Hydraulic control system for automatic vehicle transmission - has split hydraulic servo systems for rapid response gear changing, two servos operating one gear, and third operating second gear

摘要

The transmission has a planetary gearing with friction elements for selecting the gear ratios. The friction elements are driven by hydraulic servos. Two servos operate one gear and a third servo operates a second gear. A switching controller supplies the required servo, and a pressure control circuit generates the required hydraulic pressure for the gearchange operation. The split hydraulic servos operate on the same gear, first gear. One servo applies the gear and the second changes down into the first gear (retardation). The whole transmission is controlled by an electronic processor programmed for the particular vehicle. ADVANTAGE - Fast gearchange for either manual- or programmed control. No risk of gear change judder.