Clutch control system for a continuously variable transmission
First Claim
1. A clutch control system for regulating torque transfer from an engine through a continuously variable transmission to an associated driveline mounted in a vehicle, a fluid-actuated clutch operable to transfer drive torque to the associated driveline, a clutch supply line connected to supply fluid to apply the clutch and to discharge fluid to release the clutch, and a clutch control valve assembly coupled to said clutch supply line, which clutch control system comprises:
- a mode determination circuit connected to supply mode output signals to place the clutch control system in one of a plurality of operating modes, including start mode and drive mode;
means for supplying a plurality of information input signals, including a vehicle speed signal and a clutch input speed signal, to the mode determination circuit; and
means, in the clutch control system, for providing a regulating signal for the clutch control valve assembly which varies in accordance with the operating mode selected by the mode determination circuit.
3 Assignments
0 Petitions
Accused Products
Abstract
A clutch control system for a continuously variable transmission includes a mode determination system which samples input signals including position of the neutral-drive selector, driver demand, engine speed, vehicle speed, and clutch input speed. From these signals the operating mode is determined and the clutch control system operating mode is set. In starting the vehicle, a minor pressure feedback loop and a major engine speed feedback loop are used. When the clutch is locked up, these control loops are not employed in regulating the vehicle operation.
38 Citations
17 Claims
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1. A clutch control system for regulating torque transfer from an engine through a continuously variable transmission to an associated driveline mounted in a vehicle, a fluid-actuated clutch operable to transfer drive torque to the associated driveline, a clutch supply line connected to supply fluid to apply the clutch and to discharge fluid to release the clutch, and a clutch control valve assembly coupled to said clutch supply line, which clutch control system comprises:
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a mode determination circuit connected to supply mode output signals to place the clutch control system in one of a plurality of operating modes, including start mode and drive mode; means for supplying a plurality of information input signals, including a vehicle speed signal and a clutch input speed signal, to the mode determination circuit; and means, in the clutch control system, for providing a regulating signal for the clutch control valve assembly which varies in accordance with the operating mode selected by the mode determination circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A clutch control system for regulating torque transfer from an engine through a continuously variable transmission to an associated driveline mounted in a vehicle, a fluid-actuated clutch operable to transfer drive torque to the associated driveline, a clutch supply line connected to supply fluid to apply the clutch and to discharge fluid to release the clutch, and a clutch control valve assembly coupled to said clutch supply line, which clutch control system comprises:
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a mode determination circuit connected to supply mode output signals to place the clutch control sytem in one of a plurality of operating modes, including neutral mode, clutch hold mode, start mode, special start mode and drive mode; means for supplying a plurality of information input signals, including a manual selector position signal, a driver demand signal, an engine speed signal, a vehicle speed signal and a clutch input speed signal, to the mode determination circuit; and means, in the clutch control system, for providing a regulating signal for the clutch control valve assembly which varies in accordance with the operating mode selected by the mode determination circuit. - View Dependent Claims (10)
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11. A clutch control system for regulating torque transfer from an engine through a continuously variable transmission to an associated driveline mounted in a vehicle, a fluid-actuated clutch operable to transfer drive torque to the associated driveline, a clutch supply line connected to supply fluid to apply the clutch and to discharge fluid to release the clutch, and a clutch control valve assembly coupled to said clutch supply line, which clutch control system comprises:
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a mode determination circuit connected to supply mode output signals to place the clutch control system in one of a plurality of operating modes, including clutch hold mode, start mode and drive mode; means for supplying a plurality of information input signals, including a vehicle speed signal, a clutch input speed signal, a driver demand signal, and an engine speed signal, to the mode determination circuit; a pressure control loop, including a pressure loop controller, means for receiving an input signal which varies as a function of the fluid pressure in the clutch supply line, and means for providing a regulating signal for the clutch control valve assembly which varies in accordance with the operating mode selected by the mode determination circuit; and a speed control loop, including a speed loop controller, and means for receiving the engine speed signal and providing an output signal to the pressure loop controller when the speed loop is closed. - View Dependent Claims (12, 13, 14, 15, 16)
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17. The method of regulating a clutch control system which is operable to govern the torque transfer from an engine through a continuously variable transmission to an associated driveline mounted in a vehicle, comprising the steps of:
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providing a plurality of information-denoting input signals, including a driver demand signal signifying whether the driver has depressed the accelerator pedal, an engine speed signal, a vehicle speed signal, and a clutch input speed signal; operating on the plurality of input signals to determine in which of a plurality of modes the clutch control system should be operated, including a start mode and a drive mode; sensing the fluid pressure supplied to the clutch, and utilizing the clutch pressure signal to provide a control signal to the clutch to regulate its application and release; utilizing a closed pressure control loop and a closed engine speed loop to regulate operation of the clutch in the start mode; and regulating operation of the clutch without the pressure and feedback control loops when the system is in the drive mode.
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Specification