ESE's works engine tuner

[F5 Dave]

But wait. A new Ryger 4 stroke. They removed the valves and are turning the camshaft at double speed to invoke the mixture in. It's pretty hush hush but send money to. . .

[WilDun]

I think many of us would have liked to see something sensational happen with the Ryger, but I don't think that many people actually believed it would happen at the time, most of all, some people like Jan who had already developed successful engines! - (and I took notice of that), but at the same time didn't like to see someone's dreams shattered - however that's life I guess!

From the look of things, this guy has approached it from a different angle and gone on and done it all first and is now talking!
As Frits says, nothing really new or sensational, so whether it will go anywhere or not, is the question!

I feel that all the sensational breakthroughs were made in the 20th century and all that's left now is to decide whether full on development is going to keep the two stroke alive - or let it die and surrender to electricity! ...... it's all in the balance at the moment!

[Vannik]

Here is his idea, just with the "mushroom" piston the other way round and loop scavenging in place of Uniflow scavenging:

http://www.ac-aero.com/technologies/

[husaberg]

it apparently runs on small balls.


Dunlet piston and engine pre ww2


pre loop scavenged of course

[lohring]

As noted, stepped pistons have been around a long time. It really comes down to what is the most efficient pump in the size range we are talking about. In small engines it's hard to beat the crankcase pump/tuned pipe combination. It gives starting flow with some supercharge and good piston cooling. Piston pumps are most efficient in small sizes where clearances make other pumps leak. Screw compressors are good in moderate sizes where lower friction and wear makes them superior to piston pumps. it's hard to beat centrifugal and axial compressors in large sizes for the same reasons as well as compactness.

However, none of these pumps can add serious power without a system to recover energy, apply back pressure and cool the piston. Scroll expanders may be suitable in small sizes, but turbines are proven in large sizes. Piston cooling is usually done with oil flow to the piston under side in large engines.

Lohring Miller

[Vannik]

The difference between the traditional stepped piston and the new generation versions is that they no longer use the crankcase but the "scavenging" chamber between the piston and the seal to the crankcase.

[katinas]

Interesting solution for oil supply to crank big end main on Honda test NR 125 engine.

[husaberg]

i was trying to find a pic of the gm non supercharged engine i thought they had but i found out ,Detroit and GM consider the Detroit series supercharged diesel to be normally aspirated as it only uses the roots blower to scavenge.
only the turbo are considered blown.

Sorry Vannik i wasn't trying to suggest they were the same, only the stepped pistons were nothing novel.
I suspect none of the older designs up until the late 60's-early 70's were that worried about emissions other then an impolite smokey haze that concerned the flash harry rather portly cigar smoking Daimlers driving 55 year old marketing executive.

[katinas]

http://www.jicef.org/japanese/cimac/...oklet_2013.pdf

Torpedo boat Uni Flow https://glanze.sakura.ne.jp/24wz_diesel.html

[katinas]

Hi Katinas
That fact of not exceeding 5000 rpm is what attracted me

Last attempt with 4 type variation. This time, with opened under exhaust space to add trans volume. Results is the same, zero torque from 5000 to 8000 rpm.

[TZ350]

Flettner 2013 https://youtu.be/hOGZ5llowoU

Yes, its hard to patent something that has already been done.

KTM 2017 https://youtu.be/e8LgPoCQVCk

KTM tried to pinch Flettners idea. Their patent application was declined .....

[pete376403]

Interesting solution for oil supply to crank big end main on Honda test NR 125 engine.

If that arrow is pointing to some sort of "scoop" on the end of the pin to pickup oil thrown from the main bearings, that's pretty common among two strokes. My 72 F9 Kawasaki bighorn had a ring on the side of the flywheel that did the same thing

[katinas]

My 72 F9 Kawasaki bighorn had a ring on the side of the flywheel that did the same thing

Thanks, never noticed this before.

[ken seeber]

[QUOTE =KTM tried to pinch Flettners idea. Their patent application was declined ..... [/QUOTE]

Lots of good stuff happening out there and it's not always the big companies....

[ceci]

Last attempt with 4 type variation. This time, with opened under exhaust space to add trans volume. Results is the same, zero torque from 5000 to 8000 rpm.

Excellent work done, I hope it helps to develop new more efficient engines