Chrysler Corporation

Daimlerchrysler Corporation

Aaron Pfadt

Gang Chen

David L Kwapis

A method for effecting a kickdown shift in a transmission of an automotive vehicle controls turbine speed change based on a continuous desired acceleration calculation. The method determines an initial speed of a turbine that transmits torque between an engine and a plurality of gears through a plurality of releasing and engaging elements. A target speed of one of the plurality of gears is determined. A desired time required to increase the turbine speed to the target speed is determined. A desired acceleration of the turbine is calculated according to the initial speed, the target speed, and the desired time. Turbine speed change rate is controlled through controlling the clutch torque of one or more of the releasing and engaging elements based on the desired acceleration.

Method for effecting kickdown shift

A transmission control system includes a first gear engagement element that receives fluid and engages a first gear. An electromagnetic actuator selectively interrupts fluid flow to the first gear engagement element based on a duty cycle of a control signal. A control module adjusts the duty cycle so that a fluid flow rate continuously decreases as the first gear engagement element produces a first torque sufficient to hold the first gear. The flow rate is based on a first estimated volume of the fluid necessary for the first gear engagement element to produce the first torque. The control module computes a current volume of the fluid when the first gear engagement element produces the first torque. The control module adjusts a value of the first estimated volume for subsequent transmission control when a difference between the current volume and the first estimated volume is greater than a predetermined volume.

Target volume based torque phase control during upshift

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.

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Salt Lake City, UT, United States of America

Aaron Pfadt