Method and control unit for operating a drive train of a vehicle
AssigneeZF Friedrichshafen AG
InventorJonas Knör
Life of this patent
Estimating the term…
Abstract
A method for operating a drive train (1) of a vehicle monitoring the actual slip forming at a particular first shift element of a transmission (5), comparing the actual slip with a target slip, adapting a characteristic map depending on a deviation between the actual slip and the target slip. The characteristic map is used to determine a shift-element pressure for providing the target slip for a particular first shift element in order to implement a gear ratio change.
Claims9
A method for operating a drive train (1) of a vehicle that includes an electric machine (3), a transmission (5), and a driven end (6), the transmission (5) connected between the electric machine (3) and the driven end (6) and including at least three shift elements (7, 8, 9), comprising:
- in order to implement a gear ratio change from an actual gear into a target gear, actuating a first shift element of the transmission (5) with a shift-element pressure, which depends on a system pressure of the transmission (5), in order to provide a target slip at the first shift element, wherein the first shift element is engaged both in the actual gear and in the target gear;
- disengaging a second shift element of the transmission (5) for the target gear, wherein the second shift element is engaged in the actual gear;
- engaging a third shift element of the transmission (5) for the target gear, wherein the third shift element is disengaged in the actual gear;
- monitoring an actual slip forming at the first shift element;
- comparing the actual slip with the target slip;
- and
- adapting a characteristic map depending on a deviation between the actual slip and the target slip, wherein the characteristic map is configured to determine the shift-element pressure for the first shift element to provide the target slip and implement the gear ratio change.
A control unit (10) for a vehicle configured for:
- in order to implement a gear ratio change from an actual gear into a target gear, actuating a first shift element of a transmission (5) with a shift-element pressure, which depends on a system pressure of the transmission (5), in order to provide a target slip at the first shift element, the first shift element engaged in both the actual gear and in the target gear;
- actuating a second shift element of the transmission (5) to disengage for the target gear, the second shift element engaged in the actual gear;
- actuating a third shift element of the transmission (5) to engage for the target gear, the third shift element disengaged in the actual gear;
- comparing an actual slip forming at the first shift element with the target slip;
- and
- adapting a characteristic map depending on a deviation between the actual slip and the target slip,
- wherein the characteristic map is usable to determine the shift-element pressure for providing the target slip for the first shift element in order to implement the gear ratio change.
Dependencies are inferred from the claim text.