[Diy_efi] Rich detonation?
vg30dett at portugalmail.com
vg30dett
Sun Nov 19 21:22:35 UTC 2006
F1 engines dont run on alchool...AFAIK.
Citando "Becker, Damon \\(Damon\\)" <damonb at avaya.com>:
I'm not sure what you mean by "shift to use 4:1". I'm assuming you mean mass
ratio, and "shift" means they moved to using that ratio, instead of being
associated with gear shifts.
AFR is definitely a thermal management tool, among other things. What you say
does make sense if you are seeing excessive EGT. If you can infer exhaust
valve temp from an integral of the EGT, then that response would definitely
make sense. This doesn't really have much to do with detonation, though.
I'm sure the exact AFR (or lambda) that peak combustion speeds happen differ
with fuel. Although I haven't seen research to this effect, I'm sure it's the
case. I have no idea where 4:1 mass ratio methanol falls on the combustion
speed charts, as I haven't played with methanol.
-----Original Message-----
From: diy_efi-bounces at diy-efi.org on behalf of Mike
Sent: Sat 11/18/2006 11:58 PM
To: diy_efi at diy-efi.org
Cc:
Subject: RE: [Diy_efi] Rich detonation?
Is the rationale for what you say below, excess fuel, or can you
articulate just why the detonation occurs. I understand F1 engines
often shift to use 4:1 afr (with methanol) and although there is reduced
power
than running at just better than stoich for methanol - that the 4:1 ratio
still results in combustion but radically reduce stresses on exhaust
valves - vis a vis cooling the valves immediately after a hard run where the
integral of EGT over the last few seconds exceeds some maxima ?
Rgds
Mike
At 08:43 AM 11/19/06, you wrote:
>Hi, Joe! It's Damon (flyboy) from the MR2 community.
>
>Yes, it's totally possible to get rich detonation. However, you will
usually misfire before you hit this point, unless you are pretty careless with
the ignition.
>
>Combustion velocity is what dictates spark timing, and it varies with AFR.
The max velocity is around 11.0 mass air/fuel ratio (the exact value is
debatable, but the concept still holds). Therefore, rich of this value, the
combustion velocity increases again, necessitating a reduced spark advance.
>
>If you leave the spark static and add fuel, then very rich mixtures will
detonate, assuming the detonation propensity was there to begin with.
>
> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org on behalf of Joseph Obernberger
> Sent: Sat 11/18/2006 3:10 PM
> To: diy_efi at diy-efi.org
> Cc:
> Subject: [Diy_efi] Rich detonation?
>
>
>
> Hi,
> I've read in various places that it is possible to run an engine
so
> rich that detonation can occur - or at least the knock sensor would
pick
> up what sounded like detonation. Has anyone ever experienced this?
Any
> truth to it?
> Thanks!
>
> -Joe
> http://www.lovehorsepower.com
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
> Main WWW page: http://www.diy-efi.org/diy_efi
>
>
>_______________________________________________
>Diy_efi mailing list
>Diy_efi at diy-efi.org
>Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
>Main WWW page: http://www.diy-efi.org/diy_efi
_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
Main WWW page: http://www.diy-efi.org/diy_efi
__________________________________________________________
Pare de esbanjar dinheiro!
Compare o pre?o da sua liga??o ? Internet
http://acesso.portugalmail.pt/maisbarato
More information about the Diy_efi
mailing list