ESE's works engine tuner

[ceci]

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The Fuel Injected Langen achieving Euro 5 certification is brilliant.



Towards the end of the dyno runs you can hear it hitting a rev limiter.

With only one injector my guess is that its limited to about 11,500 max rpm. Not because the injector is to small but rather an injector big enough for high RPM is to big at Low RPM for clean throttle response.

Attachment 349281
This is not "Direct Injection", direct injection is injecting directly into the cylinder after the exhaust port has closed. And the limited time available for injection in direct injection engines is what limits their performance.

At some point on the engine load curve the reed block injector must be on for nearly the full 360 deg of crank rotation. And at other points the injector will be on for a significant amount of time to achieve a homogeneous air/fuel mixture in the crankcase that is ready to be drawn up the transfers.

The air/fuel mixture in the crankcase does not go directly to the cylinder but rather has to wait its turn. On each cycle the air/fuel mixture in the transfer ducts is sufficient to replenish the cylinder and the air/fuel mixture in the crankcase merely replenishes the transfer ducts ready for the next cycle. So the Langen crankcase with its reed injection has to have a proper air/fuel mixture throughout the crankcase. "B" port injection is not limited in this way.

It is interesting that they can achieve Euro 5 with the Langen by directly injecting into the crankcase because it is hard to see how that is much different to the way a carb feeds the crankcase. I would think that both would have air/fuel mixture short circuiting out the exhaust and to some extent back out the inlet.

There must be more to this story, I would love to know what it is.

You know that's not stratified scavenging like TPI is and that it's hardly better than a carburetor.
The Euro5 not includes minority group bikes (langen only 100 units) (trial offroad ones too)

[Muhr]

what are the requirements for euro 5?

https://m.youtube.com/watch?v=RwB5_lL8wyU

[breezy]

is it me or did it sound a bit boggy when he blips the throttle..?

[ceci]

what are the requirements for euro 5?

https://m.youtube.com/watch?v=RwB5_lL8wyU

https://eur-lex.europa.eu/eli/reg/2019/129/oj?locale=en

[Muhr]

https://publications.jrc.ec.europa.e...%20%282%29.pdf

Euro 5 emissions limits (petrol) CO: 1.00g/km HC: 0.10g/km NOx: 0.06g/km PM: 0.005g/km

[Flettner]

Probably the only known photo of the uniflow100 in its frame.
Other bike my daughter is sitting on is a weedeater powered bike I built for the kids.
A lifetime ago.

[husaberg]

Probably the only known photo of the uniflow100 in its frame.
Other bike my daughter is sitting on is a weedeater powered bike I built for the kids.
A lifetime ago.

only decent photo

[Flettner]

The two only known crap photos of the 100cc uniflow. 😀

[Condyn]

Hello gentleman, I have been having a difficult time trying to grasp inlets. Every time I research the matter I end up diving down some other 2T rabbit hole.

The following is my understanding and should not be taken as facts. Please correct me if needed.

From what I gather, rotary valve and piston port engines need to stay within a degree range so they can start and operate at low rpm. Those two types of engines seem to respond better to a large case volume than reed engines which I pair with reed resonance requirements. Reed engines do not seem to have the same timing drawbacks as they open and close at the right time if you get it right.

Now the questions:

First, I have read that reeds can be too big. What does that mean exactly? Is this directly tied to the requirements of effectively opening a reed?

Second, on a cylinder reed engine, is adding boyesen ports as effective as piston cuts to increase intake area in an example where the STA is the same either way?

And lastly, is the pipes diffuser strong enough to open reeds at bottom dead center or does all the mix entering the scavenging column via the boost port (cylinder reed example) come from the trapped volume in the reed block as the intake port is shrouded by the piston? Or must there be a link to the case through piston cuts during this phase?

[wobbly]

Question one - reedblock too big. This can be the effective port area , and or the petal / port edge curtain area at full lift - both combine to generate the STA metric created by the fixed
port area and the continuously changing petal lift profile.
Just like Blowdown and Transfer STA , the Inlet STA should be capable of supporting the power being generated at a specific rpm.
BUT , unlike the other two , the Inlet is self compensating to some degree - that is if the curtain area is insufficient , then as airflow rises the petals can , be held open higher , for longer.

The other side of that coin is energy recovery .
Depending upon the petals 1st Mode Natural Frequency rpm ( usually lower with bigger/longer/thicker reeds ) it can be entirely possible to not
be able to get the system into resonance at a useful rpm to use the "free" effect of much less energy needed from the Intake airflow column to get the petals off the seat, and to stay open.
Another issue is that even with a very well designed and bench tested stuffer , you will always end up with the flow finally dumping thru an excessive area change .
This is the reason also that there has been of late , a tendency to reduce the area in font of the reed tip in the case - same deal with a higher energy recovery loss created by a big area change.

Second question - increasing piston cutouts or lifting the skirt always has the down side that the area presented to the incoming flow is coninuously varying , usually from too small to too big .
Whereas Boyesens are fully open all the time.

Lastly reed lift and diffusser action. The first point here is that there is no flow from the case , up thru the ducts and into the cylinder while the transfer ports are open. There is more volume in the ducts
than that delivered into the cylinder by the scavenging streams.
In all race engines I have seen on EngMod , the petals are pulled off their seats close to TPC by the case going negative near BDC and if the Intake is tuned , the column behind the petals has a resonant wave creating
a positive ratio as well.
Cylinder reed engines will feed the boost port duct via the relatively huge volume surrounding the reedblock , the connection to the case is irrelevant.

[Condyn]

Thank you for the response. I will have to let that resonate for a bit!

[Muhr]

If it would flow. So wouldn't you have to have a pj tube at the bottom of the carb where the closed slide didn't obscure it?

Took a picture today when I had it in front of me.

[wobbly]

Here's a mod I have done on many Yamaha racebikes with the electronic solenoid PJ - move the PJ to the top of the bellmouth and shorten the dump tube so it
only protrudes around 15mm into the bore . I cut the tube end at 45* facing the reeds as this atomizes the fuel stream much better than the stock small hole does.
The slide has to be well past the tube end for flow to begin , having a low down tube richens the fuel curve way too much in the midrange.

The only other way is to use a truth table in the ecu to switch the flow depending upon TPS and rpm , but this is problematic to tune , causing jerking response on part throttle , mid corner.
Cutting the tube short works on Lectrons as well , when having to use large PJ flow ( 50 + ) to get the top end tune correct without shagging the midrange jetting.

[TZ350]

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Alex is making progress with his 2Stroke Stuffing supercharged 50. https://youtu.be/_8xbYnXuI1A

[F5 Dave]

Took a picture today when I had it in front of me.

Ahh I see, it is a lot lower than I thought it would be with quite a lot of slide cutout showing.

So if you could control 2, a short one in from the side real low down that only works high revs closed throttle and another as Wob described.