Automatic transmission with electronically controlled torque transmission during gear shift

US4228700A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Helmut Espenschied · Ludwigsburg, DE
• Uwe Kiencke · Ludwigsburg, DE
• Alfred Schulz · Oberriexingen, DE

Key dates

• Filing date: Aug 9, 1978
• Grant date: Oct 21, 1980
• Expiry date: Aug 9, 1998

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H63/502
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A first and second valve respectively associated with the then-present and the newly selected gear during a gear shift operation are operated with positive overlap at the beginning of the shift process if the engine is upshifting under load or downshifting under no and at the end of the shift process if the engine is upshifting under no load or downshifting under load. During the shift process the engine speed is lowered during upshift operations and increased during downshifts. The shifting process is terminated when the engine is operating synchronously with the transmission output. It is also terminated if the engine speed decreases excessive during upshifts or increases excessively during downshift or if a predetermined maximum allowable time has elapsed from the start of the shift operation. The main pressure in the gearing is decreased during the shift operation by a factor selected in accordance with the then-present operating condition.