ESE's works engine tuner

[Carel H]

Been there, seen that, built by my mate Martijn Stehouwer (wwwe.emot.nl). Still, I'd prefer to go the whole way: a decent two-stroke injection system.

Concurrent ideas, different layout. There is always someone with the same idea. My drawing is from 2009.

It's a way to further develop a carburettor. These crude early last century fysic devices seem to have a large bandwith.

I also think that a "decent two stroke injection system" is possible, but my calculator says that a "decent high rpm two stroke injection system" is uncharted territory where time becomes a limitation.

[TZ350]

I'd prefer to go the whole way: a decent two-stroke injection system.

Me Too .....

I also think that a "decent two stroke injection system" is possible, but my calculator says that a "decent high rpm two stroke injection system" is uncharted territory where time becomes a limitation.

Definitely ....

Big RPM means Increasingly limited time to get things done. At 15,000 rpm every thing has to happen in 4 ms.

An injector can take 2 ms to open and 0,5 ms to close so 1,5 ms at 15,000 rpm is not a lot of time to deliver a controlled amount of fuel.

At 15,000 plus rpm one might get away with alternating between two big second stage injectors. So that there is much more time for the controlled squirt to happen on one cycle and the opening and closing plus rest to happen on the alternate cycle. That way you might be able to get a controlled 3 ms squirt at 20,000 rpm.

For 13,000 rpm I run two staged TPI, transfer port injection. At 6,500 rpm my small injector is running at 6 ms and at 13,000 rpm the large injector is at 3 ms to deliver much the same amount of fuel in half the time.

[Flettner]

I see KTM have a 150 cc TPI out now, by all accounts is better than the carburetor previous.

[TZ350]

I see KTM have a 150 cc TPI out now, by all accounts is better than the carburetor previous.

Looks like Flettners original method of TPI is now being used successfully by KTM on their smaller bikes.

I have been unable to find any power/rpm specs for the KTM150, so not sure if they have ventured into the dark zone above 10,000 rpm / 10 bar bmep yet.

[TZ350]

Looks like the 2018 KTM 150 carburetor version runs in the dark zone so I guess we can assume the EFI version does too.

https://thumpertalk.com/forums/topic...-dyno-results/

The Thumpertalk page talks about dyno testing a 2018 KTM SX150 but the dyno graphs are headed SX125, so not sure whats happening here.

https://thumpertalk.com/forums/topic...150-dyno-time/

Correct labels on this one. Looks like the 2019 EFI KTM 150 is well and truly running in the dark zone. ...... They must have solved the issues I am grappling with.

Flettners original TPI idea and KTM's commercialization of it. NZ brains and European money. High performance EFI two strokes ....

[monkeyfumi]

For the EFI application the cylinder features two lateral domes which hold the fuel injectors that supply fuel to the rear transfer ports. The downstream injection guarantees excellent atomization of the fuel with the upstreaming air. Thus, the loss of unburnt fuel is minimal, resulting in less emissions, a more efficient combustion and reduced fuel consumption. A small tube in the back of the cylinder is connected with an intake pressure sensor, which supplies pressure data to the control unit.

From here

https://www.ktm.com/en/enduro/150-ex...engine-exhaust

[koenich]

Not sure how the situation is in the US, but I imagine quite similar - the previous EXC models had not near the power delivery of a SX model in Europe.

[F5 Dave]

Looks like the 2018 KTM 150 carburetor version runs in the dark zone so I guess we can assume the EFI version does too.

https://thumpertalk.com/forums/topic...-dyno-results/

The Thumpertalk page talks about dyno testing a 2018 KTM SX150 but the dyno graphs are headed SX125, so not sure whats happening here.

https://thumpertalk.com/forums/topic...150-dyno-time/

Correct labels on this one. Looks like the 2019 EFI KTM 150 is well and truly running in the dark zone. ...... They must have solved the issues I am grappling with.

Flettners original TPI idea and KTM's commercialization of it. NZ brains and European money. High performance EFI two strokes ....

Yeah last curve blie line it says STIC. That's an aftermarket needlejet tower for Keihin carb.

[husaberg]

Looks like the 2018 KTM 150 carburetor version runs in the dark zone so I guess we can assume the EFI version does too.

https://thumpertalk.com/forums/topic...-dyno-results/

The Thumpertalk page talks about dyno testing a 2018 KTM SX150 but the dyno graphs are headed SX125, so not sure whats happening here.

https://thumpertalk.com/forums/topic...150-dyno-time/

Correct labels on this one. Looks like the 2019 EFI KTM 150 is well and truly running in the dark zone. ...... They must have solved the issues I am grappling with.

Flettners original TPI idea and KTM's commercialization of it. NZ brains and European money. High performance EFI two strokes ....

.......................

The Challenges: Initially, the TPI engines experienced flameouts because the exhaust pressure wave demanded a more sophisticated EMS that could perfectly manage fuel metering. When these refinements to the EMS were finally sorted, KTM knew they were onto a winner. And they promptly slapped an international patent on the TPI technology. A lot of sceptics said that, in principle, KTM would never be able to develop a fuel-injection system for two-strokes that would perform consistently well in all conditions. For example, when you ride through a creek that suddenly makes the exhaust pipe much cooler – a situation that a carburettor bike is ‘naïve’ to – then you need to find a way to override the information that the TPI bike’s EMS is receiving to ensure it continues to run properly. That’s just one example of the complexity and challenges that came with developing the TPI system’s mapping. But the TPI system was by far the best solution when it came to meeting KTM’s primary design objectives – which were to keep the power characteristics, feel and exhaust note of the TPI models as close as possible to the carburetted engines.

https://transmoto.com.au/ktms-two-st...ow-it-evolved/

[Flettner]

KTM's patent has been denied, they didn't invent it.

[husaberg]

KTM's patent has been denied, they didn't invent it.

I thought they were referring to the specific ECU they used which they didnt invent or even develop either

[FastFred]

.
Flettner was the original inventor and the first to demonstrate a working ride-able TPI transfer port injected two stroke.

[FastFred]

.

""Initially, the TPI engines experienced flameouts because the exhaust pressure wave demanded a more sophisticated EMS that could perfectly manage fuel metering.""

Looks a lot like the issues TZ350 has faced with his project.

A small tube in the back of the cylinder is connected with an intake pressure sensor, which supplies pressure data to the control unit. https://www.ktm.com/en/enduro/150-ex...engine-exhaust

Also looks a lot like the solution Flettner proposed and TZ350 has been working on.

TZ350's idea is to measure the crankcase high and low pressure and use the changes in the difference between them as a measure of the changes in air flow through the motor. Air flow being greatly influenced by the action of the pipe.

[husaberg]

.


Looks a lot like the issues TZ350 has faced with his project.



Also looks a lot like the solution Flettner proposed and TZ350 has been working on.

TZ350's idea is to measure the crankcase high and low pressure and use the changes in the difference between them as a measure of the changes in air flow through the motor. Air flow being greatly influenced by the action of the pipe.

Maybe its more important to simply know if its a high or low value rather than what the value actually is.That would solve the speed limitations of the current electronics.
Or maybe reading every 2 or 4th revolution for the crankcase is actually enough?

[jbiplane]

Me Too .....
...
At 15,000 plus rpm one might get away with alternating between two big second stage injectors.

Stihl and Husqvarna smootly meter correct ammount or fuel in crankcase neglecting high rpm. Their ugly crankshafts smashed fuel drops better than nozzles.

I had as well small 3w UAV engine with EF* It have simple fuel pump with 2 microscopic gears. ECU regulate pump rpm. Worked perfectly.

Both solutions dont required high presure pumps, pressure regulators, numerous tubes and sensors.

For me adopting of cars EFI to small 2-strokes sometimes looks like fitting saddle on a cow