Gm Global Technolgoy Operations, Inc.

David Chris Webert

Todd R Berger

Timothy R Stockdale

Roberto Diaz

Dongxu Li

Matthew D Whitton

Xuefeng Tim Tao

John E Marano

Dara Monajemi

Scott D Biggs

Patrick M Gibson

Kristopher J Kokko

Scott R Verna

Amanda P Igel

Dustin A Nygaard

David H Moiseev

Joseph V Pittiglio

A method for controlling internal electronic range selection for an automatic transmission includes: confirming if a range change command has been ordered from a current transmission operating state; verifying expected performance from at least first and second mode valves and a park servo are present in the current transmission operating state prior to allowing a range change event; during the range change event: generating proactive commands including ordering a reduction in a hydraulic system pressure; and identifying if an unexpected event is detected; and following completion of the range change event confirming expected performance is obtained from at least the first and second mode valves and the park servo to achieve a driver intended state.

Method for controlling the internal electronic range selection for a 9 speed automatic transmission

A method of operating a motor vehicle transmission includes measuring an operating temperature of the transmission, the transmission having at least seven torque transmitting mechanisms and at least three planetary gear sets, each planetary gear set having three gear members; determining if the transmission is in a park mode; determining if the operating temperature is below a predetermined threshold; if the operating temperature is below the predetermined threshold and the transmission is the park mode, implementing a shift delay mitigation process that includes engaging a fourth torque transmitting mechanism and a firth torque transmitting mechanism of the at least seven torque transmitting mechanisms so that they are locked to a ground to prevent a first gear member of the first planetary gear set from moving, which, in turn, prevents an input torque being transferred to a park pawl.

Transmission with cold shift delay mitigation

A system for determining when a selectable one-way clutch has mechanically released includes an update timer identifying if each of a converter model engine torque, a transmission input torque, and a torque converter slip are positive for a predetermined period of time. An SOWC slip value is calculated using an output signal from each of: at least one transmission internal speed sensor producing an output signal representative of a speed of an internal component of a transmission; and at least one transmission output speed sensor producing an output signal representative of a speed of an output of the transmission. An SOWC released signal is issued if either all of the measured converter model engine torque, the measured transmission input torque, and the measured torque converter slip are positive for at least the predetermined period of time, or the calculated SOWC slip value is greater than a predetermined threshold.

System and method for determining when a selectable one-way clutch has mechanically released

A method of regulating a clutch assembly that has a set of clutch plates and a clutch piston with a fluid seal in an automatic transmission that includes a hydraulic circuit is disclosed. The method includes commanding the hydraulic circuit via the controller to apply a first hydraulic force to the clutch piston to displace the clutch piston relative to the set of clutch plates in order to affect a shift between speed-ratios in the transmission. The method also includes determining a drag force of the fluid seal. The method also includes determining a velocity of the displaced clutch piston that results from the drag force of the fluid seal acting counter to the displacement of the clutch piston. The method additionally includes regulating the clutch assembly to compensate for the determined drag force of the fluid seal acting counter to the displacement of the clutch piston.

Compensation for a drag force generated by a rotating clutch piston seal

A control system for a transmission of a vehicle includes a first angular rotation module, a second angular rotation module, and a slip module. The first angular rotation module determines a first angular rotation of a first component of the transmission during a predetermined period based on a first signal generated by a first sensor. The second angular rotation module determines a second angular rotation of a second component of the vehicle during the predetermined period based on a second signal generated by a second sensor. The slip module selectively indicates that a clutch of the transmission is slipping based on the first angular rotation and the second angular rotation.

Clutch slip identification systems and methods

A vehicle transmission includes a plurality of oncoming clutches that are hydraulically-actuated. A controller is operatively connected to the plurality of oncoming clutches. An algorithm stored on and executable by the controller causes the controller to determine if at least one predefined coast condition is met and identify the plurality of oncoming clutches configured to be engageable during a downshift event from an initial gear ratio to respective other gear ratios. The initial gear ratio is greater than each of the respective other gear ratios. The algorithm causes the controller to generate a first pressure command to at least partially pressurize a first one of the oncoming clutches to a first staging pressure (P) if the at least one predefined coast condition is met prior to the downshift event. The first staging pressure (PS) is defined as a first return spring pressure (P) minus a first variable correction factor (CF).

Partial prefill of clutch for coast downshift conditions in a vehicle

A control system for a transmission includes a pressure control module and a pressure adapt module. The pressure control module operates a hydraulic control system of the transmission at a target pressure during steady-state operation of the transmission. The target pressure is based on first and second learned pressures for different predetermined first and second torque ranges. The pressure adapt module selectively adjusts at least one of the first learned pressure and the second learned pressure based on a first pressure at which a slip condition of the transmission occurs. The first and second learned pressures define a learned pressure gain and offset. When adjusting the first and second learned pressures, the pressure adapt module limits increases and decreases in the learned pressure gain offset based on a predetermined pressure gain and offset. A method is also provided.

Control system and method for adaptive control of transmission fluid operating pressures

A control system for determining a desired gear ratio of an automatic transmission includes a pedal rate module that determines a pedal rate of an accelerator pedal, and a shift module that determines the desired gear ratio of the transmission based on a position of the accelerator pedal and the pedal rate. The shift module determines the desired gear ratio based on a comparison of the pedal rate and a predetermined rate. The predetermined rate is based on a first period since the transmission shifted into a current gear. The shift module also determines the desired gear ratio based on one of a second period the pedal rate remains less than a positive rate and a third period the pedal rate remains greater than a negative rate. A related control method is also provided.

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Livonia, MI, United States of America

David Chris Webert