Plasma Jet Ignitition

[Raymond C Drouillard]

You can buy a system that does just that.  I don't remember where or how
much, and haven't talked to anyone who has tried it.

On Wed, 24 Feb 1999 12:23:31 -0500 Wen Yen Chan <chanwe at ecf.utoronto.ca>
writes:
>Hello,
>
>Just a thought.... why not add a small HV capacitor in parallel with a
non
>resistor plug (using  a low inductance path) and switch the ignition
wires
>to solid conductor types. When the normal ignition system fires the HV
cap
>would charge 'slowly' to the breakdown voltage of the gap and dump its
>charge really quickly. The speed at which we could dump the charge
through
>the plug would not be limited by the inductance of the spark plug wires
>or the leakage inductance of the ignition coils.
>
>Wen
>
>On Wed, 24 Feb 1999, Robert Harris wrote:
>
>> Why? -  All spark ignition starts with a plasma phase.  During this 
>breakdown
>> phase the "blast wave" created will exceed 10 to the 4th meters 
>velocity at
>> several hundred atmospheres pressure.   This injects a cloud of 
>hyper
>> temperature ~60,000k free radicals into the combustible mixture.  As 
>the
>> electrodes heat up and the conductance falls, the spark transitions 
>into an
>> arc, where the expanding velocity drops to below local sonic and the
>> temperature falls to ~6000 k.   The energy transfer heat is 
>primarily
>> conduction to the combustible mixture.
>> 
>> Increasing the size of the Plasma phase of ANY spark ignition 
>results in
>> greater quantity and penetration of free radicals into the 
>combustible
>> mixture.  The larger the cloud of free radicals expelled during the 
>Plasma
>> breakdown, the faster and surer the ignition.  Translation - less 
>advance
>> needed, faster flame front generation.  More power, more tolerance 
>to the
>> cyclic F/A variations - particularly those seen by the sparking 
>device.
>> 
>> There are literally hundreds of patents which I am patiently wading 
>thru, but
>> there has been a lot of thought on this.
>> 
>> In a conventional ignition system, most of the energy is disapated 
>in the arc
>> and glow stage, yet the Plasma stage determines most of the ignition
>> characteristics.  ANY design that pumps more energy into the plasma 
>portion
>> will increase the size of the cloud and result in better 
>performance.  And
>> while the lab researchers try to reach 1 joule to virtually flood 
>the main
>> chamber and cause near instantaneous combustion ***** NOT DETONATION 
>**** , I
>> would be quite content to pump as much as practical into the plasma 
>stage and
>> suffer with only greatly extended mixture range, elimination of 
>misfire and
>> near TDC timing.  
>> 
>> How much is helpful?  Depending on the ignition design, only up to 
>about 2 %
>> of the total sparking energy is consumed in the Plasma phase.  
>Simply using
>> another CD box triggered and rigged by a diode stack to fire into 
>the first
>> and modified to quickly dump its energy could potentially increase 
>the plasma
>> energy 50 fold if it could dump fast enough.
>> 
>> >From the reading of the patents and others, simply shielding the 
>spark in a
>> pre chamber reduces the energy needed to fire an order of magnitude 
>( why
>> anti-fouler improve ignition )   Combining any small pre chamber 
>with a pumped
>> up plasma ignition should result in nice increase's in power and 
>mixture
>> range.  Also, the patents mention controls on when to plasma pump 
>and when not
>> to - just to reduce the electrical loss's to the system.  And yes, 
>there is
>> also discussion of reducing the resultant emi.
>> 
>> 
>> 
>> 
>> 1963 Ford C-600 Prison Bus Conversion "Home"
>> 1971 Lincoln Continental 460 "Christine"
>> 1972 "Whale" Mustang awaiting transplant
>> 1978 Dodge Long Bed Peeek Up "Bundymobile"
>> 
>> Habaneros - not just for breakfast anymore
>> 
>
>

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