Steve wrote in :

Bob wrote:

Why is the 2 stroke diesel dead?
I know little about diesels, just the obvious, like no sparkplug.

Bob


High emissions and lower fuel efficiency compared with competitive
4-stroke diesels

In order to get emissions down, a 2-stroke diesel engine has to be
"overblown" so that an excess of fresh air is pushed through the
cylinder to drive out the exhaust gasses fully, but doing that wastes
mechanical power. So solving the emissions problem aggravates the
efficiency problem and vice-versa. And also, 2-stroke diesels have a
lot higher lubricating oil consumption rate than similar 4-strokes, and
that aggravates emissions too.

The EMD 710 is the only remaining locomotive 2-stroke, and is being
phased out by the EMD 4-stroke "H-series" engine. Detroit Diesel was
the
biggest maker of 2-strokes for trucks, earthmovers, yachts, etc. and
they stopped 2-stroke production several years ago. And its been over
20
years since many 18-wheelers used Detroit 2-strokes anyway.
Fairbanks-Morse still builds their opposed-piston 2-strokes for a few
Navy applications and for stationary applications (flood control pumps,
backup generators, etc.) and will probably continue to do so, but
that's
a pretty small market segment.

Since 2 NGs are aviation related, that is one area where the 2-stroke
*might* hang on longer because of its weight savings, but its
ultimately
probably doomed there also.



exspecially since they are testing at least one rotary diesel, very much
lighter and quieter for unmaned small reconasinst planes. KB
--
ThunderSnake #9 Warn once, shoot twice
460 in the pkup, 460 on the stand for another pkup
and one in the shed for a fun project to yet be decided on