I just saw the "new" clean diesel emissions requirement today... I'm actually kind of laughing that it was never done before...
It's a "particulate filter" (another catalytic convertor, but with a different catalyst) that has pressure sensors on each side of it... when pressure drops too low, it enters "after burner" mode, and clears out the crap... as ash. Ash is much better than diesel particulate for the environment, thus justifying intermittent 1100*+ exhaust temps.
I love our new "Green" america...
