Process for controlling the actuating pressure in a control element of an electrohydraulically controlled motor vehicle transmission

US5335567A · kind A · utility

Assignee

• Dr. Ing. h.c. F. Porsche AG · DE

Inventors

• Willi Seidel · Lambach, DE
• Joseph Petersmann · Wimsheim, DE

Key dates

• Filing date: Jul 27, 1992
• Grant date: Aug 9, 1994
• Expiry date: Jul 27, 2012

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2061/062
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A process is described for controlling the actuating pressure in a control element (shift element) of an electrohydraulically controlled transmission of a motor vehicle during a change of the gear position. In the case of downshifts in the coasting operation, the hydraulic pressure in the transmission is preferably increased with the initiating of the shifting by way of the pressure control valve in a time-limited manner. Starting from a presettable or preset basic value, the amount of this filling pulse is automatically and in steps for each control operation in the course of the operation of the transmission adapted to a target value in such a manner that an input rotational speed of the transmission or a rotational speed of a driving engine connected in front of the transmission follows a predetermined sequence of movements.