ESE's works engine tuner

[adegnes]

From http://iffitech.com/news-and-media/d...he-two-stroke/

"Despite the setback, Lawson remained convinced that two-strokes were the way of the future, and recently performed a detailed computer analysis for Martin Aircraft that showed that a properly-designed two-stroke could result in power production that was 19 per cent denser than that of an equivalent supercharged four-stroke, while producing far less emissions than the rotary engines currently favoured for aero use.

“We started out just trying to prevent the two-stroke from smoking, and we can now make them amongst the lowest emitters of any type of combustion engine. We can equal any four-stroke on header pipe emissions and produce far less emissions than a rotary.

“With a two-stroke you can contour the combustion chambers perfectly for improved combustion. I’m reluctant to go into further details, but we use a modified form of toroidal chamber.”

Lawson says that these chambers when combined with a refined direct-injection fuel system and separate oil injection can effectively sanitise a two-stroke engine. His latest company, Integrated Forced Fuel Injection (IFFI), has been formed to complete the process of applying for patents for the fuel injection system and the accompanying piston design that have been developed"

That combustion chamber sounds familiar...

I'm talking with Kevin Nairn who worked with Denver developing and testing the ring. I'll ask if I can share some info(don't want to step on toes) or better yet if he's willing to join and share himself.
He's made a nice watercooled cylinder pressure sensor too.

Seems to have been a success!

[adegnes]

Quick question that's probably been answered before(hell I might even have asked it myself and forgotten...)

Why weren't the RSA transfers done like this? If duct volume and entrance/exit ratio were kept the same, and maybe the wall angle next to C-transfer tweaked a bit, wouldn't that be "better"?



The answer is maybe that the hook introduces some needed "swirl"?
Your RC engine has more the shape I'm thinking of Frits, why?

[adegnes]

Just received a mail from Kevin, he's going to help me out with the ring but I'm not allowed to share anything that's not already public. His call, got to respect that.

Uncomplicated design though, just a matter of getting the clearance right I suppose.

[Frits Overmars]

Why weren't the RSA transfers done like this? If duct volume and entrance/exit ratio were kept the same, and maybe the wall angle next to C-transfer tweaked a bit, wouldn't that be "better"?

The answer is maybe that the hook introduces some needed "swirl"? Your RC engine has more the shape I'm thinking of Frits, why?

The Aprilia RSW cylinder had to fit existing crankcases; the same transfer layout was used for the RSA because it had proven itself. With the RC cylinder I had complete freedom re the stud positions.
Swirl, or indeed any form of turbulence is fine for speeding up combustion, but turbulence during the transfer phase would only mix fresh mixture with spent gases.
And I don't like hooks; I'm not an angler.

[adegnes]

The Aprilia RSW cylinder had to fit existing crankcases; the same transfer layout was used for the RSA because it had proven itself. With the RC cylinder I had complete freedom re the stud positions.
Swirl, or indeed any form of turbulence is fine for speeding up combustion, but turbulence during the transfer phase would only mix fresh mixture with spent gases.
And I don't like hooks; I'm not an angler.

Yes! I had a feeling you'd say something along those lines, hurray!
I was afraid the only thing distinguishing my (distant)future cylinder project from the other RSA clones would be slightly different transfer timing and the 100% width single exhaust port... Oh, wait. Maybe a narrower C port too and maybe with a bit less upwards angle.

Need to get some machines and a foundry up and going, might take a while...

Edit: when thinking about it that sounds very much like a copy of your small creation...

[wobbly]

When the SwissAuto engine went into the Pulse I had the opportunity to measure the different Cd of the B ports you describe Adegnes.
The hooked corner design was well down on flow compared to the swoop radius style , and on the dyno its trapping efficiency was well down, needing much leaner jetting
that mad less power ( same egt. )

[adegnes]

When the SwissAuto engine went into the Pulse I had the opportunity to measure the different Cd of the B ports you describe Adegnes.
The hooked corner design was well down on flow compared to the swoop radius style , and on the dyno its trapping efficiency was well down, needing much leaner jetting
that mad less power ( same egt. )

Thanks wobbly!

[ken seeber]

[QUOTEAnd I don't like hooks; I'm not an angler.[/QUOTE]

I don’t go fishing either Frits.

The below pic is of rubberies of the ports of a TM KZ10B. The B passages do go around a tortuous path, limited by the basic engine design. Key issues being the actual stud pattern and the stud height, the latter resulting in the nut height (and resultant spanner clearance) forcing the B passage path to go around its tortuous path.

The complicated B passage can clearly be seen. Opposite the standard B passage, I crudely created (in plasticine) the shape of a B passage that wasn’t constrained by the presence of the stud position and nut height.

Whilst I am sure it’d flow better, I also recognise that if it was simply substituted instead of the standard OEM B passage, it might not perform better (after watching ESE for quite some time and understanding just how bloody finicky high performance 2 strokes are) as the flow performance and direction etc might not suit the currently developed balance of the existing A,B & C passages and ports. That aside, I would think that it would ultimately offer a higher performance level than the current arrangement.

[SwePatrick]

Quick question that's probably been answered before(hell I might even have asked it myself and forgotten...)

Why weren't the RSA transfers done like this? If duct volume and entrance/exit ratio were kept the same, and maybe the wall angle next to C-transfer tweaked a bit, wouldn't that be "better"?



The answer is maybe that the hook introduces some needed "swirl"?
Your RC engine has more the shape I'm thinking of Frits, why?

Cause they would flow a lot worse.
The flow from crankcase is secondary to flow into cylinder.
It´s the freshmixture trapped on top of the piston that produces power

You would have less control of flow into cylinder in your example.
This with the hard bend that is the result of that design, in my eyes, no good.

You need to remember that flow into the cylinder isn´t a constant flow, it´s like puncturing a ballon when piston opens the transferports.
Thereby you want a lot of volume ready just next to the pistonskirt when it pops.

[adegnes]

Cause they would flow a lot worse.
The flow from crankcase is secondary to flow into cylinder.
It´s the freshmixture trapped on top of the piston that produces power

You would have less control of flow into cylinder in your example.
This with the hard bend that is the result of that design, in my eyes, no good.

You need to remember that flow into the cylinder isn´t a constant flow, it´s like puncturing a ballon when piston opens the transferports.
Thereby you want a lot of volume ready just next to the pistonskirt when it pops.

Wouldn't my illustration have more mixture available just outside the port opening and a less torturous path to get there?
And as there is no hook, but a more or less straight path wouldn't that lead to better control?
I've been mislead by my own "common sense" more than once(most times when dealing with women or two strokes), but this just seems too wrong.

Edit: My sketch might be a bit misleading, I was trying to illustrate a wider duct vs the "around a corner and hook" design. I certainly don't want any sharp bends.

[jonny quest]

I think Adg is trying to illustrate a whole new transfer port with his blue line. No hook, no swoop, a port that has an exit directed like a modern shape but the tunnel has only a 2 dimensional arc. (No 3d swoops or hooks).

[adegnes]

I think Adg is trying to illustrate a whole new transfer port with his blue line. No hook, no swoop, a port that has an exit directed like a modern shape but the tunnel has only a 2 dimensional arc. (No 3d swoops or hooks).

Yep! Illustrations are not my strong side, though this was pretty bad even for me...

[jonny quest]

I just realized, Adeg drawing kind of represents how the FOS style transfers are laid out (kind of for ease a description)

[shnaggs]

I would think that a B-port designed as Adeg is suggesting would cause less trapping efficiency. I would think that the port's speed would be on the high side causing more mixture to be lost to the Exh port, but then again on the reverse pulse from the pipe, the stronger stream may mix less with the exhaust and purity might go up? As Adeg has said, my common thinking has been proven wrong multiple times on these 2 -strokes.

Wobbly, you are saying that the port 'with NO hook' had better trapping efficiency?

[adegnes]

Pretty much exactly like this: