Ed Taylor wrote:
>
> Bob Donahue wrote:
>
> >With all the smog discussion lately, maybe someone can clear up
> >an on going argument here at work. If I understand it correctly,
> >emission pollutants are measured as a percent of the exhaust gas.
> >Does this mean that a 5 liter engine is allowed to produce
> >5 times as much pollutants (in absolute quantity) as a one liter engine?
> >I am making the assumption that the exhaust volume is related to
> >the engine displacement.
> >
> >Bob Donahue, Still Stuck in the '50s
> >53 MG-TD, under DIY restoration
> >71 MGB, still in the shop 10 months and counting
> >
> >
> >
> Actually, it's still measured as a percentage of the volume of exhaust
> gas. You can assume that a 4L engine is going to belch out double the
> gases that a 2L engine produces, so the hydrocarbons would be double
> also - yet would still have to be within the ppm limitation.
>
> Which leads us to a discussion of the wonderful AIR PUMP, which was
> one way of beating the emissions guidelines without doing a thing to
> actually clean up the emissions from the engine. The air pump simply
> injects air into the exhaust gasses, thus reducing the ppm of pollutants
> without actually reducing the volume of pollutants. The same amount
> of hydrocarbons, CO, etc., are still present at the exhaust, there is
> just more air for them to be measured as a part of!!
>
> But try to explain this to your local smog guy. He'll still throw the
> book at you if you don't have the air pump. Oh well...
>
> Ed in Greensboro, NC
Ed-
The theoretical explanation of the air-pump is that it injects fresh air
into the exhaust mixture, thus promoting the complete combustion of
unused hydrocarbons from the exhaust. Don't know if this theory stands
up to scrutiny or not.
Regards,
Chris Delling
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