FW: re: Re: spark and MAP

[john carroll]

Increased  RPM does not increase the burn time.  A first order consideration 
is that increased RPM requires that the spark be initiated at an earlier crank position in 
order that combustion be finished at the the desired crank location.  A second order 
consideration is that because the spark is initiated earlier, the flame front must travel 
through both a larger volume and a lower density charge. 

jac at wave.sheridan.wy.us
john carroll

>Bohdan.L.Bodnar at att.com Wrote:
>
>| I can see the burn time being a function of a/f mixture (rich mixture =>
>| reduced burn time).  I don't understand why rpm alone will cause the 
>flame
>| burn time to vary unless there's a significant contribution from heat of
>| compression.   What's the involved mechanism?
>
>Increased turbulance creates a better mixture, which causes it to burn 
>faster at higher RPMs.  The ignition time is constant, that's what the rpm 
>advance is for.
>
>
>
>Steve Ravet
>sravet at bangate.compaq.com
>Baby you're a genius when it comes to cooking up some chili sauce...
>

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jac at wave.sheridan.wy.us
john carroll