Ignition system with ignition current and minimum spark duration controls
AssigneeRobert Bosch GmbH
InventorsWerner Schiele, Richard Schleupen
Life of this patent
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Abstract
To prevent misfires, the current through an ignition coil is increased in response to an error signal indicating that the actual spark duration was less than a predetermined minimum spark duration. At the start of the spark, a capacitor is discharged at a known rate. The time required for the voltage across the capacitor to reach a predetermined level is the desired spark duration. This regulation of ignition current causes the spark duration to be very close to the minimum spark duration, thereby cutting losses in the apparatus.
Claims13
In an ignition system having ignition coil means (Zs), means (T5) for producing an ignition current in said ignition coil means, and means connected to said ignition coil means for producing a spark upon interruption of said ignition current in said ignition coil means:
- apparatus for controlling said ignition current to produce a spark having a predetermined desired spark duration comprising
- current control means (40,T1) connected to said ignition coil means for controlling said ignition current in correspondence to a current control signal applied thereto;
- means (C8, R28) for furnishing a desired spark duration signal corresponding to said predetermined desired spark duration;
- means (T7) connected to said ignition coil means for furnishing an actual spark duration signal corresponding to the actual duration of said spark produced by said spark producing means;
- means (IC3) connected to said desired spark duration signal furnishing means and said actual spark duration signal furnishing means for furnishing an error signal corresponding to the difference therebetween;
- and connecting means (R20, C7, IC2) for applying said error signal to said current control means to change said current control signal in a direction for controlling said ignition current to change said actual spark duration in a direction decreasing said error signal.
Dependencies are inferred from the claim text.