US 8,296,024 B2 · Calibrating transmission motor torque

Abstract

The described system and method allow a controller to calibrate a transmission variator of a continuously variable transmission for torque control by obtaining static and dynamic qualities and parameters of the variator through an automated calibration procedure. The system and method employ a pair of transmission mode configurations and operational configurations in combination to obtain system-specific information. In this way, the system is able to calibrate out the system variations to provide effective feed forward torque control of the continuously variable transmission. In an embodiment, a first calibration operation is performed while the transmission is neutralized and a second calibration operation is performed while the transmission is engaged in a mode providing a fixed variator output speed.

Claims21

Dependent claims

A method of calibrating a transmission for open loop torque control operation, the transmission having a variator, the variator having an actuator and an output, the variator further having an internal circuit pressure, the method comprising:

engaging the transmission in neutral, such that the variator output experiences substantially zero torque;
with the transmission in neutral, commanding hydraulic pressure to the variator actuator to identify a displacement correlation between commanded hydraulic pressure to the actuator and variator displacement;
engaging the transmission into a mode wherein the variator provides a fixed output speed regardless of circuit pressure;
commanding hydraulic pressure to the variator actuator to identify a circuit pressure correlation between commanded hydraulic pressure and variator circuit pressure;
and
using the displacement correlation and circuit pressure correlation to control the transmission using feed forward torque control.

3 more elements

A system for calibrating a transmission for open loop torque control operation, the transmission having a variator, the variator having an actuator and an output, the variator further having an internal circuit pressure, the method comprising:

one or more sensors for indicating a displacement of the actuator;
one or more pressure sensors for determining the internal circuit pressure of the variator;
and
a controller for executing computer-readable instructions stored in a non-transitory storage medium for calibrating the transmission including:
instructions for engaging the transmission in neutral, such that the variator experiences substantially zero output torque, and commanding hydraulic pressure to the variator actuator to identify a displacement correlation between commanded hydraulic pressure to the actuator and variator displacement;
instructions for engaging the transmission into a mode wherein the variator produces an output having a fixed speed and commanding hydraulic pressure to the variator actuator to identify a circuit pressure correlation between commanded hydraulic pressure and variator circuit pressure;
and
instructions for using the displacement correlation and circuit pressure correlation to control the transmission using feed forward torque control.

5 more elements

Dependencies are inferred from the claim text.

Calibrating transmission motor torque

Life of this patent

Calibrating transmission motor torque

Life of this patent

Abstract

Claims21