Measuring a spark of a spark plug

A method comprising:

• measuring a power supply voltage;
• initiating a dwell for a spark plug;
• measuring a voltage from an output of a voltage divider coupled to a primary coil;
• after a duration of time following initiating the dwell, measuring an output of a first voltage comparator comparing the output of the voltage divider to a threshold voltage;
• and
• determining an output value of the voltage comparator.

An engine system comprising:

• an internal combustion engine;
• and
• an ignition system coupled to the internal combustion engine, the ignition system comprising:
• an electric power supply;
• a primary transformer coil;
• a secondary transformer coil coupled to the primary transformer coil;
• a voltage divider coupled to the primary transformer coil, the voltage divider configured to reduce the voltage to a controller voltage;
• a comparator circuit coupled to an output of the voltage divider;
• and
• a controller configured to:
• detect the voltage output of the voltage divider;
• detect the voltage output of the electric power supply;
• detect the voltage output of a comparator;
• and
• determine an estimated spark duration based on the determined comparator voltage output.