Ion sensing method for capacitive discharge ignition

摘要

A method of ion sensing in a CD ignition system for an internal combustion engine comprises: a) closing the controllable switch in synchronism with the internal combustion engine for a period of time to transfer energy to the ignition coil primary to cause a spark breakdown across the spark plug; and b) observing the current in the secondary winding circuit indicative of ionization in the vicinity of the spark plug electrodes.

主权项

1. A method of ion sensing in a capacitive discharge ignition system for an internal combustion engine having a storage capacitor for being connected to a power supply in series with the storage capacitor, an ignition transformer having primary and second windings, and a controllable switch in series with the storage capacitor and the primary winding of the ignition transformer, an electronic circuit for controlling the controllable switch, a spark plug having electrodes in series with the secondary winding of the ignition transformer, the method comprising the steps of:
a) initially closing the controllable switch in synchronism with the internal combustion engine for a period of time to transfer energy to the primary winding to cause a spark breakdown across the spark plug; b) subsequent to the initial closing, repeatedly opening and closing the controllable switch to set or adjust a ratio of opening and closing periods to achieve a desired bias voltage across the spark plug electrodes that causes a continuously positive or continuously negative current flow in a secondary winding circuit; and c) observing the current flow in the secondary winding circuit, the current flow indicative of ionization in a vicinity of the spark plug electrodes during a period when the bias voltage is present across the spark plug electrodes and the current flow is present in the secondary winding circuit, wherein ionization in the vicinity of the spark plug electrodes is observed by an increase of the current flow in the secondary winding circuit.