guessing

[Clare Snyder]

> ------------------------------
>
> Date: Sat, 04 Dec 1999 02:23:36 +1100
> From: Phil Lamovie <phil at injec.com>
> Subject: Stop guessing at facts.
>
> Hi All,
>
> I really must protest !
>

Absolutely no guessing on my part.
The reference to "best guess" is to the method used to determine how much
enrichment is required - carbed or injected. I KNOW it is not a hard and
fast calculation, and many itterations are gone through before a
"successful" calibration is arrived at.
> There is a very large amount of misinformation being posted to the
> list
> of late.
> > Stoich is the point where all of the fuel inhaled by the engine is
> combined
> > with all of the available oxygen in the cyl.
And what is a better explanation? Mabee change it to "stoich is acheived at
the point"
Lets not fight over semantics.

Any leaner means less
> than
> > optimum power. Any richer means less than optimum power per lb of
> > fuel  used, as some is not burned, as well as less power overall.

And what is wrong with this? Too lean means reduced power. Too rich means
less power  from every pound of fuel than possible, and less power period,
after a point.
> This is but a mild example.
>
> 1.0 " Stoich is the point... Not True ! Stoich is only the ratio of
> required air
>         to ingested air the quality of combustion is not in any way
> relevant.

Required air to injested air? I am not following you. We are talking
mixture - stoichiometry is a branch of Chemistry relating to composition of
compounds by weight. -
>
> 2.0 " Any leaner means.... Not True ! Optimum power is not an
>     engineering concept.  It is neither peak power, peak torque or
> peak
>     efficiency. Nothing of interest happens at stoich because it is
> only
>     theoretical.
14:1, or whatever, is theoretical. Actual stoich is the ratio at which all
hydrocarbons and all oxygen are combined to produce water and co2. Never
fully acheived in ral world conditions, but a moving target to be aimed at.

 Most engines need 15 to 20 % more fuel than stoich to
>
>     make peak power and 10% less to make peak efficiency.
>
> The problem I have with all of this is that our topic is 100% physics
> yet
> many of the posts seem to not be happy with this state of affairs.
>
Physics AND chemistry
>
> The problem remains that as long as the list is a home for risky
> physics and those who have real working answers are less inclined to
> contribute as they know that the readers/lurkers will have great
> difficulty
> sorting fact from fiction.
>
Sometimes things have to be simplified in order to be understood. Once the
basic understanding is achieved, the details can be reintroduced.