Apparatus for detecting oscillations occurring during engine knock

US4255965A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Alfred Schulz · Oberriexingen, DE
• Bernward Boning · Ludwigsburg, DE
• Uwe Kiencke · Ludwigsburg, DE
• Heinz Theuerkauf · Lehre, DE
• Theodor Gast · Berlin, DE
• Gunter Honig · Ditzingen, DE
• Rudolf Nagel · Asperg, DE

Key dates

• Filing date: Jul 5, 1979
• Grant date: Mar 17, 1981
• Expiry date: Jul 5, 1999

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L23/222
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In order to suppress the train of detector oscillations after the disappearance of the engine knock phenomenon, the invention provides a piezoelectric oscillator which is set into vibration by engine knock and includes circuitry for applying signals of opposite polarity to the oscillator at times when no engine knock is expected. Accordingly, the output of the piezoelectric engine knock detector is used only in a relatively narrow time interval during the combustion cycle. In the remaining interval, the circuit switches over to a configuration where the oscillations of the piezoelectric oscillator are damped. The construction of the invention makes it possible to discriminate between different cylinders of a multi-cylinder engine and to assign the knock phenomenon to particular engine cylinders. A number of embodiments is presented.