On Thu, 23 Aug 2007 11:08:52 -0500, "B.B."
u wrote:

In article ,
_ wrote:

[...]


The Detroit Diesel is a two stroke, diesel. The piston goes down on
the power stroke and comes up on the compression stroke. Without the
mechanical driven "blower" which simply blows air in through the
cylinder ports and through the exhaust ports at the beginning of the
compression stroke there would be no way to get a charge of air into
the engine.

If you wanted to increase the pressure and volume of this air flow you
could add a exhaust driven compressor before the "blower", But you
must have the "blower" for the engine to run.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Neither being a two-stroke nor using diesel oil (nor indeed the
combination) requires a blower/turbo for such an engine to operate. It is
true that engines can be designed so that, were the blower/turbo with which
they are normally equipped to be removed they would not run, that would be
due to other design decisions, not to the choice of fuel, method of
ignition, and/or two/four-stroke operation.

O.K. Assuming that your statement is correct And starting from the
power stroke of a two stroke diesel engine.

(1) Diesel fuel is injected into the combustion chamber where air has
been compressed until it exceeds the ignition temperature of the duel.

(2) The rapidly expanding gases created by the burning fuel act to
push the only movable part of the combustion chamber, the piston
downward. At the bottom of the power stroke the gasses inside the
combustion chamber still are far hotter then ambient temperature and
thus exceed ambient pressure.

(3) the piston having reached the bottom of its power stroke begins to
be driven upward by the crankshaft and connecting rod. When it piston
reaches roughly the top of its compression stroke another injection
event occurs.

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


Being a two-stroke, and a Detroit, it requires a blower to operate.
Come to think of it, I've never heard of any engines that are two
stroke and do not use forced induction of one form or another. Even
little chain saws use the crankcase volume as a blower.
Seems as if those two eliminated strokes--intake and exhaust--are
taken up by the blower.
How would you build an 2-stroke engine without forced induction?



Bruce in Bangkok
(brucepaigeATgmailDOTcom)