Exhaust stink

[Mike Rolica]

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
	>>>
	>>
	>