Ion-gap sensing for engine control
This article reports that in addition to detecting misfire to conform with California onboard diagnostic (OBD II) regulations, Delco Electronics and Mecel AB engineers are looking at ion-gap sensing to control knock, A/F ratio, and other possible engine control parameters. The combustion of fuel in an engine cylinder produces ions. Detection of those ions by the spark plug (ion-gap sensing), and use of the resulting ion currents, has been employed in engine management systems since 1988. Saab introduced the first application, for cam-phase sensing. The main driving force for ion-gap sensing is OBD II requirements for 100% misfire detection at all speeds and loads. The technique has been expanded in subsequent applications to include misfire, knock, and pre-ignition detection and control, and more recently in combustion-ion detection using a capacitance-type, ion-current measurement method. Use of the ion current`s wave shape to control knock allows elimination of the separate piezoelectric type (PZT) sensor. Future applications could provide additional engine-control features including air/fuel ratio measurement and control.
- OSTI ID:
- 124466
- Journal Information:
- Automotive Engineering, Vol. 103, Issue 9; Other Information: PBD: Sep 1995
- Country of Publication:
- United States
- Language:
- English
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