[Diy_efi] Re: Burning Aluminium etc.

[mark krawczuk]

testing.



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----- Original Message ----- 
From: "Adam Wade" <espresso_doppio at yahoo.com>
To: <diy_efi at diy-efi.org>
Cc: <jdeakin at advancedpilot.com>
Sent: Monday, April 18, 2005 8:20 PM
Subject: Re: [Diy_efi] Re: Burning Aluminium etc.


> --- Phil Lamovie <phil at injec.com> wrote:
> 
> > Of course all that is required is a set of scales.
> > Perhaps someone who has a partially ventilated set
> > might do the experiment and help enlighten the list.
> 
> I'd definitely be interested.  I've seen pistons where
> visually it was obvious that they much have lost
> material, and I certainly didn't find much in the
> crankcase.  Wish I had a set around to weigh, since it
> didn't occur to me to check last time I tore down an
> engine.
> 
> > A quick check of the "blue bible" gives the boiling
> > point of pure Al as 2467 Degrees C at STP. As no
> > combustion could occur prior to vaporization I would
> > posit that what is occurring is melting as a result
> > of the pressure created during a detonation or two.
> 
> That was what I thought for a long time, but it
> certainly appears that there is less aluminum than
> there should be after all is said and done.  Could be
> an "optical illusion" due to the hole itself.  Again,
> interested to have more data on the subject.
> 
> *snip bit on pre-ignition*
> 
> > Detonation is on the other hand an extremely violent
> > and unforgiving condition. It is the result of
> > spontaneous combustion of the air fuel mixture.
> 
> Do you ever see situations where the mixture is
> non-homogenous and detonation occurs fairly late in
> the power stroke, such that some areas do not "light
> off" during flashover?  I'd think that it would only
> occur under a very narrow set of circumstances, but in
> theory, you should be able to see such results.  Or
> are modern engines too good at homogenizing the
> mixture for this to occur?  I understand that
> regardles of local variations in the mixture, a
> typical detonation event will raise the temperature so
> high and so quickly that all the available fuel and
> air will combust, regardless of local variations in
> mixture.
> 
> > Of course giving the operator (pilot) a manual
> > air/fuel mixture control and reassuring them that
> > Lambda A/F (not sure why this is the A/F target
> > under these conditions) is denoted by peak exhaust
> > temps may lead directly to the impact site.
> 
> Well, pilots only "know" EGT.  They don't use O2
> sensors and don't really know what lambda they are
> running at any given time.  Ignition timing, as John
> noted in his emails to me, is often fixed for all
> throttle positions, engine speeds, and mixture
> settings.  In his last email to me, he indicated that
> there was a company coming out with a feedback system
> to best time the PPP automatically; sounds very much
> like they must be using ion sensing for this, as it
> would be the least expensive and most feasible method.
>  That would help things a great deal, I'd say,
> especially WRT setting mixtures that could cause
> elevated EGTs.
> 
> | 82 Honda CX500 Turbo (Cassandra)  90 Kwak Zephyr 550 (Daphne) |
> | "It was like an emergency ward after a great catastrophe; it  |
> |   didn't matter what race or class the victims belonged to.   |
> |  They were all given the same miracle drug, which was coffee. |
> |   The catastrophe in this case, of course, was that the sun   |
> |     had come up again."                    -Kurt Vonnegut     |
> | M/C Fuel Inj. Hndbk. @ Amazon.com -  http://tinyurl.com/6o3ze |
> 
> 
> 
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