Note: Descriptions are shown in the official language in which they were submitted.
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OIL FILTER WITH INTEGRATED COOLER
FIELD OF THE INVENTION
The present invention relates to an oil filter having an integrated oil
cooler for use in internal combustion engines.
BACKGROUND OF THE INVENTION
An internal combustion engine is typically used in automobiles,
motorcycles, buses, trucks and the lilce, the engine parts are typically
lubricated and
cooled by means of engine oil circulated through an engine lubricating system.
During engine operation, the oil absorbs heat from the engine parts and can
become
warmer than is optimal for efficient operation of the engine. Excessively high
oil
temperatures can result in rapid brealcdown and exposure to coping with
ensuing
deterioration of the lubricating characteristics of the oil. Such a turn of
events may
result in increased engine wear and shorter engine life. As a result, many
high
performance engines are designed with a special oil cooler to prevent
excessively high
oil temperatures.
Oil filters are an important part of modern internal combustion engines
since they remove particles and other contaminants from the oil which may form
in
the engine. The removal of the particles and contaminants from the oil
protects the
bearings and other moving parts of the engine from excessive wear. Integration
of an
oil filter with an oil cooler has been previously disclosed as shown in U.S.
Patent No.
5,967,111 issued to Hedman (the "Hedman patent") and U.S. Patent No. 4,831,980
issued to Nasu, et al. (the "Nasu, et al. patent"). Such prior attempts to
form a filter
and integrated cooler have been found to be either more costly to manufacture
or less
efficient in operation than is desirable as further explained below.
The Hedman patent shows a common approach to the design of a
combined oil filter and oil cooler in which two annular concentric chambers,
one for
oil, one for coolant, share a common boundary wall through which heat transfer
occurs. This design limits the efficiency of the oil cooler since the surface
area
available for heat transfer between the oil and the coolant is limited to the
shared
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common wall. Thus, there is a need for an oil filter with integral cooler
having a more
efficient design.
The Nasu, et al.patent illustrates another approach to a combined oil
filter and oil cooler. In this design, a series of staclced cooling elements
are joined
together to form a cooling chamber. In one embodiment, the cooling element is
located within the interior cavity defined by an annular filter. The
manufacture of
such a staclced cooling element has been found to be snore expensive than is
desirable.
Further, the interior placement of the cooling element limits the size of the
cooling
element and thereby the surface area available for providing heat transfer.
Still
further, Nasu et al. discloses a housing mounted against the engine bloclc of
a
motorcycle which is held in place by a hollow shafted bolt that engages a
thread
portion of an oil communication hole. The arrangement of the housing and mount
can
make replacing the filter element difficult and messy since loosening the
hollow bolt
allows oil to spill out of its housing. Accordingly, there is a need for an
improved oil
filter with an integrated cooler that transfers heat efficiently, is
inexpensive to
manufacture, and is convenient to replace a filter element.
SUMMARY OF THE INVENTION
One object of the invention is to provide an oil filter with integrated oil
cooler which has a unitary cooling element which is dimensioned to be immersed
in
the oil filter chamber to increase the surface area for heat transfer between
the oil and
the coolant.
Another object of the invention is to provide a heater with integral
cooler which includes a replaceable oil filter that is more convenient to
replace.
A still further object of the invention is to provide a cooling element
with an enlarged surface area for heat transfer between oil and coolant.
In one aspect of the invention, an improved oil filter with integrated oil
cooler is provided which includes a housing defining a chamber for receiving
oil, a
unitary cooling element located within the housing, an oil inlet for received
unfiltered
oil from aai engine and passing it into said chamber, an oil outlet for
passing filtered
oil back to an engine, a filter element located within the chamber for
filtering the oil, a
coolant inlet for receiving low temperature coolant from a cooling system and
passing
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said coolant to said cooling element; and a coblant outlet for passing warmed
coolant
from said cooling element to a cooling system. The unitary design of the
cooling
element provides a significant cost savings in manufacturing over the stacked
cooling
element discussed above. The filter with integrated cooler of the present
invention
provides a combination of efficient cooling due to the intimate contact
between the
cooling element and oil as well as low cost due to the simplified design of
the cooling
element.
In another aspect of the invention, the improved oil filter may
optionally have a housing including (1) a housing base with a first end
mounted to the
engine and a second end having a first threaded surface, and (2) a housing
cover
having a second threaded surface for threadably mating with the first threaded
surface
of the housing base. The housing may be further provided with a quick release
valve
which is actuated upon unscrewing the housing cover to allow oil to quiclcly
drain
from the oil filter chamber.
In another preferred embodiment of the invention, the improved oil
filter with integrated cooler includes a housing that has a plurality of
projections
extending outwardly from its exterior surface. The inclusion of the
projections
substantially increases the exterior surface area of the housing which is in
contact with
ambient air thereby significantly increasing the efficiency of the cooling
operation as
heat is transferred through the housing walls. While applicant does not wish
to be
bound to any one theory for the increased heat transfer efficiency of the oil
filter with
integral cooler of this embodiment of the invention, it is believed that the
projections
may contribute to the efficiency of heat transferred by increasing turbulent
air flows
adj acent to the housing. It is also believed that the proj ections provide
improved
structural stability to the housing which allows thinner materials to be used
thereby
decreasing the thermal mass of the oil filter with integral cooler. This may
also
contribute to the improved thermal transfer properties of the housing design
of this
embodiment of the invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of one embodiment of the filter
with integrated cooler of the invention.
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FIG. 2 is a perspective view of the cap portion of the filter with
integrated cooler of FIG. 1.
FIG. 3 is a top plan view of the cap of Figure 2.
FIG. 4 is a cross-sectional view tal~en along line 4--4 of FIG. 3.
FIG. 5 is an enlarged, cross-sectional view of a portion of FIG. 4.
FIG. 6 is a perspective view of the cooling element of the filter with
integrated cooler of FIG. 1.
FIG. 7 is a top plan view of the cooling element of FIG. 6.
FIG. 8 is a cross-sectional view of the cooling element of FIG. 9 taken
along line 8--8.
FIG. 9 is a side view of the cooling element of Figure 6.
FIG. 10 is an enlarged, fragmentary view of the side wall of the an
alternate cooling element similar to FIG. 6.
FIG. 11 is a bottom plan view of the cooling element of FIG. 6.
FIG. 12 is a cross-sectional view of the cooling element of FIG. 13
talcen along lines 12--12.
FIG. 13 is an alternate embodiment of a cooling element for use with
the filter with integrated cooler of FIG. 1.
FIG. 14 is a perspective view of the filter element of the filter with
integrated cooler of FIG. 1.
FIG. 15 is a perspective view of the housing base of the filter with
integrated cooler of FIG. 1.
FIG. 16 is a top plan view of the housing base of FIG. 1 S.
FIG. 17 is a cross-sectional view talcen along lines 17--17 of FIG. 16.
FIG. 18 is an enlarged, fragmentary cross-sectional view of a portion
of the housing base shown in FIG. 17.
FIG. 19 is cross-sectional view of an alternate embodiment of the
cooler with integral filter of the present invention.
FIG. 20 is a cross-sectional view of a still further embodiment of the
filter with integrated cooler of the present invention.
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FIG. 20 is a cross-sectional view of another embodiment of the filter
with integrated cooler of the present invention in which the filter element is
located
radially inwardly from the cooling element.
FIG. 21 is a cross-sectional view of the housing cap, cooler element,
and housing of yet another embodiment of the filter with integrated cooler of
the
present invention.
FIG. 22 is an enlarged, fragmentary cross-sectional view of the inlet
and housing of the filter with integrated cooler of FIG. 21.
FIG. 23 is a partial cross-sectional view of the housing cap, cooler
element, and housing of yet another embodiment of the filter with integrated
cooler of
the present invention.
FIG. 24 is an enlarged, fragmentary perspective view of the cooling
element of FIG. 23.
FIG. 25 is a cross-sectional view of the filter with integrated cooler of
FIG. 23 talcen along lines 25--25.
DETAILED DESCRIPTION
One preferred embodiment of the filter with integral cooler 10 of the
invention is shown in FIGS. 1-18 which generally includes filter element 12,
housing
base 14, cooling element 16, and cap or housing cover 18. When fully
assembled,
housing cap 18 and housing base 14 form a chamber 84 which receives filter
element
12 and cooling element 16.
More specifically, as shown in FIGS. 1 and 4, cover 18 has threaded
openings 24, 26 to receive the threaded ends 19, 21 of coolant inlet 20 and
coolant
outlet 22 , respectively. As shown in FIG. 1, coolant inlet and coolant outlet
preferably have ribs forming a "quicl~ connect" surface for receipt of
resilient coolant
tubing. Housing cover 18 has an end wall 8 with exterior surface 28 and
interior
surface 30, and annular side wall 32 with exterior surface 32a and interior
surface 32b
as best seen in FIGS. 2-4. Coolant inlet 20 and outlet 22 extends through end
wall 8
from exterior surface 28 through to interior surface 30 of cap 18. Annular
side wall
32 has threaded portion 32c extending outwardly from exterior surface 32b
which is
dimensioned and machined to engage a threaded portion 34c formed in the
interior
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surface 34a of side wall 34 of housing base 14. Flange 36 extends outwardly
from
exterior surface 32b and has a planar end surface 38 which forms a seal upon
contact
with an O-ring 39 (See FIG. 1) during downward rotation of the cap 18 onto
housing
base 14. A hex head member 27 is provided on exterior surface 28 of end wall 8
for
receiving an appropriate tool to assist in opening the cap 18. Openings 24, 26
have
internally threaded side walls 23 and 25, respectively which are adapted to
receive the
threaded end 19, 21 of inlet 20 and outlet 22. Housing cover 18 is preferably
cast
from aluminum or a similar non-corrosive, metal, and openings 24 and 26 as
well as
threaded walls 23 and 25 are machined therein. Interior surface 30 of end wall
8
further has annular sealing member 44 projecting therefrom. Sealing member 44
engages gaslcet 46 of filter element 12 thereby forming a seal between filter
element
12 and cap 18. Interior surface 30 of cap end wall 8 has an annular channel 40
formed
therein for receipt of an annular rim 95 (See FIG. 8) of cooling element 16.
Openings 24, 26 in end wall 8 are in fluid communication with cooling
element 16 so that coolant may enter from inlet 20, flow through cooling
element 16
and exit the filter with integral cooler 10 through outlet 22. One preferred
manner of
connection of the inlet 20 and outlet 22 to the engine cooling system is by
use of a
pair of resilient tubes (not shown) to bring fluid to and from the engine
cooling
system. Inlet tube (not shown) is connected to a source of low temperature
coolant,
such a radiator output, and outlet tube (not shown) is connected to the warm
side of
the engine cooling system for passage through a radiator or similar device.
In the embodiment of FIGS. 1-18, the cooling inlet and cooling outlet
preferably open to the same aperture 29 at the open end of the cooling element
16a.
In this way, the cool fluid enters the cooling element at the same end as the
warmed
coolant that is returned to the cooling system. This arrangement is preferred
for
simplicity of manufacture and installation since no complex connections are
required
for cooling inlet and outlet. However, it is further contemplated that cooling
element
16a may have a spatially separated inlet (not shown) and outlet (not shown)
where
cooling efficiency is at a premium. In which case, the outlet would be
elongated to
receive warmed coolant at the opposite end of the cooling element the inlet in
a
manner similar to that shown in FIG 19. Although, it is contemplated that
coolant
inlet, rather than the coolant outlet may be elongated so that low temperature
coolant
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maintained near the outlet 64. Cooling element 16 is preferably formed from
aluminum, but may be formed from other thermally conductive metals such as
copper.
As best seen in the embodiments of FIGS. 1-17, it is contemplated that
interior
cooling element 16 may tale one of several forms shown as 16a-16d. The
interior
cooling elements 16 share the common feature that they are dimensioned to be
located
within the filtered oil chamber 84 of the oil filter with integrated cooler.
In the first
option shoran in FIGS. 6-8, cooling element 16a has a bellows-life shape with
alternating recesses 90 and projections 91 in its exterior surface 92 which
serve to
increase the surface area of the cooling element and thereby increase heat
transfer
through, the cooling element 16a. As shown in FIG. 8, cooling element 16a has
a
smooth-walled interior surface 93, but may alternately have a series of
projections and
recesses so that the cooling element wall has corrugated appearance when
viewed in
cross-section as seen in FIG. 10. As best illustrated in FIG. 8, cooling
element 16a
has a shoulder 94 and rim 95. Rim 95 is dimensioned to be received in channel
40 of
cap 18. Shoulder 94 is brazed or welded to inner surface 30 of cap 18.
The second configuration of internal cooling element 16b is shown in
FIGS. 11-14. It is similar in most respects to internal cooling element 16
shown in
FIGS. 6-8 differing chiefly in the number and depth of alternating recesses
90b and
projections 91b in exterior surface 92b. Cooling element 16b has a smooth
inner
surface 93b and is provided with shoulder 94b and rim 95b for attaclnnent to
cap 18.
The recesses 90b and projections 91b may be formed in the surface of cooling
element 16 as a coarse exterior thread.
As best seen in FIGS. 1 and 14, filter element 12 includes gaskets 46,
48 affixed to end disk 50 and 52, respectively. End disk 50 and 52 are affixed
to
opposing ends of filter material 54 which, in the embodiment of FIGS. 1-18 are
metal
dislcs affixed by an adhesive to the filter material 54. However, end disks or
end caps
made of a moldable, elastomeric material, such as plastic or rubber, are
preferred as
their use ensure that the filter element is readily incinerable and as a
separate end cap
and gasket can be illuminated. Filter material 54 is preferably constructed of
corrugated filter media arranged to form a hollow cylinder and has an interior
region
56 bounded by interior surface 57 and exterior surface 58 defined by the
filter
material. The preferred filter material is a filter media including non-woven
paper
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fibers, polyester fibers, and a glass filler, such media are commercially
available from
Alhstrom Manufacturing of Chattanooga, Tennessee and HV Paper Manufacturing of
Charlotte, North Carolina. Such filter materials are preferred for their
superior
filtering propeuties as well as their environmentally friendly characteristics
as media is
readily incinerable after disposal of the filter element. Other filter
materials such as
traditional corrugated paper, non-corrugated nylon mesh, corrugated metallic
mesh, or
other mesh materials having appropriate pore size and having sufficient
chemical
stability for adequate filtration may be used. When filter 12 is assembled
into the
housing base 14, gaslcet 48 of filter element 12 forms a sealing relationship
with
annular sealing surface 58 seen in FIG. 18.
Turning to FIGS. 15-18, housing base 14 has an end wall 60 and
annular side wall 34. As best seen in FIGS. 17 and 18, end wall 60 has annular
sealing surface 58 extending from its interior surface 69 and an oil outlet 64
extending
through end wall 60 which is centrally located above an engine opening or
conduit
(not shown) for return of cooled, filtered oil to engine (not shown). Eight
oil inlets
66a-h are spaced apart and located radially outwardly from outlet 64. Oil
inlets 66a-
66h extend through end wall 60 of housing base 14. The exterior surface 70 of
end
wall 60 has recessed portion 72 for receiving an oil inlet conduits or
mounting in fluid
cormnunication with apertures (not shown) from the engine as seen in FIG. '18.
An
annular channel 76 is formed about the periphery of the exterior surface 70 of
end
wall 60 to accommodate a base O-ring 78 (see FIG. 1) to provide a seal between
the
end wall 60 of the housing base 14 and the engine blocl~ (not shown) when
installed.
In one preferred embodiment of the invention, oil outlet 64 is threaded to
receive a
threaded conduit (not shown) extending from the engine bloclc.
Turning to FIG. 15, annular side wall 34 of housing base 14 has a first
portion 34a with a larger diameter than portion 34b. Interior surface 80 of
side wall
34 has a threaded portion 34c which is machined to receive threaded portion
32c of
cap 18. Side wall 34 has outwardly extending lip 82 around its periphery which
is
dimensioned to engage O-ring 39 and to press it against planar surface 38 of
cap 18 to
seal the cap 18 to the housing base 14 as its rotated into a closed position.
Anotlier preferred embodiment of the filter with integral cooler lOc of
the invention is shown in FIG. 19 which generally includes a filter element
12c, base
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portion of housing base 14c, cooling element 16c, and cap or housing cover
18c.
When fully assembled, housing cap 18c and housing base 14c form a chamber 84c
which receives filter element 12c and cooling element 16c. The filter with
integral
cooler lOc of FIG. 19 is similar in many respects to the filter with integral
cooler 10
of FIGS. 1-18. The main differences are fond in the design of the cooling
element
16c, the shape of housing base 14c and housing cover 18c, the use of
elastomeric end
cap SOc, as well as the arrangement of the coolant inlet 20c and coolant
outlet 22c.
More specifically, as shown in FIG. 19, cover 18c has threaded
openings to receive the threaded ends 19c, 21c of coolant inlet 20c and
coolant outlet
22c, respectively. Coolant inlet 20c and coolant outlet 22c preferably have
ribs
forming a "quiclc connect" surface for receipt of resilient coolant tubing 13c
and 15c.
Housing cover 18c has an end wall 8c with exterior surface 28c and interior
surface
30c, and annular side wall 32d with exterior surface 32e and interior surface
32f.
Coolant inlet 20c and outlet 22c extends through end wall 8c from exterior
surface
28c through toward interior surface 30c of cap 18c. Annular side wall 32d has
threaded portion 32g extending inwardly from interior surface 32f which is
dimensioned and machined to engage a threaded portion 34g formed in the
exterior
surface 34e of side wall 34g of housing base 14c. Rim 36c extends from
exterior side
wall 32d and has a planar surface 38c with a recess 38d which received an O-
ring 39c
which forms a seal during downward rotation of the cap 18c onto housing base
14c.
A hex head member 27c is provided on exterior surface 28c of end wall 8c for
receiving an appropriate tool to assist in opening the cap 18c. Interior
surface 30c of
end wall 8c further has annular sealing member 44c projecting therefrom.
Sealing
member 44c engages resilient end cap SOc of filter element 12c thereby forming
a seal
between filter element 12c and cap 18c. Interior surface 30c of cap end wall
8c has an
annular channel 40c formed therein for receipt of an annular rim 95c of
cooling
element 16c.
One preferred manner of connection of the inlet 20c and outlet 22c to
the engine cooling system is shown in the embodiment of FIG. 19 in which a
pair of
tubes 13c, 15c bring fluid to and from the engine cooling system. Inlet tube
13c is
connected to a source of low temperature coolant, such as a radiator, and
outlet tube
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15c is connected to the warm side of the engine cooling system for passage to
the
intake of a radiator or similar device.
In this embodiment of the invention, the cooling element 16c has
spatially separated inlet 20c and outlet 22c as this design emphasizes cooling
efficiency over manufacturing cost. The improved efficiency is accomplished
through
the use of an elongated outlet tube 17c attached to coolant outlet 22c. It is
also
contemplated that coolant inlet, rather than the coolant outlet, may be
elongated by
use of an elongated tube (not shown) so that low temperature coolant
maintained near
the outlet 64. Cooling element 16c has sinuous exterior surface forming a
series of
lobes to increase surface area. The cooling element is preferably formed of a
thermally conductive metal in a unitary piece by a casting, molding or metal
forming
process. Cooling element 16c has a shoulder 94c and rim 95c. Rim 95c is
dimensioned to be received in channel 42c of cap 18c. Shoulder 94c is brazed
or
welded to inner surface 30c of cap 18c.
Filter element 12c include gasket 48c affixed to end disk 52c. Metallic
end disk 52c is affixed to one end of filter material 54c by aa1 adhesive to
the filter
material 54c. End dislc SOc or end cap is made of a moldable, elastomeric
material,
such as plastic or rubber, so that a separate gasket is not necessary. Filter
material 54c
is preferably constructed of corrugated filter paper arranged to form a hollow
cylinder
and has an interior region 56c bounded by interior surface 57c and exterior
surface
58c defined by the filter material. When filter 12c is assembled into the
housing base
14c, gasket 48c of filter element 12c forms a sealing relationship with
annular sealing
surface 58c.
Housing base 14c has an end wall 60c and annular side wall 34d. End
wall 60c has annular sealing surface 58c extending from its interior
surface.69c and an
oil outlet 64c extending through end wall 60c which is centrally located above
an
engine opening or conduit (not shown) for return of cooled, filtered oil to
engine (not
shown). Eight oil inlets 66 are spaced apart and located radially outwardly
from
outlet 64, while only two 66i, and 66j can be seen in the cross-sectional view
of FIG.
19. The inlets extend through end wall 60c of housing base 14c. The exterior
surface
70c of end wall 60c has recessed portion 72c for receiving an oil inlet
conduits or
mounting in fluid communication with apertures (not shown) from the engine. An
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f
annular channel 76c is formed about. the periphery of the exterior surface 70c
of end
wall 60c to accommodate a base O-ring 78c to provide a seal between the end
wall
60c of the housing base 14c and the engine blocle (not shown) when installed.
Oil
outlet 64c is threaded to receive a threaded conduit (not shown) extending
from the
engine block.
The operation of the internal cooling element embodiments of the
invention shown in FIGS. 1-20 is best illustrated with reference to FIG. 19 in
which
warm, unfiltered oil enters the housing base 14c through oil inlets 66i j. The
oil fills
the unfiltered oil cavity 86c formed by the exterior surface of filter element
12c and
by the housing base 14c and cap 18c. The unfiltered oil cavity 86c is upstream
of the
exterior surface 58c of the filter material 54c of filter element 12c and
forms a portion
of the chamber 84c. The oil passes through the interior surface 57c of filter
material
54c to interior region 56c of the filter element 12c where the filtered oil
comes into
contact with cooling element 16c. The filtered oil cavity 88c is the portion
of
chamber 84c which is downstream of the interior surface 57c of filter material
54c and
is generally bounded by end wall 60c, filter interior surface 57c, and cooling
element
16c. The oil is cooled as it flows along the length of the cooling element
within the
filtered oil cavity 88c toward oil outlet 64c. The cooled, filtered oil passes
of out of
filter lOc through outlet 64c and into the engine.
Turning to the coolant flow during operation, the low temperature
coolant flows from the cooling system through the inlet tubing 13 to cap inlet
20 and
into cooling element inlet l lc. The low temperature coolant circulates
through the
cooling element 16 absorbing heat from the oil flowing in the filtered oil
cavity 88
and exits the cooling element 16 at elongated coolant outlet 17. The coolant
then
passes through coolant outlet 22 into coolant return tube 15i which returns
the coolant
to the warm side of the engine cooling system for cooling by a radiator or
other
means.
FIG. 20 illustrates a still further embodiment of the filter with
integrated cooler l Od of the present invention having an internal cooling
element.
The embodiment of the filter with integral cooler 10d of FIG. 20 is similar in
many
respects to the filter with integral cooler l Oc of FIG. 19. The primary
differences
being the elongated shape of the housing base 14d and housing cover 18d, the
helical
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coiled cooling element 16d, the shape of end cap SOd, the location of and
configuration of the oil inlet 64d and outlet 66d as well as the side mounted
coolant
inlet 20d and coolant outlet 22d.
Cooling element 16d is a helical coil defining a cylindrical cavity.
Individual coils of the cooling element 16d are preferably spaced slightly
apart so that
oil may flow between adjacent coils. This cooling element design significantly
increased the surface area of the cooling element 16d in contact with warm,
unfiltered
oil within the unfiltered oil chamber 86d since the warm, unfiltered oil can
substantially surround the coil rather than contacting it only at an exterior
surface as is
common in prior designs, Sllch as the concentric chamber design of Hedrnan.
Cooling
inlet 20d and cooling outlet 22d are preferably provided with internal
threaded
surfaces (not shown) and an adapter (not shown) similar to those in FIG. 22 to
connect the cooling element 16d to inlet tubing (not shown) and outlet tubing
(not
shown).
Filter element 12d includes a gasl~et 48d affixed to end disk 52d.
Metallic end dislc 52d is affixed to one end of filter material 54d by an
adhesive to the
filter material 54d. End disk or end cap SOd is made of a moldable,
elastomeric
material, such as plastic or rubber, so that a separate gasl~et is not
necessary. As
shown in FIG. 20, it preferably includes an annular channel 45d for receiving
annular
sealing surface 44d extending from interior surface 30d of end wall 8d.
The housing base 14d and housing cap 18d are elongated in shape to
accommodate the increased height of the coiled cooling element 16d relative to
other
cooling element designs 16a-c. For certain designs including those using a
coiled
cooling element, it has been found that the cost of manufacture and assembly
for the
filter with integral cooler can be significantly reduced by arranging the
coolant inlet
and coolant outlet in the base portion of the filter with integrated cooler.
The filter
with integrated cooler of 10d is such a design and is thus shown with cooling
inlet
20d and cooling outlet 22d located in housing base 14d. The oil inlet 66d may
include one or more passages through end wall 60d of housing base 14d to
unfiltered
oil chamber 86d. The oil outlet 66d is off set from the central longitudinal
axis of the
filter with integrated cooler lOd and extends through end wall 60d to reach
filtered oil
chamber 88d.
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Two additional embodiments of the filter with integral cooler of the
present invention are illustrated in FIGS. 21-25 which are similar in many
respects to
the embodiment of FIGS 1-20, but which differs generally in the placement and
dimensions of the cooling element. These and other differences between the two
embodiments as well as the others described above will become clear in the
detailed
description of the embodiment of FIGS. 26-27 below.
More specifically, the filter with integral cooler 110 of FIG. 21
generally includes filter element 112, housing base 114, cooling element 116,
cap or
cover 118, cooling inlet 120 and cooling outlet 122. When assembled, cover 118
and
housing base 114 form a chamber 184 for receiving filter element 112 and
cooling
element 116. Cover 118 has an end wall 108 and an integral annular side wall
132
extending therefrom. End wall 108 has an exterior surface 128 and interior
surface
130. Annular side wall 132 has a threaded portion 132a on its interior surface
132b
which is machined to engage a threaded portion 134a on the exterior surface
134b of
annular side wall 134 of housing base 114. Overhang 136 of side wall 132 of
cap 118
has a planar surface 138 which forms a seal upon contact with an O-ring 139
during
downward rotation of the cap 18 on housing base 114. A hex head member 127 is
provided on exterior cap surface 128 for receiving an appropriate tool to open
the cap
118. Cap cover 118 is preferably cast from aluminum or a similar or other
thermally
conductive, non-corrosive metal; however, other moldable materials such as
plastic
may also be used. Interior surface 130 further has arch-shaped sealing surface
144
extending therefrom. Sealing surface 144 engages end cap extension 150b of
resilient
end cap 150 of filter element 112 thereby forming a seal between filter
element 112
and cap 118.
Arch-shaped sealing surface 144 has a central aperture 147 and
pressure relief valve assembly 149 which includes stopper element 151, pin 153
and
pressure sensitive member 155. Pressure sensitive member 155 is preferably a
metal
spider spring which is calibrated to deflect upon application of a critical
pressure
within unfiltered oil cavity 186 to bypass the filter during "cold engine"
start-up when
oil may be too viscous to travel readily through the filter. The bypass
mechanism is
also activated if the filter becomes so clogged that it could deprive the
engine of oil
flow. Upon deflection of member 155, pin 153 moves downwardly toward filtered
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fuel cavity 188 thereby allowing stopper 151 to travel downwardly and allowing
unfiltered oil to pass through aperture 147 from unfiltered oil cavity 186 to
filtered oil
cavity 188.
Housing base 114 has an end wall 160 and an annular side wall 162.
End wall 160 has a lip 158 extending from its interior surface 157 and located
at the
periphery of oil outlet 164. Oil outlet 164 extends through end wall 160 and
is
centrally located above an engine conduit 159 for return of cooled, filtered
oil to
engine 196. A number of oil inlets 166 are arranged radially outwardly from
the
outlet 164, and extend through, end wall 160 of housing base 114. Exterior
surface
170 of end wall 160 has a life number of recesses 172 for receiving oil inlet
conduits
173 from the engine 196. An annular channel 176 is formed about the periphery
of
the exterior surface 170 of end wall 160 to accormnodate a base O-ring 178 to
provide
a seal between the end wall 160 of the housing base 114 and the engine 196
when
assembled. In the embodiment shown in FIG. 21, oil outlet 164 is internally
threaded
to receive a threaded conduit 159 extending from the engine 196. housing base
114
has openings 124 and 126 to receive the threaded ends 119 and 121 of coolant
inlet
tubing 113 and outlet tubing 115, respectively. Openings 124 and 126 have
threaded
side walls 123 and 125, respectively which are adapted to receive the threaded
ends
119 and 121 of inlet tubing 113 and outlet tubing 115, respectively. Housing
base
114 is preferably cast from aluminum or other thermally conductive, non-
corrosive
metal; however, moldable materials such as plastic may also be used.
Side wall 134 of housing base 114 includes an exterior surface 134b
with a threaded portion 134a which is machined to receive thread portion 132a
of cap
118. Side wall 134 has a recess 182 around its periphery which is dimensioned
to
receive an O-ring 139. O-ring is pressed between recess 182 and the exterior
surface
of side wall 134. Side wall 134 has a second annular section 134c with a
larger radius
of curvature than threaded side wall portion 134a.
Cooling element 116 is a helical coil of tubing which is dimensioned to
have a central opening which surrounds filter element 112. Cooling element 116
is
held in place in housing base 114 by tubing inlet 111 and tubing outlet 117.
The use
of a helical coil as a cooling element substantially increases the surface
area available
for heat transfer relative to prior designs having concentric chambers since
the warm
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oil can completely surround the cooling element rather than contacting it
along one
substantially planar surface. As seen in FIG. 22, outlet 120 has a number of
components including outlet tubing 117, opening 126, and coupling 133. Opening
126 is provided with beveled collar retention portions 126a which retain
peripheral
rim 117a formed on outlet tubing 117. The end of outlet tubing 117 has a
threaded
portion 117b designed to receive a threaded coupling 133 for attachment to the
outlet
end of 116b. Although FIG. 22 illustrates an enlarged fragmentary view of the
connection at the coolant outlet 126, coolant inlet 124 is understood to have
a same
arrangement of parts and couplings (not shown). Openings 124 and 126 are in
fluid
communication with cooling element 116 so that coolant may move from inlet 120
through cooling element 116 and out through outlet 122. As best seen in FIG.
21,
inlet 120 and outlet 122 are preferably connected to the engine cooling system
by
tubes 113 and 115. Inlet tube 113 is connected to a source of low temperature
coolant
and outlet tube is connected to the warm side of the engine coolant system for
passage
through a radiator or similar device. Cooling element 116 is preferably formed
from
aluminum, but may be formed from other thermally conductive metals such as
copper.
Filter element 112 includes center flow tube 146 which is affixed to
end caps 150 and 152, respectively. End caps 150 and 152 are affixed to
opposing
ends of filter material 154 which is preferably constructed of corrugated
filter media
of the type discussed above which is arranged to form a hollow cylinder.
Another
reason that such filter media is preferred is that it can be readily bonded to
the
elastomeric end caps or to the thermoplastic center tube 146 through
application of
sufficient heat. Filter material 154 has an inner surface 157 bounding an
interior
region and exterior surface 158. Center tube 146 is preferably made of plastic
and is
preferably ultrasonically welded to end wall 160 at tube end.146a. The
preferred filter
element 112 is composed of a filter material 154, end caps 150 and 152, and
center
tube 146 which are made of materials which are readily incinerable. This
design is
preferred since the filter element may be disposed of in an environmentally
responsible manner through incineration. It is also contemplated that a
suitable
adhesive could be used in combination with a gasket 198 to ensure an adequate
seal as
shown in FIG. 21.
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When assembled, housing base 114 and cap 118 form a chamber 184
which is separated by filter element into an unfiltered oil cavity 186 and
filtered oil .
cavity 188. Unfiltered oil cavity 186 is that area within the chamber upstream
of the
filter material 154 and is bounded generally by side walls 132 and 134, end
walls 108
and 160, and exterior surface 158 of filter element 112. Filtered oil cavity
188 is that
area of the chamber downstream of interior surface 157 of the filter material
154, and
is generally bounded by the interior surface 157 of filter material 154 and
portion of
the center tube 146.
During operation of the filter with integral cooler of FIGS. 21-22,
warm, unfiltered oil enters the housing base 114 through oil inlets 166. The
oil fills
the unfiltered oil cavity 186 of chamber 184. The oil is cooled as it
surrounds and
flows along the length of the cooling element within the unfiltered oil cavity
186. The
oil passes through the filter material 154 into filtered oil cavity 188 and is
gathered in
center tube 146. The cooled, filtered oil passes out of filter 110 through
outlet 164
into conduit 159 of the engine 196. As to the coolant flow, low temperature
coolant
flows from the cooling system through the inlet tubing 113 into inlet 120 and
cooling
element inlet 111. The low temperature coolant circulates through the cooling
element 116 absorbing heat from the oil flowing in the unfiltered oil cavity
186 and
exits the cooling element 116 as warmed coolant at outlet tubing 117. The
coolant
then passes through outlet 122 into coolant return tube 115 which returns the
warmed
coolant to the warm side of the engine cooling system for cooling by a
radiator or
other means.
Still another embodiment the filter with integrated cooler of the
invention is shown in FIGS. 23-25. The filter with integrated cooler 210 of
this
embodiment of the invention is most-similar to the embodiment shown in FIGS.
21-
' 22 differing chiefly in the arrangement of the tubing of the cooling element
216, the
inclusion of a "quiclc drain" valve assembly 350 and channel 366, the
inclusion of
brazing members 296 between adjacent coils of the cooling element 216, the
inclusion
of fins or projections 297 (See FIG. 25) on the exterior side wall surfaces of
the
housing. These and other differences between the embodiments of FIGS. 21-22
and
FIGS. 23-25 will become clear in the detailed description of the embodiment of
FIGS.
23-25 below.
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The embodiment of the filter with integrated cooler 210 of FIGS. 23-
25 generally includes a housing top or cap 218, a housing base 214, and
cooling
element 216. The housing base 214 and cap 218, when assembled, form a chamber
284 in which the oil filter element and cooling element 216 are received. The
cap 218
has end wall 208 and an annular side wall 232 with exterior surface 232a and
interior
surface 232b. The interior surface 232b has a threaded portion 232c which is
machined to thread with thread portion of exterior surface 234a of side wall
234 of
housing base 214. Side wall 232 has a channel 240 dimensioned to receive a
seal or
O-ring 239. The interior surface 230 of end wall 208 of cap 218 has a number
of
prongs 233 extending toward the interior of the chamber 284. The prongs 233
engage
center tube 246 when filter with integral cooler 210 is fully assembled.
As illustrated in FIGS. 23-25, cooling element 216 is a vertically
undulating cylindrical coil of tubing which is dimensioned and positioned to
surround
the filter element 216. The sinusoidal or undulating configuration of the
tubing of
cooling element 216 is preferred as it maximizes the available surface area of
contact
between warmed oil and the cooling element 216. This is particularly apparent
when
comparing the low surface area contact between oil and the cooling element
that is
characteristic of the Hedman style concentric chamber filter design with the
embodiments of FIGS. 21-25. As best seen in FIGS. 24 and 25, the cooling
element
216 is dimensioned to define a central cavity which receives the filter
element 212.
Cooling element 216 has a coolant inlet 220 and coolant outlet 222 have
several
components including inlet opening 224 and outlet opening 226, inlet tubing
end 216a
and outlet tubing end 216b. Inlet tubing end 216a and outlet tubing end 216b
pass
through openings 224 and 226 and extend into engine blocl~ 396 at coolant
channels
213 and 215, respectively. Openings 224 and 226 and tubing ends 216a and 216b
are
preferably sealed by use of O-ring gaskets (not shown). Openings 224 and 226
are in
fluid communication with cooling element 216 so that coolant may move from
inlet
220 through cooling element 216 and out through outlet 222. The inlet 220 and
outlet
222 are preferably connected to the engine cooling system internal channels
formed
within the engine blocl~ as shown in FIG. 23 as this significantly reduced the
cost of
manufacture and installation of the filter. However, it is contemplated that
the inlet
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220 and outlet 222 may be connected to the coolant system by resilient tubing
in a
manner similar to that shown in FIG. 21-22.
As best seen in FIG. 24, corrugated brazing member 296 are preferably
brazed to the exterior of the tubing of cooling element 216. The corrugated
brazing
members 296 are preferably made from aluminum, but may be made from another
non-corrosive, thermally conductive metal such as copper. The additional of
the
corrugated brazing members 296 provides the cooling element 216 with
additional
cooling surface area to increase its heat transfer efficiency from the cooling
element
216 to the warm, unfiltered oil. Such fins may also be optionally used with
the
cooling element 116 of the embodiment of FIGS 21-22..
As best seen in FIG. 25, housing base 214 and housing cap 218 include
a plurality of radially outwardly extending projections or fins 297. The fins
297
preferably extend longitudinally from the end wall 208 of the housing base 214
to
near the end wall of the housing base 214 for ease of manufacture and to
increase the
structural integrity of the housing. Optionally, the fins may be oriented
latitudinally
around the curvature of the filter housing if desired. The inclusion of the
projections
297 substantially increases the surface area of the housing base 214 and
housing cap
218 which is in contact with ambient air thereby significantly increasing the
efficiency of the cooling operation as heat is transferred efficiently from
the oil into
the cooling element and through the housing walls. While applicant does not
wish to
be bound to any one theory for the increased heat transfer efficiency of the
housing
with the projections design of this embodiment of the oil filter with integral
cooler, it
is believed that the projections may contribute to the efficiency of heat
transferred by
increasing turbulent air flows adjacent to the housing. Still further, the
projections
297 provide additional structural stability to housing base 214 and housing
cap 218 so
that the areas between adjacent projections can be significantly thinner than
would be
possible with a housing having a smooth exterior surface thereby reducing cost
and
increasing thermal transfer. It is further believed that the decreased thermal
mass of
such designs also contributes to efficiency of heat transfer.
The filter with integrated cooler 210 includes a "quiclc release" valve
assembly 350 and "quicl~ release" channel 366 and port 368. The valve assembly
360
includes release valve 352, valve spring 370, a valve collar which limits the
travel of
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the release valve 352, and valve plug 376 which release valve 352 is seated
against it,
bloclcs release port 368. When housing cap 218 is unscrewed from housing base
214,
oil filter 212 no longer engages head 374 of release valve 352. In doing so,
valve
spring 370 surrounding valve plug 376 pushes head 374 of release valve 352
through
a release valve collar 372 in housing base 214. In this way, valve plug 376 is
no
longer blocl~ing release port 368 and oil may freely flow from unfiltered oil
chamber
286, around release valve 352, through release port 368, and into release
valve
channel 366. When housing cap 218 is removed from housing base 214 (for
example,
when changing the oil filter) a.ny oil that is in filter chamber 284 will
drain around
release valve 352 and into release valve channel 366 which carries the oil
baclc to the
oil pan (not shown). Therefore, instead of having excess oil present in filter
chamber
284 run out and onto the user removing the assembly cover, it will instead
drain back
into filter pan.
The applicant has provided description and figures which are intended
as an illustration of certain embodiments of the invention, and are not
intended to be
construed as containing or implying limitation of the invention to those
embodiments.
It will be appreciated that, although applicant has described various aspects
of the
invention with respect to specific embodiments, various alternatives and
modifications will be apparent from the present disclosure which are within
the spirit
and scope of the present invention as set forth in the following claims.
