ESE's works engine tuner

[teriks]

Do you know if that value includes the amount of fuel leaving the cylinder unburned?

I would _assume_ so.
The help files are rather short on the subject:
"Fuelflow The fuel flow in cc/min".
It can be found under Performance plots, you get a nice graph on fuel flow vs RPM.

[TZ350]

Did the injector pulse widths top out at the rpm you were testing?

Hard to watch the gauges and run the bike at the same time. I will check the fuel line pressure but yes I think your right, it is probably a timing thing.

This is how I understand it.

As a 2T has only half the time of a 4T to get things done, my 2T at 13,000 is equivalent to a 4t doing 26,000rpm.


The maximum time available to inject fuel is the time it takes to go through one revolution or 360 degrees less the time it takes to actually open the injector and get it fully flowing and the time to close it again and also a bit of down time so it does not over heat.

All of this open-squirt-close-rest has to be done in the time it takes to go through 360 degrees and at 12,000 rpm that is only 5ms and if you take out the open-close-rest time you only have 1ms left for full on squirt.

Every thing works OK at 8,000 rpm where the injector can be fully open and flowing for 3.5ms but there appears to be no where near enough fuel delivered with only 1.5ms available at 11,000 let alone only 0.6ms at 13,000.

Making the Alpha-N map numbers bigger only made things worse, I guess it brought the system into conflict with the time required for the injectors to be open compared to the time required for the injectors to actually open/close and have some down time.

[husaberg]

Hard to watch the gauges and run the bike at the same time. I will check the fuel line pressure but yes I think your right, it is probably a timing thing.

This is how I understand it.

As a 2T has only half the time of a 4T to get things done, my 2T at 13,000 is equivalent to a 4t doing 26,000rpm.

The maximum time available to inject fuel is the time it takes to go through one revolution or 360 degrees less the time it takes to actually open the injector and get it fully flowing and the time to close it again and also a bit of down time so it does not over heat.

All of this open-squirt-close-rest has to be done in the time it takes to go through 360 degrees and at 12,000 rpm that is only 5ms and if you take out the open-close-rest time you only have 1ms left for full on squirt.

Every thing works OK at 8,000 rpm where the injector can be fully open and flowing for 3.5ms but there appears to be no where near enough fuel delivered with only 1.5ms available at 11,000 let alone only 0.6ms at 13,000.

Making the Alpha-N map numbers bigger only made things worse, I guess it brought the system into conflict with the time required for the injectors to be open compared to the time required for the injectors to actually open/close and have some down time.

Remember the PSI Cagiva used (Later 180PSI)incidently what was the PSI Aprilia used Frits?

[Drew]

I'd fake it with ramped fuel pressure in the rail. Mind, mental maths (known for error more than accuracy) says you want to nearly triple the pressure if not more. Your injectors won't like that one little bit, even if your pump can handle it.

Hmmm, another two injectors squirting in from the front/sides?

Not an easy one to overcome without causing a whole new set of problems.

[Drew]

Remember the PSI Cagiva used (Later 180PSI)incidently what was the PSI Aprilia used Frits?

There ya go, four times the pressure at least. Bloody hell, injectors to run at that sort of pressure would need to come from something modern and common rail direct...or a diesel.

[Yow Ling]

There ya go, four times the pressure at least. Bloody hell, injectors to run at that sort of pressure would need to come from something modern and common rail direct...or a diesel.

errrr car fuel injection is modern and common rail, the big advantage with modern diesel is the piezo injectors which are capable of up to 7 separate injection events per power stroke in a modern engine , although that can be done over a much longer time both before and after tdc to maintain pressure in the cylinder

[Drew]

errrr car fuel injection is modern and common rail, the big advantage with modern diesel is the piezo injectors which are capable of up to 7 separate injection events per power stroke in a modern engine , although that can be done over a much longer time both before and after tdc to maintain pressure in the cylinder

Common rail direct is what I was getting at there. Can't imagine there's a big upside to squirting fuel at that sort of pressure, at the back of a mostly closed valve.

[husaberg]

mmmmmm..of course Cagiva were throttle body injection though....
What pressure can Robs system handle and how many injectors? bigger ones I guess are progressively slower responding......
Neils link I guess is a lot more sophisticated but that comes at a price of course.....

[Drew]

mmmmmm..of course Cagiva were throttle body injection though....

It really seems this is how Cagiva went about fixing the same issue, based on the fact that there can't be a great advantage in squirting high speed fuel at closed surfaces.

What pressure can Robs system handle and how many injectors? bigger ones I guess are progressively slower responding......
Neils link I guess is a lot more sophisticated but that comes at a price of course.....

This was talked about earlier, but I still have no fucken clue on how to use the search function for this thread.

[husaberg]

It really seems this is how Cagiva went about fixing the same issue, based on the fact that there can't be a great advantage in squirting high speed fuel at closed surfaces.
This was talked about earlier, but I still have no fucken clue on how to use the search function for this thread.

search thread use a few words like psi injection pressure and results come up.
I often search by pictures relating to the posts using view thread images.
I did find this though, it's out of pitlane. I have posted it before. From memory both Robs and Neils was both about 40psi

Aprilia was guilty of throwing out what they perfected (carburation)and introducing a totally new concept loaded with technology EFI system. It was an intelligent system that made all the theoretical calculations at light speed..... It was a perfect system....... Too perfect! For years 2 stroke engine development was being done using less than perfect carburetor. This includes rider knowledge, tire construction, and suspension..... The end result was that the riders and machinery (tires) couldn't cope with the instantaneous increase in torque when the throttle was opened while at maximum lean angles.

When I discussed how I was going to do my EFI, their main electronics engineer started clapping..... What I wanted to do (and later did) was to upload a fuel distribution curve similar to a Del'Lorto needle/tube (needle jet) combination and did not let the computer adjust it. I used a TPS, H2O sensor, Air temp sensor, and Hall Sensor for crank angle/rpm. This way I was using what I knew, but getting the benefit of 3 bar of fuel pressure and injector atomization. I had total control and could add fuel to make the fuel curve "imperfect" if need be. I used 2 injectors mounted on the engine side of the throttle valve and I alternated their firing so that I could rev upto 15000 rpm. That way each injector was mislead into thinking it was feeding a 7500 rpm max 4 stroke cylinder. In total I invested $1600 into the total system and had it running pulling load on the dyno in 3 hours.

[Drew]

search thread use a few words like psi injection pressure and results come up.
|I often search by pictures relating using view thread images.
I did find this though, out of pitlane I have posted it before.from memory robs and Neils was about 40psi

Cheers for the tip.

That alternating injector bizzo is the go.

[TZ350]

Ok, tonight I fitted two 89g/min injectors on the side transfers for starting and low speed running and a 360 g/min unit in the middle for squirting under the piston and ran it all up.

EngMod says that the 125 will consume about 260cc of fuel a minute and the big injector delivers 460cc (360 g/min) at 100% duty.

This data recorder is a pretty handy feature of the Ecotrons EFI system.



RPM ... Brown line
Maximum Injection Time Possible ... Grey Line
Injector-1 ... Blue Line
Injector-2 ... Yellow Line

The second injector is coming in after the first 80 g/min injectors top out, the second 360 g/min injector still has some head room so that is a good sign and the EFI control system looks like its trying to do the right thing.

Still detonating though so I tried bigger map numbers but no real improvement, will check the line pressure next to see if its falling off with fuel demand.

[speedpro]

Their Lambda monitoring software is pretty good as well. If you connect the injector wiring into it you can map lambda against rpm. The response time of their WB lambda is near fast enough to see individual cylinder firings but there are other limitations.
Could be time to try the autotune function again.

[marsheng]

This is how I understand it.

As a 2T has only half the time of a 4T to get things done, my 2T at 13,000 is equivalent to a 4t doing 26,000rpm.

Not quite. The fuel is delivered over approx 220 degrees of crank shaft turn in a 2 St. That is much the same for 4 strokes. The inlet valve is open for maybe 280 degrees of crank ? Even though it is firing every second stroke, the valves are opening and closing fully in less than 1 stroke.

What I understand is that on a 4 St, fuel is pumped into the carb tract even when the inlet valve is closed. The fuel sits and waits there till the valve is opened effectively making for a longer time to do the necessary. However, some 4S rev very high so it must be possible.

Yes mechanical valves just don't work very fast.


Cheers Wallace

[TZ350]

Do you know if that value includes the amount of fuel leaving the cylinder unburned?

"Fuelflow The fuel flow in cc/min". It can be found under Performance plots, you get a nice graph on fuel flow vs RPM.

If I take the fuel flow vs RPM graph and divide the fuel flow by RPM I get the red line which looks like the BSFC line.

All my fuel maps have started low and increased as the rpm goes up like the fuel flow plot but after dividing the fuel by RPM (Red Line) it looks like the BSFC line.

I may have been doing it all wrong and maybe the numbers on my Alpha-N map should decrees as the RPM increases.?????