Forum whore
Maybe 110's are the future for F4 2T Buckets.Originally Posted by cotswold
The important parts are from bikes that were commonly sold in NZ, and gets away from the questionable and rather grey practice (in Bucket terms) of buying special after market cylinders from Europe in an attempt to make a competitive 2T engine.
Like the rules, I think Buckets should be all about making best use of original non competition motorcycle engine parts not clever use of a credit card.
Hardcore Biker
Maybe at Ryger they have the same problem......
They can test for free at many dyno's in the Netherlands.
But they never do.....
Hardcore Biker
The compressed gases are more density than the suction gases.
Occupancy rate would be better
The volume of the "crankcase"may not be sufficient to supply the cylinder
Ryger works like the engines of the 1970s
Hardcore Biker
Not serious, lightly, just imagining: what it would be if no working volume under piston at all ( like Ryger main and "small" pistons would be same size), just intake (with or without reed) directly connected to transfers and exhaust. All work left to pipe. Start is impossible, but if engine is 2 cylinder, and one would normally operating, then head pipes of both cylinders connect together ( at right angles ) and then to one pipe (or two). Maybe suction waves start fill that cylinder and ........ But maybe I write nonsense.
Interesting, what influence on Ryger performance made squash between piston and small cylinder upper surface. On intake side, I left the piston skirt , because want, that last stream from squash directed to main transfers, not to reed block. Because want to make plate thin as possible, small cylinder upper surfaces hiding in piston at BDC ( 2 mm. if measure from lower edge of piston side skirt, but side gap is 1.5 mm. (piston inside dia. at top 52mm. small cylinder outside dia 49mm.) ) But on original Ryger engine ( from homologation ) small cylinder not hiding , so its ok.
Maybe, it is possible to explode the piston at BDC if gap between small cylinder outside wall and piston skirt is too small and hide too deep.
Hardcore Biker
Hi,
One thing about Ryger engine, which might have been expected, and it has proved after first static test, it is very low mechanical noise.
Very lovely, but maybe until..........
Forum whore
As Katinas wrote earlier, nor his engine, nor the Ryger has auxiliary exhaust ports because those would require a wider piston skirt, that would in turn hamper the flow into the transfers. Since I read it here, I can react without endangering my NDA (thank you Katinas). And what follows now, is purely my own guesswork since I never received any relevant information from Ryger.
From the Ryger homologation papers we can see that the exhaust timing is lower than the Aprilia RSA timing, so the Ryger's blowdown angle.area is tiny compared to the RSA's. And when taking the initially quoted maximum torque rpm of 17500 into account, the Ryger's blowdown time.area was almost non-existent. It nevertheless did not stop it from producing over 70 hp.
And before anybody says that they've never seen any proof of this amount of power in the form of a real dyno graph, let me say that neither have I, but I was lucky enough to get a seat-of-the-pants impression of the original Ryger prototype before problems with the production engines brought the operation to a halt, and my pants are not that easily fooled, having ridden motorcycles with several hundred hp.
By the way, what made me decide to step out of the project, was the lack of frankness. I would have loved to take part in the development of that engine, but it turned out that I was only recruited to generate publicity. I'm sure I could have prevented some of those technical problems if only there had been an exchange of thoughts, but all I ever got were promises. It's a pity....
OK, back to my theory. Seeing that the in-cylinder pressure of the RSA is about 12 bar at exhaust opening, and given that the Ryger is claimed to produce about 20 hp more than the RSA, and given that the Ryger's blowdown time.area is so much smaller, there must be a huge amount of spent gases that enter the Ryger's transfer ducts, raising the pressure in the sub-piston volume and the density of the mixture (well observed, Philou). The higher pressure may lead to a much faster transfer flow, with more mixture inertia. This inertia then ought to pull more fresh mixture through the reed inlet valve.
I only wonder how effective this inertia can function, as the Ryger's transfer ducts are very short and anything but flow-encouraging.
That was also my second impression after the staggering acceleration: the beautiful sound. When you would expect a regular 125 cc engine to reach the end of its power band, the Ryger started to sing; that's the best I can describe it. This lovely sound, in combination with the large amount of hot exhaust gas that enters the transfer ducts and is subsequently recycled into the cylinder, made me think in the direction of Homogeneous Charge Compression Ignition with its very fast, short combustion phase; maybe ten times as fast as regular spark-ignited combustion. HCCI would also account for low fuel consumption, comparatively clean exhaust gases, and the need for only a small cooler, although I could not verify these claims.
Could you persuade your software to take a look at these thoughts, Neels?
Hardcore Biker
frits your theory is interesting. in a normal 2t we don't want any exh pushing back into the transfers. but in katanis/ryger style engine you think plenty of exh is pushing back through the transfers and pressuring the 'crankcase' and perhaps this is how such a small pump volume is able to work ?
Hardcore Biker
I can confirm your results. Even when going beyond what would normally be realistic figures in primary compression ratio, burn duration etc., all I got was a very peaky 37ish hp in the end. More or less what I would expect a 125cc engine with reduced breathing capacity to be able to achieve.
Did you see the rpm on a rev counter, Frits? Or could it have been short gearing, that a narrow road and a shot of nitrous oxide? Did you have a second kart with a standard engine to switch to for comparison?
HCCI is very dificult to control, there is no way this can be achieved with a 30mm carb, and it is typically uses for lower load applications. What happened when you closed the throttle after a full load run? Was the engine responding with a delay? HCCI normally works with excess air, so even if you'd manage to get the required amount of air in, you'd still be better off, hp-wise, running on the rich side, e.g. AFR 12.
Forum whore
Asked and answered ages ago Haufen. I watched the revcounter until the power rush set in. Then I had to concentrate on staying alive. We were not on a race track, just on a stretch of quite narrow road with protruding manhole covers in the center.
There definitely was no on-board provision for nitrous oxide. And before you ask: I would recognize the smell of nitromethane miles away, and there wasn't any.
There was no standard kart present, but I know how a regular 125 cc kart behaves and I've got the lap times to prove it. Like I said, I'm not that easily fooled.
You might want to read what Flettner wrote about it.HCCI is very dificult to control, there is no way this can be achieved with a 30mm carb, and it is typically uses for lower load applications. What happened when you closed the throttle after a full load run? Was the engine responding with a delay? HCCI normally works with excess air, so even if you'd manage to get the required amount of air in, you'd still be better off, hp-wise, running on the rich side, e.g. AFR 12.
still basking in the glory..
Might be worth a go at sealing off the crankcase with a rubber boot, reducing the under piston area and see what you got, still running on premix.....
Forum whore
Are there any carb size restrictions for 110cc watercooled buckets?
Hardcore Biker
Yes, any 2T over 104cc is restricted to a 24mm carb.
Factual Facts are based on real Fact and Universal Truths. Alternative Facts by definition are not based on Truth.
Forum whore
Yes, the fun we hadwith the Ryger guessing game, here we go again. It certainly has 'sparked' up this thread again.
Smallish exhaust port hole, large nozzleing effect, The whole system is running at a higher pressure including the exhaust. Pulsing and ramming effect must have more energy over a standard system. Just like a water ram running a very high head of pressure (high pumping pressure), when the reverse wave happens there is still a negative pressure applied to the ram valve as to let it drop into the water flow (or lack of it at that point) to start the process all over again. Even on the highest pressure Ram Pumps.
In the Ryger I imagine no matter how high the internal 'pulse' pressure is, there will always come a time when there is a negative pressure at the transfers somewhere throughout its open cycle, to draw in more charge, past the crank case.
As the pressure in the exhaust increases, does the wave run faster? It certainly will have more energy, both positive and negative.
Hardcore Biker
This Ryger discussion is interesting, if nothing else to get the brains working in trying to understand the design subtleties that might give it its claimed advantages.
For many, many years I have been interested in a direct air inlet system, totally by passing the crankcase, ie a “wet sump” bottom end. Essentially it could mean 5 passages drawing from atmosphere and entering the cylinder in the current “conventional” positions. This would mean 5 passages, 2 entering the cylinder in the A positions, 2 into the B positions and another into the C position. Something like what it shown in the pic, this being in the B position.
The whole thing is dependent on the exhaust system having the ability to draw sufficient air into the cylinder. This would obviously mean both the delivery ratio & trapping efficiency be maintained at a high level. I figure if the 24/7 concept works, this must work bypassing the many aero losses in passing through the crankcase.
I do recognise that the power band of the engine would be limited, as it doesn’t get any benefit from crankcase pumping, particularly at the lower speeds. Obviously starting would be something to be addressed, but there might be answers there. How it is fuelled is another matter as well, but in its simplest form, it could have a carburettor attached to each passage (= 5 carbs).
Obviously, I must answer the question of “why bother?” Although I’d be keen on seeing the 70hp from a 125 cc cylinder for the world of Wobblys, I am more interested in a lower cost & cleaner 2 stroke concept.
Hardcore Biker
The pumping loss would be minimal on a Ryger. The full are of piston on bottom is not used for Primary Compression
There are currently 12 users browsing this thread. (0 members and 12 guests)
Posting Permissions
Reply With Quote
Bookmarks