ESE's works engine tuner

[TZ350]

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Turbocharged Yamaha TZR125 Two Stroke being run up on the dyno.

[andreas]

Yes, that is him talking in the other, am6 video.

[TZ350]

Turbo 50cc two stroke being dyno tested.

[ken seeber]

Well, the DCI (Direct Cylinder Induction) thing is moving slowly along, but still moving.

Finally got a piston from some joint over here.

Made up some cover plates to go over the entry flange faces, one with a pressure tapping. The gauge, which shows both +ve and -ve pressures, will be connected to this tapping. The broad plan is that the engine will be run up with just the B ports only, the original A ports being converted into the DCI intake ports.

The big hope is that the gauge will show -ve at some point in the rev range. Nary a supercharger in sight.

More to come.

[Vannik]

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Turbocharged Yamaha TZR125 Two Stroke being run up on the dyno.

This work is done by Lennarth Zander, a Swedish engineer that works at Scania. Even though the video is old, I understand he has resurrected this project and is doing his PhD at Chalmers University of Technology. The interesting thing he does is between the tuned pipe and the turbine he fits an oxidation catalytic converter which reacts with the unburnt oxygen and the fuel and ups the temperature quite a bit to improve the turbine running. The converter works so well he has to control the amount of gas being converted to prevent temperature damage to the turbine.

One of the issues with a turbine after the tuned pipe is the loss of temperature, this reverses that for no extra penalty, the fuel and oxygen is already there.

This is partially how I would do the "Worlds strongest two-stroke".

[SwePatrick]

The turbosystemZander has engineered is nothing to use in real life though.
It takes ages for the catalytic to build heat/pressure.

A guy in Sweden has copied Zanders system and runs it on an 100cc moped engine, it has dynoed nice numbers(from my mind ~58hp), but it never hits the track for some reason....(he has run it in an earlier version)
The reason is he needs to make either a HUGE LONG(about 3-5minutes long) burnout or stand in the pit on his rolling pad and run engine for a loooong time(he stood about 10 minutes) to light up the cat.
Then hit the lineup and wait for staging, while the cat cools down....

In bonneville it might work thou

[SwePatrick]

Found a video:

[Niels Abildgaard]

This work is done by Lennarth Zander, a Swedish engineer that works at Scania. Even though the video is old, I understand he has resurrected this project and is doing his PhD at Chalmers University of Technology. The interesting thing he does is between the tuned pipe and the turbine he fits an oxidation catalytic converter which reacts with the unburnt oxygen and the fuel and ups the temperature quite a bit to improve the turbine running. The converter works so well he has to control the amount of gas being converted to prevent temperature damage to the turbine.

One of the issues with a turbine after the tuned pipe is the loss of temperature, this reverses that for no extra penalty, the fuel and oxygen is already there.

This is partially how I would do the "Worlds strongest two-stroke".

See the powerpoints here

https://research.chalmers.se/publica...5_Fulltext.pdf

[SwePatrick]

Here are a pic of what's what in one of Zanders project:



And here´s a video of it, take notice about the lag before the turbo inlet get any heat.
Notice how he let´s off the throttle when headertemp is getting north of 650c, it is actually not in control.

[SwePatrick]

I actually tested turbo myself on my 212cc kawasaki engine, but i set it up different.
I used a draw through system(turbo between the reed and the carb.
No catalythic converter as i had a bigger engine.

I tuned the pipe to about 7500rpm, to get some exhaustmasses early and relied on the turbo to do the scavenging in the upper rpm band.
It actually worked really nice, but the piston couldn´t take it, i dynoed 96hp after just a couple of pulls.
But i gave it up as i figured the engine couldn´t take it in the long run, and needed constant piston service after every run on the strip.
It was a bit laggy, but spooled quite nicely in higher gears.

One importent thing is to balance the pressure delta over the inlet and the outlet.
If making it not differ from an NA engine the engine never know it´s been boosted.

This is impossible to reach with supercharger, thereby Alex is fiddeling with rotating disc in exhaust.

[andreas]

Regarding turbocharging of two stroke engines.

Lennarth Zanders work.

Power up to ~70 hp was seen on dyno (125cc) as I understand reading the paper.

https://www.sae.org/publications/tec...-0642/preview/

Pardon, it says right in the beginning 400kw/liter, =67 hp.

If there is too much lag in this engine, maybe it is possible to use the system used in rally cross cars and maybe elsewhere, I forgot what it's called, but it burns fuel in front of the turbo when the engine isn't making enough pressure itself.

[Muciek]

Normal two step used these days in cars (delaying ignition a lot ) might not be best for bike? This one was used years ago by subaru
https://www.youtube.com/watch?v=ms3U7Ztoip8

[Norman]

Pardon, it says right in the beginning 400kw/liter, =67 hp.

If there is too much lag in this engine, maybe it is possible to use the system used in rally cross cars and maybe elsewhere, I forgot what it's called, but it burns fuel in front of the turbo when the engine isn't making enough pressure itself.

Maybe one of these: https://en.wikipedia.org/wiki/Antilag_system

Here is another design version for a rotational exhaust valve.

[Frits Overmars]

This work is done by Lennarth Zander.... between the tuned pipe and the turbine he fits an oxidation catalytic converter which reacts with the unburnt oxygen and the fuel and ups the temperature quite a bit to improve the turbine running.

...the exhaust gases contain both air- and unburned fuel (HC) which can be converted to heat upstream the turbine using an oxidation catalyst, hereby also named afterburner.

Fuel need not be a problem; one can inject as much fuel in the exhaust system as one likes. But what about oxygen?
In his paper ( https://www.kiwibiker.co.nz/forums/s...post1131186140 ) Lennarth Zander only states that the exhaust gases contain air; there is no explanation how this air could pass through the combustion engine without all of its oxygen being consumed.
Is he deliberately running a very lean mixture? That would not make the piston of a turbocharged engine very happy. Have you got information beyond the paper, Neels?

[ken seeber]

Maybe one of these: https://en.wikipedia.org/wiki/Antilag_system

Here is another design version for a rotational exhaust valve.

Interesting stuff. The valve shaft, rotating at crank speed, also doubles as a balance shaft.



The good news is also that BRP are still thinking about 2 strokes.