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From: mat@amdahl.UUCP (Mike Taylor)
Newsgroups: net.physics
Subject: Re: White exhaust and cold mornings
Message-ID: <925@amdahl.UUCP>
Date: Fri, 11-Jan-85 16:06:51 EST
Article-I.D.: amdahl.925
Posted: Fri Jan 11 16:06:51 1985
Date-Received: Mon, 14-Jan-85 00:41:31 EST
References: <118@unccvax.UUCP>
Organization: Amdahl Corp, Sunnyvale CA
Lines: 30

> 
> (If you have seen this before pipe it down to /dev/null)
> 
>     The condensation from the exhaust system is virtually nil in causing
> exhaust steam. Very rich starting mixtures, combined with those extra-stinky
> T.W.C. fast-lightoff catalysts, create the steam. Air injection ahead of
> the TWC provides enough oxygen to oxidize the HC-rich stream into H20 and CO2
> raising the converter temperature until the COC can take over. At this point,
> either the choke has come off or the catalytic converter temperature is
> so high that the dew point is below the exhaust stream temperature.
> 
>     (Actually, the COC does not take over in sanitizing the exhaust stream.
> Initial oxidation, however, is provided by the TWC).
> 
>     This effect seems to be most noticable with certain brands of cars that
> have the HUGE underfloor converters (presumably to get away with richer
> choking mixtures ?).
> 
>     I have noticed the effect in my EFI Escort. Why should an EFI car require
> cold enrichment ?
> 
> dya

If that's true, why did it happen BEFORE catalytic converters existed?
Secondly, in very cold weather ( in Canada, anyway ) exhaust steam continues
at all times, even though the engine is at normal operating temperature.
-- 
Mike Taylor                        ...!{ihnp4,hplabs,amd,sun}!amdahl!mat

[ This may not reflect my opinion, let alone anyone else's.  ]