Autronic ECU and twin-spark (and other unlikely ECU tasks)

[Greg Hermann]

>
>> > You can fire all your plugs. However, certain dual plug engines
>> > adjust the timing of the two plugs independent from each other.
>> > I don't believe the Autronics is programmed to do this.
>
>> Might be noted on some it's an emission strategy.
>
>How so?
>
>GH stated very recently that you want combustion to happen as fast
>as possible. Over a large bore, multiple spark locations (or one
>very long one) would consume the end-gas more steadily.
>
>First instinct would be that it's a knock-reduction strategy.
>i.e. second spark ahead of the flame front so that combustion occurs
>at a controlled time. You can ignite later to allow the flame front
>to expand into a more-rapidly-increasing cylinder volume.

A simpler way to say this might go as follows:

If you have a given flame speed in the chamber, initiating the  flame at
two well chosen spots will cause the burn to be completed in much less
time.

A faster burn, and therefore a faster pressure rise require less overall
advance, increase cycle efficiency, and often avoid or deter detonation.

Then again, it might be useful to quote something I once heard Keith
Duckworth say in re the 3 liter three plug per cylinder V-12  Maserati F1
engine in the garage at Watkins Glen:

"If they couldn't get the fool thing to light with two plugs, what bloody
hope do they have that a third one would be of any help??!!"

Greg


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