I've posted this on rec.autos.tech
Sorry if this duplicates messages for some.
I've just pulled what I thought was a plenum chamber apart, and find
that there is a small passage to the outside of the airfilter (inside
the housing), and between this and the two exhaust connected pipes, a
set of reed valves that appear to be one way TO the exhaust ports, and
not TO the carburettor. So it appears to be air injection into the
exhaust stream? Between these reed valves and the air cleaner
(upstream from the apparent flow) there are filter pads.
It is a mystery to me, unless some silly bugger has put the reed
valves in backwards.
Hi folks. I've either stumped everyone, or no-one's interested.
I've actually found out about this apparently weird setup.
It's actually a passive air injection into the exhaust to oxidise HC
and CO. It is no longer used apparently coz modern cars (this is ~ 20
years old) have much cleaner exhausts and don't need it. Apparently
the American way was to add an air pump, but this Japanese setup uses
the pulse vacuum in the exhaust ports to drag some air into the hot
exhaust flame through the one-way flap-valves (reed valves).
On another subject, there is a white, plastic, dumbell-shaped thing
which looks like a large salt shaker with a largish pipe to the intake
under the carb, and a small pipe to the intake manifiold at one of the
inlet ports. These pipe spigots come out of the waist of the
"dumbell". It has some holes (4) in the bottom, and appears to have
filter material in there. It is labelled "Nippondenso E 301"
Anyone have a clue what this is?
I've found out what this is too.
Aren't those old parts guys a wonderful source of info? None of the
Ford mechanics had a clue, but the parts guy knew it, flicked a few
pages and told me its official name is "Anti-Afterburn Valve" which
allowed me to do a Google search and find that it is a valve that lets
a gob of fresh filtered air into the inlet manifold when the throttle
is snapped shut at high revs and it leans the rich mixture to cut
pollution, and also stops backfiring. Fascinating!
I've just downloaded a vacuum line diagram for a 87 Honda Accord.
Complicated or what!!!
Now all I have left to find out the function of is a water valve which
seems to do with the cabin heater, although I cannot yet see what
operates it, and an electrical switch on the firewall that seems to
override a vacuum line.
Seems to me that anti-pollution add-ons that fail after a few years
are probably causing more pollution, on balance.
Looks good to have a charcoal cannister for the gas fumes, but how
often do folk change them? Same with cat converters.
I reckon that if you park your car in the shade, and drive gently with
a well tuned engine, you will cause a hell of a lot less pollution. Of
course, world wide, the only pollutant that matters is CO2, and
conservation is the best go here. Use public transport where possible,
or use them funny sticks under your ass to get there :)
All the Californian pollution measures are basically because LA has
rotten weather. CO, HC and NOx are all eliminated by the environment
with little or no damage to anyone but overcrowded humans in some
cities. My city of over a million rarely gets any smog as it is very
windy. I guess Chicago doesn't have much of a problem.
Seems a silly bureacratic solution to atmospheric pollution to add a
gadget to an engine that dilutes the pollution below a certain legal
threshold. Best to reduce the use of fossil fuels I would have
thought, and the best way is conservation, and this can be achieved by
adjusting the tax laws. We have high taxation (registration fees) on
each vehicle. Surely putting this on each litre of fuel would
discourage wastage. If you have already invested in your vehicle
registration, why not use it to the max? Silly! </rant>
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