Gm Global Technolgoy Operations, Inc.

Dean E McCulloch

Bruce D Lockhart

Gordon L Tierney

Cyrus A Wehner

Chi-Kuan Kao

Raymond James Haka

Kumaraswamy V Hebbale

Joel M Maguire

A countershaft transmission and control has an input shaft, two countershafts and an output differential. Each countershaft has a fluid operated clutch connected therewith to selectively connect the respective countershaft with the output differential through reduction gearing. A plurality of drive and driven gear members are connected in meshing relation between the input shaft and the countershafts. Individually operable synchronizers are disposed on the countershafts to selectively engage the driven gears with the countershaft to establish gear ratios between the input shaft and the output differential. The synchronizers are operated by a control mechanism comprised of drive keys for selectively connecting synchronizer forks with a longitudinally movable shaft member. The control mechanism is also operable to provide a positive displacement pump assembly operated by the shaft member to deliver pressurized fluid to the clutch member for enforcing engagement thereof.

Transmission and shift control

An upshift control in which open-loop control parameters are adaptively adjusted to improve the shift quality in a subsequent upshift to the same ratio. A multi-variable adaptive control methodology attributes detected torque phase timing deviations to variability in the on-coming fill time and/or return spring pressure, and suitably corrects the parameter(s) so that in the next shift of the same type, the detected deviation will be reduced or eliminated. The torque phase timing deviations are detected by measuring specified intervals in relation to the achievement of predetermined input and output acceleration conditions, and comparing the measured intervals with reference intervals. The gradients of the deviations in relation to the respective control parameter are determined and stored in a look-up table, and subsequently used to determine adaptive correction values.

Adaptive electronic control of power-on upshifting in an automatic

The net engagement pressure of a torque converter clutch is controlled in response to a commanded slip and a slip error indication, for isolating engine torque perturbations from the vehicle driveline. The transmission of an excessive level of engine speed perturbation is detected and used to develop a correction amount for the measured slip. The correction amount increases the slip error indication and causes the slip to be controlled at a higher level, thereby reducing the amount of transmitted engine torque perturbation.

Closed loop clutch slip control system with turbine roughness control

The output power of an automotive powertrain including a throttled engine and a stepped ratio transmission is maintained substantially constant during upshifting of the transmission. The powertrain output torque is actively measured during shifting, and the output power of the powertrain is controlled by modulation of the engine throttle position and spark timing, and the transmission clutch apply pressures.

Closed loop shift quality control system

The net engagement pressure of a torque converter clutch having a negative slope capacity vs. slip characteristic is controlled to stably regulate the clutch slip, and thereby isolate engine torque perturbations from the vehicle driveline. The pressure is scheduled with a proportional term responsive to transient slip speed deviations and an integral term responsive to steady state slip speed deviations. Feed forward terms responsive to the throttle changes which force steady state slip speed deviations act to increase the speed of response of the integral term.

Gain scheduling technique for a closed loop slip control system

Vehicle operating conditions including vehicle acceleration and the position of an operator manipulated accelerator pedal are monitored to determine whether transient or steady state operation is indicated. When transient operation is indicated, the vehicle power output is brought into correspondence with a power command determined according to accelerator pedal position. When steady state operation is indicated, the vehicle power output is brought into correspondence with a power command determined according to the difference between the vehicle velocity and a remembered velocity.

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Washington, MI, United States of America

Dean E McCulloch