Hydraulic slip control method and arrangement for a driveline including a continuously variable transmission
AssigneeTransmission Cvtcorp Inc.
InventorDaniel Girard
Life of this patent
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Abstract
A slip control method and arrangement for a driveline including a continuously variable transmission is described herein. The driveline includes a hydraulic slip arrangement that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the hydraulic slip arrangement prevents the prime mover from stalling.
Claims16
A method to control the slippage of a driveline including a prime mover having an output, a continuously variable transmission (CVT) having an input connected to the output of the prime mover and an output, a controllable slippage level hydraulic slip arrangement having an input connected to the output of the CVT and an output, the hydraulic slip arrangement including a planetary gear assembly provided with one input and first and second outputs;
- the input defining the input of the hydraulic slip arrangement;
- the first output defining the output of the hydraulic slip arrangement;
- the second output being connected to a hydraulic pump provided with a controllable release valve, the method including the steps of:
- determining a usable torque of the prime mover;
- and
- controlling the slippage level of the hydraulic slip arrangement to allow the usable torque to pass through the hydraulic slip arrangement but to slip should a requested torque be greater than the usable torque by controlling the release valve to allow the hydraulic pump to rotate should the requested torque be greater than the usable torque.
A driveline including:
- a prime mover having an output shaft;
- means for determining the speed of the output shaft;
- a CVT having an input connected with the output shaft of the prime mover and an output;
- a controllable hydraulic slip arrangement having an input connected with the output of the CVT and an output;
- the controllable hydraulic slip arrangement includes a planetary gear assembly provided with one input and first and second outputs;
- the input defining the input of the hydraulic slip arrangement the first output defining the output of the hydraulic slip arrangement the second output being connected to a hydraulic pump provided with an adjustable release valve;
- a slip controller controlling the level of torque allowed to pass through the hydraulic slip arrangement before slippage occurs therein;
- and
- a main controller connected with the output shaft speed determining means and the slip controller;
- the main controller being so configured as to determine a usable portion of the available torque of the prime mover and to set the slip controller so that the adjustable release valve allows the hydraulic pump to rotate to thereby cause the hydraulic slip arrangement to slip when torques greater than the usable torque attempt to pass through the hydraulic slip arrangement.
Dependencies are inferred from the claim text.