Sorry, but this line of discussion has got me on my soapbox.
I think it is somewhat inaccurate to say "diesel engines make more NOx." Historically, the goal of engine development has been to make an engine as efficient as possible. From a thermodynamic standpoint, efficiency is achieved by raising the "input temperature" and lowering the exhaust temperature. This is what the Carnot efficiency formula tells you. The way you get the high input temperature is by increasing cylinder compression. (Basic thermo, has nothing to do with the kind of engine or the fuel.) The great success of the diesel engine is its undoing: 1) diesel engines are more efficient because they use higher compression ratios 2) diesel engines are capable of running well on really crappy fuel. 3) diesels have superior combustion efficiency because they can run very lean. (This is all explained in an excellent book, Engineering Fundamentals of the Internal Combusion Engine by W. Pulkrabek, 2nd Ed. 2004. Everyone should read it.) If you built a gasoline (spark ignition) engine with the efficiency of a diesel, it would also have high NOx production. So, the correct statement might be "very efficient engines make more NOx." There are four solutions to this problem: 1) Use less efficient engines (e.g., gasoline engines) 2) Develop the catalyst sytem that will work with diesels 3) Forget about NOx, it isn't really a pollutant anyway. The real pollutants are particulates, HCs (or VOCs) and CO. The problem comes when these react with NOx or ozone. Eliminating these removes the problem. 4) Develop a new kind of engine that gets around NOx formation. (A little harder.) Ernie Rogers In a message dated 8/20/2004 7:58:14 AM Mountain Standard Time, biofuel@yahoogroups.com writes: Date: Fri, 20 Aug 2004 00:54:59 +0100 (BST) From: Donald Allwright <[EMAIL PROTECTED]> Subject: RE: NOX and catalytic converter use --- Robert Del Bueno <[EMAIL PROTECTED]> wrote: > So does a 2 way catalytic converter have any effect on NOx, > specifically > with biodiesel usage? > I am sure you see what I am getting at. > NOx emissions combined with high ambient VOCs are very problematic > for > urban areas (specifically Atlanta, GA). > In order to be able to really push biodiesel usage, the NOx rise must > be > addressed. No, it will have no effect. Therefore, this rise must be combatted at source, by improving the combustion process. This is one of the downsides of Diesel engines over petrol engines. [Non-text portions of this message have been removed] ------------------------ Yahoo! Groups Sponsor --------------------~--> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar. Now with Pop-Up Blocker. Get it for free! http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/FGYolB/TM --------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://infoarchive.net/sgroup/biofuel/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/biofuel/ <*> 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/