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 
       [0001]    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 
       [0002]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0003]    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. 
         [0004]    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. 
         [0005]    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. 
         [0006]    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 
       [0007]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0008]    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. 
         [0009]    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. 
         [0010]    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. 
         [0011]    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 
         [0012]    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. 
           [0013]      FIG. 1  is a schematic representation of a vehicle having a engine, transmission and heat exchangers; 
           [0014]      FIG. 2  is a representation of the prior art; 
           [0015]      FIG. 3A  is a representation of the current embodiment; 
           [0016]      FIG. 3B  is a representation of the current embodiment in partial bypass condition; 
           [0017]      FIG. 3C  is a representation of the current embodiment in a full bypass condition; 
           [0018]      FIG. 4  is a detail view of the baffle; 
           [0019]      FIG. 5  is view of the baffle in the tank; 
           [0020]      FIG. 6  is a view of the baffle in the tank with a screen member; 
           [0021]      FIG. 7 . Is a representation of an additional embodiment of the flexible baffle. 
           [0022]      FIG. 8 . Is a representation of another additional embodiment of the flexible baffle. 
       
    
    
       [0023]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0024]    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. 
         [0025]    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. 
         [0026]    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 . 
         [0027]    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 . 
         [0028]    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. 
         [0029]    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. 
         [0030]    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. 
         [0031]    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. 
         [0032]    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   
         [0033]    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. 
         [0034]    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.