DIY-WB... It's alive...

[David Hunt]

Mark,

I believe that Stoich is a chemical term for complete combustion.

dh


----- Original Message -----
From: "Mark S. Riley" <turbotuneusltd at triad.rr.com>
To: <diy_efi at diy-efi.org>
Sent: Sunday, September 02, 2001 11:16 PM
Subject: Re: DIY-WB... It's alive...


> Stoich is not 100% utilization of the O2. Stoich is the point at which the
> gas emissions are the lowest and highest. I'll have to break out a book,
> can't remember  the exact numbers but stoichimetric is not neccessarily
> where you might want to run your engine. But it does give the lowest
> emissions there. So, that's why the all the OEM's are so concerned with
it.
> And that's why O2 sensors and all fuel air meters currently used are so
> concerned with it.
> As for the range 10:1 to approximately 22:1 is not really where gas
engines
> run. Quite frequently meters will read over a far larger range than what
is
> neccessary or wanted. I think the fact that the sensor will read to
20/22:1
> is like the air conditioning freon sniffers. I have one of those that is
so
> sensitive, the manufactor claims it will detect a 1 OZ. per year leak. Any
> idea what that kind of ratio that might be, 5 million to 1 or something
> ridiculous. Gasoline engine will run fairly reliably in the range of
11.5:1
> up to 16.5:1. Numbers that low don't make max power and numbers that high
> can't make much but it will run. I don't think anyone has every come close
> to 100% utilization of the O2. Top Fuel might be the closest but I still
> think they have a long way to go to 100%. later, Mark
>
> ----- Original Message -----
> From: "John Dammeyer" <johnd at autoartisans.com>
> To: <diy_efi at diy-efi.org>
> Sent: Sunday, September 02, 2001 10:21 PM
> Subject: RE: DIY-WB... It's alive...
>
>
> > Good description but if the Stoich is 100% utilization of the O2 in the
> > mixture how does the catalyst burn off the HC.  Or is that why the WB
> > sensors don't do much better than 10:1 AF ratio whereas they can go
> > considerably further in the lean direction?
> >
> > John
> >
> >
> > -----Original Message-----
> > From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org] On
> > Behalf Of rr
> > Sent: Sunday, September 02, 2001 5:15 PM
> > To: diy_efi at diy-efi.org
> > Subject: Re: DIY-WB... It's alive...
> >
> >
> >
> > As mentioned the O2 sensor responds first & foremost to O2. When the
> > exhaust is stoich, the partial pressure of O2 in the atmosphere will
> > cause the O2 sensor to generate ~450mV. In order for the O2 sensor to
> > detect a rich condition, there is a platinum coating on the sensor cone.
> >
> > Platinum being the catalyst it is will burn off the HC by pulling O2
> > through the porus cone. This action generates a voltage > 450mV.
> >
> > BobR.
> >
> > John Dammeyer wrote:
> >
> > > I have a question about O2 sensors in general.  On a fuel injection
> > > setup where the ignition has a bad miss or even fails for a 1/4 second
> >
> > > while injection continues,  will the O2 sensor go rich because the
> > > fuel isn't being burnt or lean because the O2 is still in the mixture.
> > >
> > > That then begs the question.  If the Stochimetric condition is when
> > > all the O2 used to burn all the fuel,  how can it ever show a rich
> > > condition?
> > >
> > > Regards,
> > >
> > > John Dammeyer
> > >
> > > -----Original Message-----
> >
> > <snip>
> >
> >
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> >
> >
>
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