At 12:57 PM 3/18/98 EST, you wrote:
>It is when we are almost to that no burn
>lean mixture that most cars are set up for. After years of trying a lot of
>different set-ups inlcluding one called a statified charge that used two
>connected combustion chambers the manufacturers figured out that if the spark
>was powerful enough they could ignite any lean mixture that would burn.
>Nicholas says CD's like lean mixtures, I think it's the other way around,
lean
>mixtures like powerful spark systems.
Hello Jack,
I agree with most of what you said except for this. Cars of the 70s and
early 80s were set up for the lean condition. However now that NO (nitric
oxide) and NO2 (nitrogen dioxide) have also become important to emissions,
the air/fuel ratio has been taken richer. NO is produced typically under
very high temperture conditions. Conditions like this are lean combustion,
high compression, high temperature oxidation, etc. NO then oxidizes in air
to form NO2 which is brown or orange in color (component of smog). What
the manufacturers have done is to take the air/fuel ratio back up near the
14.7:1 ratio. This creates increased HC, but then the cat can convert that
quite easily back into H2O and CO2. However at that ratio instead of the
commom 15~16:1 of the 70s and 80s, the NO is typically reduced.
I agree that lean mixtures like strong sparks, but what I was trying to
convey was that my observations have indicated that a MSD equiped motor is
more prone to flooding problems. Perhaps this is something that only
happens with the specific way that I set up motors, but it does seem to
hold true with me at least.
Regards
Nicholas McKinney
Applied Industrial Technology, Inc.
www.usaait.com
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