Plasma Jet Ignitition

[Greg Hermann]

>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

I think I saw a web site a few months ago where somebody is selling plug
mount capacitors--

Greg
>
>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
>>