Abstract: A circuit for controlling current flow to an associated inductive load is provided. The circuit includes a switching element having an open state and a closed state that intermittently connects an associated power supply to the inductive load when the switching element is in the closed state, a switch driver that generates a switch drive signal provided to a control element of the switch that controls the state of the switch to be the open state or the close state based on a desired load current set point and a feedback signal, a current sensor that measures a current flowing through the switching element and the load and generates a sensed current signal, and a summing circuit that adds a representation of the sensed current signal and a supplemental signal comprising a representation of the switch drive signal to generate the feedback signal.

Abstract: In certain embodiments, a time-varying spark current ignition system can be applied to improve spark plug ignitability performance and durability as compared to conventional spark ignition systems. Two performance parameters of interest are spark plug life (durability) and spark plug ignitability. In certain embodiments, spark plug life can be extended by applying a spark current amplitude as low as possible without causing quenching of the flame kernel while it is traveling within an electrode gap and/or by applying spark current of a long enough duration to allow the spark/flame kernel to clear a spark plug gap. In certain embodiments, ignitability can be improved by applying a high enough spark current amplitude to sustain the flame kernel once outside the spark plug gap and/or by applying a spark current for long enough to sustain the flame kernel once outside the spark plug gap.

Abstract: A circuit for controlling current flow to an associated inductive load is provided. The circuit includes a switching element having an open state and a closed state that intermittently connects an associated power supply to the inductive load when the switching element is in the closed state, a switch driver that generates a switch drive signal provided to a control element of the switch that controls the state of the switch to be the open state or the close state based on a desired load current set point and a feedback signal, a current sensor that measures a current flowing through the switching element and the load and generates a sensed current signal, and a summing circuit that adds a representation of the sensed current signal and a supplemental signal comprising a representation of the switch drive signal to generate the feedback signal.

Abstract: In order to reduce AC ringing of the secondary voltage after the spark event in a capacitive ignition system, which would influence ion-sensing, a secondary winding current (IR) flowing through the secondary winding (4) after the spark event is forced to flow through a forward-biased muting diode (D1) that is connected across the secondary winding (4).

Abstract: 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.

Abstract: In certain embodiments, a time-varying spark current ignition system can be applied to improve spark plug ignitability performance and durability as compared to conventional spark ignition systems. Two performance parameters of interest are spark plug life (durability) and spark plug ignitability. In certain embodiments, spark plug life can be extended by applying a spark current amplitude as low as possible without causing quenching of the flame kernel while it is traveling within an electrode gap and/or by applying spark current of a long enough duration to allow the spark/flame kernel to clear a spark plug gap. In certain embodiments, ignitability can be improved by applying a high enough spark current amplitude to sustain the flame kernel once outside the spark plug gap and/or by applying a spark current for long enough to sustain the flame kernel once outside the spark plug gap.

Abstract: 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.