2, the cover 4 which is provided on one side of the heat exchanger is formed from a planar closure plate 7 which, together with the plate 18 which runs at a distance therefrom and holds the housing 40, delimits a space 53 which conducts the medium to be cooled, for example oil. The cover 4, specifically either with a dome 5 corresponding to FIG. 1 or as a planar closure plate 7 as per FIG. 2, can be an integral component of an end plate of the heat exchanger 1. Depending on the design, the housing 40 can likewise be an integral component of a plate 18, in particular of the final plate in the stack, of the heat exchanger.

In the second exemplary embodiment as per FIG. 2, the housing 40 and the temperature sensor 31, which is contained therein, of the thermostat valve 6 are contained, with the entire axial length, in the inflow or outflow duct 9, 13 for the coolant. The temperature sensor 31 of the thermostat valve 6 is held completely by the housing 40. The housing 40 and the temperature sensor 31 are therefore, as per FIG. 2, plunged axially further into the inflow or outflow duct 9, 13, specifically as far as possible as per FIG. 2. The housing 40 extends, with its end-side base 48, approximately within the plane of a plate 18 of the heat exchanger 1, for example, the final plate in the stack.

In contrast to FIG. 1, in the illustrated embodiment of FIG. 2, the housing 40 is of double-walled design, in such a way that said housing 40 is surrounded, at a distance from its outer side 41, by a casing 49 which adjoins the housing 40 at the side 52 which faces away from and is situated opposite the base 48. The casing 49 extends from there approximately to the base 48 so as to form an outer annular space 50 which is closed off with respect to the coolant and is open in the direction of the space 53 which conducts the medium to be cooled, for example oil.

The casing 49 is designed for the fastening of the housing 40 to the plate 18 of the heat exchanger. For this purpose, the casing 49 has a flange 51 at its free end which points downward in FIG. 2, by means of which flange 51 the housing 40 is fastened, similarly to the first exemplary embodiment as per FIG. 1, to the plate 18, for example the final plate in the stack, of the heat exchanger 1. The housing 40 forms an integral component with the casing 49. Otherwise, the same applies, corresponding to the above description for the first exemplary embodiment as per FIG. 1, for the second exemplary embodiment as per FIG. 2. Since, in the second exemplary embodiment, the cover 4 is embodied as a planar closure plate 7 and no dome 5 is provided, the installation height of the heat exchanger 1 is yet further reduced, which heat exchanger is yet more compact as a result, with the overall package situation during installation for example in a motor vehicle being yet more favorable for said reasons. Further simplifications, in particular savings, are given when the cover 4, in the design as per FIG. 1 or FIG. 2, is an integral component of an end plate, for example a closure plate, of the heat exchanger 1. Further corresponding advantages are given if the housing 40 is an integral constituent of a plate 18, in particular the final plate in the stack, of the heat exchanger 1.

In another exemplary embodiment which is not shown, the housing 40 and an inflow duct 9 or outflow duct 13 for the coolant form an integral component. Here, the arrangement can be designed such that said integral component is arranged close to or in the axial direction of an inflow or outflow duct for the medium to be cooled, in particular oil, and is connected by means of a duct to the coolant which is conducted in the heat exchanger 1. An integral component of said type is compact, with the installation of said component not enlarging the installation height of the heat exchanger and not having any adverse effect thereon. In the region of the valve element 27 and of the associated valve seat in the passage 28, it is possible to increase the throughput, generated when the valve element 27 is in the open position of the thermostat valve 6, of the coolant through the passage 28, and to reduce any pressure loss, in a conventional manner using structural means.

Various features and advantages of the invention are set forth in the following claims.

Claims

1. A heat exchanger, in particular oil cooler, comprising: a flow duct for a coolant and a flow duct for a medium to be cooled, the flow ducts being separated from one another and being penetrated by inflow and outflow ducts;a cover on one side of the heat exchanger; anda thermostat valve operable to regulate temperature-dependent throughflow in one of the flow ducts, arranged on an inflow or outflow duct, and covered by the cover;wherein a temperature sensor of the thermostat valve is arranged in a housing, which is fastened in proximity to the inflow or outflow duct in such a way that one of the medium to be cooled and the coolant can flow around an outer side of the housing, with the temperature sensor of the thermostat valve on an inner side of the housing reacting to a local temperature and correspondingly regulating throughput of an other of the medium to be cooled and the coolant through the heat exchanger.

2. The heat exchanger according to claim 1, wherein the temperature sensor of the thermostat valve is in direct heat-exchanging contact with the inner side of the housing.

3. The heat exchanger according to claim 1, wherein an intermediate space is formed between the temperature sensor of the thermostat valve and the inner side of the housing.

4. The heat exchanger according to claim 3, wherein the intermediate space is at least partially filled with the coolant.

5. The heat exchanger according to claim 1, wherein the housing is provided with elements which enlarge its thermal contact faces on inner and/or outer sides.

6. The heat exchanger according to claim 1, wherein the temperature sensor of the thermostat valve is provided with elements which enlarge its thermal contact face.

7. The heat exchanger according to claim 5, wherein the elements are formed by projections, in particular fins.

8. The heat exchanger according to claim 6, wherein the elements are formed by projections, in particular fins.

9. The heat exchanger according to claim 1, wherein the valve element and a passage controlled by the valve element are arranged in an interior of the inflow or outflow duct for the coolant.

10. The heat exchanger according to claim 1, wherein the housing and the temperature sensor of the thermostat valve are arranged on a side of the heat exchanger opposite from the valve element.

11. The heat exchanger according to claim 1, wherein a piston of the thermostat valve is connected by a rod to the valve element.

12. The heat exchanger according to claim 1, wherein the thermostat valve is maintained in a closed position by an elastic element, and in the event of the temperature sensor being heated, can be moved by the medium being cooled into an opening position.

13. The heat exchanger according to claim 1, wherein the housing is of an approximately pot-shaped design.

14. The heat exchanger according to claim 1, wherein the housing is a heat exchanger element and is formed from a material having relatively high thermal conductance.

15. The heat exchanger according claim 1, wherein the housing is in contact with a facing plate of the heat exchanger and is fixedly and sealingly fastened thereto.

16. The heat exchanger according to claim 3, wherein the intermediate space is connected to the inflow or outflow duct for the coolant by openings which have a small passage cross section.

17. The heat exchanger according to claim 1, wherein the cover is provided on one side of the heat exchanger and is formed from an approximately pot-shaped dome, wherein the housing and the temperature sensor project into the dome, and wherein the medium to be cooled is situated in an intermediate space between the dome and the housing and can flow around the housing along an outer side of the housing.

18. The heat exchanger according to claim 1, wherein the temperature sensor of the thermostat valve is held in its entirety by the housing.

19. The heat exchanger according to claim 1, wherein the temperature sensor of the thermostat valve is contained, with an entire axial length, in the inflow or outflow duct for the coolant.

20. The heat exchanger according to claim 19, wherein the housing extends with an end-side base approximately within a plane of a plate of the heat exchanger.

21. The heat exchanger according to claim 20, wherein the housing is surrounded, at a distance from the outer side, by a casing which adjoins the housing at a side situated opposite the base of the housing and which extends from there approximately to the base so as to form an outer annular space which is closed off with respect to the coolant and is open in the direction of a space which conducts the medium to be cooled.

22. The heat exchanger according to claim 21, wherein the casing is designed for the fastening of the housing to a plate of the heat exchanger.

23. The heat exchanger according to claim 22, wherein the casing has a flange at a free end, and is fastened by the flange to a plate of the heat exchanger.

24. The heat exchanger according to claim 21, wherein the housing forms an integral component with the casing.

25. The heat exchanger according to claim 23, wherein the cover which is provided on one side of the heat exchanger is formed from a planar closure plate which, together with the plate which runs at a distance therefrom and holds the plate, delimits a space which conducts the medium to be cooled.

26. The heat exchanger according to claim 1, wherein the cover is an integral component of an end plate of the heat exchanger.

27. The heat exchanger according to claim 1, wherein the housing is an integral component of a final plate in the stack of the heat exchanger.

28. The heat exchanger according to claim 1, wherein the housing and an inflow or outflow duct for the coolant form an integral component.

29. The heat exchanger according to claim 28, wherein the integral component is arranged close to or in the axial direction of the inflow or outflow duct for the medium to be cooled.