[2stroke] Ryger engine

As allways...
In France, that thing could be renammed as « L’Arlesienne » or shadok machine.

In the Dutch Chamber of Commerce database, the company is listed as "wholesale... mopeds". If you are sufficiently interested, you can pay a few euro to obtain the financial statements of the company to find out just how much economic activity there is:

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Ryger engine – How it works

It`s been a lot of misleading information regarding the new Ryger engine. I looked at the youtube video “Is the Ryger engine shite” from The Workshop, and I think the explanation of how it works is really bad.

I`ve been following this project close, and I will try to explain how the new top end works in general, from my understanding. Hopefully this will help people to understand better. Luc, please correct me if I`m wrong. For a better understanding, please look at the homologation form with pictures and drawings of the various parts in the engine.

So, the big difference compared to newer conventional 2-stroke race engines is the scavenging process. Instead of sucking the fresh mixture into the whole crankcase and cylinder volume below piston, the mixture will only be trapped inside cylinder between piston and the new lower cylinder seal, which seals off the crankcase.

For the mixture to get there, it travels from the reed valve, trough “the new 360 degrees” lower set of cylinder ports and through the conventional cylinder inlet ports.

On downstroke, the reed valve closes and the mixture will be forced to travel from inside cylinder, through the lower set of cylinder ports and scavenged into the cylinder through the conventional cylinder ports.

When piston is at BDC, the exhaust exit pulse will reduce cylinder pressure and suck some fresh mixture from reed valve, through conventional cylinder ports and out the exhaust port. This must be the reason for still using an expansion chamber to supercharge the cylinder as conventional 2t engines.

I believe that the new scavenge process must be more effective and will give you a better cylinder filling than the conventional 2-stroke design today.

I hope my understanding is correct 😊

I believe everybody figured that out , not that difficult.

the big questions are :

how can it run 17.000 rpm with such a short rod, or even 30.000
how can it produce more power than a conventionel engine when the volume below the piston is soo much less, and the tract from exhaust to carb to suck directly is full of sharp bends.

Dear Helmers,
thanks for the serious reply, but as I wrote before, I'm not allowed not explain anything about Ryger at this moment.
Some people here on this forum have destroyed that possibility for me with indecent reactions.
So unfortunately no answer to your question, not even a yes or no !.

Well, forget 30k. They have shifted the power curve to operate at normal speeds.

Because of the better radial support of the piston, maybe a shorter rod is acceptable.  

It seems like the volume under the piston is only app 60ccm, if I did not calculate wrong. I don`t quite understand that this low volume is sufficient either.. Maybe the conventional scavenging is so bad that the even the small volume of the Ryger is better :)

Regarding flow from carb to exhaust, it`s more or less the same as conventional cylinders, but with "less damping" due to no crankcase volume.

Too bad Luc cannot comment..

Thanks Helmers for this extra explanation, I think I understand better now.

Helmers a écrit:

Well, forget 30k. They have shifted the power curve to operate at normal speeds.

Because of the better radial support of the piston, maybe a shorter rod is acceptable.  

It seems like the volume under the piston is only app 60ccm, if I did not calculate wrong. I don`t quite understand that this low volume is sufficient either.. Maybe the conventional scavenging is so bad that the even the small volume of the Ryger is better :)

Regarding flow from carb to exhaust, it`s more or less the same as conventional cylinders, but with "less damping" due to no crankcase volume.

Too bad Luc cannot comment..

30,000 RPM is nonsense for a 125 cc engine. The Ryger website has some dyno graph showing about 65 bhp at 12,600 RPM. The engine speed seems reasonable, but I cannot comment on the power rating.

I also considered the pump volume, which is indeed very small.

In a high performance 125 cc engine, the exhaust port timing is on the order of 180 degrees, thus one might say that one can effectively only trap about 62.5 cc of mixture for every revolution of the crank shaft - trapping effectively starts when the exhaust port closes. I have no experience with testing of 2T engines, but perhaps one of the experts can comment on this point: in an actual high-performance 2T engine running in the power band, how much mixture is effectively trapped in each operating cycle? I would expect that it is certainly less then the swept volume of the cylinder. But how much?

A high performance 2T engine has a volumetric efficiency exceeding 130% so quite a bit more than the swept volume.

(As an aside - volumetric efficiency is defined as the inhaled mass divided by the swept mass at standard conditions - very little to do with volume)

Vannik a écrit:

A high performance 2T engine has a volumetric efficiency exceeding 130% so quite a bit more than the swept volume.

(As an aside - volumetric efficiency is defined as the inhaled mass divided by the swept mass at standard conditions - very little to do with volume)

Aha! OK, since we are dealing with gases, it is little use to speak about "volume" because of the relations between pressure, temperature and density. In my daily work I usually deal with liquid coolants (incompressible).

What is the "swept mass at standard conditions"? Is that m_swept = V_swept * rho_standard? With m_swept the "swept mass", V_swept the swept volume (e.g. 125 cm3) and rho_standard the density of air at "standard conditions" (25 degrees C, 1 bar)?

STP in the engine world is usually 20C and 1 bar.

I realize that it is probably a bit off-topic, but.......

I guess the volumetric efficiency is a function of the operating conditions, i.e., if the engine is running in the power band with WOT the volumetric efficiency is probably very high.

Thus: how to prevent "knocking" or premature ignition if there is a large amount of mixture in the cylinder? And a second question: if direct injection is used (such as the Rotax snow mobile engines), then how can one know the amount of air in the cylinder, needed to determine the amount of fuel to be injected? One can measure the amount of air going into the engine, but the "trapped" amount of air in the cylinder depends on the exhaust system. Does one rely on a lambda sensor or similar for "fine adjustment" of the mixture?

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After a long time a small update.
First of all, see the new factory that is also a big improvement.
The engines have been reliable and ready for sale for several months.
At the moment enough people who are still very enthusiastic and have also bought an engine, and I'm sure they would not have been if the power was only 35hp.
Their enthusiasm was most intensified after making a test drive, which can take place almost every day by appointment.
The sold engines will certainly participate in competitions this year.

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LucF a écrit:

After a long time a small update.
First of all, see the new factory that is also a big improvement.
The engines have been reliable and ready for sale for several months.
At the moment enough people who are still very enthusiastic and have also bought an engine, and I'm sure they would not have been if the power was only 35hp.
Their enthusiasm was most intensified after making a test drive, which can take place almost every day by appointment.
The sold engines will certainly participate in competitions this year.

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Looks good. It will be interesting to follow.

Bad news from RYGER, as expected for some time.
They are in big financial trouble, bankruptcy is very likely.
Not so strange, as they failed to sell even 1 engine in 2 years....
After talking of 70 HP at 30.000rpm it seems they not even reach 50%
of the announced power.
Never winning a race certainly did not help.....

RYGER BV has been disbanded!

I wonder if we're allowed to know any details now?

Ryger is NOT bankrupt-yet

Jan Thiel a écrit:

Ryger is NOT bankrupt-yet

Nothing has changed since my last post !
A new 2t concept is not the same as devellopping a 100 years existing one !

Jan Thiel a écrit:

Ryger is NOT bankrupt-yet

This announcement from the Dutch Chamber of Commerce would suggest that they are, Jan:

Citation :

2019-02-12: Wijziging: Per 15-11-2017 liquidatie beëindigd.
Per 11-2-2019 is de rechtspersoon uitgeschreven wegens Geen bekende baten meer aanwezig bij rechtspersoon.

I suppose it would also mean that you are no longer bound by your Non-Disclosure Agreement   .

So now you can finally tell everything!

But Luc says he is not broke...

Frits Overmars a écrit:

Jan Thiel a écrit:

Ryger is NOT bankrupt-yet

This announcement from the Dutch Chamber of Commerce would suggest that they are, Jan:

Citation :

2019-02-12: Wijziging: Per 15-11-2017 liquidatie beëindigd.
Per 11-2-2019 is de rechtspersoon uitgeschreven wegens Geen bekende baten meer aanwezig bij rechtspersoon.

I suppose it would also mean that you are no longer bound by your Non-Disclosure Agreement   .

I would not count on that, as long as the patent is valid, the agreement will not be changed !
And don't tell more lies like on Racehelden, where you were directly called by the person you mentioned to remove his name because it was not true .
Beside the sentence you wrote was more ment for yourself !

It's a very sad story , we are all expecting infos that never come .

if the engine is runing as it should , why the people at Ryger doesnt tell more to the public , by publishing tecnical stuff , dyno runs , and racing with competitors ?

isn't that the way people "normally" do ?

but after all , they do what they wants


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