ESE's works engine tuner

[seattle smitty]

[QUOTE=136kg136ps;1130811344] In the diagrams Frits has provided there is no water passage I can see near the bore between the exhaust floor and transfer roof.The comma shape as speedpro suggested in fact tapers as it approaches the bore due to the lack of metal there for much of anything.I may be wrong but I did look first to see if it impinged on any water passages. (end quote)

No, I didn't see one either, just saying that without flowing coolant there, that localized area is likely to be a rather hot stretch of aluminum. Yes, the intake flow will cool your valves or mine (good), but conversely our valves will be heating the intake flow (bad).

As for incorporating a spring, with either of our schemes at least a small spring might at least be wanted to take lash out of the linkage (since we want control of the port timing to be as crisp as possible). If we have a spring for taking up slack, maybe we should consider incorporating it to go on and perform part of the opening/closing operation.

This is fun (I have kept walking back to the computer today, to see the comments on this)!! Still, I hope Frits will comment in detail, even if it's to tell me my ideas have some obvious killer-flaw I should have seen.

[136kg136ps]

http://www.google.co.ug/patents/WO1992003645A1?cl=en
http://www.mavintech.com/resume.html

Only mentions I found of variable height patents,though they have been discussed,even early on in this thread.

I am the same way,watch every new idea get confirmed or denied by Frits,Jan or Wobbly and in the process learn more.A long way from the late 70s and early 80s grinding away unknowing of TA or flow characteristics on RDs or putting whatever TZ parts we could get on them.

[Flettner]

What are we after, timing changes yes but also nozzleing down the port to increase flow speed into the cylinder at lower transfer gas volumes. If we don't change the transfer open / shut timing but maintain high gas flow with this " nozzleing" will that alone help?
I have several proposals but probably want to think about them a little more.
Although for simple nozzeling I would move the transfer floors ( the complete inside curve shape of the transfer port) up and down ( x6 ) as a single machined piece, like a six spline looking from underneath the cylinder, the center of this machined part would form part of the cylinder (x6 slots). The transfers would become open slots with the foor curve shape being moved up and down, full open to full closed. But this will NOT change transfer open and shut timing.
I have thought about using silicon ports and adding pressure ( oil?) behind to change the shape, I think too inconsistant.

[136kg136ps]

That patent mentions using a liquid to deform some type of material to change the shape of the ports.Maybe a bladder of sorts.Can't see that being as accurate as a solid part moving.

[peewee]

If the main Ex is at 72% .

unmodified i measured it to be 68.5% or so if i recall. ive since went to 70% with flat roof and 8mm top corners. if i went to 72% do you see any problem staying flat on the top with the 8mm corners ? the huge cc engines im used to working with would make me a bit nervous doing that but maybe the small cylinders will do fine

perhaps i would be better off using a slight roof arc and smaller top corners such as 6mm ? ?

[lodgernz]

A small question: Why does the FOS cylinder have to have individual transfer passages?
Since the ports are all close together, surely there can't be much flow impedance by simply having a large transfer "gallery" surrounding the cylinder and feeding all the ports? Obviously there would be some CSA issues at the crankcase entry points, and maybe this would mandate a pair of such galleries rather than a single one.
If this is logical and workable, would such a system make some of your ideas for movable transfer roofs and/or floors more achievable?

[wobbly]

The reason each transfer port needs its own dedicated duct length is again pointing back to what I said before about creating coherent
shaped streams entering the cylinder.
What you are proposing goes back to old Mac chainsaw based engines, where they had exactly as you describe, a large pocket on each side of the bore
with several port "holes " simply bored in from outside the cylinder, and the outer face filled with a pressed in plug.
The scavenging regime of these engines was super basic and super ineffectual.
To prevent chronic short circuiting, the only way to achieve a band of coherent columns that hold their shape and direction vector, and then coalesce into a single rising loop stream, is to have
sufficient, shaped, duct length below the port from the case.

Re the 72% chordal Ex width.
In pistons of the RZ size this is the practical limit, and must be combined with a roof radius and corner rads to prevent ring snagging.
This sort of shape and size goes back to the TD and later the TZ350, so search out how the Ex port was done by Yamaha in the previous century - nothing has changed.

[lodgernz]

The reason each transfer port needs its own dedicated duct length is again pointing back to what I said before about creating coherent
shaped streams entering the cylinder.
What you are proposing goes back to old Mac chainsaw based engines, where they had exactly as you describe, a large pocket on each side of the bore
with several port "holes " simply bored in from outside the cylinder, and the outer face filled with a pressed in plug.
The scavenging regime of these engines was super basic and super ineffectual.
To prevent chronic short circuiting, the only way to achieve a band of coherent columns that hold their shape and direction vector, and then coalesce into a single rising loop stream, is to have sufficient, shaped, duct length below the port from the case.

Fair enough. I thought FOS system might be different in that all the transfers aim radially to the centre and axially up at the same angle so transfer passage wall inner and outer would be the main control factors.
Perhaps a gallery would be feasible if each port separator had a short wall back into the gallery to direct the flow radially at the port window. Getting too complicated really.

[TZ350]

Alpha-N maps need to be smooth without any peaks or severe troughs between cell steps.

Ecotrons has a function where you can export a map to an Excel spread sheet and use the charting function to help smooth the map data.



Raw data and the chart showing how rough the data is and the engine ran just as roughly.



Smoothed data and chart.

No Idea if I have done this right, will get to find out tomorrow, hopefully ....

[seattle smitty]

What you are proposing goes back to old Mac chainsaw based engines, where they had exactly as you describe, a large pocket on each side of the bore
with several port "holes " simply bored in from outside the cylinder, and the outer face filled with a pressed in plug.

Lots of engines were made like that, back then. The incoming charge streams were made "coherent" by running into a big deflector atop the piston, LOL. Not a pretty system, at least for high performance, but we hopped them up and raced them and had a real good time. Plus, the open megaphones were easy to make, and produced a wonderful shriek (that some of the neighbors hated; eff them!!), well, good as long as your ignition was working properly, otherwise the sound could be highly embarrassing!!



I finally got a chance to flop down on a recliner chair, close my eyes, and try to "see" how the hell my notion of how best to do variable intake timing in a Frits-motor (FOS) could be BUILT. Of course, it would entail a cylinder-bock made in at least two sections, to be held together with studs, O-rings, etc.. So far, I can't figure out how to do it without having a pressed-in iron cylinder sleeve. Frits has said that this is sub-optimal for bikes and karts (although IMHO it is not a deal-killer for an outboard). I tried to envision a way to move the whole upper wall of the transfers up and down, to change volume along with timing and keep the contours of the long-turn and short-turn un-altered, . . . at least up to about the final 4-5mm (cyl. sleeve thickness) before the port window. Big problem. I'm starting to agree with the other fellows that their "comma-valves" are a better idea than mine. But those still would be a real challenge to actually construct (for one thing, how would you keep them from bouncing at some resonant frequency?).

Personally, the whole idea of variable intake timing in a Frits-motor interests me less than how one might apply one of his other cool ideas, the 24/7 intake, both to a conventional cylinder and to this FOS cylinder.

I keep clinging to the hope that the brainy guys here will give me some reaction to my notions about running the boost port and probably the B transfers of a conventional cylinder directly from a 24/7 carb (Page 1074, post #16109, hint , hint). To do this on a Frits-motor gets more involved (but again, not so bad on an outboard motor as a bike motor). The Frits-motor has two of its six transfers directly under an exhaust port and pipe, so I'd leave those to be fed from the "primary" carburetor that feeds the engine through the crankcase full-time. The other four transfers could possibly be treated as adjacent pairs, each pair being connected at their bottom ends directly to a 24/7 carburetor (remember this system only opens when the engine comes on the pipe). But what a lot of STUFF! Three carbs and two pipes per cylinder, and all the controls for them!! Maybe an old deflector engine wasn't such a bad thing!!

[seattle smitty]

Oops. Admin, please delete this (and tell me how to delete an entire post).

[TZ350]

Oops. Admin, please delete this (and tell me how to delete an entire post).

To completely remove a post.



Click "Delete"



Then click "Delete Message"

Then click "Delete Post"

[breezy]

how about a crecy sleeve set up to completly close the exhaust ports... make Sir Harry Ricardo happy..

"Lower operating temperatures of all power-connected engine parts, cylinder and pistons, Harry Ricardo showed that as long as the clearance between sleeve and cylinder is adequately settled, and the lubricating oil film is thin enough, sleeves are 'transparent to heat'."

[seattle smitty]

Lower operating temperatures of all power-connected engine parts, cylinder and pistons, Harry Ricardo showed that as long as the clearance between sleeve and cylinder is adequately settled, and the lubricating oil film is thin enough, sleeves are 'transparent to heat'.

Well THAT's new to me!!! I thought any discontinuous interface was a barrier to heat transfer to a greater or lesser degree, even if it was, say, an aluminum sleeve in an aluminum casting. What is "adequately settled"?? Do you know where I might find this in Sir Harry?

Frits has described the problem as one of the iron sleeve and aluminum block each moving around when hot; small gaps appear, which are then filled with exhaust soot, a poor thermal conductor. Obviously this doesn't affect what Sir Harry said, since, as I take it, the sleeve would no longer be "adequately settled." But I still wonder at his statement, which is at varience to what I've read (but I'm full of bum information, unfortunately).


TeeZee, I saw no "Delete" box at all. (I have endless problems with this laptop, this steaming pile of dog-doo, possibly because its running Win 8.1. A local kid, computer whiz, says he's going to help me convert to some form of Puppy Linux; I hope that helps me).

[136kg136ps]

smitty,turbines use something similar to heim joints to remove lash and ensure all parts move in unison.

I had taken a look at variable valve timing and compression in foul strokes to see if there was anything useful in that respect.I think we are better served with variable exhaust timing, volume and or length along with 3D PJ,PV and timing curves as our esteemed resident professionals have described. Adding in the variable transfers is the next logical and attainable step.Go Team ESE.