Method of controlling a transmission

US6374688B1 · kind B1 · utility

Assignee

• Wabco GmbH & Co. Ohg. · DE

Inventors

• Gerhard Bockmann · Laatzen, DE
• Andreas Böhm · Wennigsen (Deister), DE

Key dates

• Filing date: Jul 17, 2000
• Grant date: Apr 23, 2002
• Expiry date: Jul 17, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T74/1926
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A method for controlling a transmission in a motor vehicle by operation of a transmission control system which evaluates the actuating wishes of the driver and by an electrical/pneumatic adjusting device, permits rapid shifting of gears in a non-synchronized transmission. In certain cases, for example when traveling uphill, the speed of the vehicle may decrease by the end of the gear changing process to such an extent that an engagement of the gear selected by the driver would lead to a drop below the engine idling speed. Similarly, the corollary applies to the highest acceptable engine speed, for example during down-hill travel. Therefore, the evolution in time of the actual transmission input speed or of the engine speed during a gear changing process is compared with the transmission input speed calculated on the basis of the gear ratio of the selected gear and the speed to be expected in case of synchronization of both speeds is calculated in advance. If the engine speed calculated in advance does not fall within the acceptable engine speed, another gear resulting in a rotational speed within the acceptable engine speed range is selected automatically.