Patent Application
20170211715
The disclosure generally relates to a temperature based fluid bypass valve, and more specifically to a fluid bypass valve for a transmission fluid cooling circuit of a vehicle, and a method of assembling the transmission fluid cooling circuit.
Some fluid circuits will include a temperature based fluid bypass valve to open or close fluid communication in a fluid circuit based on a temperature of the fluid. For example, a transmission fluid cooling circuit of a vehicle may include a fluid bypass valve that opens and closes fluid communication between a transmission and a fluid cooler, based on a temperature of the transmission fluid circulating through the fluid bypass valve. When the temperature of the transmission fluid is less than a pre-defined temperature, the fluid bypass valve closes fluid communication between the transmission and the fluid cooler, thereby allowing the transmission fluid to warm up quickly. When the temperature of the transmission fluid increases to a temperature greater than the pre-defined temperature, the fluid bypass valve opens fluid communication between the transmission and the fluid cooler to cool the transmission fluid. In transmission fluid cooling circuits, the pre-defined temperature at which the fluid bypass valve opens is typically around 85° C.
Accordingly, when the temperature of the transmission fluid is less than the pre-defined temperature, such as during assembly of the vehicle and/or initial filling of the fluid circuit, the fluid bypass valve is normally closed, i.e., is positioned to close fluid communication between the transmission and the fluid cooler. This prevents the transmission fluid from circulating through the fluid bypass valve, and the portions of the fluid circuit downstream of the fluid bypass valve. This prevents leak testing all of the connections in the fluid circuit downstream of the fluid bypass valve until the temperature of the transmission fluid is increased to the pre-defined temperature, and the fluid bypass valve opens.
A fluid bypass valve assembly is provided. The fluid bypass valve assembly includes a housing that defines a first port, a second port, and a valve chamber. A valve member is disposed within the valve chamber. The valve member is moveable between a first position and a second position. The valve member closes fluid communication between the first port and the second port when the valve member is disposed in the first position. The valve member connects the first port and the second port in fluid communication when the valve member is disposed in the second position. The valve member includes a temperature based actuating mechanism that is operable to position the valve member in the first position when a temperature of a fluid circulating through the housing is equal to or less than a pre-defined temperature. The temperature based actuating mechanism is operable to position the valve member in the second position when the temperature of the fluid is greater than the pre-defined temperature. A temporary spacer is disposed within the valve chamber, and positions the valve member in the second position. The temporary spacer has a melting temperature that is approximately equal to the pre-defined temperature at which the temperature based actuating mechanism moves the valve member between the first position and the second position.
A transmission fluid circuit is also provided. The transmission fluid circuit includes a transmission, a fluid cooler, and a bypass valve assembly. The bypass valve assembly includes a housing that defines a first port, a second port, a third port, a fourth port, a first passage connecting the third port and the fourth port in fluid communication, and a valve chamber. A transmission outlet line is attached to and disposed in fluid communication with the transmission and the first port for circulating fluid from the transmission to the bypass valve assembly. A cooler supply line is attached to and disposed in fluid communication with the second port and the fluid cooler for circulating fluid from the bypass valve assembly to the fluid cooler. A cooler outlet line is attached to and disposed in fluid communication with the fluid cooler and the third port for circulating fluid from the fluid cooler to the bypass valve assembly. A transmission supply line is attached to and disposed in fluid communication with the fourth port and the transmission for circulating fluid from the bypass valve assembly to the transmission. A valve member is disposed within the valve chamber, and is moveable between a first position and a second position. When disposed in the first position, the valve member closes fluid communication between the first port and the second port. When disposed in the second position, the valve member connects the first port and the second port in fluid communication. The valve member includes a temperature based actuating mechanism that is operable to position the valve member in the first position when a temperature of the temperature based actuating mechanism is equal to or less than a pre-defined temperature. The temperature based actuating mechanism is operable to position the valve member in the second position when the temperature of the temperature based actuating mechanism is greater than the pre-defined temperature. A temporary spacer is disposed within the valve chamber, between the first port and the second port. The temporary spacer positions the valve member in the second position when the temperature of the temperature based actuating mechanism is equal to or less than the pre-defined temperature. The temporary spacer has a melting temperature that is equal to or greater than the pre-defined temperature.
A method of assembling a transmission fluid circuit of a vehicle is also provided. The method includes providing a bypass valve assembly. The bypass valve assembly includes a housing defining a first port, a second port, and a valve chamber. A valve member is disposed within the valve chamber. The valve member is moveable between a first position closing fluid communication between the first port and the second port, and a second position connecting the first port and the second port in fluid communication. The valve member includes a temperature based actuating mechanism that is operable to position the valve member in the first position when a temperature of the temperature based actuating mechanism is equal to or less than a pre-defined temperature. The temperature based actuating mechanism is operable to position the valve member in the second position when the temperature of the temperature based actuating mechanism is greater than the pre-defined temperature. A temporary spacer is disposed within the valve chamber, between the first port and the second port. The temporary spacer positions the valve member in the second position when the temperature of the temperature based actuating mechanism is equal to or less than the pre-defined temperature. The temporary spacer has a melting temperature approximately equal to the pre-defined temperature. Fluid communication between the bypass valve assembly and a transmission is established. Additionally, fluid communication between the bypass valve assembly and a fluid cooler is established. The transmission, the bypass valve assembly, and the fluid cooler cooperate to define a fluid circuit through which a fluid circulates in a loop. The fluid is circulated through the fluid circuit with the fluid at a temperature of less than the pre-defined temperature. The fluid circuit is then inspected for leaks. The fluid is then circulated through the fluid circuit with the fluid at a temperature equal to or greater than the pre-defined temperature, to melt the temporary spacer and dissolve the temporary spacer into the fluid.
Accordingly, during initial assembly of the fluid circuit, prior to fluid circulating through the fluid bypass valve at temperatures greater than the pre-defined temperature at which the valve member moves between the first position and the second position, the temporary spacer positions the valve member in the second position to open fluid communication between the first port and the second port, thereby allowing the fluid to circulate through the entire fluid circuit, even though the fluid is at a temperature less than the pre-defined temperature when the fluid bypass valve normally closes fluid communication between the first port and the second port. This enables the inspection of the entire fluid circuit during initial assembly and filling of the fluid circuit. Once the fluid is heated to a temperature equal to or greater than the melting temperature of the temporary spacer, the temporary spacer melts and is dissolved into the fluid, thereby allowing the fluid bypass valve to operate normally.
The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the teachings when taken in connection with the accompanying drawings.
Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Furthermore, the teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions.
Referring to the Figures, wherein like numerals indicate like parts throughout the several views, a bypass valve assembly is generally shown at 20. The bypass valve assembly is shown and described herein as part of a transmission fluid cooling circuit, which is generally shown in
Referring to
The bypass valve assembly 20 controls fluid communication between the transmission 24 and the fluid cooler 26. The bypass valve assembly 20 may be configured in any suitable manner that is capable of closing fluid communication between the transmission 24 and the fluid cooler 26 when a temperature of the transmission fluid is less than a pre-defined temperature, and opening fluid communication between the transmission 24 and the fluid cooler 26 when the temperature of the transmission fluid is equal to or greater than the pre-defined temperature. The pre-defined temperature may be set to any temperature, and is dependent upon the specific system and type of fluid. For example, the pre-defined temperature for the transmission fluid cooling circuit 22 may be defined approximately equal to 85° C.
An exemplary embodiment of the bypass valve assembly 20 is shown and described herein. However, it should be appreciated that the bypass valve assembly 20 may be configured and operate differently than the exemplary embodiment. Referring to
The bypass valve assembly 20 is connected to the transmission 24 and the fluid cooler 26 in fluid communication. As shown in
Referring to
The housing 28 includes a first position land 52 defined by the valve chamber 42. The valve member 30 includes a seal surface 54 that seals against the first position land 52 when the valve member 30 is disposed in the first position to prevent fluid communication between the first port 32 and the second port 34. The seal surface 54 of the valve member 30 is axially spaced from the first position land 52 along a central axis 56 of the bypass valve assembly 20 when the valve member 30 is disposed in the second position.
The bypass valve assembly 20 includes rod 58 that extends along the central axis 56, and is generally concentric with the central axis 56. In the exemplary embodiment shown in the Figures and described herein, the rod 58 is fixed in position along the central axis 56 relative to the housing 28. However, in other embodiments that incorporate a pressure bypass system (not shown) into the bypass valve assembly 20, the rod 58 may be moveable along the central axis 56 relative to the housing 28. The valve member 30 includes an outer shell 60, which encapsulates a wax material 62. The rod 58 partially extends into an interior of the outer shell 60, and is partially surrounded by the wax material 62.
The housing 28 further defines a pocket 64, adjacent the valve chamber 42 along the central axis 56. A biasing device, such as but not limited to a coil spring 66, is disposed within the pocket 64, adjacent the valve member 30. The coil spring 66 biases against the valve member 30, axially along the central axis 56, to bias the valve member 30 toward and into sealing engagement with the first position land 52.
The bypass valve assembly 20 includes a temperature based actuating mechanism 68. The temperature based actuating mechanism 68 is operable to position the valve member 30 in the first position when the temperature of the transmission fluid is equal to or less than the pre-defined temperature. The temperature based actuating mechanism 68 is operable to position the valve member 30 in the second position when the temperature of the transmission fluid is equal to or greater than the pre-defined temperature.
In the exemplary embodiment shown and described herein, the temperature based actuating mechanism 68 includes the rod 58, the wax material 62 encapsulated within the valve member 30, and the coil spring 66. The temperature based actuating mechanism 68 operates based on the melting temperature of the wax material 62 of the valve member 30. The wax material 62 of the valve member 30 includes a melting temperature approximately equal to the pre-defined temperature, e.g., approximately 85° C. It should be appreciated that the melting temperature of the wax material 62 of the valve member 30 may differ from the exemplary temperature noted herein. It should also be appreciated that the temperature of the wax material 62 within the valve member 30, and thereby the temperature of the temperature based actuating mechanism 68 increases and/or decreases as the temperature of the transmission fluid increases and/or decreases respectively. When the temperature of the wax material 62 encapsulated within the valve member 30 increases to the melting temperature of the wax material 62, the wax material 62 begins to melt. As the wax material 62 melts, it expands, and biases against the portion of the rod 58 disposed within the valve member 30 and surrounded by the wax material 62, thereby moving the valve member 30 relative to the rod 58 and into the second position. As the wax material 62 cools and begins to solidify, the wax material 62 contracts, and the coil spring 66 biases the valve member 30 toward and into sealing engagement with the first position land 52, thereby moving the valve member 30 relative to the rod 58 into the first position. It should be appreciated that the temperature based actuating mechanism 68 may differ from the exemplary embodiment shown and described herein.
Referring to
The temporary spacer 70 has a melting temperature that is approximately equal to or greater than the pre-defined temperature. For example, the melting temperature of the temporary spacer 70 may be between 60° C. and 115° C. The specific value of the melting temperature of the temporary spacer 70 may vary from the exemplary range described above, and is dependent upon the pre-defined temperature at which the valve member 30 moves between the first position and the second position.
Preferably, the temporary spacer 70 includes and is manufactured from a wax compound. In some embodiments, the wax compound of the temporary spacer 70 and the wax material 62 encapsulated in the valve member 30 are the same material, having the same melting temperature. This ensures that the temporary spacer 70 and the wax material 62 encapsulated within the valve member 30 will melt at approximately the same temperature.
As noted above, the temporary spacer 70 of the exemplary embodiment is disposed between the seal surface 54 of the valve member 30 and the first position land 52. Referring to
A method of assembling the transmission fluid circuit 22 described above is also provided. The method includes providing the bypass valve assembly 20. The bypass valve assembly 20, such as shown in
Once the fluid cooler 26, the bypass valve assembly 20, and the transmission 24 have been connected to each other in fluid communication, the transmission fluid is circulated through the fluid circuit 22, with the transmission fluid being at a temperature less than the melting temperature of the temporary spacer 70, and less than or equal to the pre-defined temperature at which the valve member 30 moves between the first position and the second position. The temporary spacer 70, which is positioned in the bypass valve assembly 20 to position the valve member 30 in the second position, allows the transmission fluid to circulate or flow between the first port 32 and the second port 34, even though the temperature of the transmission fluid is less than the pre-defined temperature, and the bypass valve assembly 20 would be positioned in the first position to close fluid communication during normal operation. Accordingly, the temporary spacer 70 enables initial fluid flow between the first port 32 and the second port 34 during the initial filling and testing phase of the assembly. This enables the transmission fluid to be introduced into and circulate through the entire fluid circuit 22, even when the transmission fluid is at ambient temperatures and less than the pre-defined temperature at which the valve member 30 of the fluid bypass valve would normally open fluid communication to the entire fluid circuit 22. Because the transmission fluid is at a temperature that is less than the melting temperature of the temporary spacer 70, the temporary spacer 70 does not melt as the transmission fluid circulates through the fluid circuit 22.
Circulating the transmission fluid through the entire fluid circuit 22 during the initial assembly of the transmission fluid cooling circuit 22, allows the entire fluid circuit 22 to be inspected for leaks, without having to operate the vehicle and raise the temperature of the transmission fluid and/or the temperature based actuating mechanism 68 to a temperature equal to or greater than the pre-define temperature.
Once the fluid circuit 22 has been inspected for leaks and completely filled, the transmission fluid may be circulated through the fluid circuit 22 with the transmission fluid at a temperature equal to or greater than the melting temperature of the temporary spacer 70. At the first occurrence of the transmission fluid temperature increasing to a temperature that is equal to or greater than the melting temperature of the temporary spacer 70, the temporary spacer 70 will melt and dissolve into the transmission fluid, thereby allowing the bypass valve assembly 20 to operate as normal, with the valve member 30 able to move between the first position and the second position as the temperature of the transmission fluid changes, such as shown in
The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed teachings have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims.
