Gm Global Technolgoy Operations, Inc.

Mark A Rushing

Jeffrey E Shultz

John P Kresse

Randall S Conn

Edmond M Etchason

William J Wegeng

Bradley L Mc Cafferty

Joseph K S Johansson

Vickie M Rushing, Legal Representative

Ricke D Katko

A method for controlling a transmission in a motor vehicle includes determining a temperature of a fluid in the transmission, determining whether the torque converter lockup clutch is applied, and determining an engine torque of the motor vehicle. Then, the torque converter lockup clutch is applied and the transmission is prohibited from up-shifting if the temperature of the fluid exceeds a threshold, the torque converter lockup clutch is not applied, and the engine torque exceeds a second threshold. Next, a tractive effort of the motor vehicle is determined and the torque converter lockup clutch is deactivated when the temperature of the fluid is less than a third threshold, the tractive effort is less than a fourth threshold, or the engine torque is less than the second threshold.

Method and system for controlling transmission temperature

A vehicle transmission retarder control apparatus is provided including an engine, a throttle, a brake, a transmission having an output member with an actual transmission output speed, a speed sensor operable for measuring the actual transmission output speed, a plurality of user-commandable input devices for selecting a desired transmission output speed, and a controller having an algorithm for controlling the amount of retarder request to provide a zero or constant rate of deceleration independently of weight and axle ratio. Additionally, a method is provided for controlling a transmission retarder, including measuring the actual transmission output speed, sensing a desired transmission output speed using a plurality of user-commandable input devices, communicating the actual and desired speeds to a controller, and commanding the retarder to apply a continuously variable opposing torque to the transmission based on the actual and desired output speeds to achieve a constant rate of deceleration.

Adaptive retarder control method and apparatus

A method of controlling a driveline retarder of a powertrain including a transmission having a rotatable input shaft connected to an engine and an output shaft connected to the driveline retarder is provided. The method includes determining a set speed value and comparing the set speed value plus a customer modifiable constant value to a current rotational speed value of the output shaft. A driveline retarder cruise modulation torque request value is then calculated when the current rotational speed value of the output shaft is greater than or equal to the set speed value plus the customer modifiable constant value. The driveline retarder is controlled as a function of the driveline retarder cruise modulation torque request value. A powertrain configured to implement the aforementioned method is also disclosed.

Powertrain and method for controlling a driveline retarder

The method of the present invention is adapted to control transmission oil temperature. According to a preferred embodiment, the engine coolant temperature may be controlled in addition to or regardless of transmission oil temperature. To maintain transmission and/or engine temperature, the present invention is preferably configured to limit the engine's power when required to ensure the powertrain (engine and transmission) does not overheat.

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Martinsville, IN, United States of America

Mark A Rushing