Patent application title: LUBRICATION SYSTEM AND OIL COOLER WITH BYPASS
Daniel J. Hommes (Shelby Township, MI, US)
GM GLOBAL TECHNOLOGY OPERATIONS, INC.
IPC8 Class: AF01M500FI
Class name: Flow passages for two confined fluids interdigitated plural first and plural second fluid passages stacked plates or shells form interplate passages
Publication date: 2008-12-25
Patent application number: 20080314572
An oil cooler for an engine or other lubricated mechanism includes a
connector through which the oil cooler is connected to an oil supply
passage and a return oil passage in an engine crankcase or other supply
source. The connector includes a seal face to which inlet and outlet
passages from the cooler are connected with oil supply and return
passages in a connected mechanism. A continually open oil bypass is
provided by forming a groove or slot in the seal face of the oil cooler
extending between the inlet and outlet passages of the oil cooler and
forming the cooler oil bypass. Alternatively, a bypass may be formed by a
slot in a mating engine or mechanism connector connecting with the supply
and return oil passages. Using a perimeter gasket between mating
connectors can increase the bypass oil flow by the area of the clearance
within the gasket opening created by the thickness of the gasket.
1. A lubrication system for a lubricated mechanism, the system
comprising:an oil cooler including a plurality of cooling oil passages
disposed in heat exchange relation with internal coolant passages, the
cooling oil passages terminating in spaced adjacent inlet and outlet ends
opening through a seal face of an oil cooler connector;a lubricated
mechanism having oil supply and oil return passages terminating in spaced
adjacent outlet and inlet ends opening through a seal face of a mechanism
connector disposed in opposed face relation with the oil cooler
connector, with the outlet end of the mechanism oil supply passage
connected with the inlet end of the oil cooler passages and the outlet
end of the oil cooler passages connected with the inlet end of the
mechanism oil return passage; anda bypass groove extending in the seal
face of at least one of the oil cooler connector and the mechanism
connector, the groove extending between the inlet and outlet ends of the
passages associated with the at least one connector for carrying oil
through the groove to bypass the oil cooler passages.
2. A lubrication system as in claim 1 wherein the bypass groove is in the oil cooler connector.
3. A lubrication system as in claim 1 wherein the bypass groove is in the mechanism connector.
4. A lubrication system as in claim 1 wherein the groove is a slot of generally rectangular open sided cross section extending directly between the inlet and outlet ends of passages terminating in an associated connector.
5. A lubrication system as in claim 4 including a peripheral gasket disposed between and engaging the seal faces of the oil cooler connector and the mechanism connector and forming a sealed joint surrounding the slot and the inlet and outlet ends of the passages terminating in the connectors.
6. An oil cooler for use in cooling oil used in operation of a lubricated mechanism, the oil cooler comprising:a core including a plurality of core oil passages extending through the core between and connecting with inlet and outlet headers, the core including coolant passages disposed in heat exchange relation with the core oil passages;oil inlet and outlet passages connected respectively with the inlet and outlet headers and terminating in spaced adjacent inlet and outlet ends opening through a seal face of a connector attachable to a source of inlet oil connectable with the inlet end and a cooled oil receiver attachable with the outlet end;the connector including a bypass groove extending in the seal face between the inlet and outlet ends for carrying oil through the groove to bypass the core oil passages.
7. An oil cooler as in claim 6 wherein the groove is a slot of generally rectangular open sided cross section extending directly between the inlet and outlet ends of passages terminating in the connector.
8. An oil cooler as in claim 6 including a peripheral gasket disposed between and engaging the seal face of the oil cooler connector and adapted to form a sealed joint with an associated mechanism connector surrounding the slot and the inlet and outlet ends of the passages terminating in the connector.
This invention relates to a lubrication system for a lubricated mechanism, such as an engine, transmission or other mechanism including an oil cooler and a bypass for the oil cooler.
BACKGROUND OF THE INVENTION
It is known in the art, relating to engines, transmissions and other mechanisms, to provide an oil cooler for maintaining the oil temperature below a desired maximum operating limit. The cooler may have a core with a plurality of oil passages in heat exchange relation with coolant passages adapted to carry cooling fluids such as water or air.
In operation, oil degradation or deposits, as well as high oil viscosity when the oil is cold, may impede oil flow through the cooler oil passages. To avoid inadequate lubrication of the mechanism, a cooler bypass may be provided to maintain oil flow to the mechanism components until the oil warms to normal operating temperature, or the cooler oil flow is restored by changing the oil or servicing or replacing the oil cooler. Devices such as a pressure actuated bypass valve or a simple orifice may be provided for this purpose. However, such arrangements may add cost or complexity to a lubrication system.
SUMMARY OF THE INVENTION
The present invention provides a lubrication system with an oil cooler for an engine or other lubricated mechanism. The oil cooler includes a connector through which the oil cooler is connected to an oil supply passage and a return oil passage in an engine crankcase or other supply source. The connector includes a seal face to which inlet and outlet passages to and from a cooler core are connected with oil supply and return passages in an engine or other connected mechanism. A continually open oil bypass is provided by forming a groove or slot in the seal face of the oil cooler connector, the slot extending between the inlet and outlet passages of the oil cooler and forming the cooler oil bypass. Alternatively, a bypass may be formed by a slot in a mating engine or mechanism connector, connecting with the engine oil supply and return oil passages.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of part of an engine lubrication system having an oil cooler with a cooler bypass according to the invention;
FIG. 2 is a side view of an oil cooler adapted for attachment to an automotive engine or other lubricated mechanism;
FIG. 3 is a face view of a connector for inlet and outlet passages to and from the oil cooler core and including a bypass slot extending between the passages;
FIG. 4 is a view similar to FIG. 3 showing an alternative mating engine connector with an oil cooler bypass slot;
FIG. 5 is a view similar to FIG. 3 including a perimeter gasket in position for attachment of the oil cooler connector to a mating engine connector; and
FIG. 6 is a diagrammatic cross-sectional view through the oil cooler connecter along the line 6-6 of FIG. 5 showing the bypass flow area through the slot and between the assembled flanges of an oil cooler attached to an engine.
DESCRIPTION OF AN EXEMPLARY EMBODIMENT
Referring now to the drawings in detail, numeral 10 generally indicates part of a lubrication system for a lubricated mechanism, such as an engine 12, a transmission or other mechanism, not shown. Engine 12 includes a suitable housing such as a cylinder block or crankcase 14 with an oil sump or oil pan 16 for containing a supply of lubricating oil. Within the crankcase or oil pan, an engine driven oil pump, not shown, is provided for supplying pressurized oil from the oil pan 16 to the various internal moving components of the engine 12.
The lubrication system includes an oil cooler 18 having a housing 20 which may be mounted at any convenient location, such as on a side 22 of the cylinder block or crankcase 14. An exemplary form of oil cooler 18 with housing 20 is illustrated in FIG. 2. The oil cooler is provided to cool the engine oil as needed to maintain a desired temperature below a maximum operating temperature level. The oil cooler housing 20 may include a core 24 having a plurality of cooling oil passages 26 extending between inlet and outlet cooling oil headers 28, 30. The headers are connected by inlet and outlet passages 32, 34 with an oil cooler connector 36, FIG. 3, in which the passages 32, 34 terminate at inlet and outlet ends 38, 40 extending to a generally flat oil cooler seal face 42.
The oil cooler connector is fastened, as by bolts 44, in opposed face relation with a similar seal face 46, FIG. 4, of a mechanism/engine connector 48 provided on the side 22 of the cylinder block or crankcase 14 of the associated mechanism or engine 12. The mechanism/engine seal face 46 communicates with an outlet end 50 of an oil supply passage 52 connecting internally with the engine oil pump, not shown. The seal face 46 also communicates with the inlet end 54 of a return oil passage 56 connecting internally with the mechanism/engine oil system 10 for delivering the cooled oil to the lubrication system.
In order to provide a cooling fluid for the oil cooler 18, the oil cooler core 24 includes coolant passages 58, or an equivalent volume, with which the oil passages are in heat exchange relation within the oil cooler core 24. The passages 58 or volume may have any suitable flow path through the core, such as a return flow path from a coolant inlet header 60 to a return flow header 62 and back to a coolant outlet header 64. Inlet and outlet connections 66, 68 connect the headers 60, 64 with the engine cooling system, not shown, to provide engine coolant to the cooler core passages (volume) 58.
If the oil cooler is connected to a transmission or other lubricated mechanism, coolant may be supplied by an associated engine cooling system, or another source of coolant or cooling fluid may be provided. Any suitable coolant may be used including antifreeze containing liquid coolants, as well as air or other suitable gaseous fluids if desired.
In accordance with the invention, a simplified oil bypass passage is provided between the engine 12 and the oil cooler core 24. The passage replaces a higher cost pressure actuated bypass valve of a prior system and avoids the addition of an orifice, which would involve additional costs. Preferably, as shown in FIG. 3, the bypass passage is formed in the oil cooler connector 36 and takes the form of a slot 70 of generally rectangular open sided cross section. The slot 70 preferably extends directly between the inlet and outlet ends 38, 40 of the cooler inlet and outlet oil passages 32, 34. The slot is easily machined, as by an end mill, into the seal face 42 of the oil cooler connector with the slot open side 71 facing out from the seal face 42 toward the position of the engine connector 46, when assembled with an engine, as shown in FIG. 1 of the drawings.
It should be understood that other forms of open sided grooves or slots (such as V-shaped, or U-shaped or forming a curved passage in the seal face, could be substituted for the preferred, straight slot with rectangular cross section configuration.
FIG. 4 shows another alternative embodiment of the invention wherein the bypass passage, or slot 72 with its open side 73, is formed in the seal face 46 of the engine connector 48. The configuration is shown as a mirror image of the arrangement of FIG. 3 in that the seal face 46 of the engine connector 48, the outlet and inlet ends 50, 54 of the oil supply passage 52 and the return oil passage 56, respectively, as well as the slot 72 are similar to the comparable features of FIG. 3 except that the oil supply passage 52 and the return oil passage 56 and their outlet and inlet ends 50, 54 are positioned on opposite ends of their seal face 46 from the outlet and inlet ends 38, 40 of the oil cooler connector of FIG. 3 with which they connect in assembly. The FIG. 4 embodiment should give equivalent bypass flow to that of FIG. 3, if the dimensions are equal, but the embodiment of FIG. 3 is considered preferable because the smaller oil cooler is perceived as being easier to handle for machining of the associated connector than that of the larger engine block or crankcase.
Assembly of the oil cooler onto the engine requires only the addition of a "perimeter seal" gasket 74, shown in FIG. 5 in position on the oil cooler connector 36. The gasket 74 is clamped between the seal faces 42, 46 of the oil cooler connector 36 and the engine connector 48 as the oil cooler 18 is mounted on the engine 12.
The gasket 74, FIG. 5, includes a racetrack shaped central opening 76, which has semicircular edges 78 that border the outer perimeters of the passage ends, which terminate in both the engine and oil cooler connectors 48, 36. The opening 76 also has connecting straight edges 80 that join tangentially with opposite ends of the semicircular edges 78. The opening thereby surrounds the oil passage ends 38, 40, terminating in both the oil cooler and engine connectors as well as the volume between the seal faces 46, 42 within the opening 76 between the passage ends. This volume includes the volume of the associated bypass slot 70 in the oil cooler connector or the alternative bypass slot 72 in the engine connector. Use of the perimeter seal gasket is more economical than a previous edge bonded rubber gasket which separately sealed the inlet and outlet passages from bypassing the oil cooler flow.
FIG. 6 illustrates the configuration and total cross-sectional area 82 of an exemplary oil cooler bypass opening formed between and within the seal faces 46, 42 of the engine and oil cooler connectors 48, 36. The shorter and thicker rectangle 84 illustrates the cross-sectional bypass flow area of the slot 70 in the seal face 42 of the oil cooler connector 36. The thinner and longer rectangle 86 illustrates the cross-sectional area of the volume formed between the engine and oil cooler connector seal faces 46, 42 which equals the thickness of the perimeter gasket within the width of the gasket opening 76. The total of the two rectangles 84, 86 equals the flow area of the bypass passage for oil flow bypassing the oil cooler core when the associated engine is in operation and providing a continuous oil flow to the bearings and other lubricated parts of the engine, even though there is excessive oil viscosity or the cooler core becomes clogged by contaminants that prevent adequate oil flow through the oil cooler core.
It is apparent that the present invention provides a simple but effective oil bypass for an oil cooler, which provides continuous oil bypass flow to protect the lubricated components of an engine or mechanism from damage due to oil starvation in spite of high oil viscosity or plugging of the oil passages of an associated oil cooler. The bypass arrangement is easily formed in a junction of inlet and outlet oil passages in a connector in which a bypass groove or slot may be machined or formed between the passages.
While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims.
Patent applications by Daniel J. Hommes, Shelby Township, MI US
Patent applications by GM GLOBAL TECHNOLOGY OPERATIONS, INC.
Patent applications in class Stacked plates or shells form interplate passages
Patent applications in all subclasses Stacked plates or shells form interplate passages