US20150247678A1

US20150247678A1 - Heat exchanger with integrated flexible baffle

Info

Publication number: US20150247678A1
Application number: US14/195,035
Authority: US
Inventors: Daniel Tylutki; Saurabh Desai
Original assignee: Denso International America Inc
Current assignee: Denso International America Inc
Priority date: 2014-03-03
Filing date: 2014-03-03
Publication date: 2015-09-03

Abstract

A heat exchanger of the type having a tube assembly made up of a number of tubes through which a first medium flows and around and between which a second medium flows to accept heat from, or transfer heat to, the first medium. The first media is constrained by a baffle to follow a path through the heat exchanger. According to the disclosure, the baffle is flexible and acts as a flapper valve permitting the baffle to allow bypass flow of the first media to bypass the tube assembly of the heat exchanger. The baffle self-adjusts based on a pressure balance of the first medium, with the result that heat exchangers according to the invention are more versatile than conventional heat exchangers where the baffles are fixed to the tubes.

Description

FIELD

This present invention relates to the field of automotive heat exchangers, more specifically this invention relates to an oil cooler with an integrated flexible baffle.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.
In automotive vehicles, it is common to have a series of different heat exchangers transferring heat to or from a variety of liquids or gases. A typical vehicle may contain a heat exchanger to cool a fluid that is used to cool an engine. Charge air coolers are used to cool the air that is being compressed before leading into the intake of an engine. Additionally heat exchangers may be used to cool oil that lubricates the internal components of the engine; transmission fluid may also flow through a heat exchanger to maintain the transmission at an optimum temperature. Current heat exchangers utilize a multi-pass circuitry for enhanced heat transfer. A drawback of multi-pass heat exchangers is the increase in pressure drop. This increase in pressure drop may become a larger issue as the fluid is colder and the viscosity increases, this is most common during engine startup in a cold ambient environment when the cooling fluid is at its coldest. This can lead to many issues including plumbing and heat exchanger damage from the excessive pressure which ultimately could lead to system failure.
Typical construction of multi-pass heat exchangers generally have an inlet and an outlet on one of the heat exchanger tanks and a fixed baffle that separates the warm medium to be cooled from the cool medium exiting the heat exchanger tank. The baffle is fixed so that the medium entering the inlet passes through a fixed number of tubes and the medium exiting has passed through a fixed number of tubes. As previously stated this construction may be an issue for a cold oil application due to the increase in viscosity. As the cold oil enters into the volume of the tank it builds up pressure within the tank as the thick cold oil tries to enter into the small diameter tubes. This increases the back pressure in the inlet tank and the plumbing lines leading to the heat exchanger.
A current solution is to install a bypass system. This system would allow the medium, during certain conditions, to bypass the heat exchanger entirely until the correct conditions are met. Such systems add complex components like control modules with sensors to regulate the system driving up overall costs and difficulty in implementation. Other similar bypass solutions add additional plumbing connected to valves, this becomes difficult to implement in automobiles based on packaging constraints. However, if the heat exchanger was versatile to contain a simple bypass there would be no need for complex solutions.
It would be desirable to have a heat exchanger which has greater versatility, and the present development seeks to provide such a heat exchanger.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
A heat exchanger for transferring heat from a liquid that comprises a first tank and also a second tank. In between the two tanks are a plurality of tubes, these fluidly join the first tank and the second tank. Contained within the first tank is a flexible baffle. This baffle may divide the first tank into a first chamber and a second chamber. The flexible baffles acts as a bypass valve that fluidly joins the first and second chamber.
An additional embodiment may be an automotive heat exchanger with a plurality of tubes which medium flows through, at least two tanks which connect the tubes and which the heat exchange medium flows in and out. One of the tanks encloses a resilient baffle. The baffle is for dividing one of the tank portions into different independent tank chambers. The resilient baffle may be in circular shape and have slits intersecting at the center of the baffle.
An additional embodiment may be an oil cooler for a vehicle with a first end tank divided into a first portion and a second portion. The division is made by a flexible baffle. An inlet of the tank is at the first portion, the second portion contains an outlet. The oil cooler has a plurality of a first section of tubes in fluid communication with the first portion of the first end tank. The section of first tubes has a fluid that flows to a second end tank. A section of second tubes may be in fluid communication with the second end tank and the second portion of the first end tank. The flexible baffle is a flapper valve that restricts the flow of oil through the valve during normal operation. The valve is then open to direct oil directly from the first portion to the second portion of the tank during a high pressure condition.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a schematic representation of a vehicle having a engine, transmission and heat exchangers;

FIG. 2 is a representation of the prior art;

FIG. 3A is a representation of the current embodiment;

FIG. 3B is a representation of the current embodiment in partial bypass condition;

FIG. 3C is a representation of the current embodiment in a full bypass condition;

FIG. 4 is a detail view of the baffle;

FIG. 5 is view of the baffle in the tank;

FIG. 6 is a view of the baffle in the tank with a screen member;

FIG. 7. Is a representation of an additional embodiment of the flexible baffle.

FIG. 8. Is a representation of another additional embodiment of the flexible baffle.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring to FIG. 1, an automotive vehicle 10 with an engine 12 and transmission 14 representations shown. Vehicle 10 includes heat exchangers at the front of the vehicle 10, a radiator 16 and an oil cooler 20. It is known in the art that the radiator 16 cools an engine coolant (not shown) that flows through the engine 12 and then back to the radiator 16. Additionally the vehicle has a transmission 14 that contains some lubricating fluid (not shown), that fluid may be cooled by oil cooler 20. Also, it is known that the engine 12 has lubricating oil for internal components; this may also be cooled in oil cooler 20. A series of pumps, tubing, and piping is needed to connect the heat exchangers to the engine 12 and transmission 14; this is understood in the art and will not be described in detail.
With reference to FIG. 2 shows a typical multi-pass oil cooler heat exchanger that is used on a typical vehicle, it may be understood that this style of heat exchanger can be used for any fluid, however the current disclosure will describe it as a oil cooler. It is also understood in the art that this is a two pass system but the description is the same for multi-pass heat exchangers with greater than two passes. The oil cooler 20 has an inlet 22 and outlet 24 in the first tank 26. A core section 28 connects the first tank 26 to the second tank 30. The core section includes a first plurality of tubes 32, in between the tubes is a series of fins 34. The first tank 26 is separated into two chambers, an inlet chamber 36 and an outlet chamber 38. The two chambers are separated in the first tank 26 by a baffle 40. It is understood in the art that the baffle 40 may be known as a partition or any piece to isolate the two chambers from each other. The baffle 40 is in a fixed position that separates the medium (not shown) in the inlet chamber 36 and the outlet chamber 38. The typical function of the oil cooler 20 is the oil or liquid medium (not shown) would flow into inlet 22 represented by arrow 42. The medium would fill the inlet chamber 36 and flow through the tubes 32, the flow is represented by group of arrows 44. The medium flows through the first plurality of tubes 32 into the second tank 30. The second tank 30 may just be a single chamber with no baffles or partitions; however it is understood in the art that oil coolers or any heat exchangers can be incorporated with each other and share end tanks. The medium represented by arrows 46, flows down tank 30 and into second portion of tubes 48. The medium then flows back to the first tank 26 to the outlet chamber 38 and out the outlet 24, the flow represented by arrow 50.
With reference to FIG. 3A, the oil cooler 60 is very similar to the current art. The oil cooler 60 has an inlet 62 and outlet 64 in the first tank 66. A core section 68 connects the first tank 66 to the second tank 70. The core section includes a first plurality of tubes 72, in between the tubes is a series of fins 74. The first tank 66 is separated into two chambers, an inlet chamber 76 and an outlet chamber 78. The two chambers are separated in the first tank 66 by a flexible baffle 80. The flexible baffle 80 separates the medium (not shown) in the inlet chamber 76 and the outlet chamber 78. The typical normal operating function of the oil cooler 60 is the oil or liquid medium (not shown) would flow into inlet 62. The medium would fill the inlet chamber 76 and flow through the first plurality of tubes 72. The medium flows through the tubes 72 into the second tank 70. The second tank 70 is just a single chamber with no baffles or partitions, the medium flows down tank 70 and into second portion of tubes 82. The medium then flows back to the first tank 66 to the outlet chamber 78 and out the outlet 64. In a normal operation condition it is understood that the oil cooler 60 with the flexible baffle 80 would operate similar to the prior art oil cooler 20 previous described, however under normal operation little to no flow of the medium would flow through the flexible baffle 80.
The flexible baffle 80 is stationary within the tank 66, but is flexible and acts as a bypass valve within the tank. As previously stated during a cold situation the viscosity of oil in the system (not shown) is increased and the oil flow is reduced. This viscosity increase increases the pressure of the oil flowing into the tank 66 and inlet chamber 76. Under extreme pressure like an initial engine 12 startup, during a very cold ambient temperature condition, the pressure in the inlet chamber 76 may be the greatest. The baffle 80 would flex under the pressure and allow for a full bypass mode, the oil flow represented by arrow 84 in FIG. 3B flows through the baffle 80 and then out the outlet 64, completely bypassing the core section 68. However after the oil warms and the pressure in the inlet chamber 76 reduces; the baffle 80 will restrict, reducing the area of bypass opening, allowing for a partial bypass displayed in FIG. 3C. This condition oil flow 86 partially bypasses the core section 68 by flowing through the flexible baffle 80, also there is some oil flow 87 through the core section 68, through the first section of plurality of tubes 72, then through the rest of the heat exchanger similar to normal operation described previously.
Referring to FIG. 4, the flexible baffle 80 is further described. The flexible baffle 80 preferred embodiment is a flapper style valve, further provided with a plurality of diametric slots or cuts 88 intersecting at the center of the circular baffle 80 (as shown in FIG. 4), defining a plurality of pie-shaped portions 90 of the baffle 80 which point to each other at the center of the flexible baffle 80, with the outer ends of pie-shaped portions 90 joined together at the perimeter of baffle 80. The baffle 80 is made of resilient material like rubber, polymer/plastic, or spring metal by way of non-limiting example. As stated above in normal operation, where little to no bypass is wanted or needed, the pie-shaped portions 90 of the baffle 80 will remain constant in a non-flexed position on the same plane. However if the pressure of the medium increases in the inlet chamber 76, as described above, the pie-shaped portions 90 will flex into the outlet chamber 78 allowing some of the medium to flow directly from the inlet chamber 76 to the outlet chamber 78 while some additional medium flows through the core section 68. Additionally, as described above and in FIG. 3B, in a cold start full bypass situation, the pie-shaped portions 90 are fully flexed allowing for the maximum opening area of the baffle 80 and maximum flow from inlet chamber 76 to outlet chamber 78. It is understood in the art that the number of cuts 88 and pie-shaped portions 90 are determined based on the application and stiffness of the chosen material. It is also understood that the general shape of the flexible baffle 80 can be any form; a circular form is illustrated by non-limiting example.
Referring to FIG. 5, which is a cross section cut of the tank 66 illustrating the baffle 80 inside the tank 66. The baffle 80 is attached to an intermediate support member 92 which is the same shape as the inside surface 94 of the tank 66. It is understood in the art that the tank 66 may be square/rectangular, circular, or any combination by way of non-limiting example. The support member 92 can be shaped to be used in any tank shape configuration. The flexible baffle 80 may be attached to the support member 92 by over-molding, clamping, adhesive, or fasteners by way of non-limiting example. The support member 92 may be of any rigid material that will support the flexible baffle 80. The support member 92 may be attached to inside of the tank surface 94 by brazing, welding, a molded feature inside tank 66 or a fastener by way of non-limiting example.
It is understood in the art the pie-shaped portions 90 may deflect upward or downward inside the tank 66; while the base ends 96 thereof at the perimeter of baffle 80 do not deflect. A screen member 98 may be disposed on top of baffle 80 as shown in FIG. 6. The screen member 98 only allows flow of oil one direction through the flexible baffle 80. The screen member 98 can be any shape or configuration to allow for one direction flow, the current embodiment illustrates the screen member 98 taking the shape of the inside surface 94 of the tank 66. The screen member 98 may be any structure that prevents the flexible baffle 80 from flexing both up and down inside the tank 66. A screen 98 is illustrated; however any constricting structure that does not restrict flow of oil through the flexible baffle 80 may be used as known in the art.
It can be understood in the art that there are alternatives to the pie shaped portions previously discussed. A second embodiment of the flexible baffle 100 is illustrated in FIG. 7, which a single slit or cut 102, spanning linearly across the horizontal center axis 104 of flexible baffle 100, wherein two pie shaped portions 106 are formed at the end of the single slit 102 to allow for flexibility and more flow through the flexible baffle 100 in high pressure situations. The pie shaped portions are symmetrical around the vertical center axis 108 of the flexible baffle 100. A third embodiment, shown if FIG. 8, shows a flexible baffle 110, with a single slit 112 spanning across the horizontal center axis 114 of the flexible baffle 110. The single slit is symmetrical around horizontal axis 116
Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.

Claims

What is claimed is:

1. A heat exchanger for transferring heat from a liquid comprising:

a first tank;

a second tank;

a plurality of tubes fluidly joining the first tank and the second tank,

a flexible baffle which is provided within first tank, dividing the first tank into a first chamber and a second chamber; wherein the flexible baffle is a bypass valve that fluidly connects the first chamber and second chamber.

2. The heat exchanger for transferring heat from a liquid according to claim 1, wherein the flexible baffle is generally circular in form having a plurality of diametric cuts therethrough intersecting at the center of the flexible baffle to provide a plurality of pie-shaped portions joined at the periphery of the flexible baffle.

3. The heat exchanger for transferring heat from a liquid according to claim 2, wherein the plurality of pie-shaped portions are adapted to be deflected into the second chamber when the liquid is flowing from the first chamber to the second chamber.

4. The heat exchanger for transferring heat from a liquid according to claim 1, wherein the flexible baffle further comprises a single slit linearly spanning across the center of the flexible baffle.

5. The heat exchanger for transferring heat from a liquid according to claim 4, wherein the single slit has a first end and a second end;

a plurality of slits extending from the first end and the second end;

wherein the plurality of slits form pie shaped portions.

6. The heat exchanger for transferring heat from a liquid according to claim 1, further comprising a screen member disposed adjacent the flexible baffle to maintain a generally flat configuration of the flexible baffle and restrict the flow of liquid from only from the first chamber to the second chamber.

7. The heat exchanger for transferring heat from a liquid according to claim 1, wherein the flexible baffle perimeter is surrounded by a rigid frame member, the rigid frame member is attached to an interior surface of the first tank.

8. An automotive heat exchanger comprising:

a plurality of tubes through which flows a heat exchange medium,

at least two tank portions which connect a multiplicity of the tubes and through which the heat exchange medium flows in and out;

a resilient baffle for dividing one of the tank portions into a plurality of independent tank chambers, wherein the flexible baffle is circular in form and having a plurality of slits therethrough intersecting at the center of the flexible.

9. An automotive heat exchanger according to claim 8, wherein the slits provide a plurality of pie-shaped portions joined at the perimeter of the resilient baffle the pie-shaped portions act as a flapper valve fluidly connecting the independent tank chambers.

10. An automotive heat exchanger according to claim 8, wherein the resilient baffle perimeter is surrounded by a rigid frame member, the rigid frame member is attached to an interior surface of the tank portion.

11. An automotive heat exchanger according to claim 8, wherein a resilient baffle, divides one of the tank portions into a first chamber and a second chamber.

12. An automotive heat exchanger according to claim 11, wherein the slits provide a plurality of pie-shaped portions joined at the perimeter of the resilient baffle; the plurality of pie-shaped portions are adapted to be deflected into the second chamber when the liquid is flowing from the first chamber to the second chamber.

13. An automotive heat exchanger according to claim 12, further comprising a screen member disposed adjacent resilient baffle to maintain a generally flat configuration of the resilient baffle and restrict the flow of liquid from only from the first chamber to the second chamber.

14. An automotive heat exchanger according to claim 7, wherein one of the tank portion chambers contains an inlet and another tank portion chamber contains an outlet.

15. An automotive heat exchanger according to claim 14, wherein the resilient baffle separates the tank portion chamber with the inlet and tank portion chamber with the outlet.

16. An oil cooler for a vehicle, comprising:

a first tank divided into a first portion and a second portion by a flexible baffle;

a plurality of a first tubes in fluid communication with the first portion of the first tank, the plurality of first tubes configured to have a fluid flow there-through to a second tank;

a plurality of second tubes in fluid communication with the second tank and the second portion of the first tank; wherein the flexible baffle further comprises a flapper valve and is adapted to restrict flow of oil through the valve during normal operation, and to open and allow oil directly from the first portion to the second portion of the first tank during a high pressure operation.

17. An oil cooler for a vehicle according to claim 16, wherein the flexible baffle partial bypass opening is determined by the pressure inside the first portion of the first tank.

18. An oil cooler for a vehicle according to claim 16, wherein the flexible baffle is made of a synthetic material.

19. An oil cooler for a vehicle according to claim 16, wherein the flexible baffle has a plurality of slits spanning radially from the center forming a plurality of pie-shaped portions; the pie-shaped portions are deflected into the second chamber when the liquid is flowing from the first chamber to the second chamber.

20. An oil cooler for a vehicle according to claim 19, wherein a screen member is disposed adjacent to the flexible baffle only allowing flow of the fluid from the first chamber to the second chamber.