U.S. patent application number 10/404015 was filed with the patent office on 2004-09-09 for oil cooler and production method.
Invention is credited to Moser, George, Ostapowicz, Adam, Sommer, Gordon.
Application Number | 20040173341 10/404015 |
Document ID | / |
Family ID | 33309459 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040173341 |
Kind Code |
A1 |
Moser, George ; et
al. |
September 9, 2004 |
Oil cooler and production method
Abstract
The present invention uses a plurality of extruded tubes 8 to
lead the oil from one oil cooler tank to the other oil cooler tank
(one tank is the inlet tank of the oil cooler and the other one is
the outlet tank of the oil cooler). In one application, the oil
cooler tanks are identical. One tank functions as an inlet tank and
the other tank functions as an outlet tank. Typically the ends of
the tanks are threaded or equipped with some type of connector that
allows the connection to the hydraulic lines leading the oil. The
complete oil cooler is immersed in the cooling medium (the radiator
coolant, typically a mixture of 50% water and 50% glycol). The heat
of the oil is transferred through the tube walls to the cooling
medium, so that the temperature of the oil leaving the oil cooler
is significantly lower than the temperature of the oil flowing into
the oil cooler.
Inventors: |
Moser, George; (Mason,
MI) ; Sommer, Gordon; (Plymouth, MI) ;
Ostapowicz, Adam; (Westland, MI) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Family ID: |
33309459 |
Appl. No.: |
10/404015 |
Filed: |
March 31, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60375920 |
Apr 25, 2002 |
|
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60448086 |
Feb 15, 2003 |
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Current U.S.
Class: |
165/148 |
Current CPC
Class: |
F28F 9/0234 20130101;
F28F 1/40 20130101; F28F 2001/027 20130101; Y10T 29/49359 20150115;
F28D 7/08 20130101; F28F 1/02 20130101; F28F 1/022 20130101; F28D
7/082 20130101 |
Class at
Publication: |
165/148 |
International
Class: |
F28D 001/00 |
Claims
What is claimed is:
1. An oil cooler immersed in a cooling medium, the oil cooler
comprising an oil inlet tank connected to an oil outlet tank by a
plurality of substantially flat, pressure-resistant, seamless heat
transfer tubes, the tubes connected to the tanks by brazing or
other suitable process.
2. The oil cooler of claim 1 wherein the heat transfer tubes are
aluminum extrusions with internal webs for pressure resistance.
3. The oil cooler of claim 1, wherein multiple extruded tubes allow
the oil to flow from the inlet port to the outlet port, thus the
oil travel distance between the inlet and outlet ports is
approximately the distance between said inlet and outlet tanks,
while the heat exchange area is approximately equal to the heat
exchange area of one tube multiplied by the number of tubes in the
oil cooler.
4. The oil cooler of claim 1, wherein the inlet and outlet tanks
are approximately round, rectangular or any other suitable
shape.
5. The oil cooler of claim 1, wherein the extruded tubing is
modified by dimples on one or both sides of the flat sides of
tubing.
6. The oil cooler of claim 6, wherein the dimples are round in
shape.
7. The oil cooler of claim 6, wherein the dimples are oval,
rectangular or any other suitable shape.
8. The oil cooler of claim 6, wherein the dimples are arranged in a
linear fashion between the webs of said tubing.
9. The oil cooler of claim 6, wherein the dimples are arranged in a
zigzag fashion.
10. The oil cooler of claim 1, wherein the extruded tubing is
modified by convolutions formed by approximately 90 degree bends,
or by convolutions of any other suitable angle or shape, in order
to force the oil to repeatedly change its flow direction, thereby
increasing turbulence and heat transfer.
11. The oil cooler of claim 1, wherein turbulators are inserted in
the passages of the extruded tubes to increase heat exchange, said
turbulators consisting of bent wire, formed metal strips or any
other bodies placed in the oilstream with the purpose of forcing
the oil to repeatedly change direction and cause turbulence leading
to an increase in heat transfer.
12. The oil cooler of claim 1, wherein the cooling medium is the
coolant contained in the inside of a radiator tank (water-cooled
oil cooler).
13. The oil cooler of claim 1, wherein the cooling medium is air
(air-cooled oil cooler).
14. The oil cooler of claim 13, wherein cooling fins are inserted
between the tubes in order to increase the heat exchange area. In
such a case the tubes may need to be banded together or otherwise
held tightly together through brackets or other means in order to
ensure tight contact between fins and tube surfaces, which is
needed for efficient heat transfer.
15. The oil cooler of claim 1, that can be used to cool automatic
transmission fluid (transmission oil cooler).
16. The oil cooler of claim 1, that can be used to cool engine oil
(engine oil cooler).
17. The oil cooler of claim 1, that can be used to cool steering
oil, hydraulic fluid, and any other fluids requiring cooling in
vehicles or other machinery.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the area of cooling of the
fluids that are used in machinery such as engines, transmissions
and other power equipment to lubricate components and/or transfer
power. In one application, the present invention more particularly
relates, but is not limited to, the area of cooling of transmission
oil and/or engine oil in automotive applications. Numerous other
applications exist in diverse areas such as railways, ships,
aircraft, machine tool, power generation equipment and others.
BACKGROUND OF THE INVENTION
[0002] In the automotive industry it is necessary to cool the oil
used in automatic transmissions. The automotive transmission fluid
(ATF) reaches high temperatures in the operation of the
transmission. These high temperatures need to be reduced to avoid
breakdown of the fluid. A device called a transmission oil cooler
is conventionally used for that purpose.
[0003] With reference to the simplified prior art view of FIG. 1, a
typical transmission cooler 3 is illustrated in an automotive
application. The exemplary application is shown to generally
include an engine 4 and a transmission 5. The oil cooler 3 is
typically located inside one of the tanks 2 of a radiator 1. The
coolant inside the tanks 2 is used as the cooling medium for the
oil cooler 3. This is possible despite the fact that the coolant
itself is relatively hot, because the oil temperature is
substantially higher. The temperature differential between the
coolant in the radiator tank 2 and the oil in the oil cooler 3 is
used to cool the oil. The oil circulates through hydraulic lines 6
between the transmission 5 and the oil cooler 3, and the oil gets
cooled in the oil cooler 3.
[0004] FIG. 2 illustrates one typical transmission oil cooler 3 in
further detail. The oil cooler 3 is located inside the tank 2 of
radiator 1. This type of oil cooler, which consists of concentric
brass tubes between which the oil flows, is typically made by
brazing, a high temperature process that requires expensive brazing
equipment and complex process control. The result is a relatively
expensive and heavy oil cooler. FIG. 2A shows the cross section of
the oil cooler.
[0005] FIG. 3 shows a more modern transmission oil cooler 3'. The
oil cooler 3' is again located inside the tank 2 of radiator 1.
This type of oil cooler 3' is called a plate cooler, because it
basically consists of several flat plates inside which the oil
flows. Plate oil coolers are typically made using aluminum strips
which are joined together along their perimeter in a brazing
process. The use of flat plates leads to a better heat exchange
performance than a concentric tube cooler, but the result is still
a relatively expensive and heavy oil cooler. The very large number
and length of brazed joints creates many potential failure modes
(leaks), which has a potential negative impact on the reliability
of this oil cooler. FIG. 3A shows the cross section of the oil
cooler.
[0006] FIG. 4 shows an engine oil cooler 7, in addition to the
previously shown transmission oil cooler 3. Some vehicles require
both oil coolers. Virtually every vehicle with an automatic
transmission requires a transmission oil cooler, and many high
powered or high rpm engines require also an engine oil cooler.
Typically the engine cooler and the transmission oil cooler are on
two separate, independent cooling circuits. The engine oil
circulating through the engine oil cooler 7 is typically cooled by
placing the oil cooler 7 in a housing that contains coolant.
Another possibility (not shown here) is to place the engine oil
cooler in the second radiator tank (the first one is already
occupied by the transmission oil cooler). This finishes the
description of the state of the art in oil coolers.
[0007] While known oil coolers have proven to be suitable for their
intended purpose, a need remains in the pertinent art for a
lightweight, low cost, highly reliable oil cooler with highly
efficient heat transfer characteristics.
SUMMARY OF THE INVENTION
[0008] It is a general object of the present invention to overcome
the drawbacks of the prior art discussed above by providing a
lightweight, low cost, highly reliable oil cooler with highly
efficient heat transfer characteristics.
[0009] It is another object of the present invention to provide a
simplified oil cooler that increases reliability and
reduces/eliminates potential failure modes such as leaks.
[0010] It is a further object of the invention to use extruded
aluminum tubes as the primary heat transfer mechanism. The
advantage of the extruded tubes is the simplification of the
manufacturing process, as well as the reduction or elimination of
potential failure modes (leaks), which directly impact reliability,
production cost, testing cost and warranty costs. The use of
extruded tubes dramatically reduces the need to join surfaces
through brazing in a watertight and oil tight manner. Since every
joint in a pressurized heat exchanger is always a potential failure
mode, the elimination or reduction in the number of joints provides
a major reliability advantage.
[0011] It is another object of the present invention to further
increase the heat transfer capability of the oil cooler by
modifying the extruded tubes (for instance, by bending or
convoluting them or creating dimples in them in order to increase
turbulence in the tubes).
[0012] It is another object of the present invention to further
increase the heat transfer capability of the oil cooler by
modifying the geometry of the extruded tubes (for instance, by
modifying the cross-section of the extruded tubes in ways that
increase heat exchange).
[0013] It is another object of the present invention to provide
different configurations of oil cooler inlet and outlet tanks, so
that the optimal tank configuration can be chosen for each
particular application. Connection of extruded tubes to tanks is by
brazing or other suitable joining method.
[0014] In one particular embodiment, the present invention uses a
plurality of extruded tubes 8 to lead the oil from one oil cooler
tank to the other oil cooler tank (one tank is the inlet tank of
the oil cooler and the other one is the outlet tank of the oil
cooler). In one application, the oil cooler tanks are identical.
One tank functions as an inlet tank and the other tank functions as
an outlet tank. Typically the ends of the tanks are threaded or
equipped with some type of connector that allows the connection to
the hydraulic lines leading the oil. The complete oil cooler is
immersed in the cooling medium (the radiator coolant, typically a
mixture of 50% water and 50% glycol). The heat of the oil is
transferred through the tube walls to the cooling medium, so that
the temperature of the oil leaving the oil cooler is significantly
lower than the temperature of the oil flowing into the oil
cooler.
[0015] An additional advantage of the extruded tubes used in this
invention is the strength of the cross-section (see FIG. 6A). The
multiple bridges connecting the opposite walls of the tube to each
other (called webs) provide high resistance to pressure, so that
the oil cooler can handle the high test pressures (typically about
500 psi) to which the oil cooler will be subjected.
[0016] The oil cooler of the present invention provides a
breakthrough in the manufacturing of oil coolers, with major cost
and weight reductions as well as major improvements in reliability.
Instead of having potential leaks along the brazed seams of each
tube, as in a conventional flat plate oil cooler, now the only
potential leak path is at the joint between tube and port. This
represents a major reduction in potential failure modes.
[0017] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic illustration of a prior art
transmission oil cooler circuit.
[0019] FIG. 2 is a view of a prior art conventional oil cooler of
concentric tube design shown in partial section.
[0020] FIG. 2A is a cross-sectional view taken along the line
2A-2A.
[0021] FIG. 3 is a view of another prior art oil cooler of plate
design shown in partial section.
[0022] FIG. 3A is a cross-sectional view taken along the line
3A-3A.
[0023] FIG. 4 is a schematic illustration of prior art engine oil
cooler and transmission oil cooler circuits.
[0024] FIG. 5 is a top view of an oil cooler constructed in
accordance with a first preferred embodiment of the present
invention.
[0025] FIG. 6 is a side view of the oil cooler of FIG. 5.
[0026] FIG. 6A is a cross-sectional view taken along the line
6A-6A.
[0027] FIG. 7 is a top view similar to FIG. 5, illustrating an oil
cooler constructed in accordance with a first alternative
embodiment.
[0028] FIG. 8 is a top view similar to FIG. 5, illustrating an oil
cooler constructed in accordance with a second alternative
embodiment.
[0029] FIG. 9 is a top view similar to FIG. 5, illustrating an oil
cooler constructed in accordance with a third alternative
embodiment.
[0030] FIG. 10A is a cross-sectional view of one of the tubes of
the oil coolers of the present invention prior to any tube
modification.
[0031] FIG. 10B is a cross-sectional view of the tube of FIG. 10A
taken along a line perpendicular to the line of the FIG. 10A
cross-section.
[0032] FIG. 11A is a cross-sectional view similar to FIG. 10A,
illustrating a first tube modification.
[0033] FIG. 11B is a cross-sectional view of the tube of FIG. 11A
taken along the line perpendicular to the line of the FIG. 11A
cross-section.
[0034] FIG. 12A is a cross-sectional view similar to FIG. 10A,
illustrating a second tube modification.
[0035] FIG. 12B is a cross-sectional view of the tube of FIG. 12A
taken along the line perpendicular to the line of the FIG. 12A
cross-section.
[0036] FIG. 13 is a side view of a portion of one of the tubes 16
modified in accordance with a third tube modification of the
present invention.
[0037] FIG. 13A is a cross-sectional view taken along the line
13A-13A.
[0038] FIG. 14 is a top view of an oil cooler similar to FIG. 5,
the oil cooler including a plurality of tubes according to a fourth
tube modification.
[0039] FIG. 15 is a side view of the oil cooler of FIG. 14.
[0040] FIG. 16 is a top view of an oil cooler similar in
construction to the oil cooler of FIG. 14, the oil cooler
alternatively including end tanks having a rectangular shape.
[0041] FIG. 17 is a side view of the oil cooler of FIG. 16.
[0042] FIG. 18 is a top view of an air-cooled oil cooler in
accordance with the teachings of the present invention.
[0043] FIG. 19 is a side view of the oil cooler of FIG. 18.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] The following description of the preferred embodiments is
merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses.
[0045] With initial reference to FIG. 5, an oil cooler constructed
in accordance with the teachings of a first preferred embodiment of
the present invention is illustrated and identified at reference
character 10. The oil cooler 10 is shown to generally include first
and second end tanks 12 and 14. The tanks 12 and 14 are round. The
end tanks 12 and 14 are connected by a plurality of tubes 16. In
the embodiment illustrated, the oil cooler 10 is shown to include
five (5) tubes 16. The tubes are preferably brazed to the end
tanks. The first end tank 12 defines a first port 18 as the inlet
of oil to be cooled and the second end tank 14 defines a second
port 20 as the outlet.
[0046] It will be understood that the oil cooler 10 may be
alternatively constructed to include any particular number of tubes
16. For example, FIG. 7 illustrates a first alternative embodiment
of the same type of oil cooler 30 as shown in FIG. 5 except three
(3) tubes 16 are used when less heat transfer is required. FIG. 8
illustrates a second alternative embodiment of the same type of oil
cooler 32 as shown in FIG. 5 except four (4) tubes 16 are used.
FIG. 9 illustrates a third alternative embodiment of the same type
of oil cooler 34 as shown in FIG. 5 except six (6) tubes 16 are
used for greater heat transfer.
[0047] FIG. 10A is an enlarged cross-section of one of the tubes 16
before modification. The tube 16 is shown to include a pair of
sidewalls 38 and internal webs 40 connecting the sidewalls 38. The
internal webs are incorporated to provide strength to the tube 16
to meet the requirement of high-pressure test the oil cooler 10
must pass for validation. FIG. 10B is a cross-sectional view of
tube 16 of FIG. 10A taken along a line perpendicular to the
cross-sectional line of FIG. 10A.
[0048] FIGS. 11A and 11B illustrate one of the tubes 16 modified in
accordance with a first tube modification. The tube 16 has
indentations 44 the full width of the tube 16 alternately spaced on
both sides of the tube 16. Turbulation of the flow through the
tubes 16 occurs at each indentation 44, increasing the heat
transfer.
[0049] FIGS. 12A and 12B show a second tube modification. Dimples
46 are formed alternately on both sides of the tubes 16. The
dimples 16 can be of round, oval or other shapes as desired.
Turbulation of the flow through the tubes 16 occurs at each dimple,
increasing the heat transfer.
[0050] FIG. 13 and FIG. 13A illustrate one of the tubes 16
including a third tube modification. According to the third tube
modification, dimples 46 are formed in one of the sidewalls 38 of
the tube 16 in a staggered or zigzag pattern. In the embodiment
illustrated, the opposite sidewall does not include any
dimples.
[0051] An oil cooler similar to the oil cooler 10 of FIG. 5 is
illustrated and generally identified at reference number 50. In
this particular embodiment, the oil cooler 50 includes a plurality
of tubes modified according to a fourth tube modification.
According to the fourth tube modification, the tubes 16 are formed
into a convoluted shape. The multiple direction change of each tube
16 provides good turbulence for efficient heat transfer. This oil
cooler 50 again has round end tanks 12 and 14. Another tube
modification not shown is the insertion of turbulators within the
passages of the tube. These turbulators can be bent wire or bent
metal strips, etc.
[0052] With reference to FIGS. 16 and 17, an oil cooler 52 similar
in construction to the oil cooler of FIGS. 14 and 15 is
illustrated. In the embodiment illustrated, the oil cooler 52 is
constructed to include first and second end tanks 54 and 56 that
are rectangular in shape. Other shapes of tanks are possible, such
as oval, etc., without departing from the teachings of present
invention.
[0053] Turning to FIGS. 18 and 19, an oil cooler 80 is illustrated
that is air-cooled. This is an example of an oil cooler that is not
immersed in a cooling liquid, as in all previous examples, but
instead it releases its heat to the surrounding air, similar to a
typical engine radiator. The oil cooler 80 includes fins 82 placed
between tubes 16 to provide additional cooling surface. End tanks
12 and 14 are shown as round in shape but can be rectangular, oval
or any other shape desired.
[0054] The description of the invention is merely exemplary in
nature and, thus, variations that do not depart from the gist of
the invention are intended to be within the scope of the invention.
Such variations are not to be regarded as a departure from the
spirit and scope of the invention.
* * * * *