US 11,767,911 B2Granted

Method and control apparatus for operating a multiple-speed vehicle transmission

AssigneeZF Friedrichshafen AG

InventorsFabian Ley, Jürgen Blaser, Sascha Fiesel, Wolfgang Rapp

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Abstract

Disclosed is a method for operating a multi-speed vehicle transmission having a plurality of shift elements (A, B, C, D, E) for engaging the gears of the vehicle transmission. The method includes decoupling between an input (AN) and an output (AB) of the vehicle transmission in a neutral gear, and coupling the input (AN) and the output (AB) of the vehicle transmission in a drive gear for propelling the vehicle by closing at least one shift element (B). At least one transmission state is determined when the neutral gear is engaged, where a shift element (D) for a reverse gear of the vehicle transmission is closed at least partially if the transmission is in a state with increased drag losses when the neutral gear is engaged.

Claims11

Dependent claims

A method for operating a multi-speed vehicle transmission, comprising:

providing a plurality of shift elements for engaging gears of the vehicle transmission having an input and an output;
engaging a neutral gear in which the input and the output are decoupled from each other such that propulsion is not transmitted therebetween via the vehicle transmission;
coupling the input to the output in a drive gear for propelling the vehicle by closing at least one shift element of the plurality of shift elements;
determining, when the neutral gear is engaged, at least one transmission state of the vehicle transmission;
and
of the plurality of shift elements, closing, at least partially, another shift element for a reverse gear when the vehicle transmission is determined to be in a transmission state with increased drag losses when the neutral gear is engaged;
and
determining an actuation state of a vehicle brake in addition to the transmission state when the neutral gear is engaged;
ventilating the other shift element for the reverse gear when the neutral gear is engaged and the vehicle brake is actuated;
and
of the plurality of shift elements, preloading or prefilling with a pressure medium the at least one shift element for a forward gear.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/864,816Filed 14 Jul 2022
Priority: DE 10 2021 207 810.921 Jul 2021
Published: US 2023/0023472 A126 Jan 2023
Granted: 26 Sep 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

F16H 61/0437
Smoothing ratio shift: by using electrical signals
F16H 61/682
Specially adapted for stepped gearings: with interruption of drive
F16H 59/40
Of gearing elements: output shaft speed
F16H 59/44
Inputs being a function of speed: dependent on machine speed , e.g. the vehicle speed