[Diy_efi] Rich detonation?

[Bernd Felsche]

On Tuesday 21 November 2006 01:51, Adam Wade wrote:
> --- "Becker, Damon (Damon)" <damonb at avaya.com> wrote:
> > Combustion velocity increases to a max rich point.
> > That exact point is usually much richer than most
> > cars run.  That's why it's usually a non-issue.

> That doesn't make sense.  Richer burns cooler, plus
> there are not enough oxygen atoms to completely
> combust the fuel in any given area.  Less fuel burning

I'd tend to agree; except that I'd be looking for oxygen molecules
as many oxygen atoms are already "otherwise occupied". :-) 

> + fuel burning at lower temp = slower burn rate (on
> both counts), if basic physics is correct.  Cooler
> temps mean fewer actual molecular breaks and
> reformations, as there's less energy available to do
> the breaking; fewer oxygen atoms mean that some
> fraction of the energy used in breaking apart the
> hydrocarbon chains never gets "returned-and-then-some"
> from oxidization.

ISTM that people are mis-interpreting their instrumentation such as
"knock" sensors. There are conditions other than detonation that can
cause those sensors to indicate the presence of knock.

OTOH, in a supercharged engine, there may not actually be as much
combustible fuel injected as is planned for the "desired" AFR,
resulting in a lean mixture with the actual mass of air.

Again, something of a problem with interpreting what the sensors are
saying.

-- 
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