ESE's works engine tuner

[sonic_v]

It's homologated with the blanking plate and the spacer, so no problem.

Really! If the CIK were to accidentally homologate an engine that in actual fact does not meet their regulations then I would think that the legal eagles at the competitor companies might just do something about it.

Some years ago when the CIK 100cc direct drive kart class was dying a death due to competition from non CIK one make kart engine series that used clutches and electric starters, the CIK decided they would go "green" and change over to four-stroke engines. The Italian kart industry with one voice told the CIK that they will be staying with two-strokes, that four-strokes were too expensive to manufacture.

The Italian kart industry comfortably represents over 90% of all CIK engines produced. Ryger is not Italian and neither is VM - the manufacturer of the Ryger engine.

[Niels Abildgaard]

I'm sure there is a simpler way to get rapid pressure change after TDC, but I haven't opened that Ryger box yet.

Hello Fletner


Will it be possible to adjust the compression ratio with the small upper piston?
I mean get that toothed belt away and and put a handle on the upper crank
The compression needs only to be adjusted as fast as load,fuel supply and temperature varies and this does not sound difficult with modern electronics and a servodrive and a couple of traingauges on cylinderbolts that tell when combustion is to early or correct at TDC.

[ken seeber]

I think there are belts with teeth at both sides; they could drive the balance shaft.

I have thought about the Freetech 50 cc bikes and saw a few pics of these with CVT running directly on the crank, 15/16,000 rpm. I would think this would create a lot of friction compared to a CVT running much slower, eg 1/2 engine speed. So, combining this with a balance shaft running off the back of chain or double sided timing belt, one could create a layout something like this:



Another benefit would be to be able to run a much smaller rear wheel sprocket.

[lohring]

Hello Fletner


Will it be possible to adjust the compression ratio with the small upper piston?
I mean get that toothed belt away and and put a handle on the upper crank
The compression needs only to be adjusted as fast as load,fuel supply and temperature varies and this does not sound difficult with modern electronics and a servodrive and a couple of traingauges on cylinderbolts that tell when combustion is to early or correct at TDC.

That's called a "diesel" engine by model engine builders. They run on a mix of kerosene, ether and oil. They've been around for years and are still used in a variety of applications. See http://www.davisdieseldevelopment.com/index.htm

Lohring Miller

[Niels Abildgaard]

That's called a "diesel" engine by model engine builders. They run on a mix of kerosene, ether and oil. They've been around for years and are still used in a variety of applications. See http://www.davisdieseldevelopment.com/index.htm

Lohring Miller

Thank You

I am fully aware of that ,but they were never regulated during running to keep combustion/explosion /Knock or wharever exactly at TDC.
The engine Neil has made will be very suitable to test that .The idea of combining a normal piston movement plus one that runs double so fast corresponds to a movement with a single piston on a shorter connecting rod.The worlds most efficient engines (danish two strokes from Man B&W)
have connecting rod to crankthrow under 3 that is a 125 connecting rod of less than 81 mm between eyes.

[Frits Overmars]

Will it be possible to adjust the compression ratio with the small upper piston?I mean get that toothed belt away and and put a handle on the upper crank. The compression needs only to be adjusted as fast as load, fuel supply and temperature varies and this does not sound difficult with modern electronics and a servodrive and a couple of traingauges on cylinderbolts that tell when combustion is to early or correct at TDC.

In theory it can be done Niels, but in practice we need a pressure rise that is much steeper than can be achieved with just one piston; with the latter you won't have sufficient control over the ignition timing, notwithstanding all these modern electronics.

The idea of combining a normal piston movement plus one that runs double so fast corresponds to a movement with a single piston on a shorter connecting rod.

Again, in theory you are correct, provided we confine ourselves to what happens in the vicinity of TDC (around BDC it's a completely different kettle of fish).
But did you calculate how short that con rod ought to be in order to achieve the same effect that Flettner achieves with his double-speed compression crank?
It would be completely impractical, not even counting the effect of such a short rod on piston friction.

The worlds most efficient engines (danish two strokes from Man B&W) have connecting rod to crankthrow under 3 that is a 125 connecting rod of less than 81 mm between eyes.

I did not know Wärtsilä was Danish . And they have not only short con rods, they also have pressure-lubricated cross-heads. And finally they are diesels; their ignition timing is governed by the fuel injection pump, not by compression pressure.

I have thought about the Freetech 50 cc bikes and saw a few pics of these with CVT running directly on the crank, 15/16,000 rpm. I would think this would create a lot of friction compared to a CVT running much slower, eg 1/2 engine speed. So, combining this with a balance shaft running off the back of chain or double sided timing belt, one could create a layout something like this:

Another benefit would be to be able to run a much smaller rear wheel sprocket.

Ken, if you run the CVT at half the speed, it has to cope with double the torque, so you'll have to double the clamping force of the pulley sheaves or the belt will slip. That won't do much good for friction reduction. Moreover, if you lay out the system for more torque, everything becomes heavier.
Most CVTs have a gear reduction somewhere between the secondary pulley and the rear wheel, so the sprocket size isn't that important.
Here is some more reading on the subject.
EDIT: darn, can't attach the 6,69 MB file.

[Flettner]

Twice engine speed balance shaft? Can the crank in the head be used as a balance shaft as well? Have to have a think about that.

[Frits Overmars]

Twice engine speed balance shaft? Can the crank in the head be used as a balance shaft as well? Have to have a think about that.

Yes it can, but then you will need two of them. L4 car engines sometimes employ them.

[tjbw]

Really! If the CIK were to accidentally homologate an engine that in actual fact does not meet their regulations then I would think that the legal eagles at the competitor companies might just do something about it.

...

If CIK decided that they'd make that mistake, then Ryger could replace the blanking plate with something that looks like a carb.

The spacer plate replaces the lower end of the cylinder, and is not part of the crankcase.

[jonny quest]

Has anyone tried putting seals on inside of main bearings, and let gearbox oil lubricate mains? And just let oil splash on flywheel like a four stroke?

[FastFred]

Has anyone tried putting seals on inside of main bearings, and let gearbox oil lubricate mains? And just let oil splash on flywheel like a four stroke?

The Suzuki RG50 and TF/TS range of Suzuki's (and probably others) drive side main bearing have the oil seal on the crankcase side with the gearbox oil lubricating the main brg.

[Niels Abildgaard]

I did not know Wärtsilä was Danish

Wartsila is Finnish and has sold the Swiss Sulzer two stroke division to China.
Are these engines more efficient than the MAN B&W examples developed in Copenhagen?

[dark art]

Has anyone tried putting seals on inside of main bearings, and let gearbox oil lubricate mains? And just let oil splash on flywheel like a four stroke?

Gas Gas trials engines are like that. a real PITA to change a crank seal

[jonny quest]

I'm wondering if there's a performance advantage of having bearings and seals "reversed". Better lubrication being the advantage

[husaberg]

Yes it can, but then you will need two of them. L4 car engines sometimes employ them.

Honda 250T and N and 400T&N had two.



Yamaha TX500 had a Omi phase something
Well I am not totally so sure looking at it (that it is two shafts) but its pretty unique.