2-stroke radial engine

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kcnegemen

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hello.

I designed 2-stroke radial engine.

Radial Engine work?




fyj6h.jpg


fyj7u.jpg
 
G'day mate,
Looks good but how will it scavenge the crankcase to provide fuel mixture for the cylinders :confused:
Cheers
Terry
 
Yup.

You’ll need forced induction.

Similar to the 2-stroke Detroit diesels, which use superchargers.

It could be an easy way to build a radial – in that you wouldn’t have to construct a complex cam-gear, rocker arms, valves, etc.
 
This requires a positive displacement pump. Vane type is common in model engines. Rootes or screw compressor in full scale.
 
The radial flow compressor you have will not work at crankshaft speeds. You must use a positive displacement pump for this to be successful at model scale. A radila flow compressor could work, but there would be a lot of issues to work out in the design of the compressor itself and it would have to turn at very high speed. A vane pump displacing ~1.5 times cylinder swept volume will work perfectly.
 
hello
diesel pilot
Can you give an example of a positive displacement pump

Can you give an example of a radila flow compressor ...

sufficient to run 2 times speed compressor will ya?

What's your suggestion to me.

then waiting for the answer.
 
looks interesting, not sure a impeller is the way to go for forced induction in this application as it needs some serious rpms before it starts building some pressure. also not sure of the plumbing arangement, unless thier is something im missing.......
 
I would not say that a blower doesn't work at all. They do and did on 2-stroke Diesels. But I doubt that they work at crank-RPM unless they have a relatively huge diameter.
It would need some calculating (blowers can be calculated) before making the first chips.


Nick
 
the problem here is that a centrifugal compressors pressure ratio is roughly proportional to the tip velocity regardless of restriction so flow is not steady it is mostly determined by pressure (rpm) and resriction. the pressure will change slightly with flow but if you look at pressure maps of turbo chargers the rpm lines are almost horizontal, both pressure and flow increase exponentially with rpm. i don't know all the math but a ~ .5 to 1" compressor wheel wont make much pressure even at full throttle and it's not too practical to achieve the required rpm with mechanical means. the engine may run at very high speeds but it wont idle.

you need a positive displacement pump like a vane, roots, screw, or possibly wenkel if you really want a challenge. positive displacement means that a revolution moves a determined amount of air. the flow increases linearly with rpm. this is needed to precisely evacuate the exhaust effectively without blowing fuel through the exhaust

http://image.moparmusclemagazine.co...opar_superchargers+types_of_superchargers.jpg
 
hello
diesel pilot
Can you give an example of a positive displacement pump

Can you give an example of a radila flow compressor ...

sufficient to run 2 times speed compressor will ya?

What's your suggestion to me.

then waiting for the answer.

Vane type was shown in the link I provided before. http://en.wikipedia.org/wiki/Rotary_vane_pump other positive displacement types work, but are a bit more complicated to manufacture. A single cylinder engine using the crankcase for primary compression is a type of positive displacement pump.

Even twice crank speed would not be enough for a radial flwo compressesor( what you've drawn in simplest form). I have a 31mm Borg Warner turbocharger compressor wheel for a turbine engine project. To achieve 1.5 pressure ratio it must spin 185,000 RPM. Yes, that's right, one hundred eighty five thousand RPM. This is off the compressor map supplied by the manufacturer. Matching flow to the engine speed is an issue as well. Even a much large compressor say 100mm, properly designed I might add, would need ~50,000 RPM.
 
Don't forget piston pumps. In small sizes they are surprisingly efficient and can easily be incorporated into the pistons of the engine. With some clever piping, the pump delivery can be timed to match the intake porting in a multi-cylinder engine.

Lohring Miller

Two Stroke Radial.jpg
 
hello

period of 4 times the belt off. There is a picture.

waiting for your comments ...


h2fs1.jpg
 

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