Gm Global Technolgoy Operations, Inc.

Colin Hultengren

Craig J Hawkins

Dongxu Li

Christopher E Whitney

Ronald F Lochocki, Jr

Matthew D Whitton

Xuefeng Tim Tao

Christopher Jay Weingartz

David W Wright

Krishnendu Kar

Michael A Kropinski

Crystal Nassouri

Klaus Pochner

Kenneth K Lang

Timothy R Stockdale

Jonathan P Kish

Leon O Cribbins

Glenn W Hoefflin

James L Abington

Tobias Berndtson

Krishnedu Kar

Johan Larsson

Manmeet Mavi

Chet Daavettila

Sriram Venkataramanan

A continuously variable transmission, a control system, and a method are provided. The control system and method are configured to learn a desired running pressure to be applied to a clutch that is lower than a pulley clamping pressure and higher than a pressure at which the clutch would slip (a clutch critical pressure), so that the clutch can act as a fuse to avoid pulley slip. A plurality of clutch slip tests are performed, each of which include decreasing pressure supplied to the clutch until a clutch slip occurs. Clutch slip data points are collected at the point of slip and used to determine a gain and an offset, where the gain is a clutch pressure versus clutch torque capacity gain, and the offset is a clutch pressure offset, which is used to determine the clutch critical pressure.

Adaptive clutch slip learning for critical capacity clutch fusing in a continuously variable transmission

A vehicle includes an engine, a transmission having a position-controlled clutch with a synchronizer sleeve and a synchronizer fork, an input member with an input speed, and an output member with an output speed, and a controller. The controller is programmed to register a slip-away condition when the input speed falls within a calibrated speed band and the output speed remains below a calibrated threshold speed. In response to the registered slip-away condition, the controller records a diagnostic code indicative of the synchronizer sleeve being disengaged, changes an engaged position of the synchronizer sleeve by a calibrated amount to thereby adapt the engaged position, and commands the clutch to disengage and the fork to move to a neutral position after increasing the engaged position. The controller also moves the synchronizer sleeve toward the adapted engaged position and applies the clutch when the synchronizer sleeve attains the adapted engaged position.

Synchronizer fork position control

A vehicle includes an engine, transmission, engine control module (ECM), and transmission control module (TCM). The transmission includes an input member and an input clutch which selectively connects a crankshaft of the engine to the input member. The TCM identifies a target clutch torque of the input clutch during a creep maneuver of the vehicle, and communicates the identified target clutch torque to the ECM. The ECM maintains engine idle speed at a threshold level through the creep maneuver and a requested launch using the target clutch torque as a feed-forward term. A method includes identifying a target clutch torque of the input clutch during a creep maneuver, and communicating the identified target clutch torque to the ECM. The idle speed is maintained at a threshold level by the ECM through the creep maneuver and a detected launch using the target clutch torque as a feed-forward idle speed control term.

Feed-forward engine idle speed control

A system and method can control the dry dual clutch transmission (dDCT) of a vehicle. The method includes modifying a recorded torque-to-position (TTP) table based on a calculated clutch torque difference between a calculated clutch torque and a commanded clutch torque. The commanded clutch torque is provided by a transmission control module and is defined as a clutch torque sufficient to move the vehicle without applying the accelerator applier after the brake applier has been released. The calculated clutch torque is a function of the actual engine torque value, the engine inertia, and the engine acceleration.

System and method for controlling a dry dual clutch transmission of a vehicle

A vehicle includes an engine, an engine control module (ECM), and a dual clutch transmission (DCT) assembly. The DCT assembly has first and second input clutches, first and second gear sets selectively connected to the engine via the respective first and second input clutches, and a transmission control module (TCM). In executing a launch control method, the TCM receives a launch request, receives an actual engine torque, and determines the inertia and acceleration of the engine. The TCM then calculates a clutch torque for the particular input clutch used for vehicle launch as a function of the actual engine torque and the product of the inertia and the acceleration, compares the calculated clutch torque to the commanded clutch torque, modifies a torque-to-position (TTP) table depending on the comparison result, and transmits a clutch position signal to the designated input clutch to command an apply position extracted from the TTP table.

Dual clutch transmission vehicle launch control

A method of controlling the performance of a vehicle from a stationary condition includes operating a vehicle powertrain in a creep mode following the disengagement of a driver-operated braking device; and operating the vehicle powertrain in a launch mode following an engagement of a driver-operated acceleration device subsequent to the disengagement of the driver-operated braking device. Operating a vehicle powertrain in a creep mode includes: applying a friction clutch to couple an engine crankshaft of the vehicle powertrain with an input shaft of the transmission; determining a torque command to accelerate the vehicle powertrain at a predetermined rate; providing the torque command to an engine controller to controllably increase the input torque to the transmission; and operating a closed loop engine speed control module to prevent the crankshaft speed from slowing below a predetermined engine idle speed.

Automatic transmission input clutch control

A vehicle simulation system includes a first simulation model that when executed simulates a software ring along with other software of a vehicle module. The vehicle simulation system further includes a second simulation model of the software ring. A bypass switch that has a first state and a second state. A bypass switching module switches the bypass switch between the first simulation model and the second simulation model based on a bypass signal and a ring enabling signal. A simulation control module executes code of a vehicle simulation model including software in-the-loop (SIL) testing of a selected one of the first simulation model and the second simulation model based on state of the bypass switch.

Vehicle simulation system with software-in-the-loop bypass control

Growing community of inventors

New Hudson, MI, United States of America

Colin Hultengren