Apparatus for controlling gear shifts in automatic transmissions

US4258591A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Konrad Eckert · Stuttgart, DE
• Helmut Espenschied · Ludwigsburg, DE
• Georg Rothfuss · Sonthofen, DE
• Alexander Witte · Bremen, DE

Key dates

• Filing date: Aug 9, 1978
• Grant date: Mar 31, 1981
• Expiry date: Aug 9, 1998

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2059/183
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

To improve vehicle operator comfort and safety and to reduce wear and tear on the automatic transmission, the apparatus prevents an upshift whenever the accelerator pedal is released very quickly. The apparatus stores the load signal which prevailed when the load was abruptly reduced, thereby simulating to the transmission controller a continuation of high load and preventing an undesired upshift, for example in downhill operation and during roll-outs. Normal load signals are restored whenever the accelerator pedal is returned to a predetermined point. In one embodiment, the stored load signal is a hydraulic pressure and in another embodiment, for use with an electronic transmission controller, the load signal is an electrical signal. In a third embodiment, the upshift control signal from the controller to the transmission is interrupted when the apparatus indicates a complete release of the accelerator pedal.