Miatapower List Archive

This read-only message was archived from a public mail list.
Mail From: "Ross Kuhns" <(email redacted)>

This just came up on a Triumph list Graham and I are on, thought it was
interesting; I wasn't even aware of the metal fragmentation theory...


---------------------------------------

listen up spark ignition fans:

which of the following is the correct scenario for the
way a "spark ignition" fires the plug and sets the fuel/air
mixture alight-

1.the "thermal theory" where it is the HEAT of the spark
that does the deed (just like a match)

2.the "ping-pong theory" where the high velocity electron
crashes into the gasoline molecules as the electrons speed
across the spark plug gap

3. the "metal fragmentation theory" wherein the tiny, highly
charged fragments of metal ripped off the electrodes by the
spark ignite the fuel simply by coming in contact with the
fuel molecules

extra points for those who correctly describe the function
of a plasma and/or laser injector as a substitute for spark plugs
in an Otto cycle engine!

all the best from the gearhead ranch,

Michael

-------------------------------------------------------------------

Ross Kuhns

This read-only message was archived from a public mail list.
Mail From: "Abraham Mara" <(email redacted)>

Somehow I would think it has to do with ionizing the fuel and air itself
- you get all those molecules lined up and due to the induced electric
field of the molecules themselves, they would pull together, and now
being close enough (with any inconvienent electrons temporarily spending
more of their time out of the way) the reaction happens. Of course,
it's sustained by heat, so it would seam the first one is reasonable.
Curious to see what the "right" answer is
-Abe.

-----Original Message-----
From: Ross Kuhns [mailto:(email redacted)]


listen up spark ignition fans:

which of the following is the correct scenario for the
way a "spark ignition" fires the plug and sets the fuel/air
mixture alight-

1.the "thermal theory" where it is the HEAT of the spark
that does the deed (just like a match)

2.the "ping-pong theory" where the high velocity electron
crashes into the gasoline molecules as the electrons speed
across the spark plug gap

3. the "metal fragmentation theory" wherein the tiny, highly
charged fragments of metal ripped off the electrodes by the
spark ignite the fuel simply by coming in contact with the
fuel molecules

extra points for those who correctly describe the function
of a plasma and/or laser injector as a substitute for spark plugs
in an Otto cycle engine!


--
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This read-only message was archived from a public mail list.
Mail From: "Ross Kuhns" <(email redacted)>

There's been no "answer" as yet...I copied it just about the time it
appeared....

I'll post the synopsis after it works thru discussion et al.


Ross Kuhns


----Original Message Follows----
Somehow I would think it has to do with ionizing the fuel and air itself
- you get all those molecules lined up and due to the induced electric
field of the molecules themselves, they would pull together, and now
being close enough (with any inconvienent electrons temporarily spending
more of their time out of the way) the reaction happens. Of course,
it's sustained by heat, so it would seam the first one is reasonable.
Curious to see what the "right" answer is
-Abe.

-----Original Message-----
From: Ross Kuhns [mailto:(email redacted)]


listen up spark ignition fans:

which of the following is the correct scenario for the
way a "spark ignition" fires the plug and sets the fuel/air
mixture alight-

1.the "thermal theory" where it is the HEAT of the spark
that does the deed (just like a match)

2.the "ping-pong theory" where the high velocity electron
crashes into the gasoline molecules as the electrons speed
across the spark plug gap

3. the "metal fragmentation theory" wherein the tiny, highly
charged fragments of metal ripped off the electrodes by the
spark ignite the fuel simply by coming in contact with the
fuel molecules

extra points for those who correctly describe the function
of a plasma and/or laser injector as a substitute for spark plugs
in an Otto cycle engine!


--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.296 / Virus Database: 265.6.7 - Release Date: 12/30/2004

This read-only message was archived from a public mail list.
Mail From: "Ross Kuhns" <(email redacted)>

Here was an intersting reply; answer has not been posted yet.


-----------------------------------------------------------

British Toys said:
>1.the "thermal theory" where it is the HEAT of the spark
>that does the deed (just like a match)
>
>2.the "ping-pong theory" where the high velocity electron
>crashes into the gasoline molecules as the electrons speed
>across the spark plug gap
These two are kind of the same theory, are they not? Essentially, you're
imparting energy to induce an exothermic reaction. Heat is just atoms
vibrating faster - once they're vibrating fast enough, they have enough
energy to knock off a loosley attached hydrogen atom in the hydrocarbon
chain that is fuel, and then the carbon and hydrogen look around wildly
for something to attach to (mostly oxygen, some nitrogen), attach and
produce a larger molecule - hence the expansion that pushes the piston
down. This is accompanied by a burst of enrgy on various visual
wavelengths (hence "flame").

This is a real simplification, but hey.

Essentially, you're raising the temperateure of fuel in the locale of the
spark to above it's flash point.

>3. the "metal fragmentation theory" wherein the tiny, highly
>charged fragments of metal ripped off the electrodes by the
>spark ignite the fuel simply by coming in contact with the
>fuel molecules
I've never ever heard that one before. Sounds like a fascinating theory,
though.

This read-only message was archived from a public mail list.
Mail From: "Murray, Richard" <(email redacted)>

I don't buy #3. If electrons ripped off more than a few single atoms of the
cathode, then sparkplugs would only last a thousand miles, if that. Or,
maybe in this application they do only last a thousand miles. There is a lot
of ionization and heat, but not a shotgun of molten metel.

-----Original Message-----
From: Ross Kuhns [mailto:(email redacted)]
Sent: Tuesday, January 04, 2005 01:44
To: (email redacted)
Cc: (email redacted)
Subject: Re: spark igntion quiz

Here was an intersting reply; answer has not been posted yet.


-----------------------------------------------------------

British Toys said:
>1.the "thermal theory" where it is the HEAT of the spark
>that does the deed (just like a match)
>
>2.the "ping-pong theory" where the high velocity electron
>crashes into the gasoline molecules as the electrons speed
>across the spark plug gap
These two are kind of the same theory, are they not? Essentially, you're
imparting energy to induce an exothermic reaction. Heat is just atoms
vibrating faster - once they're vibrating fast enough, they have enough
energy to knock off a loosley attached hydrogen atom in the hydrocarbon
chain that is fuel, and then the carbon and hydrogen look around wildly
for something to attach to (mostly oxygen, some nitrogen), attach and
produce a larger molecule - hence the expansion that pushes the piston
down. This is accompanied by a burst of enrgy on various visual
wavelengths (hence "flame").

This is a real simplification, but hey.

Essentially, you're raising the temperateure of fuel in the locale of the
spark to above it's flash point.

>3. the "metal fragmentation theory" wherein the tiny, highly
>charged fragments of metal ripped off the electrodes by the
>spark ignite the fuel simply by coming in contact with the
>fuel molecules
I've never ever heard that one before. Sounds like a fascinating theory,
though.