Gm Global Technolgoy Operations, Inc.

Joseph William Tatangelo

Paul G Otanez

Zhen J Zhang

Virinchi Mallela

Hari C Perla

Alexander J Severt

A control system and method for controlling a continuously variable transmission in a vehicle propulsion system includes measuring a speed ratio of the continuously variable transmission, determining whether the measured speed ratio is drifting away from a commanded speed ratio, and adjusting the commanded speed ratio to a value that is different than a desired speed ratio if the measured speed ratio is drifting away from the commanded speed ratio.

Method and system for controlling a continuously variable transmission for a vehicle propulsion system

A continuously variable transmission pump limited stop controls system includes a continuously variable transmission (CVT) including primary and secondary variator pulleys. The primary and the secondary variator pulley each have a mating half with a conical face, defining a variable-width gap between each pulley and its mating half. A flexible member is positioned within the gap and is movable on the conical faces defining a CVT ratio. A secondary pulley valve controls flow of a fluid to the secondary variator pulley. A secondary pulley pressure boost system identifies if a rapid stop event is occurring and issues a command to fully open the secondary pulley valve during the rapid stop event. As the CVT ratio reaches a predetermined threshold of a desired relaunch ratio during the rapid stop event, an engine speed request is issued to an engine connected to the CVT to increase engine speed.

Continuously variable transmission pump limited stop controls

A continuously variable transmission (CVT) including a hydraulically-controllable variator is described. A method for controlling the CVT includes detecting a transient event causing a commanded change in a speed ratio of the variator and disabling feedback control of hydraulic pressure to the variator during the transient event. A target pressure that achieves the commanded change in the speed ratio of the variator is determined, and a pressure trajectory is determined based upon the target pressure. A feed-forward control of the hydraulic pressure to the variator is executed in response to the pressure trajectory during the transient event.

Method and apparatus to control a continuously variable transmission

A method and apparatus for controlling a continuously variable transmission (CVT) of a powertrain system includes determining a target clamping pressure and an actual clamping pressure, and determining a proportional correction term and an integral correction term based upon the target clamping pressure and the actual clamping pressure. An adapt correction term is determined based upon the target clamping pressure and a temperature of the CVT. A commanded clamping pressure for controlling the CVT is determined based upon the proportional correction term, the integral correction term and the adapt correction term. A pressure command is employed to drive an actuator of a moveable sheave of a pulley of a variator of the CVT based upon the commanded clamping pressure.

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Wolverine Lake, MI, United States of America

Joseph William Tatangelo