Transfer case clutch calibration method
First Claim
1. A method of enhancing transfer case performance in a motor vehicle comprising the steps of:
- providing a transfer case having an input, a clutch and a secondary output,providing a motor for supplying torque to said input, a controller for controlling a drive signal to said clutch and means for sensing torque delivered to said secondary output,modulating said drive signal so as to move said transfer case clutch through a complete engagement cycle, wherein said engagement cycle commences and ends at a disengagement position or at a maximum engagement position,determining a drive signal versus torque function for said clutch,associating a drive signal versus torque function profile with said transfer case, andstoring said associated profile in machine readable format with said transfer case.
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Abstract
A method of improving performance of secondary driveline clutches in motor vehicle transfer cases includes the steps of testing each manufactured transfer case to determine the clutch drive current versus torque transfer function, fitting such determined function to one of a small number of predetermined performance curves and incorporating an identification of the selected one of such predetermined performance curves in the transfer case. When the transfer case is installed in a vehicle, the curve identification is read and the transfer case control module (TCCM) adjusts its clutch drive signal in accordance with the predetermined curve to achieve known and desired torque transfer through the clutch with a given clutch drive signal.
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Citations
20 Claims
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1. A method of enhancing transfer case performance in a motor vehicle comprising the steps of:
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providing a transfer case having an input, a clutch and a secondary output, providing a motor for supplying torque to said input, a controller for controlling a drive signal to said clutch and means for sensing torque delivered to said secondary output, modulating said drive signal so as to move said transfer case clutch through a complete engagement cycle, wherein said engagement cycle commences and ends at a disengagement position or at a maximum engagement position, determining a drive signal versus torque function for said clutch, associating a drive signal versus torque function profile with said transfer case, and storing said associated profile in machine readable format with said transfer case. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of improving transfer case performance comprising the steps of:
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providing a transfer case having an input, a secondary output clutch and a secondary output, providing a drive motor for supplying torque to said input and a sensor for sensing torque delivered to said secondary output, cycling said secondary output clutch from a minimum drive signal to a maximum drive signal and returning to said minimum drive signal, determining a drive signal versus torque function for said secondary output clutch, matching said drive signal versus torque function to one of a number of predetermined function profiles, and associating the matched profile with said transfer case. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method of improving transfer case performance in a motor vehicle comprising the steps of:
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providing a transfer case having an input, a secondary output clutch, a variable engagement signal governing the engagement of the secondary output clutch, and a secondary output, determining an engagement signal versus torque output function for said secondary output clutch, fitting said engagement signal versus torque output function to one of a plurality of predetermined function profiles, storing the profile with said transfer case, and providing said profile to a transfer case control module. - View Dependent Claims (17, 18, 19, 20)
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Specification