Apparatus and method for predicting the health of a power transmission
First Claim
1. A method for predicting via a controller the health of an automatic transmission having at least one torque transmitting device with a calibrated air volume and a calibrated number of friction faces, the method comprising:
- determining a free running clearance of the at least one torque transmitting device;
determining a free running clearance per face of the at least one torque transmitting device;
determining if said free running clearance per face is greater than a calibrated free running clearance per friction face for failure of the at least one torque transmitting device;
determining if a shift has converged;
determining a total number of completed converged shifts when said shift has converged;
determining if said total number of completed converged shifts is greater than a threshold number of completed converged shifts;
determining an initial clutch volume if said total number of completed converged shifts is greater than said threshold number of completed converged shifts;
determining an initial free running clearance of the at least one torque transmitting device;
determining a change in free running clearance per face of the at least one torque transmitting device;
determining if said change in free running clearance per face is greater than a calibrated change in free running clearance per friction face of the at least one torque transmitting device for failure; and
activating a service indicator configured to signal that transmission service is required in response to at least one of said free running clearance per face being greater than said calibrated free running clearance per friction face for failure and said change in free running clearance per face being greater than said calibrated change in free running clearance per friction face for failure.
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Accused Products
Abstract
An improved method for predicting the health of a power transmission and an apparatus for practicing the same are provided. The method includes: monitoring a total number of converged shifts after a first shift has converged; determining if the total number of converged shifts is greater then a calibrated number of completed converged shifts; if yes, determining an initial clutch volume, an initial free running clearance, a free running clearance, and a free running clearance per face and monitoring a change in free running clearance per face; determining if either the free running clearance per face is greater than a calibrated free running clearance per friction surface for failure or if the change in free running clearance per face is greater than a calibrated change in free running clearance per friction surface for failure; if yes, activating a service indicator configured to warn vehicle occupants that transmission service is required.
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Citations
19 Claims
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1. A method for predicting via a controller the health of an automatic transmission having at least one torque transmitting device with a calibrated air volume and a calibrated number of friction faces, the method comprising:
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determining a free running clearance of the at least one torque transmitting device; determining a free running clearance per face of the at least one torque transmitting device; determining if said free running clearance per face is greater than a calibrated free running clearance per friction face for failure of the at least one torque transmitting device; determining if a shift has converged; determining a total number of completed converged shifts when said shift has converged; determining if said total number of completed converged shifts is greater than a threshold number of completed converged shifts; determining an initial clutch volume if said total number of completed converged shifts is greater than said threshold number of completed converged shifts; determining an initial free running clearance of the at least one torque transmitting device; determining a change in free running clearance per face of the at least one torque transmitting device; determining if said change in free running clearance per face is greater than a calibrated change in free running clearance per friction face of the at least one torque transmitting device for failure; and activating a service indicator configured to signal that transmission service is required in response to at least one of said free running clearance per face being greater than said calibrated free running clearance per friction face for failure and said change in free running clearance per face being greater than said calibrated change in free running clearance per friction face for failure. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for predicting the health of an automatic transmission having at least one torque transmitting device with a calibrated air volume and a calibrated number of friction faces, said method comprising:
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determining if a shift has converged; monitoring a total number of completed converged shifts when said shift has converged; determining if said total number of completed converged shifts is greater than a calibrated number of completed converged shifts; determining an initial clutch volume if said total number of completed converged shifts is greater than said calibrated number of completed converged shifts; determining an initial free running clearance of the at least one torque transmitting device; determining a free running clearance of the at least one torque transmitting device; monitoring a change in free running clearance per face of the at least one torque transmitting device; determining if said change in free running clearance per face is greater than a calibrated change in free running clearance per friction face for failure of the at least one torque transmitting device; and activating via a controller a service indicator configured to warn vehicle occupants that transmission service is required in response to said change in free running clearance per face being greater than said calibrated change in free running clearance per friction face for failure. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A control apparatus for a transmission having an input shaft in powerflow communication with an output shaft, at least one differential gear set, at least one clutch mechanism positioned between the transmission input and output shafts and operable to effect a speed ratio change through selective engagement and disengagement thereof, and at least one fill chamber to which hydraulic fluid is supplied for hydraulic actuation of the at least one clutch mechanism, the control apparatus comprising:
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a controller in operative communication with the transmission to control the selective engagement and disengagement of the at least one clutch; and a service indicator operatively connected to said controller and configured to warn vehicle occupants that transmission service is required; wherein said controller is programmed and configured to monitor a total number of completed converged shifts when a first shift has converged; wherein said controller is programmed and configured to determine if said total number of completed converged shifts is greater than a calibrated number of completed converged shifts; wherein said controller is programmed and configured to determine an initial clutch volume, an initial free running clearance, a free running clearance, and a free running clearance per face of the at least one clutch; wherein said controller is programmed and configured to monitor a change in free running clearance per face of the at least one clutch; wherein said controller is programmed and configured to determine if said free running clearance per face is greater than a calibrated free running clearance per friction face for failure of the at least one clutch and if said change in free running clearance per face is greater than a calibrated change in free running clearance per friction face for failure of the at least one clutch; and wherein said controller activates said service indicator in response to at least one of said free running clearance per face being greater than said calibrated free running clearance per friction face for failure and said change in free running clearance per face being greater than said calibrated change in free running clearance per friction face for failure. - View Dependent Claims (17, 18, 19)
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Specification