Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site amdahl.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!zehntel!hplabs!amdahl!mat 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. ]