ESE's works engine tuner

[Frits Overmars]

Frits can you answer whether the motor idles like a normal 2T. For example 1500-2000 RPM idle speed

Frits, can you answer this? Is the Ryger easy to start?

You guys ask me if I can answer your questions. The answer is: yes, I can .

(OK, the Ryger is easy to start and idles like a normal 2T. I wonder what this candour is going to cost me; I hope I can settle the matter with some ice cream).

[Flettner]

Not hard to draw its a rack.
Are you meaning this

Actually have a look here

https://grabcad.com/library/most-lik...m?per_page=100

Yes they do, some good some bad all in patterns. Wob and Frits have mentioned them pretty sure Jennings covers them. harmonic?
I remember there was alternate length calculations in the old 4 stroke intake calculations.

https://youtu.be/fiJKeyHk-II

I think you will find it's a variation of this setup, not quite like this.

[husaberg]

Yes, sort of like that.

that link has hundreds of linkages and so forth
https://grabcad.com/library/most-lik...m?per_page=100

Rhomboid drive ?
is the 98% by mass or parts count?

Yow mentioned Rhombic but I was thinking one with more control over dwell.
https://youtu.be/loi4Uln2VLQ
the counter rotating cranks are pretty cool though.

[TZ350]

Page ... 1200

An 8K wide power spread is meaningless. Any difference between the maximum and minimum rpm values of a power band is meaningless. It is the ratio between those maximum and minimum rpm values that counts: http://www.kiwibiker.co.nz/forums/sh...post1130525788

I decided to write this little story about power curve comparison after reading the following posts from fellow members AAAA and BBBB.

Originally Posted by AAAA
A 2000 rpm wide powerband at 5000 rpm is the same width as a 4000 rpm powerband at 10000 rpm once the gearing has been corrected to give them both the same performance.

Originally Posted by BBBB

If the rpm ratio is the same and the average power within the range is the same, the two powerbands would be "functionally equivalent". That is, a change to the overall gear ratio would make them perform the same...... The same average power over a given rpm range will produce the same average acceleration. It does not matter what the "shape" of the powerband is -- sloping upward, sloping downward, or flat.

I could not agree more, BBBB. But it requires a fundamental definition of 'average power'. And that is not 'the area under the power curve'.

also from BBBB: Although we can narrow the powerband down to the absolute limit and have it show excellent results in a simulation like Dynabike, I'd want to have more margin than that for any application except maybe drag racing or bench racing. It is one thing to operate out front at "full speed" on the track, but traffic can cause you to operate in an undesirable part of the powerband. Similarly, recovering from a mistake (missed shift, forgetting how many downshifts a particular corner requires, etc.) is another reason we need a broader powerband.

Once again I fully agree and I would add that this could only come frome someone with actual competition experience. Any engine builder who thinks he can base his powerbands on the ratios of a gearbox, is not going to make his riders very happy - in fact he is not going to keep them very long.

Peak power alone does not say much about the usefulness of an engine. The combination of power curve and transmission, the sort of application the engine will be used for, and the abilities of the rider, together define which is the optimum engine character.

An example: a 125 cc road race engine can always be kept between 10.000 and 14.000 rpm thanks to its six-speed gearbox. Wether this engine produces 2 hp or 20 hp at 6000 rpm, is unimportant.
But a kart engine with direct drive without a gearbox has trouble staying above 5000 rpm in slow corners; it only can manage to do so by means of a very short gearing that forces the engine to rev over 17.000 rpm on the straightaway. For such a kart it is imperative that acceleration out of slow corners does not cost too much time. There may be only one such corner on the whole circuit, but time lost there cannot be made up by a higher top speed on the straight.
Therefore a sensible tuner will not concentrate on peak power; he will make sure that the power is never really bad in the whole range from 5000 to 17.000 rpm (in this kart-example).

I prefer to work not with a powerband but with a power range, which I define as the highest rpm of a power curve, divided by its lowest rpm.
Experience has taught what kind of power range is needed for a certain application. Road racing calls for a range of about 1.4 . When a CVT is involved, I imagine 1.2 over even less might be enough (though I'm only guessing here as I have next to no experience with these things). Motocross calls for something like 2. A touring bike needs at least 3 to be comfortable. And the direct-drive kart in the above-mentioned example needs about 3.4 (17.000/5000).

Let us asume we have a measured power curve from 7000 to 14000 rpm. That gives a power range of 2.
Within this power curve all possible range values are investigated, from range=1.00; range=1.01; range=1.02; etc, up to range=2.
For each of these range values the whole power curve is examined in order to find which lower and upper rpm values yield the highest average power.
For range=1.5 for instance, we start with calculating the average power between 7000 and 10.500 rpm. Then we proceed with 7010--10.515; then with 7020--10.530; and so on, until the final possibility of 9333--14.000 rpm. And the highest value found is stored as THE average power for range 1.5, together with its corresponding lower and upper rpm limits.

All stored values for average power are displayed in range graphs. So when you are preparing an engine that will need a range of 1.6 , you can see at a single glance which engine delivers the best average power at range 1.6 . Furthermore you can see between which rpm values this engine is most effective. And you don't need to fall into the trap that ALL engine builders have fallen into at some time: attaching too much importance to peak power.

Maybe you are used to comparing the acceleration times of different engines on an inertial dyno. But that only makes sense if these engines are all run between the same initial rpm and the same final rpm, AND all with the same gearing.
The range concept does not suffer from any of these limitations; it functions under all circumstances. And because you can compare the range graphs of all your engines, you'll be able to distinguish much quicker which range is best for a specific application. That is an experience you would otherwise only gather after years of trial and error.

Suppose you are preparing an engine for an application that requires a power range of 1.5. Then which of the two power curves below should you pick? Hard to say, isn't it? But when you look at the power range curves on the right, it is clear as day: the yellow curve wins.
Attachment 280962Attachment 280963

Two more power curves. The yellow curve does not look very useful. But maybe it could work with a CVT.... The power range curve on the right tells us what we need to know. If the CVT can keep within a 1.2 rpm range, the yellow curve is OK. And if the CVT can keep within a 1.1 rpm range, the yellow curve is a winner!
Attachment 280964Attachment 280965

Another advantage of the power range curve: it can show you the rpm limits you should operate between. At range 1.2 the yellow power curve works best between 9970 rpm (the blue curve) and 11.964 rpm (the white curve).
Attachment 280966

Earlier I claimed that average power is NOT the area under the power curve. A claim like this calls for an explanation, so here goes.
Attachment 280967
Take a look at the power curve above. It is a peculiar curve where at rpm-point E the power totally collapses, but then comes back. The reason I drew it like this will become clear in a minute.
We can look at the red area under the curve and convert that to a rectangle. The yellow rectangle in the picture below has the same area as the red areas under the original power curve. So you could say the average power between rpm-point A and rpm-point B has a magnitude equal to the height A--D. Or could you?
Attachment 280968
Let us put the engine with the peculiar red power curve in a vehicle and start accelerating, from rpm-point A to rpm-point B. How long will that take? It will take forever because the power at rpm-point E is zero, so acceleration at point E is zero; we will never get past that point. Acceleration from A to B will take an eternity which means that average power between A and B is zero!

Admittedly you won't encounter a power curve like the one in the first red picture very often. But the acceleration versus area argument holds for any power curve. Let's take a look at a 'normal' curve without a zero-power point. The curve below is split up into 9 equal rectangles, each with a horizontal dimension A--B that represents rpm, and a vertical dimension A--G that represents power.
Attachment 280969
When you convert the sum area of those 9 rectangles into a single rectangle with the same rpm spread A--F, it will have a height A--H that is 1.8 * A--G. Assuming A--G equals 1 HP, then the average power A--H would be 1.8 HP (picture below).
Attachment 280971
Now let us look at the same power curve and determine the average power via the acceleration approach. We will assume that acceleration from A to B with the available power A--G takes 1 second.
Between B and C the power is twice as much, so acceleration from B to C will take ½ second. And so on.
Total acceleration from A to F takes 20/6 s. If this acceleration were to have a constant value, it would take 1/5 * 20/6 = 4/6 s from A to B. This would require a constant power of 6/4 * A--G. Assuming again that A--G equals 1 HP, then the average power would be 1.5 HP instead of the 1.8 HP that came out of the area-approach...
Attachment 280972

[TZ350]

that link has hundreds of linkages and so forth:- https://grabcad.com/library/most-lik...m?per_page=100x

Followed Husaburgs link and found this:- https://grabcad.com/library/hypocycl...ne-mechanism-1



30,000 crank rpm and workable piston velocity's in the more normal 15,000 rpm range that we are used too. At 2:1 the usual port STA's would easily work for 17,000 hypocyclic crank rpm ( which would be, 8,500 old school engine rpm).

[Flettner]

Followed Husaburgs link and found this:- https://grabcad.com/library/hypocycl...ne-mechanism-1



30,000 crank rpm and workable piston velocity's in the more normal 15,000 rpm range that we are used too. At 2:1 the usual port STA's would easily work for 17,000 hypocyclic crank rpm ( which would be, 8,500 old school engine rpm).

Thank you TZ, I was just trying to post this. There's your answer!
And that's what the machined plate is, a guide in the centre that the round conrod moves up and down in with a seal of some sort to stop the fourstroke bottom end ( oil pressure ) spewing up to the top past this guide bushing. Piston need not rub on the cylinder wall. Simple ( ish ).
Arr, now I can sleep at night again.

[chrisc]

I thought the patent for the Ryger was found? Wouldn't that show or describe the crank/piston arrangement?
I love the interest and discussion the Ryger engine has stirred! I bet we all are chewing on the bit to ride/drive something with an engine like that.

[husaberg]

I thought the patent for the Ryger was found? Wouldn't that show or describe the crank/piston arrangement?
I love the interest and discussion the Ryger engine has stirred! I bet we all are chewing on the bit to ride/drive something with an engine like that.

98% of what was found didn't fit the simple definition.

[lodgernz]

Followed Husaburgs link and found this:- https://grabcad.com/library/hypocycl...ne-mechanism-1



30,000 crank rpm and workable piston velocity's in the more normal 15,000 rpm range that we are used too. At 2:1 the usual port STA's would easily work for 17,000 hypocyclic crank rpm ( which would be, 8,500 old school engine rpm).

Are you sure Rob? It looks to me like the crankshaft still only does one revolution per up and down of the piston, as a normal 2T.
Even if the crank did spin at twice the "piston revs", what would be the point of that? Number of power strokes per unit time is one of our power determinants. The crank turning twice as fast, or any other relatve speed, won't alter that.
Or have I completely missed the point?

[TZ350]

Are you sure Rob? It looks to me like the crankshaft still only does one revolution per up and down of the piston, as a normal 2T.

No not sure, and you could be right.

Even if the crank did spin at twice the "piston revs", what would be the point of that?

Two advantages I can think off straight away.

1) Width of the power spread, if a normal crank has a power spread of 4K then a 2:1 crank would be 8K. An 8K wide power spread from a 2T would be handy.

2) The magic exhaust port duration of 192 for reinforced superimposition of the wave action in the chamber would be easier to achieve with the lower blowdown STA required for a motor doing only half the rpm it was before.

[peewee]

do you rekon i can put in some proper size exh ports now

[husaberg]

No not sure, and you could be right.



Two advantages I can think off straight away.

1) Width of the power spread, if a normal crank has a power spread of 4K then a 2:1 crank would be 8K. An 8K wide power spread from a 2T would be handy.

2) The magic exhaust port duration of 192 for reinforced superimposition of the wave action in the chamber would be easier to achieve with the lower blowdown STA required for a motor doing only half the rpm it was before.

Not following the engine speed and power strokes are unchanged only the crankshaft speed, (might be missing something?)
I only see advantage in the counter rotations bob weights and linear motion though.

[Frits Overmars]

if a normal crank has a power spread of 4K then a 2:1 crank would be 8K. An 8K wide power spread from a 2T would be handy.

An 8K wide power spread is meaningless. Any difference between the maximum and minimum rpm values of a power band is meaningless.
It is the ratio between those maximum and minimum rpm values that counts: http://www.kiwibiker.co.nz/forums/sh...post1130525788

[Flettner]

No not sure, and you could be right.



Two advantages I can think off straight away.

1) Width of the power spread, if a normal crank has a power spread of 4K then a 2:1 crank would be 8K. An 8K wide power spread from a 2T would be handy.

2) The magic exhaust port duration of 192 for reinforced superimposition of the wave action in the chamber would be easier to achieve with the lower blowdown STA required for a motor doing only half the rpm it was before.

The two cranks are half stroke. 54mm equals 27mm each, that would give high rpm so long as it was ballanced.

[TZ350]

do you rekon i can put in some proper size exh ports now

Good Effort. ....