Clutch end-of-fill detection strategy
First Claim
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1. A method of controlling a transmission having a plurality of hydraulic clutches for shifting between one or more transmission ratios, the method comprising:
- determining to execute a shift of the transmission between a first ratio associated with an off-going hydraulic clutch of the transmission, which is currently engaged, and a second ratio associated with an on-coming hydraulic clutch of the transmission, which is currently disengaged;
commanding a decrease of hydraulic pressure to the off-going hydraulic clutch to begin disengagement of the off-going hydraulic clutch;
commanding a flow of hydraulic fluid to the on-coming hydraulic clutch to fill a clutch chamber of the on-coming hydraulic clutch via a clutch fill pressure command;
detecting a pressure spike greater than a predetermined magnitude in the chamber of the on-coming hydraulic clutch; and
determining based on the detected pressure spike that the clutch chamber is filled, and thereafter initiating a clutch modulation phase to fully engage the on-coming hydraulic clutch, whereby the on-coming hydraulic clutch is able to fully accept torque transferred from the off-going hydraulic clutch.
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Abstract
A system and method for controlling a hydraulic transmission uses a solenoid valve having a pressure sensor linked to the valve body operable to sense a hydraulic fluid pressure within a cavity of the valve body and to transmit an electrical signal based on the sensed pressure. The transmitted signal is used to identify the end of fill time, and thus to end a clutch fill phase and commence a clutch modulation or lock-up phase.
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Citations
19 Claims
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1. A method of controlling a transmission having a plurality of hydraulic clutches for shifting between one or more transmission ratios, the method comprising:
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determining to execute a shift of the transmission between a first ratio associated with an off-going hydraulic clutch of the transmission, which is currently engaged, and a second ratio associated with an on-coming hydraulic clutch of the transmission, which is currently disengaged; commanding a decrease of hydraulic pressure to the off-going hydraulic clutch to begin disengagement of the off-going hydraulic clutch; commanding a flow of hydraulic fluid to the on-coming hydraulic clutch to fill a clutch chamber of the on-coming hydraulic clutch via a clutch fill pressure command; detecting a pressure spike greater than a predetermined magnitude in the chamber of the on-coming hydraulic clutch; and determining based on the detected pressure spike that the clutch chamber is filled, and thereafter initiating a clutch modulation phase to fully engage the on-coming hydraulic clutch, whereby the on-coming hydraulic clutch is able to fully accept torque transferred from the off-going hydraulic clutch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of controlling a transmission having a plurality of hydraulic clutches for shifting between one or more transmission ratios, the method comprising:
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determining to execute a shift of the transmission between a first ratio associated with an off-going hydraulic clutch of the transmission, which is currently engaged, and a second ratio associated with an on-coming hydraulic clutch of the transmission, which is currently disengaged; commanding a decrease of hydraulic pressure to the off-going hydraulic clutch to begin disengagement of the off-going hydraulic clutch; commanding a flow of hydraulic fluid to the on-coming hydraulic clutch to fill a clutch chamber of the on-coming hydraulic clutch via a clutch fill pressure command; detecting a pressure rise greater than a predetermined magnitude in the chamber of the on-coming hydraulic clutch; determining based on the detected pressure rise that the clutch chamber is filled, and thereafter initiating a clutch modulation phase to fully engage the on-coming hydraulic clutch, whereby the on-coming hydraulic clutch is able to fully accept torque transferred from the off-going hydraulic clutch; and setting a clutch fill timer following commanding the flow of hydraulic fluid to the on-coming hydraulic clutch and prior to detecting a pressure rise in the chamber of the on-coming hydraulic clutch, and initiating the clutch modulation phase if the pressure rise is not detected prior to expiration of the clutch fill timer. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A transmission control system for controlling a transmission having a plurality of hydraulic clutches, the system comprising:
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a transmission controller for controlling a flow of hydraulic fluid to an on-coming clutch and an off-going clutch, the controller having a loop time less than about 2.5 ms; and a solenoid valve associated with each of the plurality of hydraulic clutches, each solenoid valve having a coil element linked to the transmission controller and usable to control a flow of hydraulic fluid through the solenoid valve, each solenoid valve further comprising; an inlet for receiving pressurized fluid from a hydraulic pump; an outlet for supplying a regulated flow of hydraulic fluid to a clutch chamber of the associated hydraulic clutch; and a pressure sensor fixed to the solenoid valve and being in fluid communication with the outlet and the clutch chamber, wherein the pressure sensor is adapted to sense a pressure within the solenoid valve and to transmit a signal indicative of a sensed pressure to the transmission controller for causing the transmission controller to modify operation of the solenoid valve. - View Dependent Claims (18, 19)
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Specification