Gm Global Technolgoy Operations, Inc.

Minh Q Truong

Steven Patrick Moorman

Bret M Olson

Paul G Otanez

Christopher Jay Weingartz

Craig J Hawkins

Chinar S Ghike

Glenn W Hoefflin

Mohamed O Egal

A target module determines a target ratio between a speed of an input shaft and a speed of an output shaft of a continuously variable transmission (CVT) based on an accelerator pedal position. A maximum rate of change (ROC) module determines a maximum ROC of the target ratio. A switching valve control module, based on a comparison of the maximum ROC and a ROC of the target ratio, selectively actuates a switching valve of the CVT one of (i) from a closed position to an open position and (ii) from the open position to the closed position. The switching valve prevents transmission fluid flow through a flow path between a transmission fluid pump and a pressure regulator valve of the CVT when the switching valve is in the closed position. The switching valve allows transmission fluid flow through the flow path when the switching valve is in the open position.

Pump switching control systems and methods for continuously variable transmissions

A switching valve control module selectively actuates a switching valve of a continuously variable transmission (CVT) either: (i) from a closed position to an open position; or (ii) from the open position to the closed position. The switching valve prevents and allows transmission fluid flow through a flow path between a transmission fluid pump and a pressure regulator valve of the CVT when the switching valve is in the closed position and the open position, respectively. An adjustment determination module determines a pressure adjustment when the switching valve actuates. A target pressure module determines a target pressure output from the pressure regulator valve. An adjusting module determines an adjusted target pressure based on the pressure adjustment and the target pressure. A regulator valve control module controls opening of the pressure regulator valve based on the adjusted target pressure.

Transmission fluid pressure control systems and methods for continuously variable transmissions

A method and system for controlling movement of an actuator fork of a transmission through a pre-synchronization phase of a synchronization event at a pre-synchronization fork velocity includes adjusting the level of fluid pressure applied to an actuator operatively attached to the actuator fork to control the pre-synchronization fork velocity within a predetermined range of a velocity target. The method determines, via a controller, the fork velocity during the pre-synchronization phase of a current synchronization event, compares the determined fork velocity to a velocity target, and adjusts the pressure level of fluid applied to an actuator piston of the actuator to control the velocity of the actuator fork within a predetermined range defined by the velocity target during a subsequent pre-synchronization phase. The velocity target may be defined for a shift type, such as a fast or slow shift, where the shift type is determined by the controller.

Method of controlling a synchronizer actuator fork of a transmission

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Commerce Township, MI, United States of America

Minh Q Truong