BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a heat exchanger mounted in front of an engine.
More specifically, the present invention relates to circular passage for a power take
off shaft through the front face of a heat exchanger/exchangers.
2. Description of related art
[0002] In typical engine cooling systems the heat exchangers are mounted together in the
front of the engine. Vehicles and other systems that require auxiliary devices to
be powered by a power take off have a powered shaft emerging from the engine, through
the front end of the vehicle. As a typical result, the shaft protrudes through the
cooling system of the engine. In order to accommodate the power take off, the heat
exchanger in the path of the shaft must include an opening in the face of the heat
exchanger's core in order to provide a passage for the power take off shaft.
[0003] Historically, a radiator that is used to cool the cooling jacket of water from the
engine occupies a majority of the cooling system area. Therefore, such a radiator
must contain a power take off hole through which the power take off shaft is housed.
The charge air coolers used to cool the hot compressed air from the turbo charger
previously has been sized so as not to interfere with the power take off shaft. Similarly,
air conditioning condensers, oil coolers and other auxiliary heat exchangers did not
interfere with the power take off shaft. The emergence of higher engine power requirements,
lower emissions, smaller packaging area, and therefore higher cooling requirements,
are dictating the need for power take off holes in more of the cooling system components,
namely charge air coolers.
[0004] The radiator heat exchangers currently fabricated with power take off holes are made
primarily from copper/brass and/or aluminum. The radiators then require extensive
handwork after baking or brazing of the core. The handwork must be completed manually
and is time consuming. Additional parts are also required to complete this process.
The overall effect is a significant increase in the cost of production.
[0005] FIG 1. depicts a traditional heat exchanger 1 in the form of a heat exchanger with
a power take off hole 5, the hole is characteristically rectangular in shape. The
traditional power take off hole 1 in a heat exchanger 1 consists of two small manifolds
3 on either side of the opening 5. The manifolds are connected to each other with
two to four large bypass tubes 7. Fluid, indicated by the arrows in FIG. 1, flowing
through the power take off portion 5 of the heat exchanger 1 flows from the core tubes
9 into the first manifold 3a, through the large tubes 7, into the second manifold
3b, and finally back into the core tubes 9. Located between the core tubes 9, are
a series of fins 10. The fins 10 properly position the core tubes for structural support
and provide an adequate surface for cooling as well.
[0006] The rectangular nature of the power take off hole 5 creates sharp angles and changes
in flow direction of the internal fluid. Such a design shape restricts the flow of
the internal fluid caused by radical flow changes during flow.
[0007] As is typical, anywhere from two to four rows of core tubes are blocked off due to
design constraints. Blocking off of these core tubes 11 decreases the heat rejection
capacity of the heat exchanger 1.
[0008] Airflow must be kept from flowing around the power take off shaft, through the power
take off hole and into the engine compartment to maintain proper heat rejection. A
seal, not shown, is therefore normally attached to the power take off hole that serves
primarily to prevent by pass air from flowing through the opening and not the heat
exchanger during operation. Typically, a frame or bracket is attached to the power
take off opening 5 to support the seal and will also prevent fingers or hands from
pinch points during operation.
[0009] The prior art also does not presently have a means to connect any additional accessories.
[0010] The prior art design is not easily adaptable to aluminum radiators or to charge air
coolers.
[0011] The need exists for a power take off assembly having a passage for power take off
shaft through the front face of a heat exchanger. With this arrangement, handwork
is minimized and completed prior to brazing/baking. Similarly, this design will eliminate
any hand welding, brazing or soldering, as the assembly should have the individual
parts joined during a single brazing operation rather than multiple attempts at brazing.
Such a design would be self-contained and adaptable to aluminum radiators and charge
air coolers. Such an improved power take off assembly would reduce the internal flow
restrictions created by the prior art by increasing flow area and providing contoured
surfaces that gradually change the flow direction. The extended closure tube option
design would allow power take off air seals to be mounted directly to the heat exchanger's
power take off assembly.
[0012] There exists a need to reduce the number of components necessary to seal the opening.
Additionally, the use of a commercially available seal to reduce the costs associated
with the assembly of a power take off assembly is also required.
[0013] The present invention improves on the prior art and achieves the desired results
described above.
SUMMARY OF THE INVENTION
[0014] It is therefore an advantage of the present invention to provide a power take off
assembly having a passage for power take off shaft through the front face of a heat
exchanger, whereby handwork is minimized and completed prior to brazing/baking. There
is no need for any hand welding, brazing or soldering, as the individual parts are
joined during the brazing operation, allowing for a one shot braze of the power take
off assembly. The design of the present invention is self-contained and adaptable
to aluminum radiators, charge air coolers, and other heat exchangers. The power take
off assembly will reduce the internal flow restrictions created by the prior art by
increasing flow area and providing contoured surfaces that gradually change the flow
direction. Power take off air seals are mounting directly to the power take off assembly's
tube housing, thus eliminating special bracket and fasteners. The preferred embodiment
utilizes a power take off hole that is generally circular in shape.
[0015] Thus, the present invention is primarily directed toward a heat exchanger for a vehicle,
comprising a heat rejection source including an inlet port and an outlet port. The
internal combustion engine has a core portion operably connected to the heat source
including a plurality of tubes through which fluid flows and a plurality of fins each
of which is disposed between adjacent tubes for facilitating heat exchange of a fluid.
A power take off assembly is disposed within the core portion and includes a rectangular
frame having a plurality of passages along two parallel sides thereof, a sleeve, a
face plate and a back plate.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0016] A better understanding of the present invention will be had when reference is made
to the accompanying drawings, wherein identical parts are identified by identical
reference numbers and wherein:
FIG. 1 is a plan view of the prior art.
FIG. 2a is an isometric view of the preferred embodiment.
FIG. 2b is a profile view of the one-piece frame.
FIG. 3 is an exploded perspective view of the preferred embodiment.
FIG. 4 is an exploded view of the preferred embodiment .
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0017] The features of the invention as explained above provide power take off assembly
having a power take off hole designed for inclusion with a heat exchanger.
[0018] According to Figure 2a, the assembly of the one-shot braze power take off assembly
in the preferred embodiment begins with the one-piece frame 15. The one-piece frame
15 is constructed generally in a box shape. Theone-piece frame15maybe constructed
of any material compatible with the system in which the one-piece frame 15 is to be
inserted, for example, aluminum or brass. The one-piece frame 15 has a lattice work
or passages 20 compatible with the core tubes 9 found on the heat exchanger whereon
the one-piece frame is to be connected.
[0019] When assembled, the one-piece frame 15 is essentially a hollow structure. As seen
in FIG. 2b, the one-piece frame 15 is constructed from a single sheet of material.
The one-piece frame 15 is cut and formed in stamping press operations, or another
method known to those skilled in the art. The one-piece frame 15 is formed with four
main sections that make up the side walls 34 and horizontal walls 36 of the one-piece
frame 15. In the present description of the preferred embodiment, certain terminology
will be used for descriptive purposes only and is not intended to be limiting. The
terms "side" and "horizontal" designate directions in the drawings to which reference
is made. Said definitions apply to the terms specifically mentioned above, derivatives
thereof and words of similar import.
[0020] It is important to mention that while the reference to the frame 15 indicates a single
sheet of material is used, it should be appreciated that use of multiple sheets or
components to create the frame would also encompass the scope of the invention.
[0021] Passages 20 are formed in the side walls 34. The passages 20 align with core tubes
9 once the assembly is installed within a charge air cooler or similar device.
[0022] Located along the peripheral edges of the one-piece frame 15 are a series of tabs
25 and 26. Once folded over, tabs 26 allow for the face plate 16 to be located into
position prior to the brazing step. Tabs 26 are folded at approximately right angles
to the face portion of the side walls 34. Once formed, the tabs 26 provide a contact
surface for the brazing step once the face plate 16 is assembled.
[0023] In order to secure the face plate 16 prior to brazing, tabs 25 fold over during the
assembly of the one-piece frame 15 creating a groove as best scene in FIG. 3. More
specifically, the face plate 16 or the grill side front cover plate 16 is inserted
into the frame 15 as the last wall of the frame 15 is closed squaring the 90° corners
giving the frame 15 a box shape. The face plate 16 is slid from the side, the tabs
25 also provide a contact surface between the face plate 16 and the one-piece frame
15 for brazing.
[0024] With reference to Figs. 3 and 4, the face plate 16, one-piece frame 15 and a back
plate 17 are formed with tabs 25 that prevent the various elements from misaligning
during the assembly process, as well as acting as temporary locks prior to braze.
[0025] The assembly of the face plate 16 and the frame 15 is best seen in Figure 3. The
face plate 16 is slid into the slots made by tabs 25. .A sleeve 13 is fit into a hole
30 in the face plate 16. The face plate 16 has flange 31 located around the hole 30
to guide the sleeve into position during assembly. The flange 31 that guides the round
sleeve 13 into place also provide surface area for improving the integrity of the
braze junction. The sleeve 13 is cylindrical in nature and can vary in length depending
on the spatial requirements within the engine compartment. The sleeve 13 diameter
may also vary depending upon the power take off shaft's required clearance. Thus,
the sleeve 13 must have a diameter large enough to receive a power take off shaft,
not shown in the drawing. While the preferred embodiment indicates the sleeve is cylindrical,
the sleeve may also be oval or any other shape to accommodate a power take off shaft,
while maintaining smoothly contoured surfaces.
[0026] In an alternate embodiment, the tabs located on the periphery edges of the frame
and fold down over the face plate temporarily to lock the sleeve 13 into position
before brazing.
[0027] In an alternate embodiment indicated in Figure 4, the assembly containing the back
plate 17, sleeve 13, and one-piece frame 15 is inserted into the heat exchanger's
core during the stacking operation. At this point, an inner support ring 40 is added
onto the sleeve and the back plate 17 is slid into place. It should be observed that
the inner ring 40 is not an essential item to the present invention. It is possible
to complete the stacking of the assembly into the core without the need for a support
ring. The flanges or tabs 25 of both the front and back plates 16 and 17 face the
same direction in order to guide the sleeve when inserted into the assembly. The back
plate 17 is finally pressed against the one-piece frame 15 and the tabs 25 along the
rear of the one-piece frame 15 are used to locate the back plate into position before
brazing. The assembly is now ready for brazing.
[0028] Contact surfaces are formed via the tabs 25 and 26 to provide sufficient surface
area for brazing. In other words, the flanges 31 that guide the round sleeve 13 into
place also provide surface area for improving the integrity of the braze junction.
[0029] After the brazing process, the completed power take off hole 30 has a clean smooth
appearance. The resistance to internal fluid flow within the assembly comprised of
the one-piece frame 15, the face plate 16 and the back plate 17 is minimal due to
the increased internal flow area when compared to the prior art. The power take off
assembly's internal flow path indicated by the arrows is smooth without any sudden
direction changes in Figure 5. The round opening of the sleeve 13 is the optimum physical
shape for structural integrity and resistance to damage. As seen in Figure 5, the
shape allows for external forces exerted on the assembly to deflect and minimize any
impact damage. Thus, fluid traverses, or circumvents, the arcuate body referred to
above as the sleeve 13 from the passage 20 serving as inlet ports to the passage 20
serving as outlet ports. Air seal attachment is inherent to the design. The sleeve
13 permits attachment of an air seal attachment, not shown in the drawings, to be
installed on the assembly after braze.
[0030] While the foregoing invention has been shown and described with reference to several
preferred embodiments, it will be understood that various changes in form and detail
may be made without departing from the spirit and scope of the present invention.
For example, while the above described embodiment utilizes a radiator or a charged
air cooler system. The present invention may also be used for stationary engines as
well, an example of which includes a stationary engine driven pumping station. Similarly,
the sleeve need not be circular and can be oval to accommodate a variety of shafts
therethrough. The sleeve may also have radii forming corners with curves to facilitate
fluid flow therearound.
1. A heat exchanger for a vehicle, comprising:
a heat source including at least one inlet port and at least one outlet port;
a core portion operably connected to said heat source including a plurality of tubes
through which fluid flows and a plurality of fins each of which is disposed between
adjacent tubes for facilitating heat exchange of the fluid; and
a power take off assembly disposed in said core portion, said power take off assembly
having inlet ports and outlet ports in fluid communication with said plurality of
tubes, wherein fluid flowing from said inlet ports traverses an arcuate body.
2. The heat exchanger according to claim 1, wherein said power take off assembly further
comprises:
a rectangular frame having a plurality of passages defining said inlet port and outlet
port along two vertical sides thereof, a sleeve defining said arcuate body, a face
plate and a back plate.
3. The heat exchanger according to claim 2, wherein said arcuate body passed through
said core portion.
4. The heat exchanger according to claim 2, wherein plurality of passages are operably
connected with said plurality of tubes allowing the flow of fluid therethrough.
5. The heat exchanger according to claim 2, wherein said rectangular frame has at least
one flange along a perimeter for holding said face plate and said back plate in place
during a manufacturing process.
6. The heat exchanger according to claim 2, wherein said face plate has a first hole
proximate a center of said front plate and said back plate has a second hole proximate
a center of said pack plate, wherein said first and second holes are substantially
equal in diameter.
7. The heat exchanger according to claim 6, wherein said face plate and said back plate
have at least one of a flange located along the circumference of said first and second
holes for guiding said sleeve into position.
8. The heat exchanger according to claim 6, wherein said first hole is circular.
9. The heat exchanger according to claim 6, wherein said first hole is oval.
10. The heat exchanger according to claim 6, wherein said sleeve is tubular having a circumferential
geometry equal to that of said first hole in said face plate and said second hole
in said back plate.
11. The heat exchanger according to claim 10, wherein said sleeve is secured to said front
plate and said back plate via one of welding, brazing, and soldering.
12. The heat exchanger according to claim 2, wherein said assembly is assembled and bonded
during a one shot brazing process.
13. The heat exchanger according to claim 2, wherein fluid enters and leaves an internal
environment defined by said assembly exclusively through said plurality of passages.
14. The heat exchanger according to claim 1, wherein said heat source is an internal combustion
engine.