Date:         Mon, 25 Feb 2008 00:31:31 EST
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      Re: A Comment on TDi Engine rpm vs. Longevity and Economy
Comments: To: d23haynes57@hotmail.com
Content-Type: text/plain; charset="US-ASCII"

In a message dated 2/24/08 4:38:46 PM, d23haynes57@hotmail.com writes:


> You forgot to mention that as you lower the engine speed increasing the
> torque load, chamber pressures, and combustion temps, you are also
> increasing the production of NOx. NOx is one of the pollutants making it
> difficult for new Diesels to get compliance.
>
>
Dennis,

Definitely true. I'm certainly guilty of oversimplification. The MTZ papers I
cited in a previous reply map the emissions characteristics showing how
strong this effect is. The ECU typically triggers extra EGR juice under these
conditions to try to minimize the effect. This also effects the heavy coking
buildup in the intake tract an effects efficiency (but that is taken into account in
the full load BSFC curves).

Frank Grunthaner



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