The Bucket Foundry

[Pursang]

It is not my cup of tea.
Unbalanced and low efficiency.

Opposed piston engines have one problem and that is getting power from the two pistons to the user(s) and keeping the pistons in step.
The lasting solution was first seen by me in 1994 and that was to put an AC generator on each shaft and let them rotate in opposite directions to cancel out torque reactions.

Sorry Niels, I obviously misunderstood.
I assumed that electrical field synchronicity, between the two AC generators, was the opposed piston timing & power transmission method.
I then extended that idea to using linear generators, to eliminate the mechanical complexity of cranks & con-rods.
As Frits has stated, it seems that someone is now working on this configuration!

Is the 1994 solution just using the counter rotating alternators as flywheels?

Daryl, what you show us is neither a boxer nor an opposed piston engine. But let's forget the semantics; something like it has already been running (and shaking like hell).

Now the builders are concentrating again on an opposed free piston engine with the combustion chamber in the center where it belongs (right Neil?) and coils around the cylinder.

Agreed, Not a Boxer (more of a street fighter, using his fist & elbow) and as admitted in the post, Not an O/P. (couldn't find one)

It was the linear piston motion & linear generator I was using the gif to demonstrate.

Do you have any pics or links to the New engine? Sounds similar to what I proposed.

Cheers, Daryl.

[Niels Abildgaard]

Sorry Niels, I obviously misunderstood.

Is the 1994 solution just using the counter rotating alternators as flywheels?

Cheers, Daryl.

They act as flywheels,synchronizer and generator.
There is an order of magnitude less expensive,children dug out,poissoneous magnetic material involved than in the linear magnetic investor trapping solutions.
These linear solutions surface every 15 years.The cheated former investors have to be dement or dead first.A very cyclic market.

[Flettner]

I agree Neils a good system for a larger instalation BUT
joining OP cranks on say my 175cc off road bike, with generators (x2) would be too big and cumbersome.
This engine Im building now uses a tooth belt but later I'll be going back to gears. Four, two smaller crank gears, one large clutch gear and an idler that will more than likely run the water pump and autolube pump. So essentially only one extra small gear over a conventional layout. If you were to add a balance shaft on a conventional layout, my OP engine would have no extra gears at all. Cranks counter rotating balance naturally so clearly no need for a balance shaft.

[lohring]

If I use a piston with a full skirt, I can solve the short transfer vs intake port issue. Neels flooded me with opposed piston engine papers. Several things I noticed so far is that exhaust lead can be produced by offsetting the crankshafts from the piston bore center. This allows synchronized crankshafts, eliminating unequal torques and balance issues. The other is that the OPEC (Eco Motors) engine had two rows of intake ports. The upper row was angled to produce swirl while the lower row is straight in. They run dished pistons. They suggest that two symmetrical intake and exhaust passages give better CFD flows.

All the combustion chamber shapes in the papers are for diesel injection. They use dished piston crowns with squish at the edge. I still think central squish would be better for dual spark ignition. A central squish would probably scavenge best with some ports with both a swirl angle and an up angle. The other ports would be straight in with no swirl. This would scavenge both the central and wall areas. The diesel dished pistons look like they mostly use straight in ports with a swirl angle. I may try these ideas to see what happens. What are your thoughts?

Lohring Miller

[Pursang]

These linear solutions surface every 15 years.The cheated former investors have to be demented or dead first.A very cyclic market.

Better dump your Toyota shares, those scammy pricks are at it too! And claiming 42% thermal efficiency!

http://www.extremetech.com/extreme/1...to-power-an-ev

Not an O/P Two Stroke, but at least uniflow. Once again, it's just a demonstration of the linear generator approach.

And, I think I found the group that Frits referred to (DLR):



Cheers, Daryl

[WilDun]

If I use a piston with a full skirt, I can solve the short transfer vs intake port issue. Neels flooded me with opposed piston engine papers. Several things I noticed so far is that exhaust lead can be produced by offsetting the crankshafts from the piston bore center. This allows synchronized crankshafts, eliminating unequal torques and balance issues. The other is that the OPEC (Eco Motors) engine had two rows of intake ports. The upper row was angled to produce swirl while the lower row is straight in. They run dished pistons. They suggest that two symmetrical intake and exhaust passages give better CFD flows.

All the combustion chamber shapes in the papers are for diesel injection. They use dished piston crowns with squish at the edge. I still think central squish would be better for dual spark ignition. A central squish would probably scavenge best with some ports with both a swirl angle and an up angle. The other ports would be straight in with no swirl. This would scavenge both the central and wall areas. The diesel dished pistons look like they mostly use straight in ports with a swirl angle. I may try these ideas to see what happens. What are your thoughts?

Lohring Miller

What is the reason for employing swirl? - ie what does it achieve in our situation? and is squish necessary? - doesn't it cause problems? - I was led to believe that it did! (I perhaps don't read enough - because I'm lazy).

[Niels Abildgaard]

Better dump your Toyota shares, those scammy pricks are at it too! And claiming 42% thermal efficiency!

http://www.extremetech.com/extreme/1...to-power-an-ev

Not an O/P Two Stroke, but at least uniflow. Once again, it's just a demonstration of the linear generator approach.

And, I think I found the group that Frits referred to (DLR):



Cheers, Daryl

I have worked on some WW2 Junkers 200 bar compressors 55 years ago made the same way.
They made compresser air for some even older german torpedoes in danish navy and were same idea.
It is not the way You make 200 bar today.

The future way to make electrcity for transport vehicles can be this:



There is some thoughts on air travel that is almost as important as buckets:
https://www.homebuiltairplanes.com/f...ircraft.33811/

[lohring]

What is the reason for employing swirl? - ie what does it achieve in our situation? and is squish necessary? - doesn't it cause problems? - I was led to believe that it did! (I perhaps don't read enough - because I'm lazy).

Good question. Swirl is necessary for combustion in diesel engines. Except for Fletner's efforts, I'm not aware of spark ignition engines. Swirl scavenges the cylinder walls while colliding flows result in a rising central column. Does swirl past the plugs help ignition? Does a central squish displacing mixture outwards do the same thing? Are either or both needed? I'm probably not going to be able to test all these theories. So far I'm guided by the FOS full circle intake exhaust and transfer designs as well as conventional port layouts. Colliding columns need a small up angle, while swirl ports might need a higher up angle. Below is a picture of the OPEC cylinder with both types of ports.

Lohring Miller

[Flettner]

Found an old photo album, OP uniflow in aviation. Pitty it never flew but it did do a lot of ground running, as I said earlier I didn't have the balls ( or the licence for that matter ) to fly it back then.
A real OP engine doing real work in the real world, not just drawing or speculation. As Lohring is doing, the only real way to find out is build one and see, good on him.

[Flettner]

Lohring, my first uniflow, 100cc twin cylinder, ran domed weedeater pistons with a central squish. With single spark plug needed in the order of 40 degrees advance to run right. With dual plugs back to approx 20 degrees, still not wonderful considering the size of the pistons. Im not sure its a wonderful combustion chamber shape. Although it had only six transfers set up for swirl also not wonderful.

[F5 Dave]

All together now;

Who wears short shorts?
We wear short shorts
They're such short shorts
We like short shorts
Who wears short shorts?
We wear short shorts

[WilDun]

Good question. Swirl is necessary for combustion in diesel engines. Except for Fletner's efforts, Im not aware of spark ignition engines. .....................
Lohring Miller

I guess the swirl in diesel engines aids high pressure direct injection, but (in the case of petrol / HCCI), relatively low pressure injection, carburation or whatever and complete homogenous (if that's a word) mixing earlier on, might also be a solution if used in the right way (that's only how I see it of course!).

[WilDun]

Found an old photo album, OP uniflow in aviation. Pitty it never flew but it did do a lot of ground running, as I said earlier I didn't have the balls ( or the licence for that matter ) to fly it back then.
A real OP engine doing real work in the real world, not just drawing or speculation. As Lohring is doing, the only real way to find out is build one and see, good on him.

Well, that's something which none of us knew before!! and we've got to applaud you for trying it!

So, I guess you have grown the necessary balls and licenced them in order to try again, this time with an improved version?

Be careful, - plenty of ground and dyno testing first - we don't want to lose your input here!........ maybe buy yourself a set of airbag type leathers instead of a new pair of shorts!

BTW, 'speculation' is also my middle name these days and I would dearly love to be able to sort stuff out by trial and error as you do, but some of us just can't - forget about the old "no such thing as can't" rhetoric, sometimes it aint possible because of ' other circumstances'.

[husaberg]

Found an old photo album, OP uniflow in aviation. Pitty it never flew but it did do a lot of ground running, as I said earlier I didn't have the balls ( or the licence for that matter ) to fly it back then.
A real OP engine doing real work in the real world, not just drawing or speculation. As Lohring is doing, the only real way to find out is build one and see, good on him.

Hi Neil, Does the seat also double as the fuel tank?

[Flettner]

You know it, smiley emoji.