ESE's works engine tuner

[teriks]

I assume 33000rpm is close to resonance teriks? What happens past peak?
I still think the pressure rise after EPO is a great indicator of the following suction pulse (pipe boost effect in general) and therefore next cycle fueling. It worked really well when I tested it, but my ECU couldn't adjust for the delay by RPM vs. crank angle. So it only worked around the RPM range I had it adjusted for. Also the piezo disc I used was too big, so the signal output was huge and it quickly destroyed itself.

Just need to find a few hundred bucks to get the YZ cylinder plated before I can get it running again and continue testing.

Yes, 33kRPM is close to peak power, will do another run to show past peak later.
-Dont have access to the sim here.

For sure measuring the pulse close to the port at EPO would give better data. I also like the idea posted earlier where you sample combustion pressure thru the cylinder wall right before EPO. But as seen from your and TZ's work there seems to be no simple, cheap and robust method.. yet.

No, I was looking at the crankcase pressures, although I did look at the pipe some time ago and what you say about it makes sense.

I would love to know more about your pressure transducer. It sounds like something I could use if its affordable.

Unfortunately the data was from the sim.
As far as real world stuff you are miles ahead already with your carbs, not to mention your injection systems.
We have a very crude form of carb where a simple needle acts as main jet, and the fuel tank, vented to the pipe belly, can be compared to the float bowl. No electronics, varying fuel level in the "bowl", and not even a throttle.. still works surprisingly well.

[Muhr]

Yes, 98% clean mixture at WOT and 9,000 rpm, 15% polluted with only 85% purity at minimum throttle and 9,000 rpm according to this simulation of my engine.

Hello tz
I have a bit of a difficulty understand what you have for value of the y axis in the graph?
As I understand this is the crankcase?

[Vannik]

Hello tz
I have a bit of a difficulty understand what you have for value of the y axis in the graph?
As I understand this is the crankcase?

1.0 is 100% pure air,
0.0 is 100% burnt gas.

[DoldGuy]

Interesting injector placement....


https://patentimages.storage.googlea...80023528A1.pdf

[TZ350]

Interesting injector placement.... https://patentimages.storage.googlea...80023528A1.pdf

I think with 2S EFI they should forget trying to look like a carburetor. Just my opinion.

Trying to mimic a carburetor is unlikely to work well everywhere because the air flows all the time and the fuel is injected in discreet amounts so homogeneous mixture can be a problem. In extreme situations most of the fuel could be in the bit of air that disappears down the exhaust or gets blown back out of the inlet.



Although it does look great and it allows for staged injection so it could be spun faster than 10,000 rpm and make real power at WOT.

What I would very much like to know, is how do they account for the changes in air flow that occurs when the pipe is working or not.

There are two situations.

RPM + TPS and Pipe working, and engine making power.

Same

RPM + TPS but Pipe not working, different air flow, less fuel required, how do they see that? This is where I am stuck with my own project.

[Muhr]

1.0 is 100% pure air,
0.0 is 100% burnt gas.

Thanks Vannik

Then I think I understand! The red and dark blue etc are simulated values ​​from the combustion chamber or somewhere nearby

[tdc211]

My cylinder purity not good in sim on new 105. Like 93-94%..
With or without combustion %, set on higher %.
So I assume my purity is higher in real life.
Which I think a lot of this comes back to the new tranfers.

[ceci]

I think with 2S EFI they should forget trying to look like a carburetor. Just my opinion.

Trying to mimic a carburetor is unlikely to work well everywhere because the air flows all the time and the fuel is injected in discreet amounts so homogeneous mixture can be a problem. In extreme situations most of the fuel could be in the bit of air that disappears down the exhaust or gets blown back out of the inlet.



Although it does look great and it allows for staged injection so it could be spun faster than 10,000 rpm and make real power at WOT.

What I would very much like to know, is how do they account for the changes in air flow that occurs when the pipe is working or not.

There are two situations.

RPM + TPS and Pipe working, and engine making power.

Same

RPM + TPS but Pipe not working, different air flow, less fuel required, how do they see that? This is where I am stuck with my own project.

Another mark more than to regressed (KTM first), direct injection to the cylinder, has to inject into the crankcase

[ceci]

Another mark more than to regressed (KTM first), direct injection to the cylinder, has to inject into the crankcase

bimota also backed down

[teriks]

I assume 33000rpm is close to resonance teriks? What happens past peak?.

Not too many data points, but for sure the average pressure drops after peak power.

[husaberg]

I think with 2S EFI they should forget trying to look like a carburetor. Just my opinion.

Trying to mimic a carburetor is unlikely to work well everywhere because the air flows all the time and the fuel is injected in discreet amounts so homogeneous mixture can be a problem. In extreme situations most of the fuel could be in the bit of air that disappears down the exhaust or gets blown back out of the inlet.



Although it does look great and it allows for staged injection so it could be spun faster than 10,000 rpm and make real power at WOT.

What I would very much like to know, is how do they account for the changes in air flow that occurs when the pipe is working or not.

There are two situations.

RPM + TPS and Pipe working, and engine making power.

Same

RPM + TPS but Pipe not working, different air flow, less fuel required, how do they see that? This is where I am stuck with my own project.

I think they mimic it as it works.
I dont think its a co-incidence that if you plot the fuel flow of a carb against a engines power graph that they are the same shape.
One advantage a carb has is its immediate response to changes in airflow.
This has to be built into a 2t injection system from the get go as 4ts are much more forgiving as they are less time constrained and have lesser speed requirements.
that being said i think for it to work great in your situation on petrol it needs tiny injectors in multiple stages and extremely fast processing speeds.
These have only really became affordable and available in the last few years.
The work around for these current constraints with current tech as i see it is using very high injector pressures and multiole fast responding small injectors.
I think the timing of the injection sequence is the most important thing in regards to reducing emissions rather then getting the right amount of fuel ad a given rpm /load etc.
Flets transfer injection seems to be the go.

[Flettner]

intetesting, some spy photos I've just seen of TM's secret test enduro bike, (next years model? Im not sure its that secret if I got to see them��) but clearly seen on the side of the cylinder is TPI B port lugs to accept injectors, Same as KTM and the YZ250 TPI.
I did dangle the advantages of the Mk2 TPI in front of TM but they seemed not intetested.
Yes a modified version of the TPI is the answer, more power, better fuel economy.
But just like the original TPI system no one is interested, untill, suddenly, they are. I intend to have some fun with this next design before, 'suddenly they are'.

[husaberg]

its a bit late for april fools.
https://latestmxvideos.com/index.php...nounces-cr500/

this has been floating about for a while now along with its injected and accompanied by a 125 and 250.

https://latestmxvideos.com/index.php...back-for-2019/

I think its a pipe dream myself

[TZ350]

One advantage a carb has is its immediate response to changes in airflow. This has to be built into a 2t injection system from the get go.

Injector and CPU speed are good enough now and it is easy to build in immediate response to changes in airflow if you can see the changes clearly. Which is something I cant do yet and suspect nobody else can either, especially above 10,000 rpm and 10 bar BMEP. Like you say, being able to read the airflow situation is the key to successful two stroke EFI.

[husaberg]

Injector and CPU speed are good enough now and it is easy to build in immediate response to changes in airflow if you can see the changes clearly. Which is something I cant do yet and suspect nobody else can either, especially above 10,000 rpm and 10 bar BMEP. Like you say, being able to read the airflow situation is the key to successful two stroke EFI.

When i say injector speed and CPU speed i are meaning to get the injector timing screwed down to make the emissions tiny as with DI yet still be drive-able with similar response as a carb. Plus decent HP.
CPU might be there but i dont think the common injector are.
I cant remember what Cagiva and Honda were using but the pressure was huge.
he looks 180PSI..............
Honda no idea but i think they had to go with mechanical pump like Cagiva did so likely a lot as well
I should note that F1 race car also use mechanical pumps running i presume huge pressures
I know bosch do a 200 bar and a 500 bar version for something
i GUESS THE 500 BAR ONE IS dI
http://www.bosch-motorsport.de/conte...63.html#teaser
http://www.formula1-dictionary.net/d...injection.html