Abstract: The subject matter of this specification can be embodied in, among other things, a method that includes receiving a collection of measurements of electric current amplitude in a primary winding of an engine ignition system having the primary winding and a spark plug, identifying an ignition start time, identifying an inflection point based on the plurality of measurements, determining an inflection point time representative of a time at which the identified inflection point occurred, determining a spark start time based on an amount of time between the ignition start time and the inflection point time, and providing a signal indicative of the spark start time.

Abstract: Methods and systems for a unique material and geometry in a high temperature spark plug extender and may include a spark plug extender with a conductive core encased in a liquid crystal polymer where opposite ends of the conductive core are not encased in the liquid crystal polymer. A coil may be coupled directly to the spark plug extender. The spark plug extender and the coil may include threads at a first of the opposite ends of the conductive core for the direct coupling of the coil to the spark plug extender. The first of the opposite ends of the conductive core may include an O-ring that provides a seal with the coil. The spark plug extender may include an insulating wire that is coupled to a coil remote from the spark plug extender, the insulating wire extending from an end of the conductive core.

Abstract: The subject matter of this specification can be embodied in, among other things, a method that includes receiving a collection of measurements of electric current amplitude in a primary winding of an engine ignition system having the primary winding and a spark plug, identifying an ignition start time, identifying an inflection point based on the plurality of measurements, determining an inflection point time representative of a time at which the identified inflection point occurred, determining a spark start time based on an amount of time between the ignition start time and the inflection point time, and providing a signal indicative of the spark start time.

Abstract: Methods and systems for a unique material and geometry in a high temperature spark plug extender and may include a spark plug extender with a conductive core encased in a liquid crystal polymer where opposite ends of the conductive core are not encased in the liquid crystal polymer. A coil may be coupled directly to the spark plug extender. The spark plug extender and the coil may include threads at a first of the opposite ends of the conductive core for the direct coupling of the coil to the spark plug extender. The first of the opposite ends of the conductive core may include an O-ring that provides a seal with the coil. The spark plug extender may include an insulating wire that is coupled to a coil remote from the spark plug extender, the insulating wire extending from an end of the conductive core.