Multidependent valve timing overlap control for the cylinders of an internal combustion engine

US4856465A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Helmut Denz · Stuttgart, DE
• Martin Person · Oberriexingen, DE

Key dates

• Filing date: Nov 29, 1983
• Grant date: Aug 15, 1989
• Expiry date: Nov 29, 2003

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

The oil pressure applied to a hydraulic device for controlling within a limited angular range of a cam shaft and its drive gear is controlled by a magnetic valve (35) which is switched between its open and closed position under control of the same microcomputer which controls engine ignition and/or fuel injection with reference to a predetermined function of some of the same engine operation parameters, namely engine speed and engine load, which are used to control ignition and/or fuel injection. The control function can advantageously also take account of rate of change of engine load or engine speed. A transducer (43) for reporting back the sleeve (22) which controls the mechanical rotary shift in response to oil pressure can be used to provide an actual value signal to the computer for generation of an error signal for controlling the magnetic valve so as to provide a continuous control of the overlap of the open periods of the intake and exhaust valves of the engine. The control function for the operation of the magnetic valve provides for hysteresis to prevent excessive switching back and forth.