Gm Global Technolgoy Operations, Inc.

Jeryl McIver

Xuefeng Tim Tao

David H Vu

Christopher Jay Weingartz

Jayson S Schwalm

Matthew Kempeinen

Craig J Hawkins

Greg J Perantoni

Daniel Deras

Leo P Dion

Woowon Chung

A pressure sensor rationality diagnostic for a dual clutch transmission includes a series of sensor tests. One such test includes charging an oil accumulator to a maximum pressure and storing the maximum pressure value. After performing a discharge pressure event and measuring the pressure value, the difference between the max pressure value and the discharge pressure value is calculated to determine if the difference is less than a predetermined threshold. If the difference is less than the predetermined threshold then at least one remedial action is performed which may include a driver alert or default charging mode. Additionally, similar sensor tests are performed to determine if faults exists and, if true, at least one remedial action is performed.

Pressure sensor rationality diagnostic for a dual clutch transmission

A method of controlling a transmission includes detecting a first inflection point and a second inflection point in the movement of the accelerator pedal. An amplitude between the first inflection point and the second inflection point is then calculated, and a period of time between the first inflection point and the second inflection point is measured. An attenuation coefficient is defined from the amplitude and the measured period of time between the first and second inflection points. A current iteration temporary gear ratio is defined as the gear ratio calculated during the most recent iteration of an iterative gear ratio selection algorithm, and is adjusted with the defined attenuation coefficient to define a current iteration final output gear ratio. The operation of the transmission is then controlled to change the transmission from a previous iteration final output gear ratio to the current iteration final output gear ratio.

Method of controlling a gear ratio of a transmission

A method for learning the bite point of a position-controlled clutch in a vehicle having an engine and a transmission includes commanding an engagement of a clutch fork via a controller when the transmission is in park and the engine is idling. The method also includes controlling an apply position of the clutch via the controller, calculating a clutch torque capacity of the clutch, and measuring the apply position via a position sensor. The apply position is recorded as the clutch bite point when the calculated clutch torque capacity equals a calibrated clutch torque capacity. The transmission is then controlled using the recorded clutch bite point. A system includes the transmission, input clutches, and a controller configured to execute the method. A vehicle includes an engine, the transmission, the position-controlled input clutch, and the controller, as well as a clutch position sensor.

Transmission system with clutch bite point learning logic

A method of learning a kiss point of a first clutch of a dual clutch transmission includes controlling a rotational speed of the input shaft to be within a pre-determined range. When both the first clutch and the second clutch are determined to be disengaged from the input shaft, and the rotational speed of the input shaft is within the pre-determined range, then the first clutch is moved from a disengaged position into an engaged position. An increase in a rotational speed of a first transmission shaft, which is coupled to the first clutch, is detected. When the increase in the rotational speed of the first transmission shaft is detected, a position of the first clutch is identified. The identified position of the first clutch is saved in a memory of a transmission control module as a learned first clutch kiss point.

Method of learning a clutch kiss point for a clutch of a dual clutch transmission

A method of identifying a synchronous position of a synchronizer actuator fork includes sensing a deceleration rate of a first shaft, when a synchronizer is positioned in a neutral position, to define a first rate of deceleration. The synchronizer is moved along the first shaft from the neutral position toward a gear with a synchronizer actuator fork. A deceleration rate of the first shaft is sensed, while the synchronizer actuator fork moves the synchronizer along the first shaft, to identify a change from the first rate of deceleration to a second rate of deceleration. The location, of the synchronizer actuator fork relative to the first shaft, at which the rate of acceleration of the first shaft changes from the first rate of deceleration to the second rate of deceleration, is identified as the synchronous position of the synchronizer actuator fork.

Method of identifying a synchronous position of a synchronizer actuator fork of a dual clutch transmission

A method of controlling a dual clutch transmission includes repeatedly moving a synchronizer into interlocking engagement with a first gear with an actuator fork, and repeatedly sensing a position of the actuator fork for each occurrence that the actuator fork moves the synchronizer into the interlocking engagement with the first gear. The sensed positions of the actuator fork are averaged to define a first engaged position of the actuator fork for engaging the first gear. A second engaged position at which the actuator fork couples the synchronizer to a second gear may be determined in the same manner. A neutral position may be determined by identifying the axial locations of peak acceleration of the actuator fork while moving between the first engaged position and the second engaged position. The identified axial locations are averaged to define the neutral position of the actuator fork.

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Inkster, MI, United States of America

Jeryl McIver