Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Fri, 13 Jun 2003 23:55:22 -0400
Message-ID: <redirect-2421655@logan.com>
From: Epijk@aol.com
Subject: Re: [LML] Hotter Sparks
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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.