2-stroke diesel is the (near) future?

Sport Pilot wrote:

Steve wrote:

wingsnaprop wrote:


Guess why?
*Duh* Pollution laws, and no need for the power to weight
requirements of Aviation! Duh... whats that got to do with this

topic?

Other than to show that 2 stroke Compression ignition engines are a
proven concept?


As already stated, 2-stroke diesels really don't have a

power-to-weight

advantage over 4-strokes. They still have to have a camshaft and
exhaust valves (they aren't like weed whacker engines, you know), so
they don't save that weight. Plus they have to have a blower for
scavenge air. The only area where they save weight is in that the
connecting rod and crank can be lighter, and that only helps offset

the

added weight of the blower.



I said something similar, but I don't know that a desiel has to have
the valve, as the old locomotive two strokes. Could it not be ported,
as the two stroke spark engines?

In order to scavenge the cylinders properly, the inlet ports need to be
at the bottom of the cylinder and exhaust valves have to be located at
the top. The only viable alternative is the opposed piston engine (ala
Fairbanks-Morse) in which one piston uncovers an inlet port array and
the other uncovers the exhaust ports. But then you have the weight of an
additional CRANKSHAFT, without any increase in output power!

The fuel is already oily so if the
bearings are sealed ball bearings, you may not have to add oil to the
fuel.

I think you're confusing a weed-whacker/outboard motor type 2-stroke
with a 2-stroke diesel. A 2-stroke diesel has a closed crankcase just
like a 4-stroke.