BACKGROUND OF THE INVENTION An internal combustion engine is typically used in automobiles, motorcycles, buses, trucks and the like, 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 breakdown and exposure to coking 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

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 stacked 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 stacked cooling element has been found to be more 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 block 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 an 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

said coolant to said cooling element ; and a coolant 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 quickly 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 adjacent to the housing. It is also believed that the projections 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.

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 taken along line 4--4 of FIG. 3.

I 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 taken 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. 15.

FIG. 17 is a cross-sectional view taken 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.

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 taken 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"quick 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

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 gasket 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

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 take 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 shown in FIGS. 6-8, cooling element 16a has a bellows-like 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 attachment 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 disks 50 and 52, respectively. End disks 50 and 52 are affixed to opposing ends of filter material 54 which, in the embodiment of FIGS. 1-18 are metal disks 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

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 properties 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, gasket 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 communication 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 block (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 block.

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.

Another 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

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 10c of FIG. 19 is similar in many respects to the filter with integral cooler 10 of FIGS. 1-18. The main differences are found in the design of the cooling element 16c, the shape of housing base 14c and housing cover 18c, the use of elastomeric end cap 50c, 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"quick 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 50c 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

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 an adhesive to the filter material 54c. End disk 50c 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

t 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 block (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 10c 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 lie. 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 15 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 I Od 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

coiled cooling element 16d, the shape of end cap 50d, 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, such as the concentric chamber design of Hedman. 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 gasket 48d affixed to end disk 52d.

Metallic end disk 52d is affixed to one end of filter material 54d by an adhesive to the filter material 54d. End disk or end cap 50d is made of a moldable, elastomeric material, such as plastic or rubber, so that a separate gasket 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 10d and extends through end wall 60d to reach filtered oil chamber 88d.

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

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 like 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 accommodate abase 0-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

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.

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"quick 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.

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 block 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 block 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

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 wann, 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"quick release"valve assembly 350 and"quick 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

the release valve 352, and valve plug 376 which release valve 352 is seated against it, blocks 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 blocking 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) any oil that is in filter chamber 284 will drain around release valve 352 and into release valve channel 366 which carries the oil back 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.