ESE's works engine tuner

[Dutch Fisher]

If its a 3 port or a T port, then the duct exit should be around 75% of the total effective Ex area, then the spigot should transition to 100% round diameter.

Wob have you got a formula or fixed length for the transition to the 75% choke point from the port and again from the choke point to 100%

[jonny quest]

Here's a Ryger question you may be able to answer Frits. Does the Ryger make more than 54hp at 13,000 RPM? Or less?

[Frits Overmars]

Here's a Ryger question you may be able to answer Frits. Does the Ryger make more than 54hp at 13,000 RPM? Or less?

You're right Jonny. I'm able to answer that. But I'm not allowed to.

[husaberg]

A reed if it was to be mounted against the cylinder wall (screws at the bottom) opening up of a high mounted transfer passage (likey easiest a c port) would open with flow pushing out into the cylinder(once the cylinder had been vented by the exhaust port lowering the pressure) yet be able to be shut quite gently by a rising piston. The skirt of the piston would then not allow it to open until the top of the piston again descending down towards BDC.
This would direct flow away from the exhaust as it would flow upwards it would allow airflow direct towards the cylinder head and should allow greater cylinder filling.

Neil whip one up this arvo.

You're right Jonny. I'm able to answer that. But I'm not allowed to.

No love for the high reed controlled transfers?

[Bert]

And now for a sideline question

Hi Rob, how's the fuel injection project going?

It's been a little quite from the ESE boys for a while now and I suspect that means great things are happening.
Give us a little progress snippet while we wait for the patient office & FIA.
North island series is just around the corner and I'm looking forward to seeing the beast in full flight.

[Frits Overmars]

A reed if it was to be mounted against the cylinder wall (screws at the bottom) opening up of a high mounted transfer passage (likey easiest a c port) would open with flow pushing out into the cylinder(once the cylinder had been vented by the exhaust port lowering the pressure) yet be able to be shut quite gently by a rising piston.

So you want the piston to close the reeds that close the ports? The piston can do that on his own, no reeds required. Think of an opposed piston. Or a sleeve valve...

The skirt of the piston would then not allow it to open until the top of the piston again descending down towards BDC.

I see; the reeds would be leaning against the piston skirt. As oil scrapers, so to speak .

This would direct flow away from the exhaust as it would flow upwards it would allow airflow direct towards the cylinder head and should allow greater cylinder filling.

And how do you propose to scavenge the bottom part of the cylinder (the part were there used to be scavenging ports)?

No love for the high reed controlled transfers?

Lots of love, if you can make them work.

[husaberg]

So you want the piston to close the reeds that close the ports? The piston can do that on his own, no reeds required..

I only want it to be open when the piston is descending and after the cylinder pressure is lower so it has to have a reed, I see it like a super high C port in a cylinder reed engine.only two of them feed from the rear there is space not utilised currently if the cylinder studs are moved out. the space is on either side of the C port entry to feed them.

I see; the reeds would be leaning against the piston skirt. As oil scrapers, so to speak ..

Yes they would be flat against both the cylinder wall and skirt unless open where it would pivot from the bottom out into the port at much the same angle as a C port in a cylinder reed engine it should be able to be gently shut by an ascending piston. Yet not be open when the cylinder pressure is high so no exhaust gases down the ports.

And how do you propose to scavenge the bottom part of the cylinder (the part were there used to be scavenging ports)?.

In the same manner as a normal one. I just see some more real estate available higher in the wall, plus maybe it should keep the incoming inertia higher with less stop start of flow as it should continue to flow for longer maybe just long enough to switch over to crankcase induction without a inertia robbing stop of flow.This might only work if it was breathing direct to the inlet rather than the transfers

Lots of love, if you can make them work.

Unlikely given my general malaise and proclivity for procrastination, but Neil could.

The question is would it make any useful contribution to increasing the output.
Maybe the greater transfer area of incorporating a high transfer would allow a wider ex port in a single 2 AUX ex Port set up as the AUX ports would be able to be less compromised by making the a ports smaller as the a ports show a compromise on the RSA to fit in the 2 wide AUX EX ports currently.
Maybe the high transfer might be also cleaner as it is directed well away from the EX port.

[Frits Overmars]

Initially I understood that you wanted to put those additional transfer ports above the exhaust, but your drawings made me see the light. I must say it's not as silly as I first thought, although I still shiver at inward-hinging reeds that are to be 'gently' closed by a piston that at 13000 rpm encounters the reeds at about 37 m/s .

[breezy]

The cylinder pressure at exhaust opening can be as high as 7 bar, so if you put your transfer reeds even higher up, they must be able to cope with more than 7 bar.
This means strong, heavy reeds that will be very reluctant to open at the very limited scavenging pressure differential that the exhaust suction can generate.
And how would you start the beast? No running = no pipe suction = no starting...


................. and make a provision for crankshaft and piston lubrication. And again: how would you start it?

http://www.google.co.uk/patents/US5816211.... maybe this would eliminate some lubrication for the piston/sleeve

[wobbly]

If I had a R&D dept with 100 people all looking for things to do i would be testing the relationship of the duct length,its exit area and
the optimum transition length.
There will be a direct relationship to how long the well cooled duct wall is, to the length of the A/F slug sitting outside the port waiting to be shoved in by the returning wave front.
All I can say is that in any normally dimensioned cylinder we usually end up with a duct and spigot around 2X bore length, and that a slip joint
spigot is usually around 1/2 bore - and that works.
Technically correct as Frits has pointed out, would be to derive a relationship between duct exit area and the blowdown needed to develop the target bmep.
But in any scenario keeping the duct volume down by lifting the floor and filling in the bottom corners, then restricting the exit and connecting that to a transition WITH NO STEPS
will make better power than any other solution that has actually been tested to date.

[Flettner]

http://www.google.co.uk/patents/US5816211.... maybe this would eliminate some lubrication for the piston/sleeve

So - if you had a super ceramic fit, no piston rings. Piston sides are spherical with no gudgin pin (fixed) so that the piston is forced to rock forward and aft through the cranshaft rotation (like these silly little chinese compressors). On the way down there would be more blowdown time because the piston would be rocked forward as the crank turns around BDC the piston would rock the other way giving more transfer time. Substantial asymmetric timing. How the underside of the piston would shut the exhaust off at TDC I can't say, so this is clearly not how it's done but just another thought.

Perhaps an articulated piston so just the head could rock? 30000K, I don't think so!

[F5 Dave]

If I had a R&D dept with 100 people all looking for things to do i would be testing the relationship of the duct length,its exit area and
the optimum transition length.
There will be a direct relationship to how long the well cooled duct wall is, to the length of the A/F slug sitting outside the port waiting to be shoved in by the returning wave front.
All I can say is that in any normally dimensioned cylinder we usually end up with a duct and spigot around 2X bore length, and that a slip joint
spigot is usually around 1/2 bore - and that works.
Technically correct as Frits has pointed out, would be to derive a relationship between duct exit area and the blowdown needed to develop the target bmep.
But in any scenario keeping the duct volume down by lifting the floor and filling in the bottom corners, then restricting the exit and connecting that to a transition WITH NO STEPS
will make better power than any other solution that has actually been tested to date.

I'd have them all changing tyres cause I hate changing tyres and it turns out I'd be a vindictive power tripping control freak of a boss.

Ohh the things you find out about yourself in a moment of fantasy.

[Haufen]

I know the feeling Neil. I'm very glad to be involved with the Ryger engine, but it has also made me very reluctant about everything I thought I knew about two-strokes.

When you first saw / heard of the numbers, what was your reaction? And how many times did you double-check that everything is just as it seems and that there is no miscalibrated dyno, rpm gauge etc?

[husaberg]

Initially I understood that you wanted to put those additional transfer ports above the exhaust, but your drawings made me see the light. I must say it's not as silly as I first thought, although I still shiver at inward-hinging reeds that are to be 'gently' closed by a piston that at 13000 rpm encounters the reeds at about 37 m/s .

Yeah but remember Trademarked (HUSA HIGH REED TRANSFERS) do exit higher as they are directed near straight up.
I would not expect the reeds to last forever.
I bet if you told a designer that did piston rings that had only ever seen four strokes that you want to cut these huge holes in a liner some up to a 70 Degree unsupported arc he would say the rings will not last.
But that's R&D's problem to solve I work in the silly ideas design department.

Maybe Mr Frits would prefer a loose ball valve arrangement in the port as a means of preventing reverse flow

[lodgernz]

Wobbly and Frits:
I've read and re-read and re-read the stuff about exhaust flange being 75% of effective ex port area for 3-port and T-port engines, and 90% for single port engines.
I've been unable to determine whether the flange DIAMETER should be that percentage of the ex port effective DIAMETER, or the flange AREA should be that percentage of the ex port AREA. I'm guessing it's area, but I'd like confirmation (or otherwise) please. Obviously 90% of diameter would mean 81% of area, so need to be sure before I start hacking.
Thanks to both of you for all your help.