Sigma Powertrain, Inc.

Sigma Powertain, Inc.

R William Davis

John W Kimes

Graham Scott Russell

Daniel E Knieper

A method calculates a time for which a force is to be applied to a strut to have the strut lockingly engage a notch of a notch plate. The notch plate has a plurality of notches equidistantly spaced about a surface of the notch plate at a predetermined distance from each other. The method begins by measuring a rotational speed of the notch plate. The method then identifies the predetermined distance between the notches in the notch plate. The predetermined distance is divided by the measured speed to create a positioning time. A pivot time is added to the positioning time allow the strut to travel along the notch plate and into the notch a sufficient distance to physically lock the pocket plate and the notch plate together.

Method for operating clutch elements of a transmission

A method calculates a rotational speed of a node of a linkage in a transmission allows the continued operation of the transmission even when rotational speeds are difficult to sense due to the lack of rotational speed. The method begins by sensing rotational speed at each node to define a sensed rotational speed for each node. The sensed rotational speed at each node is compared to a threshold rotational speed. The sensed rotational speed continues to be used if an absolute value of the sensed rotational speed of the node is greater than the threshold rotational speed. A calculated rotational speed is calculated when the sensed rotational speed is less than the threshold rotational speed. The sensed rotational speed value is replaced with the calculated rotational speed for the node when the sensed rotational speed is less than the threshold rotational speed.

Method for determining the rotational speed of a node of a transmission

A transmission is shifted into a reverse state. The transmission includes a clutch. The clutch includes a pocket plate, a notch plate, a first strut housed within a pocket of the pocket plate, and a second strut housed within another pocket. A command is received to shift the transmission to reverse. It is then determined whether the at least one second strut has retracted into the pocket plate. If it remains extended, the first actuator is activated. A first rotational torque is applied to the notch plate in a direction allowing the notch plate to abut the first strut. By doing so, the second strut is released from abutting engagement with the notch plate. A second rotational torque is applied to the notch plate opposite the first rotational torque to rotate the notch plate out of engagement with the first strut, resulting in the transmission entering the reverse state.

Method for shifting a transmission of a vehicle into reverse

A method selectively locks a notch plate to a pocket plate such that the notch and pocket plates rotate together. The pocket plate includes struts that work in opposite directions. The pocket plate rotational speed and the notch plate rotational speed are identified. Once the notch plate rotational speed is close to the pocket plate rotational speed, the struts in one direction are activated. Once seated, the struts in the other direction are activated. This two-step engagement of the struts provides a smoother transition between clutch engagements (gear shifts) while not requiring the precision of having all struts activated at the same time.

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Orion, MI, United States of America

R William Davis