ESE's works engine tuner

[Orengo98]

Hi Joan,
In case you do not have it already, you can read about it in the below SAE paper. If you cannot get it through university, try and register on JSTOR portal and you might find it there to read online. BTW, Sometimes "PrtScn" button is useful.

1985-02-01
Two-Stroke Cycle Engine with Flow Induction Corrected at the Intake and Transfer Phases 850184
The implementation of a single-cylinder two-stroke engine equipped with an auxiliary cylinder is described. The purpose of such a cylinder is to modify the diagram of flow induction through the inlet and transfer ports in the main cylinder in order to make it asymmetrical relative to tdc.
Subsidiarily, the piston in the auxiliary cylinder is used to improve the balance of reciprocating forces.
This engine has been developed for specific use in trial motorcycles.

Thank you Norman!

Didn't know that there was a SAE paper on this engine! My university doesn't have access to SAE papers and this one seems that's not posted on JSTOR. But looking on JSTOR, I found another paper supervised by the same professor and Montesa consultant, about throttle body and transfer fuel injection for two strokes, in 1986! It's called: Low-Pressure Discontinuous Gasoline Injection in Two-Stroke Engines 860168, if someone wants to read it. Seems that the system was installed on the Montesa Crono 350 of the professor.

By the description of the paper on the motor with the additional cylinder, seems that it has nothing to do with a compressor or supercharger (at least an efficient one) as all the magazines of the era said. Also, that additional cylinder seems not to be connected in any way to the motor, so only the underside is working. So seems that my suspicions on the system were right. I decided to plot the crankcase volume of that motor, knowing the bore, stroke and crank length. As I don't know the minimum crankcase volume, I didn't use units on the graph. Also, once plotted I realized the conrod of the additional cylinder is a bit shorter than the standard one, so the graph is going to be a little bit off.

The graph shows two main differences, first the maximum volume of the crankcase is not reached at TDC, but around 45º earlier, and that the difference between maximum and minimum crankcase volume is a bit greater on that configuration.

[PVO]

Not in order sorry



you click on Neels name and hit view forum posts.

not sure if this link will work
https://www.kiwibiker.co.nz/forums/s...rchid=16464070

How do you get the results to show the full Post? I’ve viewed user posts this way before but all I can see is the first couple sentences of the post without clicking on it?

[husaberg]

How do you get the results to show the full Post? I’ve viewed user posts this way before but all I can see is the first couple sentences of the post without clicking on it?

You will have to click onto the posts, i then multi quoted each post and then used the quoted one post in each thread then pasted them together
it took about 30 minutes though.

The first time i tried it I thought there was a limit on the number of posts but it was dropping posts from other threads.

[Muhr]

.
Two Stroke stuffings dyno looks more stable:- https://youtu.be/1IZSBuhn26A

Attachment 351004

20hp but no were near getting the best from the engine yet.

I think people mean that if you have a car with a trailer and a constant uphill. If you then load the trailer until the car maintains a constant speed of eg 30km / h with full throttle. If you then start applying the brake on the trailer alone, will the load on the tow hook increase then?

You have a rotating mass in and around an engine to be able to start measuring a power, you have to overcome that friction without being able to credit it as power.

If you then think of eg crank piston and connecting rod and clutch of eg 3kg and an inertia of eg dia 60mm and a braking force of 1000rpm / s (3m / s2) a gear ratio of say 1:10 from crank to drum.
becomes about 2.8 NM of gravy on top of the reading if you do not compensate.

I may be way off track but my first thought.

[wobbly]

To me it seems that Stuffings dyno is set up to allow a certain rpm , then it reads the torque required to slow the engine down.
I know technically this will read accurate numbers , but why do something no one else in the world is doing , just for the sake of it.
It means the engine is initially free reving with no load , the opposite of what every other Eddy Current software does.
Using Eddy Current means you could easily replicate what inertia dynos do , that is the engine does exactly what it does on a track , accelerate faster as it makes more power on WOT from lower rpm..
ie its real

[ken seeber]

I just wish Alex would just set the eddy current dyno to a series of set rpms, say 12, 14, 16, 18, 20k etc. Or even just one or two set rpms. The thing should be eminently capable of doing this. Takes away any doubt as to any dynamic or inertia effects.

However, it’s his project though and it is interesting.

[OopsClunkThud]

maybe his target load case is being towed up to top speed and then doing a hill climb with an ever increasing slope...

[Vannik]

What Stuffing is doing is known in the engine world (well, turbo diesel world) as a lug down curve. The diesel guys use this to better simulate a big truck hitting an uphill stretch. This way the turbo does not have to build boost as in an acceleration run. There is a substantial difference in the acceleration curve and lug down curve on these turbo diesel engines and their motivation is understandable. I would really like to see Stuffing do at least one set of acceleration curves compared with a set of lug down curves to prove that in his case they are the same. I have my doubts though.

[SwePatrick]

I actually think that if he did a regular upwards pull like IRL usage he would gain either more power or more rpm.
This due to during the pull engine is clearing its throat and build heat to condensate fuel better, allowing for cleaner and more complete burn at the end of the pull.

But, dynosoftware if written correctly and correct data is typed in, the power should be correct if doing either upwards or downwards pull if dynoing an electric motor that doesn´t have same problems as a rich running nitro/meth twostroke.

[TZ350]

Speedpro resurrected his old MB100 Bucket engine into a FZR250 frame. Makes a good 24rwhp. Speedpro took it to Hampton last Sunday but he elected to ride his fuel injected twin instead.

I rode my rotary valve Suzuki RG50. I had a very enjoyable day but the 50 was not so happy. Sure it lasted, but it had fits of stomach ache all day. I could not understand why it was un happy. It would start off sweet then become very bilious as the race progressed.

Before the race I had wondered about the ability of the RG50 water pump so I had fitted an electronic cylinder head temperature gauge but true to form it packed up out on the track. The temperature gauge worked OK in the pits, nothing on the track. Ok again back in the pits. It would run good again until it got out onto the track. Changed it for another new one, same issue. Vibration?



Also none to sure about my choice of total loss battery and the porcelain insulator cracked in the plug. There were a host of other clues, like the engine vibrating through the rev's but not every time and the engine going "pop" sometimes when revved out and it took a few moments to recover. Also the engine note changed noticeable when cornering to the left. Induction noise reflected off the road surface or fuel draining away to one side in the carb? Thought it may be fuel starvation under load. So I took to the float needle seat with a battery drill and opened up some other holes around the float needle for good measure. No real improvement.

Last race the gear lever broke. DNF, maybe should have kept going in 4th, the gear it was stuck in and clutched out of the corners for a finish.

Plenty to think about but one thing for sure, when it ran well it ran very well.

[wobbly]

But Neels , my assertion is that a race bike engine will never see that sort of " lug down " scenario in its life.
In the real world this engine will be accelerating almost constantly , with only aero load substantively increasing with velocity to reduce the rate.

[TZ350]

The graph shows two main differences, first the maximum volume of the crankcase is not reached at TDC, but around 45º earlier, and that the difference between maximum and minimum crankcase volume is a bit greater on that configuration.

Good work graphing it out. My take on it is, that the green line showing the extra volume from the slave piston in the graph before TDC makes sense. As the point of lowest crankcase pressure in a standard two stroke engine is noticeably before TDC. The slave piston in the graph just increases the crankcase volume to take advantage of inhaling more mixture at that point. They could have achieved the same thing with a very sucky pipe and much more static crank case volume. But I guess at the time people did not understand the potential of sucky pipes and were focused on crankcase pumping efficiency.



EngMod2T simulation of the crankcase pressure cycle for my 110cc engine. There is a significant low pressure area before TDC and the pressure at TDC is a bit higher. I guess the higher pressure at TDC is brought about by the ram effect of the moving column of gas in the inlet tract.

For performance two strokes. The old "Transfer Efficiency" thinking was pumping the mixture up through the transfers with a tight crankcase volume using crank stuffers etc., all to get a high pumping efficiency delta. I guess you could also use a slave piston to help with this high crankcase volume delta objective.

Current thinking is to not worry so much about crankcase pumping efficiency but to have a much bigger crankcase volume for the sucky pipe to suck the mixture up from and through well formed transfers for better "Transfer Efficiency".

Sucky pipes rely on good transfer flow control and port angles so the fresh mixture does no short circuit wastefully out of the exhaust port during the preliminary transfer phase. See "Transfer Port Theory" https://www.kiwibiker.co.nz/forums/s...tuner/page2000 Transfer flow control is a big part of "Trapping Efficiency". Also the ramming return exhaust pulse plays a large part in "Trapping Efficiency" too.

[Vannik]

A very good presentation on using cylinder pressure data, and yes, it is for a 4T engine but they use the latest instrumentation and software from AVL. It will require you to register at SEMA but it is free.

https://www.sema.org/news-media/enew...ne-performance

[TZ350]

I need help with this. I know that wind across the bell mouth causes issues. Does this windshield look Ok or does it look like it might be causing me problems? What would a good windshield look like?

Advice from anyone who has experience with a rotary valve carburetor running around naked out in the breeze would be very welcome.

[pete376403]

I need help with this. I know that wind across the bell mouth causes issues. Does this windshield look Ok or does it look like it might be causing me problems? What would a good windshield look like?

Advice from anyone who has experience with a rotary valve carburetor running around naked out in the breeze would be very welcome.

Have a look at Harry Klemms Bighorn racer (rotary valve.) Some good pics on the website including how he shields the carb http://www.klemmvintage.com/bighorntech.htm