Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site unccvax.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxj!houxm!whuxlm!akgua!mcnc!unccvax!dsi
From: dsi@unccvax.UUCP (Dataspan Inc)
Newsgroups: net.physics
Subject: White exhaust and cold mornings
Message-ID: <118@unccvax.UUCP>
Date: Tue, 8-Jan-85 23:03:52 EST
Article-I.D.: unccvax.118
Posted: Tue Jan  8 23:03:52 1985
Date-Received: Fri, 11-Jan-85 23:43:30 EST
Organization: UNC-Charlotte
Lines: 22


(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