Circuit for ion current measurement in combustion space of an internal combustion engine

US5801534A · kind A · utility

Assignee

• Temic Telefunken Microelectronik · DE

Inventors

• Peter Hohner · Echterdingen, DE
• Jens Schirmer · Heilbronn, DE

Key dates

• Filing date: Jul 3, 1996
• Grant date: Sep 1, 1998
• Expiry date: Jul 3, 2016

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02P2017/128
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

An alternating current ignition system which can be used in one of two ways for ion current measurement. On the one hand, an oscillating circuit at the primary end of the ignition coil can be driven such that, after ignition has taken place, an alternating current signal is generated at the primary end; the amplitude of the alternating current signal must be sufficiently low so as not to cause any sparks at the secondary end, but lead to an alternating voltage signal which is modulated in relation to the ionisation degree of the ignition spark gap and thus represents an ion current measurement signal. On the other hand, however, if an auto transformer is used as an ignition coil, the intermediate circuit voltage applying at the primary end will be modulated in the medium-high voltage range of, e.g, 180 V in relation to the degree of ionisation, so that this supply voltage is used as a measurement signal.