ESE's works engine tuner

**wobbly** · 2nd February 2016, 11:16

This is the same wave action that makes a big power boost in a 180* twin that has a 2-1 header, and the pistons cut short
so the port is open when the pistons are at TDC.

**Tunisti** · 2nd February 2016, 11:35

Originally Posted by nasone32

Or better, there's a full wave cycle to be exploited there, when the piston hovers around TDC. with the lowest pressure ratio being exactly like the one we use to suck from the cylinder, and the highest pressure ratio in the 1.5 range.
As someone previously suggested, the port under the exhaust port could be connected to the exhaust port, through the "fake booster" channels in the drawing.

I'm wondering why Frits hasn't commented that theory I wrote couple pages back.. Ofcourse, the amount of text in here is huge and time is a limited source.. Though I wish there is some other reason not to be involved.

Can't really demonstrate right now, but Mota gives these dynamic graphs with crank rotation vs. distance from certain point vs. pressure/velocity/purity etc. And those graphs show that double wave effect very clearly. It's hard to translate the theory accurately, but in short: there is a wave/pulse, that has capability to modify "static" pressure at a certain point at a certain time and with a certain amount of pressure. So if we look at pressure at exhaust port with time intervals X and pressure units Y we can see that the pressures might be somewhat X1=3Y X2=5Y X3=6Y X4=6Y X5=3Y.

Let's say that the time intervals line up close to exhaust port closing. We also happen to know that the "static" cylinder pressure at the same intervals is this: X2=3Y X2=4Y X3=5Y X4=5,5Y X5=6Y.

So, let's calculate (very roughly) how much of the pulse can be exploited (subtraction of the pressures at certain time intervals): X1=0Y X2=1Y X3=1Y X4=0,5Y X5=-3Y. Now we can see that we managed to exploit only 3 out of 5 time intervals to help raising cylinder pressure. So, let's assume that exhaust port closed bethween intervals X4 and X5. We have this leftover pressure of 3Y, that couldn't have been used to raise cylinder pressure, yet is is much higher than pressure in the cranckcase, so why shouldn't we take an advantage of it?

Wow, it was one clumsy presentation, should have just drawn it... In a nutshell there is a p/t graph for wave, and only certain area under that curve can be exploited in traditional case. Not to say that you could ever exploit it all.

**nasone32** · 2nd February 2016, 14:02

Originally Posted by wobbly

This is the same wave action that makes a big power boost in a 180* twin that has a 2-1 header, and the pistons cut short
so the port is open when the pistons are at TDC.

At maximum power the depression wave front presents at 60 degrees before TDC and the peak pressure wavefront at about 60 after TDC.
this gives a port height of about 17mm in a 54 stroke. which looks also pretty realistic from the drawings.
when the engine is overreving the wavefront arrives later, some 15 degrees every 1000 rpm, but since the available window is 120 degrees it can continue its action for a long range of revolutions, this explains the nice overrev.

It could be also possible to use some overlap with the exhaust port, to raise the pressure in the crankcase even more. But i cannot confirm this.

howver if i'm guessing even only a part of this the right way, good job there.

Wobbly you could confirm those numbers with engmod, plotting the pressure traces at the exhaust port.

I'm wondering why Frits hasn't commented that theory I wrote couple pages back..

Frits is under NDA. NDAs can cost you a lot of money

**wobbly** · 2nd February 2016, 18:41

Here is the pressure ratio at 10mm inside the duct of a KTM85 that will rev to 17,000 like a Ryger.
Its done at peak torque ( 14,000 ) and shows the positive ratio over a large period around TDC, when the piston will
have uncovered the port below the main Ex to help fill the space above the divider plate and below the larger piston diameter.
The only issue I see is that the volume of this space that is later compressed, is very small - but then that appears to be another
part of the overall operating mechanism, as that small volume gets highly compressed BTPO.

**nasone32** · 2nd February 2016, 23:54

Originally Posted by wobbly

Here is the pressure ratio at 10mm inside the duct of a KTM85 that will rev to 17,000 like a Ryger.
Its done at peak torque ( 14,000 ) and shows the positive ratio over a large period around TDC, when the piston will
have uncovered the port below the main Ex to help fill the space above the divider plate and below the larger piston diameter.
The only issue I see is that the volume of this space that is later compressed, is very small - but then that appears to be another
part of the overall operating mechanism, as that small volume gets highly compressed BTPO.

thank you Wobbly.

I've made an educated guess, by drawing the crankcase from the fiches schematics. there's also a dimensioned drawing of the reed cage, it was useful. Bear in mind there's some good volume in the reed cage duct, in front of the reed valve. At the beginning i thought the crankcase was very small, but i was forgetting about the volume there.
my best guess is 270 - 300cc (provided i guessed correctly the internal crankcase geometry)
this gives a compression ratio of 1.35 - 1.3 :1 taking into account 70cc of piston motion.

Transfer ducts included.

The volume is smaller than we are accustomed to, but it's not that small afterall.

edit: Wobbly there's some impressive depression going on after exhaust port closure!

**MotleyCrue** · 3rd February 2016, 06:30

Originally Posted by wobbly

Here is the pressure ratio at 10mm inside the duct of a KTM85 that will rev to 17,000 like a Ryger.
Its done at peak torque ( 14,000 ) and shows the positive ratio over a large period around TDC, when the piston will
have uncovered the port below the main Ex to help fill the space above the divider plate and below the larger piston diameter.
The only issue I see is that the volume of this space that is later compressed, is very small - but then that appears to be another
part of the overall operating mechanism, as that small volume gets highly compressed BTPO.

If I understand the trace then if the exhaust was connected to the crankcase for awhile around TDC on a KTM85 at 14000 rpm it would be a bad thing, exhaust gases would flow into the crankcase and there wouldnt be any flow from the crankcase into the exhaust. But on a Ryger engine well maybe it is workable somehow.

**nasone32** · 3rd February 2016, 06:59

Nope, the first thing that happens 60 degrees before TDC is a suction wave.
and as you can see, a strong one! even stronger than the one that sucks from the cylinder.

It should suck the air out from the crankcase, and as a consequence, from the intake.
some would go into the exhaust port.
then a reverse pressure wave arrives, and puts the escaped (FRESH!) air back into the crankcase, pressurizing it.
then the piston compresses the trankcase and seals the auxiliary port.

much like what already happens with the transfer ports, just in the crankcase...

**SwePatrick** · 3rd February 2016, 07:04

About this speculations about a port in exhaustduct connected to crankhouse(house under piston, maybe call it 'pumphouse'?)
I just can´t get it.

Why on earth would you want to pressurise the crankcase with dirtygasses when you want to draw fresh gasses through carb?
In that way you lose pressuredifferances between free air and crankcase.
Result is that the carb stops flowing, reed closes.

Convince me.. i just don´t get it.
To me it seems like a perfect way to destroy a perfect running engine.

**wobbly** · 3rd February 2016, 07:47

You have to "get " that what is sitting in the duct just ouside of the port face ( but before the header starts ) is a slug of fresh A/F mixture.
This can only be usefully used by two effects if they exist.
The mixture can be moved inward by a depression in the " crankhouse " or by a positive pressure ratio sitting in the duct.
In this case when the extra port below the main Ex is opened by the rising piston we see a really big positive pressure ratio, so the A/F sitting in the duct
is easily moved into the expanding volume under the piston.
Just as the dropping piston has very little to do with getting mixture thru the transfers in a "normal " race engine, the Ryger uses the much stronger wave action
to shift extra A/F into the volume above the guide plate.

And yes the really big depression around BDC in that KTM pressure trace is due to a highly optimized pipe shape working with port superposition
to pull plenty of mixture thru the transfers when they are fully open, achieving a high bulk flow rate - again nothing to do with the dropping piston creating
pressure in the case.

**Tunisti** · 3rd February 2016, 07:52

If you take time to read couple of the last pages, you'll understand that in optimal situation there shouldn't be any exhaust gas in the cranckase. Imagine that the exhaust duct and the header act as a pump, first they're filled, then they're drained. And it all happens with somewhat fresh mixture. The same operation that happens already once in the cycle, but in a slightly different place.

Btw. The operating of this system outside the "sweet spot" would be somewhat terrible. It'd be good to have some kind of governor in the "Ryger port". And that governor could shut the duct fully, when necessary.

Edit. Couple pages back (P. 1453) I also introduced this theory of that tight gap and homogenous mixture. No one hasn't commented anything about it? Wondering that what if this pulse-efficiency theory of mine works, but it's not found in the Ryger engine...

**nine-thirtysix** · 3rd February 2016, 08:08

I like the idea of a piston controled exhaust to crankcase connection in the Ryger engine and with the homologation paper in mind this is a possible solution.
But the leaked pictures of a early stage engine (which I will not further share) show definitly no connection between the lower ports and the exhaust duct.

If we then look again and see the not really drawn bridge between C-port and intake, the uncorrect half section of the baseplate as well as the not matching lower duct to the port window, I think there are no channels in the exhaust duct.

But keep on thinking maybe it will lead to another development

**nasone32** · 3rd February 2016, 08:17

Originally Posted by Tunisti

If you take time to read couple of the last pages, you'll understand that in optimal situation there shouldn't be any exhaust gas in the cranckase. Imagine that the exhaust duct and the header act as a pump, first they're filled, then they're drained. And it all happens with somewhat fresh mixture. The same operation that happens already once in the cycle, but in a slightly different place.

Btw. The operating of this system outside the "sweet spot" would be somewhat terrible. It'd be good to have some kind of governor in the "Ryger port". And that governor could shut the duct fully, when necessary.

Edit. Couple pages back (P. 1453) I also introduced this theory of that tight gap and homogenous mixture. No one hasn't commented anything about it? Wondering that what if this pulse-efficiency theory of mine works, but it's not found in the Ryger engine...

About The gap. If I understand what gap you mean, it's not connected to anything. probably it's just space clearance for the piston skirt when it goes down to bdc.

About the sweet spot.
That wave action works in a broad range.
outside this (rather big) sweet spot there are only small fluctuations present at the auxiliary port, the engine works just like a normal engine would do

obviously this is only speculation

**breezy** · 3rd February 2016, 09:40

Originally Posted by nasone32

About The gap. If I understand what gap you mean, it's not connected to anything. probably it's just space clearance for the piston skirt when it goes down to bdc.

About the sweet spot.
That wave action works in a broad range.
outside this (rather big) sweet spot there are only small fluctuations present at the auxiliary port, the engine works just like a normal engine would do

obviously this is only speculation

Having again looked at the posted ryger homogenization pictures , there are quite a few inconsistency s between the pictures that i feel they have been doctored and not all is revealed...

**MotleyCrue** · 3rd February 2016, 09:56

Originally Posted by nasone32

Nope, the first thing that happens 60 degrees before TDC is a suction wave.
and as you can see, a strong one! even stronger than the one that sucks from the cylinder.

It should suck the air out from the crankcase, and as a consequence, from the intake.
some would go into the exhaust port.
then a reverse pressure wave arrives, and puts the escaped (FRESH!) air back into the crankcase, pressurizing it.
then the piston compresses the trankcase and seals the auxiliary port.

much like what already happens with the transfer ports, just in the crankcase...

When Wobbly described it before (for a 2 into 1 pipe twin) he mentioned about half as much timing as the transfer timing so I reckon +/30 degrees, but there is no suction between + 25 and -30 degrees on that trace. A 2 into 1 pipe twin would have different pressures I would think.

Even if the crankcase connected to the exhaust much earlier than that, like +/-60, port timing is symmetrical so it looks to me like there is a lot more time of flow from the exhaust to the crankcase than from the crankcase to the exhaust, so there might be more flow through the reeds for a bit but the net would be pumping exhaust (real burnt exhaust gases) back into the crankcase.