Quote:
Originally Posted by Daox
You are quite right that diesels are a much larger polluter of NOx when compared to gasoline engines. I just still see the effects of NOx as horrible. At the very least I would go have a 5 gas analysis done to make sure my NOx emissions weren't too out of check. I'd be happy increasing FE by 10% if NOx goes 10%, but not if NOx increased faster than FE.
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I agree. There is a saturation point where the reducing cat cannot help anymore, and that depends on the size of the cat and the vehicle. A 5-gas analyzer and a dyno is the best way to determine this.
Unfortunately GM has deleted the EGR valve off of several vehicles, using other means to control NOx. This is ok, but they have also killed a little bit of spark timing to hedge in the emissions requirements, which kills a bit of economy. If they kept the EGR valve, the other improvements would have made it possible to maximize the efficiency of the engine... strange decisions they make, while claiming to improve fuel economy! But then it looks like they were trying to save some money somewhere.
Ok, enough ranting...
BTW for all those wanting to know what NOx is: Nitrogen Oxides in it's various forms that are a particularly nasty pollutant responsible for acid rain and such.