Did you red the link in #3092078. I describe the timing, voltage, and energy for the spark gap.
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To transfer the maximum energy to the gas column, you want the initial phase to be as energetic as possible - that means start at the highest voltage you can engineer, not the lowest. If you allow it to establish the arc channel at the lowest possible voltage, then more of the energy of the spark is wasted in the second and third phases.
No one is arguing low energy or low voltage spark initiation but you.
How much energy is delivered per phase is determined by the ionization physics of the plasma channel.
When the ECU commands a current pulse to the ignition coil's primary, you want as fast a drop in current as possible in order to create a high voltage at the coil's secondary.
You want the highest voltage available in the shortest amount of time at the SP gap to ignite the plasma. The overall rise time of the voltage on the coil's secondary is a function of the coil's leakage inductance, resistance of wiring and plug, capacitance of external circuit, gap width and cylinder pressure, and gas species. That rise time is designed into the ignition system.
Too much ignition system delay wrt piston position affects combustion efficiency, which in turn affects engine performance and mpg.
When I am speaking of the SP gap rise time, I am speaking of the initial curve showing the leading edge of the SP gap current as the voltage rises to about 35,000 volts and just before current flows. Upon ignition of the plasma, the current rises to about 200 Amps but only sustains this level for about 10 (10^-9) seconds or 10 nanoseconds.
And please explain your comment:
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- big friction belt generators in science fairs demonstrate this point quite well. A sudden rise will trigger an arc at a much lower voltage than a slow-rising voltage.