Daimlerchrysler Corporation

Chrysler Corporation

Chrysler Group LLC

David L Kwapis

Maurice B Leising

Hussein A Dourra

Ali M Mourtada

Gerald L Holbrook

Gang Chen

Aaron Pfadt

A transmission for a vehicle includes a first gear set and a second gear set. A first plurality of elements are operable in an applied state and a released state and a second plurality of elements are operable in an applied state and a released state. A controller toggles the first and second plurality of elements between the applied state and the released state to achieve a desired gear ratio. The controller times entry of at least one of the first and second plurality of elements into the released state with entry of at least another of the first and second plurality of elements into the applied state by controlling a hold pressure applied to the at least one element entering the released state. The controller determines the hold pressure by referencing current operating conditions of the transmission in a lookup table stored in a memory of the controller.

Swap shift control scheme for an automatic transmission

An automatic transmission for a vehicle includes an input shaft, an output shaft, a first and second plurality of gears, and a series of engagement elements. The series of engagement elements includes at least one overrunning engagement element in mechanical communication with the second plurality of gears. A controller is operable to disengage a first engagement element associated with a first one of the first plurality of gears and apply a second engagement element associated with a second one of the first plurality of gears to achieve a speed change of the first plurality of gears. The controller is adapted to disengage one of the overrunning engagement elements from engagement with one of the second plurality of gears within a range of 20 to 120 milliseconds after the speed change of the first plurality of gears to accomplish a gear shift of the transmission.

Swap shift control

A transmission control method improves shift feel during kickdown shifts. The release clutch is fully released at the initiation of the kickdown shift. The release clutch is then reapplied when the volume of the release clutch reaches a threshold capacity. The volume of the release clutch is slowly ramped down, thereby increasing turbine speed. When the turbine speed reaches a threshold, the apply clutch is actuated. The apply clutch is actuated by controlling the volume of the apply clutch according to a target volume.

Model based kickdown shift method for clutch to clutch shift transmissions with accumulators

An electronic transmission coastdown shift control method in which the transmission controller has the capacity to predict timing of apply element application. The control method of the present invention improves the shift sequence by accurately prefilling the apply element. The transmission controller vents the release element when apply element application is imminent and controls the application of the oncoming element to achieve a controlled element exchange for a smooth coastdown shift. A duty cycle is then applied to complete the oncoming element application with a soft yet quick application and control the engagement of the oncoming element. The identification of the application point of the oncoming element enables the apply element fill volume to be learned during coastdown shifts. It also enables the calculation of a line pressure correction factor necessary in accurately predicting application of the apply element. Anticipation of a coastdown tip-in condition is also provided. When a tip-in condition is sensed, a more aggressive fast fill of the apply element is undertaken in order to handle an approaching input torque increase.

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Auburn Hills, MI, United States of America

David L Kwapis