Method of controlling frictionally engageable couplings of an automatic transmission of a motor vehicle

US4742461A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Gerhard Eschrich · Tettnang, DE
• Achim Schreiber · Schwieberdingen, DE
• Manfred Schwab · Gerlingen, DE

Key dates

• Filing date: Sep 30, 1985
• Grant date: May 3, 1988
• Expiry date: Sep 30, 2005

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/72
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

Reference values are stored for various conditions of gear shift operations of a vehicle motor of a particular type and model for various motor speed and load combinations, the reference values having a magnitude characterizing the gear shifting operation, for example the time interval required from the appearance of a gear shift command until the end of slip in a coupling indicates that the gear shift is complete. As the vehicle is driven, actual values of this magnitude are stored and averaged for a predetermined number of shift operations under the same class of condition. Correction values for the pressure of hydraulic fluid of the gear shift control, originally set at zero for all conditions, are determined by comparison of reference values with average actual values and stored. In subsequent driving, the stored correction values are used to control the pressure of the hydraulic medium to maintain a standard of comfort for all shift operations and new average actual values are used from time to time to modify the correction values for compensation of aging effects.