Thermactor?

[sgw_88FoxGT]

I know it's a smog pump, but how does it work?

 

[NIKwoaC]

Basically, it pumps air into the exhaust to help finish burning unused hydrocarbons. It also aids in the function of the catalytic converters by including oxygen in the exhaust gasses.

I'm sure jrichter will show up with a sweet diagram, so stay tuned.