[AT] Continuing "What to do"

[Dennis Johnson]

Steve,

Excellent post. You obviously have good understanding of engines.

Thanks
Dennis


Sent from my iPad

> On Jan 13, 2016, at 7:49 AM, Stephen Offiler <soffiler at gmail.com> wrote:
> 
> Cecil:
> 
> (By the way I loved that rant on concrete and culverts!  I'm a mechanical
> engineer and I see similar "we've always done it this way" idiocy in my
> world every day)
> 
> Different subject, see below...
> 
> 
> On Wed, Jan 13, 2016 at 7:44 AM, Cecil R Bearden <crbearden at copper.net>
> wrote:
> 
>> That is what I read also.  However, the result is a less reliable engine
>> that uses more fuel.   How can you pollute less if the engine you are
>> operating has all this crap on it but uses twice the mount of fuel?
> 
> 
> Ask Volkswagen ;-)
> 
> Seriously, the answer lies in the definition of "pollution".  One pollutant
> in particular is NOx.  A diesel engine inherently makes very high NOx
> emissions.  The chemical reaction to form NOx happens at high temperature
> and pressure, so, the more thermally efficient your diesel engine (the
> better the engine at converting heat into motion) then the more NOx it will
> emit.  The trick to emitting less NOx is to detune the engine, so it
> operates at lower temperatures and pressures.  It uses more fuel because
> you took away thermal efficiency.
> 
> And then there's yet another form of pollution called particulate matter,
> PM.  Microscopic soot and ash, basically.  Modern diesels must be fitted
> with traps to capture PM.  And the traps tend to fill up.  The way to clean
> them is called a "regen" and it involves heating up the trap to a higher
> temperature to burn the soot down.   The extra heat comes from extra fuel.
> So there's another reason modern diesels use more fuel.
> 
> 
> Steve O.
> _______________________________________________
> AT mailing list
> http://www.antique-tractor.com/mailman/listinfo/at