SYSTEM AND METHOD FOR OPTIMIZING DOWNSHIFTING OF A TRANSMISSION DURING VEHICLE DECELERATION

A method of selecting a gear ratio of a transmission. The method includes measuring a current road grade with a sensing device and communicating the current road grade measurement to the controller. The controller receives a signal corresponding to a service brake input and determines a desired maxi...

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Bibliographische Detailangaben
Hauptverfasser: DYGERT, Todd, BYERLY, John, A, KRESSE, John, RAINS, Mark, A
Format: Patent
Sprache:eng ; fre ; ger
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Zusammenfassung:A method of selecting a gear ratio of a transmission. The method includes measuring a current road grade with a sensing device and communicating the current road grade measurement to the controller. The controller receives a signal corresponding to a service brake input and determines a desired maximum acceleration limit of the vehicle. The method also includes calculating a predicted vehicle acceleration, measuring a current vehicle acceleration, and calculating an error value as a function of the predicted vehicle acceleration and measured vehicle acceleration. The method also computes an estimated required tractive braking effort and estimated tractive braking effort for at least one of N automatically selectable gear ratios of the transmission and selects one gear ratio of the N automatically selectable gear ratios for the operation of the transmission based on a comparison of the estimated required tractive braking effort and estimated tractive braking effort.