Cooler bypass assembly

A cooler bypass apparatus housing has a first fluid passageway connecting a first inlet and a first outlet port, and a second fluid passageway connecting a second inlet port and outlet port. A transverse passageway extends between the first and second fluid passageway. A first valve is disposed in the transverse passageway for one-way fluid flow from the first to the second passageway. A second valve and a thermal actuator coupled to the second valve are disposed in the second passageway. The thermal actuator moves the second valve to fluid flow blocking or fluid flow allowing positions dependent upon fluid temperature.

BACKGROUND

The present invention relates to cooler bypass assemblies which permit fluid flow to a cooler only when the temperature of the fluid is above a certain temperature.

SUMMARY

It would be desirable to provide a cooler bypass apparatus which can readily be connected to machinery which has fluid which may need to be cooled, and which can also be readily connected to the cooler lines. A typical example of such machinery is an automotive transmission.

Cost reduction and fuel economy improvement initiatives brought about the need for a cooler bypass apparatus or device that can cheaply and effectively regulate transmission fluid temperatures. The apparatus ensures that the transmission fluid ramps up to optimum operating temperature as quick as possible and then regulates the fluid at the optimum temperature once it has been reached resulting in a measurable improvement in fuel economy.

The device includes a thermal relief valve circuit in addition to a separate pressure relief circuit. The thermal relief circuit includes a thermal actuator which acts upon a check valve when the optimum transmission fluid temperature has been reached, opening the valve and allowing the fluid to flow through the cooler circuit. As the fluid cools, the thermal actuator modulates the valve effectively regulating the fluid temperature. Until such time that the fluid reaches optimum temperature, the fluid is forced to re-circulate through the pressure bypass circuit which includes a check valve. The forced recirculation of fluid bypassing the cooler circuit results in a drastically reduced warm-up time as opposed to existing systems. This results in an even greater improvement in fuel economy in colder climates. Once the fluid has reached optimum temperature, the thermal relief valve opens and fluid begins circulating through the cooler circuit; the pressure relief closes and serves as a pressure “pop-off” if there is a blockage/restriction in the system of any kind in the cooler circuit, allowing the fluid to re-circulate and avoid serious damage to the machinery or transmission.

In one aspect, the cooler bypass apparatus includes a housing adapted to be secured to a structure having a fluid to be cooled. First and second inlet ports and first and second outlet ports are carried on the housing, the housing having a first fluid passageway in communication with the first inlet port and the first outlet port. A second fluid passageway in communication with the second inlet port and the second inlet port. A transverse fluid passageway is extends between the first and second fluid passageways. A first valve is disposed in the transverse fluid passageway to insure one way flow of fluid between a portion of the second fluid passageway and a portion of the first fluid passageway. A second valve and a thermal actuator are coupled to the second valve. The second valve and the thermal actuator are disposed in the second passageway. The thermal actuator moves the second valve to a position in the second fluid passageway allowing fluid flow through the second passageway when the temperature of fluid in the second passageway exceeds a threshold temperature.

DETAILED DESCRIPTION

A cooler bypass apparatus includes a housing securable to a structure carrying a fluid to be cooled. Areas of inlet and outlet ports in the housing are coupled by first and second fluid passageways. A transverse fluid passageway extends between the first and second fluid passageways and has a first valve disposed for one way flow between the second passageway through the transverse passageway to the first fluid passageway. A second valve and a thermal actuator coupled to the second valve are disposed in the second passageway. The thermal actuator moves the second valve to a fluid flow allowing position when the temperature of the fluid exceeds a threshold.

With reference toFIGS. 1-9, a cooler bypass apparatus includes an aluminum casting or bypass mounting plate or housing indicated generally at10to which first and second fluid line coupling subassemblies SA1and SA2are secured, along with various other components. The casting10is provided with a relatively flat bottom surface10.1which may be secured to a corresponding flat surface on the machinery which carries a fluid that needs to be cooled. In order to insure a non-leak connection the casting10is provided with a groove10.2(FIG. 3) on its bottom surface which receives an O-ring20. In order to secure the casting10to the machinery, a plurality of bolt holes10.3are provided through which bolts (not shown) may pass to secure the casting10to the machinery (not illustrated). The casting10is provided with two generally vertical passageways10.4and10.5and a transverse connecting passageway10.6. As can best be seen fromFIG. 4, the first vertical passageway10.4has an inlet port10.7which is adapted to be aligned with an outlet port in the machinery, and has a treaded outlet port10.9which is adapted to receive the first fluid line coupling subassembly SA1. The second passageway10.5also has a threaded inlet port10.10which is adapted to receive the second fluid line coupling subassembly SA2. Each of the first and second passageways10.4and10.5is adapted to be connected with a cooler through the fluid line coupling subassemblies SA1and SA2to cooler lines, which have special end portions L1and L2, respectively. Each of the end portions L1and L2is generally tubular, but is provided with an outwardly extending abutment of ferrule. Quick connect coupler10.6will be described below.

As can best be seen fromFIGS. 6 and 7, the transverse passageway10.6has first and second portions10.61and10.62of differing diameters to one side of the vertical passageway10.5, passageway10.61being of a larger diameter than passageway10.62, there being a seat10.63between the passageways10.61and10.62to receive a check valve such as a ballcheck valve, for example. As can best be seen fromFIG. 6, the larger diameter portion10.61is provided with inwardly extending ribs10.61awhich act as ball guides, but which do not restrict fluid flow. The transverse passageway10.6also has a further large diameter portion10.64which extends from the vertical passageway10.5to the exterior of the aluminum casting10, the end portion being threaded as at reference number10.65inFIG. 4.

Mounted within the casting or housing10are various subassemblies. The first of these subassemblies includes a check valve in the form of a ball12, a spring14to normally force the ball12into the valve seat10.63, and a ballcheck retainer16best illustrated inFIGS. 8 and 9. The ballcheck retainer16is provided with a relatively large diameter end portion16.1, a relatively small diameter end portion16.2which is adapted to be disposed within the spring14, flutes16.3which are adapted to bear against one end of the compression spring14, and a small diameter intermediate portion disposed between the flutes16.3and the large diameter portion16.1. It can be seen from an inspection ofFIG. 8that the large diameter portion16.1is adapted to be disposed within the larger diameter portion10.64of the passageway10.6, and the small diameter portion16.2is adapted to lie across the passageway10.5so that flow through the passageway10.5will not be impeded.

Associated with this check valve subassembly12,14,16is a plug subassembly which includes a plug18and an O-ring20. When the parts are assembled, and then there is no fluid flow within the housing, the plug18and associated O-ring20will be screwed into the normally open end10.65of the passageway10.6, the plug18and O-ring closing the end of the passageway10.6so no fluid can pass out of the housing10though the passageway10.6. As seen inFIG. 8, the right hand end of the plug18will bear against the left hand end16.1of the retainer16. The left hand end of the spring14will pass over the small diameter right-hand end16.2of the retainer16, and will be held in compression, with the right hand end of the spring14forcing the ball12towards and into contact with the seat10.63when there is no fluid pressure within the assembly10. At the same time the left hand end of the spring will bear against the flutes16.3of the retainer. When the ball12is against the seat10.63, there is no flow through the passageway10.6.

However, when the pressure within passageway10.4to the right of the ball12, as viewed inFIG. 8, is greater than the spring force, the ball12will be forced off the seat10.63permitting flow from the first vertical passageway10.4, through the smaller diameter passageway10.62, past the seat10.63, then into and through the larger diameter passageway10.61, and finally into the other vertical passageway10.5. The flutes16.3of the ballcheck retainer16permit unimpeded flow of fluid past the flutes16.3.

The first fluid line coupling subassembly SA1is best illustrated inFIG. 10. This coupling assembly is similar to the female coupling assembly shown in U.S. Pat. No. 4,640,534, the subject matter of which is incorporated herein by reference thereto. Thus, the subassembly SA1has a principal body28having a fluid passageway24.4extending therethrough it, a first O-ring30, a spring clip32, and a second O-ring34. The body28has a threaded end portion28.1which is screwed into the threaded port10.10. The body28also has an enlarged portion28.2, hexagonal in cross section, by example, which may be engaged by a wrench or the like for the purpose of screwing the body28into the port10.10. The O-ring34is received in a groove between the threaded portion28.1and the hex-shaped enlarged portion28.2to insure a leak-tite seal when assembled. The body28is further provided with a groove28.3adjacent the end spaced away from the threaded end28.1, the groove having suitable apertures so that it may receive the spring clip32. The passageway28.4of the body10of the female coupler is provided with a groove28.5which receives O-ring30. When the cooler line end portion is fully inserted into the fluid line coupling assembly SA1, the spring clip32will engage on side of the abutment on the cooler line end portion to prevent it from being withdrawn, and the O-ring30will hear against the tubular portion to prevent leakage.

The second fluid line coupler assembly SA2is best shown inFIGS. 8 and 11. This assembly SA2includes a coupler subassembly similar to the coupler assembly SA1, a ball check valve subassembly, and a thermal actuator. The coupler subassembly SA2includes a body38having a fluid passageway extending through it, a first O-ring40, a spring clip42, and a second O-ring44. The body38has a threaded end portion38.1which is screwed into the threaded port10.9. The body38also has an enlarged portion38.2, hexagonal in cross section, for example, which may be engaged by a wrench or the like for the purpose of screwing the body38into the port10.10. The O-ring44is received in a groove between the threaded portion38.1and the hex portion38.2to insure a leak-tite seal when assembled.

The body38is further provided with a groove38.3adjacent the end spaced away from the threaded end38.1, the groove38.3having suitable apertures so that it may receive the spring clip42. The passageway38.4of the body38of the fluid coupler is provided with a groove38.5which receives O-ring40. When the cooler line end portion L1is fully inserted into the fluid line coupling assembly SA2, the spring clip42will engage on side of the abutment on the cooler line end portion to prevent it from being withdrawn, and the O-ring40will bear against the tubular portion below the abutment to prevent leakage.

A cross drilled ball seat member50is secured to end of the passageway38.4remote from the spring clip42by force fit or any other suitable manner. The ball seat member50has a ball seat50.1which a ball52may rest against. The ball52is normally forced into contact with the seat50.1by a compression spring54, the spring54being retained within a ballcheck sleeve56. The sleeve56bears against a shoulder38.6in the body10to hold the spring54and ball52in a proper operating condition. A thermal actuator60is secured to the end of the ball seat member50at a location spaced away from the seat50.1suitable means, such as press fit, threads, etc.

The thermal actuator60has a piston62which may contact the ball52. In operation, the piston62of the thermal actuator60, which may be of the type sold by Caltherm of Columbus, Ind., for example, will raise the ball52away from the seat50.1when the fluid temperature is above a certain point, permitting flow through the cross drilled apertures50.2, past the ball52, and then into line L1.

The design described above allows for any type of attachment to a mating port. The mating plate can be designed to any customer specification, and the assembly can also be incorporated into a stand-alone housing that could be connected in-line with the transmission cooling lines utilizing quick-connects.

In order to understand the operation of the cooler bypass assembly, it will be assumed that it mounted on an automatic transmission. It is well known in the art that the fluid within a transmission has a desired operating temperature, typically in the range of 175-225° F., depending upon vehicle make and model. When the automatic transmission fluid (ATF) is below this temperature, the transmission will have operating inefficiencies due to its higher viscosity, which causes the vehicle to consume more fuel. At temperatures above the desired operating temperature, the life of the ATF will begin to plummet. In order to prevent loss of life of the ATF, the transmission fluid is passed through a cooler, which may be in the automotive radiator. Alternatively, if the vehicle is equipped with a trailer towing package, the transmission fluid is passed through an external cooler. At normal ambient temperature ranges, it typically takes only about 10 minutes for the ATF to reach its desired operating temperature. However, in extreme conditions, for example, a vehicle having an external cooler which is not towing a trailer, and when the temperature is quite cold, for example, 10° F., the ATF fluid may never attain the desired operating temperature range if passed through a cooler. In any event, passing the ATF through a cooler decreases the efficiency of a vehicle until the desired operating temperature has been achieved.

In operation, the cooler bypass assembly will be secured to the transmission with the inlet port10.7in communication with the ATF outlet port indicated by the arrow Poand with the outlet port10.8in communication with the AFT inlet port Pi. When the vehicle is initially started, the ATF will be at ambient temperature, for example 55° F. At this temperature, it will flow through port Pointo the inlet port10.7and then through the transverse passageway10.6, and then out of the assembly through outlet port10.8and inlet port Pi. It will not flow to the cooler, as the temperature is not high enough to cause the thermal actuator60to expand and raise the ball52against the spring pressure to permit ATF flow past the ball52and to the cooler represented graphically at C inFIG. 2. If for any reason the cooler restricts flow, the ball12will open up, allowing bypass of the fluid past the cooler.