Ambitious newby

[jcb121]

clever boy :)

That engine is pretty clever, using manual rods from the crank to open and close ports.

So the piston is connected to one or both of the valves? If you made the valves come off the piston at 90 degress then you could have one cylinder with two expansion strokes as you could have a combustion area on either side of the piston.

[russell]

As for diesel 2strokes, they have existed in the past. Some had conventional valve trains, some were ported, but pretty much all of them were supercharged.

Diesel 2-strokes used to be used extensively for model aircraft without supercharging before the days of outrunner electric motors. I'm not sure how well they scale up though.

Russell

[Robin Hewitt]

Diesel 2-strokes used to be used extensively for model aircraft without supercharging before the days of outrunner electric motors. I'm not sure how well they scale up though. Russell

I think they ran on nitro, but maybe this one runs on nitro.

[mocha]

yep, model aircraft, hydroplanes, boats... they were and are still used today, mainly found in buses and marine engines and some main battle tanks. The "diesel" part of the model engine refers to the compression ignition rather than the fuel type. The fuel as I recall was nitromethane (or something exotic that now comes with a Health and safety warning if you can still get it!)

The flat fronted buses after the routemasters - the name escapes me, used the same engine design as the Chieftan tank, but that was with two opposed pistons for every cylinder.

[John S]

The flat fronted buses after the routemasters - the name escapes me, used the same engine design as the Chieftan tank, but that was with two opposed pistons for every cylinder.

The Leyland L60 that engine was like an hand grenade looking for a war.

main difference between small diesel two strokes and large is that in the small ones they use crankcase compression and need a fuel oil mix.
The large ones used pressure oiling like a 4 stroke but this precludes crankcase compression hence the supercharger taking over this roll.

[brsanko]

Actually a good share of commercial diesel engines are two stroke even today. Catapiller, and Detroit Diesel to name 2 big ones. The main concern with this design, I think, is that injection starts after the exhast port is closed, which I don't think will be a problem.

[brsanko]

clever boy :)

That engine is pretty clever, using manual rods from the crank to open and close ports.

So the piston is connected to one or both of the valves? If you made the valves come off the piston at 90 degress then you could have one cylinder with two expansion strokes as you could have a combustion area on either side of the piston.

Look at it again, there are no valves, only ports. There are already two combustion chambers per cylinder. The rods you see are the scotch yoke/connecting rod for the piston. Actually though if I had them go 90 degrees and then down I wouldn't have the difference in exhast flow on the bottom chambers.

[russell]

I think they ran on nitro, but maybe this one runs on nitro.

We used to make our own fuel. A mixture of paraffin, castor oil, and ether with a tiny amount of amyl nitrate if more power was needed.

Russell.

[m_c]

Diesel 2-strokes used to be used extensively for model aircraft without supercharging before the days of outrunner electric motors. I'm not sure how well they scale up though.

I wasn't talking about model engines. I was talking about ones that could power real vehicles!

[brsanko]

Well I took some of your suggestions and made some changes to my model.  I staggard the cylinders, increased the stroke a bit, made the intake ports longer than the exhast ports, and completely redesigned the crankshaft and crancase, including some counter weights.  I still need to redo the manifolds and induction system as well as add injectors and systems for cooling and oiling.  I wonder if one could design the lubrication and cooling systems as one system.  As in oil cooling, running the oil through a radiator and such.