Method of controlling downshift after braking in automatic transmissions of motor vehicles

US4501170A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Alfred Muller · Krefeld, DE
• Dieter Schaller · Neubulach, DE
• Manfred Schwab · Gerlingen, DE

Key dates

• Filing date: Jun 23, 1982
• Grant date: Feb 26, 1985
• Expiry date: Jun 23, 2002

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H59/54
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

After the gear ratio of an automatic transmission has been increased in response to a braking operation the return to normal operation of the automatic transmission is controlled by logic circuits interconnecting threshold switches operated by the brake pedal and the accelerator pedal and by a read-only memory that stores a maximum engine speed for all values of vehicle speed so that the higher gear ratio is maintained until either the brake is released or the maximum engine speed is exceeded and then the return to normal transmission operation is further delayed until the accelerator pedal is again actuated. In one method, during the period of further delay the gear ratio continues at its raised value. In another embodiment the period of further delay begins with storage of the vehicle speed at the moment and proceeds with control of the transmission to maintain that speed. It is also possible to operate the system so as not to restore normal operation of the transmission after braking when there is only a slight depression of the accelerator pedal.