Keith Addison wrote:
> ASomeone's been trying to sell me on an additive > to reduce NOx. Apparently it does indeed reduce NOx, and > simultaneously CO, but otoh I think NOx is an overblown problem, I'm > always a bit suspicious when people chuck the NOx objection at > biodiesel. Better to debunk the thing rather - "solving" it via an > additive lends it too much credence: ie, biodiesel ain't no use on > its own unless you use an additive. Correct. NOx is not caused by high combustion temperatures, but by "crevice combustion" - combustion in tight spaces with a high ratio of cooled perimeter to volume - which entails rapid quenching and "freezing" of the back-reaction which otherwise converts NOx back to free nitrogen and oxygen. Southwest Research Institute proved this at least twenty years ago, in research sponsored by DoE. I read the report that long ago, and it could have already been some years old at that time. What this means is that NOx is a combustion chamber and piston design problem; SRI showed that relatively minor changes in piston crown design reduced NOx significantly in their test engines. Leaving out crevice combustion, diesels should have lower NOx emissions than spark-ignition engines because their pressure "spike" is not as pronounced. Marc de Piolenc Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://www.webconx.com/2000/biofuel/biofuel.htm To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
