Ignition only

[Peter Gargano]

Axel, Just a small correction here about current. I've seen a lot of people
make this same claim...

Axel Rietschin wrote:

> <snip>
> .... One of the
> cylinders is at the end of the compression stroke and the other, where the
> second - wasted - spark occurs, is at the end of the exhaust stroke where
> pressure is near atmospheric, thus that other spark consumes very little
> current.

The same current flows across both spark gaps - this must be the case unless
we're losing or gaining electrons somewhere. The high voltage winding of the
coil moves the electrons across both spark gaps in much the same way a
battery moves electrons through (say) two light bulbs in series (note Bruce:
that's series, not parallel, as you stated).

Okay, the electronic engineers among us may invoke the high frequency nature
of the actual spark current, and note that the capacitance and inductance of
the high voltage leads and the coil itself have a major influence on what 
currents actually flow where and when. But I'm not going to argue the point,
just to note that when one of the HT leads comes off, then these factors do
become important, but this isn't the usual mode of operation for DIS.
 
> In other words, a wasted spark DIS doesn't save you a gap compared to a
> distributor based system. It just moves it.

Correct - my original contention  8^)

Peter.
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