Method for reducing jerking during gear shifting
AssigneeZF Friedrichshafen AG
InventorDirk Habeck
Life of this patent
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Abstract
The invention relates to a method to reduce jerking during shifting in an automatic gear box. The automatic gear box has a selection lever (22) with a forward drive (D) and reverse (R) operating positions, in addition to a parking position (P) and a neutral position (N). A first coupling is closed in positions R, N and D (first gear). By moving from position D and shifting to N, a second coupling is opened or by moving from position R and shifting to N, a third coupling is opened. The inventive method provides that the pressure level of the first coupling (K1) is reduced from a first (p1) pressure level to a second pressure level when a gear shifting condition is met. The first coupling (K1) is opened for a specific amount of time when a D/N or R/N shift in the selection lever is recognized.
Claims4
A method for reducing jerking during shifting in an automatic transmission driven by an internal combustion engine (1) with a selector lever (22) operable by a driver and having at least one forward drive (D) and one reverse drive (R) operating position, and one parking (P) and one neutral (N) position, the method comprising the steps of:
- closing a first clutch (K1) in the positions R, N and D (first gear);
- opening a second clutch (K2) when moving from the position D and shifting to N;
- opening a third clutch (K3) when moving from the position R and shifting to N;
- and
- wherein upon detection of a gear shift condition, reducing the pressure level of the first clutch (K1) from a first (p1(K1)) to a second (p2(K1)) pressure level, the second pressure level (p2(K1)) being above a slip limit so that the first clutch remains closed.
Dependencies are inferred from the claim text.