Ignition system using a Wiegand wire

US4217874A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Gerhard Sohner · Schorndorf, DE
• Walter Ruf · Ditzingen, DE

Key dates

• Filing date: Jun 28, 1978
• Grant date: Aug 19, 1980
• Expiry date: Jun 28, 1998

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02P7/067
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

Changes in the magnetic field around a Wiegand wire created by a magnetic rotor coupled to a shaft of the engine induce a signal in a sensing coil. The signal is applied to an input switch which forms part of a control circuit. The output of the control circuit is connected to an interrupter switch connected in series with an ignition coil such that a spark is created at the secondary of the ignition coil when the interrupter switch opens. The control circuit maintains the interrupter switch in the nonconductive state for a predetermined percentage of the ignition cycle at low engine speeds and for a lesser percentage at high engine speeds so that enough energy can build in the ignition coil prior to the next interruption at the higher speeds.