DIS

[xxalexx at ix.netcom.com]

> Date:          Fri, 20 Mar 1998 12:41:15 +0000
> From:          steve ravet <steve at sun4c409.imes.com>
> Organization:  International Meta Systems
> To:            diy_efi at efi332.eng.ohio-state.edu
> Subject:       Re: DIS
> Reply-to:      diy_efi at efi332.eng.ohio-state.edu

> Bruce Plecan wrote:
> > 
> > OK for a chemical engineer inert would be the wrong word, but GM
> > has used the word inert to cover exhaust gases.  How about prior
> > chemically reacted?.
> 
> How about combustionally challenged?
> 
> >   Either way, doesn't there need to be a iononized path for a spark
> > to occur?...
> 
> No, although that makes it easier.  A spark can form in a complete
> vacuum.  An ionized path will allow current to flow without a spark,
> which is I guess how those electrical knock detection schemes work.
> 
> --steve
> 
> obCSH:  Electrical discharges tend to form around sharp discontinuities,
> such as the point on your Cone Shaped Hat.
> 
A spark is a ionized path both happpen simutanusally.
If there is enough potential such as a sharp point the gas will 
ionize, the free electrons will accelerate in the potential field 
ionizing more molecules in a avalanche creating a current path
to a lower potential .  The ionization of the gas molecules will
also generate electromagnet waves(the  light from spark)
If the current path widens all the gas in a area is ionized and
plasma is generated. 
 If the pressure is low the mean free path before collision is 
greater generating more ions due to higer impact velocity.
A low ionization potential of gas will also allow spark at low 
voltage. 
Ions can also be formed by heat in chemical diasociation in
combustion.
The quanity of gas ions have same property as variable
resistor.  In a spark you have rapid break down ionization
to ground by path of  least resistance(a short circuit or blowing
up a capacitor) If only some of gas is ionized as after combustion 
you will have greater resistance between potentials and less current. 
Thus if you monitor ion current at same time, you can determine
properties and changes in  combustion gas.  Knock would generate
more ions.  A lean mixture will make less ions than rich since
hydrocarbon molecules have lower ionization potential than air.
Inert gases are highly stable with high ionization potential.
The gases could be considered more inert after combustion.
In chemistry inert gases are in a column of periodic table
He and  Ar  very inert.

alex
alex