Science Forums 2

[marcringuette]

Regarding lean mixtures and diesel engines, I found
a couple of points to consider using search inside
amazon.com/gp/reader/012370619X for "diesel", on page 99,
and also at en.wikipedia.org/wiki/Diesel_engine .
Please bear in mind that I'm all theory, all the time. :-)

Diesel engines never throttle the intake air, so at part load
they're always running very lean, and even at full load they're
significantly lean of stoichiometric. They don't seem to have
the problems with slow or incomplete burning of lean mixtures
that Otto cycle engines do -- in fact, somewhat the opposite.
Local pockets of lower temperature where the fuel is not fully
atomized can cause incomplete burning and soot; this happens
more often with the richer mixtures, hence the "black smoke limit"
when you stomp too hard on the accelerator despite the fact that
this richer mixture is still lean of stoichiometric.

So, theory suggests to me that for diesel, lean mixtures won't
run hotter.


Marc