Allison Transmission, Inc.

Gm Global Technolgoy Operations, Inc.

Jared S Shattuck

Jeffrey E Shultz

Peter G York

Stephen T West

Mark A Rains

John Andrew Byerly

Scott E Mundy

Burton Vance Krehbiel

Jeffrey E Schultz

A multi-speed automatic transmission having a control circuit for managing a hill climb event is provided. The control circuit may detect the hill climb event, such as by identifying when an upshift from a climb gear to an upshift gear would cause deceleration on a hill. The control circuit may also respond to the hill climb event based on desired performance characteristics, including fuel economy, speed, acceleration, and other performance characteristics. In one embodiment, the control circuit responds to the hill climb event by cycling the multi-speed automatic transmission between the climb gear and the upshift gear.

System and method for hill climbing gear selection

A device, system, and method for controlling transmission torque to provide hill ascent and/or descent assistance to a vehicle includes applying a clutch hold pressure to one or more clutches of a transmission to lock an output shaft of the transmission to resist roll-back of the vehicle. The clutch hold pressure is applied based on one or more of a transmission output speed signal, an engine throttle signal, and a vehicle brake signal.

Device and method for controlling transmission torque to provide hill ascent and/or descent assistance

The present invention provides a method of selecting and implementing a shift schedule for a transmission in a vehicle that includes an output speed sensor and a controller. The method includes measuring output speed with the output speed sensor and comparing the measured output speed to an output speed threshold. The controller receives throttle percentage and compares the throttle percentage to a throttle threshold. The method also includes calculating output acceleration and transmission gear ratio with the controller. The shift schedule is selected based on the measured output speed, calculated output acceleration, calculated transmission gear ratio, and throttle percentage.

Acceleration based mode switch

A device, system, and method for controlling transmission torque to provide hill ascent and/or descent assistance to a vehicle includes applying a clutch hold pressure to one or more clutches of a transmission to lock an output shaft of the transmission to resist roll-back of the vehicle. The clutch hold pressure is determined as a function of the tractive effort of the vehicle and is applied based on one or more of a transmission output speed signal, an engine throttle signal, and a vehicle brake signal.

Device, system, and method for controlling transmission torque to provide hill ascent and/or descent assistance using road grade

A powertrain incorporating an automatic transmission and an electrical control unit for control thereof, the electrical control unit implementing a return-to-range feature that will return to the automatic transmission to a previously selected forward (and, in some embodiments, reverse) gear when the service brake is applied first and then the parking brake is released while the service brake remains applied. Other embodiments are also disclosed.

System and method for automatic neutral and automatic return-to-range for use with an automatic transmission

A method for determining the condition of a transmission fluid filter and controlling an operator indicator to alert the operator that the fluid filter requires replacement is disclosed. The method includes monitoring a fluid pressure switch, determining an operating mode of the transmission, determining whether the operating mode of the transmission is changing, activating a timer if the operating mode is changing, recording the time, comparing the time to a predefined time threshold, determining whether the recorded time is greater than the predefined threshold, and activating the operator indicator to indicate that the fluid filter requires replacement if the recorded time is greater than the predefined threshold.

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Indianapolis, IN, United States of America

Jared S Shattuck