Gm Global Technolgoy Operations, Inc.

Allison Transmission, Inc.

Scott T Kluemper

Jeffrey E Shultz

Jeffrey Kurt Runde

Bruno Re

Kevin Kluemper

John P Kresse

Scott E Mundy

Andrew L Mitchell

Phillip F Mc Cauley

Steven Franklin James

Transmissions, control systems for transmissions, and methods of operating transmissions are disclosed. A transmission includes an input shaft, an output shaft, one or more clutches, and a control system. The input shaft is configured to receive rotational power supplied by a drive unit. The output shaft is coupled to the input shaft and configured to provide rotational power supplied to the input shaft to a load. The one or more clutches are coupled between the input shaft and the output shaft to selectively transmit rotational power between the input shaft and the output shaft in one or more operating modes of the transmission. Each of the one or more clutches is selectively engageable in response to one or more fluid pressures applied thereto. The control system is configured to control operation of the one or more clutches to select the one or more operating modes of the transmission.

Transmission control systems to adjust clutch pressure and torque based on grade

Transmissions, control systems for transmissions, and methods of operating transmissions are disclosed herein. A transmission includes an input shaft, an output shaft, one or more clutches, and a control system. The input shaft is configured to receive rotational power supplied by a drive unit. The output shaft is coupled to the input shaft and configured to provide rotational power supplied to the input shaft to a load. The one or more clutches are coupled between the input shaft and the output shaft to selectively transmit rotational power between the input shaft and the output shaft in one or more operating modes of the transmission. Each of the one or more clutches is selectively engageable in response to one or more fluid pressures applied thereto. The control system is configured to control operation of the one or more clutches to select the one or more operating modes of the transmission.

According to a preferred embodiment of the present invention, a clutch is applied when the vehicle comes to a stop. The application of this clutch locks the output shaft with energy stored therein. When the shift selector is then moved to the park position, the clutch releases the stored energy in a controlled manner by slipping the clutch plates. The controlled slipping reduces the noise as the park pawl tooth contracts an output gear tooth.

Method for improving a drive-to-park shift

A process for learning the pressure and volume characteristics for a given torque-transmitting mechanism is established on the final assembly line wherein a powertrain incorporating the desired transmission learning is installed within a vehicle. During the test process, the vehicle speed is generally maintained at Idle and the vehicle shift mechanism is maintained in Park, thereby mechanically locking the transmission output shaft. The torque-transmitting mechanisms to be learned are then engaged and disengaged in a predetermined sequence and the volume of the torque-transmitting mechanisms and the pressure characteristics of the controlling solenoid are learned.

Method of determining initial transmission calibration

An engine control for a motor vehicle powertrain coordinates engine speed and torque limiting during automatic transmission range changing so as to provide both vehicle rocking capability and adequate protection for the transmission. A transmission controller temporarily limits the engine speed to a predetermined value on each transition to or from the forward or reverse ranges, and superimposes continuous engine speed and torque limitations when an abusive rocking maneuver is detected. An abusive rocking maneuver is detected when the driver commands at least a specified number of successive range shifts during a predetermined time interval, and the speed and torque limitations are imposed until range shifting is discontinued for at least a calibrated period of time.

Engine control method responsive to transmission range changing

An improved downshift control for an automatic transmission optimized for sequential shifting achieves skip-downshifting to a target gear by shifting the transmission to neutral and controlling the engine output torque while the transmission is reconfigured to establish the target speed ratio. The engine torque control is designed to allow the transmission input speed to reach the synchronization speed for the target speed ratio at a desired time, and the shift is completed when the transmission input speed actually reaches the synchronization speed. The engine torque control is predicated on a modeled engine torque parameter, and the torque control includes an adaptive parameter for adaptively adjusting the torque control to ensure that the input speed reaches the synchronization speed at the desired time.

Multi-stage skip downshift control for an automatic transmission

A transmission control method comprises the steps of determining whether a shift requiring an output shaft lock-up is commanded, wherein such a shift involves a first torque transmitting mechanism either being applied or released while a second torque transmitting mechanism is held engaged. The control determines whether the vehicle is stopped by one or all of the following: verifying the vehicle service brakes are applied, the transmission output speed is near zero, the engine speed is low, the oil sump temperature is greater than a calibration temperature, and the turbine speed is near zero if the vehicle is in forward drive. If the vehicle is stopped, a lock-up torque transmitting mechanism is applied prior to the shift operable to prevent torque transmission to the output shaft. When the lock-up mechanism reaches capacity, the shift proceeds by one of applying and releasing the first mechanism, while maintaining the second mechanism engaged. Once the first mechanism has one of reached capacity and released pressure below a threshold, the lock-up mechanism is released to complete the shift.

Transmission shift control

An assembly of housings is secured is secured together by a plurality of bolt members. The assembly is subject to a source of vibration, such as an internal combustion engine. To ensure the natural frequency of the bolt is outside the operating range of the engine, tolerance support rings are installed to reduce the effective length of the bolts and thereby increase the natural frequency.

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Greenwood, IN, United States of America

Scott T Kluemper