Calibration System For Hydraulic Transmission
First Claim
1. A method of calibrating a hydraulic transmission for a machine, the transmission being driven by an engine and having an input shaft and an output shaft and a plurality of selectable gear ratios for altering a transmission ratio between the input shaft and output shaft, and a plurality of hydraulic clutches, each operable to select one of the plurality of selectable gear ratios when actuated, the method comprising:
- initiating at least one shift between a first gear ratio selected by a first one of the hydraulic clutches and a second gear ratio selected by a second one of the hydraulic clutches during operation of the machine;
determining a pulse width for a fill pulse usable to fill the second one of the hydraulic clutches based on torque transfer characteristics of the transmission during a shift;
determining a hold level current for the second one of the hydraulic clutches based on a duration of a shift; and
executing a subsequent shift between the first and second gear ratios by applying a fill pulse of the determined pulse width to fill the second one of the hydraulic clutches and then applying the derived hold level current.
1 Assignment
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Accused Products
Abstract
A calibration system for calibrating a transmission adjusts a clutch fill pulse width and hold level current for an oncoming clutch via calibration shifts during operation of the associated machine, thus establishing the desired shift timing and duration. The pulse width is calibrated based on torque transfer characteristics of the clutch during a test shift, and the hold level current is calibrated based on the shift duration of a further test shift.
59 Citations
20 Claims
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1. A method of calibrating a hydraulic transmission for a machine, the transmission being driven by an engine and having an input shaft and an output shaft and a plurality of selectable gear ratios for altering a transmission ratio between the input shaft and output shaft, and a plurality of hydraulic clutches, each operable to select one of the plurality of selectable gear ratios when actuated, the method comprising:
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initiating at least one shift between a first gear ratio selected by a first one of the hydraulic clutches and a second gear ratio selected by a second one of the hydraulic clutches during operation of the machine; determining a pulse width for a fill pulse usable to fill the second one of the hydraulic clutches based on torque transfer characteristics of the transmission during a shift; determining a hold level current for the second one of the hydraulic clutches based on a duration of a shift; and executing a subsequent shift between the first and second gear ratios by applying a fill pulse of the determined pulse width to fill the second one of the hydraulic clutches and then applying the derived hold level current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16)
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11. A computer-readable medium having computer-executable instructions for calibrating a transmission associated with a machine, the transmission having an input and an output and a plurality of selectable gear ratios between the input and output, the computer-executable instructions comprising:
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instructions for initiating a first test shift and a second test shift between a first gear ratio and a second gear ratio during operation of the machine; instructions for determining a first shift parameter based on torque transfer characteristics of the transmission during the first test shift; and instructions for determining a second shift parameter based on a duration of the second test shift; and instructions for executing a subsequent shift between the first and second gear ratios by applying the first and second shift parameters.
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17. An automatically calibrated transmission system for a machine comprising:
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a transmission having an input shaft and an output shaft and a plurality of selectable gear ratios between the input shaft and output shaft; a plurality of clutches, each having a piston and being operable to select one of the plurality of selectable gear ratios; a plurality of solenoid valves, each solenoid valve being associated with a respective one of the plurality of clutch pistons for controlling the operation of the clutch; a control module electrically linked to the plurality of solenoid valves for driving said solenoid valves; and a computer-readable memory electrically accessible to the control module and having computer-executable instructions for;
initiating a plurality of calibration shifts between a first gear ratio selected by a first one of the clutches and a second gear ratio selected by a second one of the clutches during operation of the machine, calibrating a fill pulse width for the second one of the clutches based on torque transfer characteristics of the transmission during a first shift, and calibrating a hold level current for the second one of the clutches based on a duration of a second shift. - View Dependent Claims (18, 19, 20)
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Specification