ESE's works engine tuner

[bjorn.clauw.1]

This is what I 'think' i see

Pic2
1. Under the piston there is a 3mm window all around, the same height as the lower transfers (minus the area where the skirt goes in the plate) for the piston to push the charge through the lower transfers.
1a. When the piston is at tdc the skirt area (red) opens up the transfer under the exhaust with the other ones into the cilinder (the sides are always connected to the other transfers, Pic1 1)

Pic1
1. The transfer under the exhaust is a semicircle that loops and connects the left lower transfers to the right ones.
1a. X-ray goggles are broken so no way of telling if this transfer is connect to the exhaust. (I like the bernoilli/venturi idea posted above)
Would be hard to get this connected to the exhaust duct due the location of the water cooling channels though.
2. Normal intake port goes straight in (rotax style) and is closed from the cilinder above the piston at bdc (as usual). Normal C transfer port above the intake.
2b. Boyesen ports from intake into the lower transfer ports (you can see the rounded curves where they enter on the right transfers)
If there were no boyesen ports, why would the dividerwalls between the transfer ducts not be flush with the bottom of the cilinder?
3. Maybe just me, I think the conventional transfers open when the exhaust is fully opened (top of transfer port same height as bottom of exhaust port).
Don't think they raised the port as a whole, just filled in the bottom, maybe not all the way to the top of the transfers but still a considerable amount.

Again, all just visual observations from a low-res, bad angle picture.


Edit: like this


Nevermind my drawing skills drawn on my phone during lunchbreak.

[bjorn.clauw.1]

Hmmm, L plate rider doesn't sound so bad right now...

[F5 Dave]

You can change that in profile settings when you have a few posts under your belt

[Norman]

When the piston moves from TDC to BDC the outlet transfers (upper windows) are open and the mixture should to some extent move in that way. This route is not closed until the lower edge of the piston reaches the lower side of the transfers. Right? It's therefore less mixture left that needs to be squeezed through the 3 mm gap at the transfer (lower) inlets?

[jfn2]

bjorn.clauw;
Yes I agree with you. The intake has to be connected with either boyesen ports or open into the channel around the bottom into the transfers. With that said the rest of the cycle is like any other 2-stroke. It still needs good blowdown time and area and it needs a good exhaust port design and pipe. Keep in mind that these people wanted a cleaner burning engine 1st and any performance gain is 2nd. It wouldn't surprise me if the ruling federation told them to tame the engine down by eliminating the sub exhaust ports to keep the power in line with other engines.
My way of thinking is that the piston (squeezing the smallish lower cylinder volume) is acting like a supercharger and this is where the power is coming from.
I'm sure the HCCI helps. But I also think it would work just as well with a regular ign system, maybe not as clean burning. But I could be wrong.
Just my thoughts!

[Larry Wiechman]

Restricted or throttled exhaust port area is a key feature of HCCI systems.

[136kg136ps]

Larry,could that be the anonymous lump in the exhaust drawing?
It would seem that lump would heat the mixture returning from the pipe.

[Norman]

Restricted or throttled exhaust port area is a key feature of HCCI systems.

Could a pipe be tuned so that it pushes the mixture back in together with exhaust gas? A pipe tuned for HCCI? Then it would not be cooled of that much as if it would return below the piston.

[Larry Wiechman]

Larry,could that be the anonymous lump in the exhaust drawing?
It would seem that lump would heat the mixture returning from the pipe.

I don't have much faith in the drawings that have been provided.

[yesyes]

the power comes from very high Rpm ; how to deal with piston speed well above known limits for a reliable 125 two stroke ??

[tjbw]

Larry,could that be the anonymous lump in the exhaust drawing?
It would seem that lump would heat the mixture returning from the pipe.

There is no lump in the exhaust.

What you see on the "Section View Of Cylinder Drawing" is an artefact from a previous triple exhaust port design, m4r suggested this earlier.

[Tunisti]

To quote myself:

So, is there connection between the wide "Ryger port" below the exhaust port and the assumed ducts on the side walls of the exhaust duct? If so, It´d change the concept of short circuiting for good.

As said, I somehow tend to believe that fresh mixture is intentionally introduced into the exhaust duct. Could it allow the HCCI to take place, or could it amplify the pulse actions in the pipe, or could it be some kind of mobile "catalytic conventer", which would keep the emissions in strict bounds? Or could it be all that at the same time?

The timing of the port below the exhaust, seems to be controlled by the skirt of the piston. Therefore I´d say that the port is not for "traditional scavenging". But, if we think the Ryger's peak power rpm vs. pipe lenght vs. exhaust port timing, we can see that there must be somewhat high temperatures/pressures in the exhaust pipe, just to work satisfactionary at such rpm's. What if there was mixture burning inside the exhaust pipe? Wouldn't the pressure and temperature be higher, thus raising the pipe's rpm-band? As mentioned earlier, Ryger tends to run somewhat cool, and therefore there would not be enough heat to keep the pipe super hot for such rpm numbers?

Or what if the (assumed) fresh mixture burning in the pipe would create artificial " extra pressure wave" to charge the cylinder even more with somewhat fresh mixture, before the exhaust would close up. The combustion of such mixture would be much slower and placid compared to the combustion at combustion chamber. Therefore there could be somewhat stabile "extra pulse" created by the combustion in the exhaust pipe.

[wobbly]

The problem is that if " 3 port " ducts are shown in the section drawing, but they are not there in the engine - then any technical inspector
can quite rightly make the assumption a "tuner " has filled these in, thus you get failed in tech.
Rule Number 1 in KZ2 - you are NOT allowed to add material anywhere.

[tjbw]

The problem is that if " 3 port " ducts are shown in the section drawing, but they are not there in the engine - then any technical inspector
can quite rightly make the assumption a "tuner " has filled these in, thus you get failed in tech.
Rule Number 1 in KZ2 - you are NOT allowed to add material anywhere.

The inspector could see from "Photo Of Base Of Cylinder", and "Drawing Of Cylinder Development" that there is only one exhaust port, and this is as stated on page 2 of the homologation.

Regarding the apparent duct in the exhaust port, shown on the "Section View Of Cylinder" they could state that that was a raised feature for anti-detonation which they had removed.

[tjbw]

To quote myself:


As said, I somehow tend to believe that fresh mixture is intentionally introduced into the exhaust duct. Could it allow the HCCI to take place, or could it amplify the pulse actions in the pipe, or could it be some kind of mobile "catalytic conventer", which would keep the emissions in strict bounds? Or could it be all that at the same time?

The timing of the port below the exhaust, seems to be controlled by the skirt of the piston. Therefore I´d say that the port is not for "traditional scavenging". But, if we think the Ryger's peak power rpm vs. pipe lenght vs. exhaust port timing, we can see that there must be somewhat high temperatures/pressures in the exhaust pipe, just to work satisfactionary at such rpm's. What if there was mixture burning inside the exhaust pipe? Wouldn't the pressure and temperature be higher, thus raising the pipe's rpm-band? As mentioned earlier, Ryger tends to run somewhat cool, and therefore there would not be enough heat to keep the pipe super hot for such rpm numbers?

Or what if the (assumed) fresh mixture burning in the pipe would create artificial " extra pressure wave" to charge the cylinder even more with somewhat fresh mixture, before the exhaust would close up. The combustion of such mixture would be much slower and placid compared to the combustion at combustion chamber. Therefore there could be somewhat stabile "extra pulse" created by the combustion in the exhaust pipe.

Take a look at pic1 in posting above by bjorn.clauw.1, this shows that there is an annular transfer space connecting the port below the exhaust to the other transfer ports.