Exhaust stink

[Programmer]

I think we read the same article <BG>

Lyndon.
-----Original Message-----
From: Mike Rolica <mrolica at meridian-mag.com>
To: 'gmecm at efi332.eng.ohio-state.edu' <gmecm at efi332.eng.ohio-state.edu>
Date: November 2, 1999 6:42 AM
Subject: RE: Exhaust stink


>Doh! Me too. Was reading article that lower nox's but ends up increasing
>sox's  Sox go up to sky and mix with water  giving h2so4  (acid rain)..
same
>with nox makes nitric acid.
>Mike Rolica
>EXT. 260
> :-)
>
>
> -----Original Message-----
> From: Programmer [SMTP:nwester at eidnet.org]
> Sent: Monday, November 01, 1999 8:10 PM
> To: gmecm at efi332.eng.ohio-state.edu
> Subject: Re: Exhaust stink
>
> Ha--put my foot in my mouth again. H2S it is <g>...Good thing I'm
>not a
> chemist....just browsing through some old TSB's on the
>subject--repair was
> to relocate the O2 sensor so it read off BOTH sides and replace the
>PROM.
> Basic problem was richness at idle...
>
> Lyndon.
> -----Original Message-----
> From: Rudi Machilek <Rudi at vnet.net>
> To: gmecm at efi332.eng.ohio-state.edu
><gmecm at efi332.eng.ohio-state.edu>
> Date: November 1, 1999 4:16 PM
> Subject: RE: Exhaust stink
>
>
> >The stink is Hydrogen Sulfide (H2S) not Sulfuric Acid (H2SO4).  The
>sulfur
> >comes from the fuel (No sulfur in fuel or oil, no rotten egg
>smell).  You
> >pretty well need a significant lack of oxygen (real rich burn) to
>make
> >Hydrogen Sulfide. The catalytic converter has to be running rich
>also.  The
> >problem is only evident when the catalytic converter is not yet lit
>or
> >poisoned by lead.  The converter provides a great deal of surface
>area to
> >promote undesirable reactions (Harder to smell rotten eggs from a
>non
> >converter car).  Some designs are a lot worse than others. As soon
>as there
> >is enough oxygen around at temperature, in either the combustion
>chamber or
> >catalytic converter, one gets the various oxide forms instead.
>These oxide
> >forms are acid rain and smog problems, but do not smell like rotten
>eggs.
> >At very high combustion temperatures (lean burn conditions),
>thermal NOx is
> >formed and SOx is formed (in greater abundance) which when combined
>with
> >water make Nitric Acid and Sulfuric Acid.  These are also valve
>burn or at
> >least high EGT conditions.
> >
> >ECM content; work on fuel map to keep A/F ratio in range and EGT
>under
> >control.  If running cats, keep air pump.  Rotten egg smell is not
>as much
> >of an issue with newer ECMs with post cat O2 sensor.
> >
> >Kept most of the chemistry and thermo out, but I believe accurate
>enough.
> >
> >Rudi Machilek
> >formerly Project Engineer/Manager under contract with EPA, both
>Stationary
> >Sources and Mobile Sources, RTP, NC
> >
> >
> >>> Whats the reason some vehicles STINK from unleaded fuel / cat
> >>> convertors and others don't
> >>> Geoff
> >>>
> >>
> >