On Thu, 23 Aug 2007 21:15:47 -0700, "Calif Bill"
wrote:


"Del Cecchi" wrote in message
...

wrote in message
news snip

Now, as temperature of the gasses within the combustion chamber and
thus the pressure, is higher then ambient temperature and pressure at
the bottom of the power stroke the flow should be from the high
pressure area to a lower pressure area. In which case the engine would
not receive any air for the next stroke.

So, where does the two stroke diesel engine get the air necessary to
support combustion of the next injection of diesel fuel if not through
the use of a mechanical air pump, usually referred to as a "Blower" in
D.D. parlance

Presumably it would get them by using the crankcase as a compressor like a
gas 2stroke does.

Whether it is possible to get the necessary compression for ignition,
especially while at cranking speed, while dealing with transfer ports etc
is left as an exercise for the student.

del


2 stroke diesels will run without a blower. I have a model airplane engine
diesel that jsut uses the crankcase like a gas rig. And there were a lot of
those 1 lunger diesels in Montereys, etc, that did not have a blower.


Sure you do and it worked just like a glow plug engine. You mixed oil
for lubrication and some nitro-benzine, or something like that, and it
ran. Exactly as do sea scooters, 2-stroke motor cycles and chain saws.

And the reason is that you use the bottom of the piston coming down on
the power stroke to compress the fuel/oil mixture in the crank case to
force it into the combustion chamber.

But we were talking specifically about a Detroit Diesel 2-stroke and
the fact that it does need the mechanical driven "blower" to run.




Bruce in Bangkok
(brucepaigeATgmailDOTcom)