Various emission questions

["Storhok, Eric (E.M.)" <estorhok@domain.elided>]

I must have missed a few...

I've seen the correct answer about the air pumps- my '77 Alfetta California car had both the pump and catalyst (well, supposed to have cat, darn P.O.).  Back in the 70's, the state of the art automotive catalyst would only do oxidation, so the only thing that it was effective at "cleaning" was CO and HC.  NOx was still an issue...  Alfa, like a few other companies (say BMW), decided to run the engine a little rich (which really reduces NOx), and add air to the exhaust to give the catalyst a good a/f mixture to burn.

As pointed out, this also burned in the exhaust manifold pretty well, so its possible that you could pass emissions w/o the catalyst, but with only the pump.

Oddly enough, this technology is making a comeback.

What I find interesting is that Honda was able to NOT run with a catalyst up to 79-80 or so.  Their CVCC design burned VERY cleanly.

As for EGR, its possible for a modern catalyst and emissions system to pass emissions tests without EGR.  Not easy, but possible.  When you can, EGR is also commonly used to increase (yes, increase) fuel economy.  If Alfa could make emissions without it, and it didn't come on the European package, why add it?

Eric Storhok
Core Emissions and Fuel Economy Team
Advanced Powertrain Engineering
(313)33x75011
MD 35, FPC-B
Ford Motor Company

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