Rob:

I hope I'm not being too presumptuous by answering a question you directed to
George.

>From your research, you probably already know that, although ignition in an
SI engine is essentially a binary event, the resulting peak pressures reached
fall into an asymmetric statistical distribution which is fairly tightly
clustered around the mean, but the low side of the curve has a greater population
than does the high side.  And, from say 100 sequential conbustion events, there
are one or two misfires (depending, of course, on a bunch of things like
mixture homogeneity and the probability that one or more fuel molecules and a few
O2 molecules are in sufficient proximity of the spark for combustion to begin).


The idea behind the longer, multi-strike-style ignition system is to increase
the probability of a light-off during conditions which are more difficult. We
saw small, but measurable, gains from our first design dual-plug V8 heads
which had the two plugs located side-by-side (easier to accomplish). Turning one
or the other ignition system off during a steady state dyno run would drop the
observed power by about 1% (one set produced more drop than the other,
showing me that the one set was better-located in the combustion chamber than the
other). My take on that observation was that the second plug simply increased
the probability of a light-off.

I think Klaus' system does the same thing, not so much under high power
conditions, but more at the reduced MAP's when his system starts to add advance to
take better advantage of  the lower charge density. Probably it would help
under lean operating conditions as well.

BTW, when I tested my new design cylinder head (with the plugs located at
opposite ends of the combustion chamber, ala LycoNental, I saw a much more
significant power loss from killing either ignition system, but that's a different
phenomenon caused by the same thing that causes an RPM drop on your LycoNental
during runup: lighting the fire from two points an opposite ends of the
chamber produce a faster pressure rise, more complete combustion, lowered propensity
to detonate (all other things being equal) and a significantly reduced need
for spark advance.

The single and adjacent-dual plug engines need about 34 degrees of spark. The
opposite-end dual plug engines only need about 26 degrees. There's
significantly more power from the opposite-end dual plug heads, but it can't be
attributed to plug location: there is a much-improved port and chamber layout which
produces more flow at higher velocity, better swirl, better mixture quality, so
there's no value in comparing power-drop on single ignition.

Hope that long babble helps some.
Jack Kane
EPI, Inc.