Re: Twin Spark heads

[bearbvd@domain.elided (Greg Hermann)]

At 7:54 AM 6/10/02, C M Smith wrote:
>I thought the main advantage of twin spark heads was the ability to operate
>with higher compression without detonation.

This effect is simply a by-product of the shorter burn time.

 With single spark heads the end
>gas preignites if the compression ratio is too high.

Yep--detonation is a function of time.

This results from the
>expanding flame front further compressing the mixture before it has time to
>ignite.

Yes.

 The second plug ignites the end gas in a controlled fashion
>preventing this source of detonation.

No, not necessarily. More likely, the flame front gets there sooner with a
dual plug.
>
>I also thought this technique had been refined to increase fuel efficiency
>and reduce emissions by delaying the second spark a little.

This approach is pretty much a Wankel thing.

The shorter burn time, faster pressure rise rate is the real source of the
improved power/efficiency with a twin plug.

Greg
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