Re: Clogged cat?

[Paul Nicholson <paul@eisusa.com>]

At 14:11 -0500 2/1/99, johnc@together.net wrote:
>>From what I hear, it seems that there is one hypothetical enviro downside to
>cats - that all the nasty stuff - CO & hydrocarbs, etc. - gets converted
>to CO2
>which adds to greenhouse gasses.  Other than that, the cat eliminates
>80-90% of
>the CO, hydros & Nitrogen oxides.  So how is putting out 800% more pollutants
>more enviro friendly?

Gosh, don't they teach chemistry anymore?

Unburned pollutants ultimately get converted to C02, N2 and H20. It is the
intermediate C0, unburned hydrocarbon, and N0x that does the damage. In an
ideal gasoloine engine, fuel would be reduced to H20 and C02 directly. Not
all fuel gets burned completely, resulting in C0 and hydrocarbon (HCx)
polluntants. In addition, the higher the burning temperatures, the more NOx
compounds are formed. The cat just finishes the burning that did not get
done right in the engine.

Modern engines are optimized for fuel effiency, power and low pollution.
There are some tradeoffs in doing so. You can increase effiency and power
at the cost of cleanliness. Ultimately the net amount of C02 released by
fossil fuels depends on the amount burned. So if you optimized only for
fuel effiency, the net CO2 released would be slightly less. Locally
however, you will be releasing CO, HCx, and N0x, all of which are dangerous.

When I travel outside the U.S., I immediately notice the exhaust fumes from
automobiles, it's the same smell as following an older U.S. car without
emissions controls. Go breathe the air in Beijing for a few days and tell
me we don't have a better system.

Paul

If we Americans really want to reduce CO2 emmissions, then we should stop
hauling our kids to soccer practice in 5000 pound trucks, and we should get
Audi to import manual 6 speed transmissions ;-).