Ecotrons Engine Management

[Cheesy]

Is the middle (small) injector squirting into the crankcase? Is it possible to fire the injector earlier at low speed into the crankcase at lower engine speeds to try and get better mixing?

[TZ350]

Is the middle (small) injector squirting into the crankcase? Is it possible to fire the injector earlier at low speed into the crankcase at lower engine speeds to try and get better mixing?

In the Ecotrons EFI software there is a way of mapping (seperate to the fuel map) the injection end point. But I am afraid the Ecotrons manual is not very clear about the details.



As best as I can tell, that is a 4T map and the Injection end point is so many degrees before TDC on the firing stroke.

For me it would be something like 120 degrees if I wanted to finish the injection squirt as the transfers close.

[speedpro]

Been a while as I only have a few spare hours each week to do any work on the bike. It hasn't come off the dyno for a few months I think. I have taken it off the rolling road, which had been giving good results as far as the Lambda readings were concerned, and put it on the inertia dyno. Tuning the VE table was pretty much sorted and I played with the ignition table by filling tables with one value, say 24degrees and doing runs, then 28degrees and doing runs, etc. Then it was on to the TPS table which I have it set to only be used over 98% throttle. We had tuned it on the rolling road for good Lambda but with the inertia dyno and how it increased revs through a run, and the turbo spooled up, I had to completely rehash it. I took a stack of fuel out below about 10,000rpm where it wasn't really building boost on the inertia dyno, and added a bit more at the top over 14,000rpm.

I was experiencing ECU problems all through this time over a few weeks. I'd change map values at high load and rpm and the engine would refuse to start. I'd load the previous map and away it would go. So I'd try the new map again and this time it would fire straight up and run fine. At one point the engine lost a bunch of power when I tried something and when I reversed that it was still down on power. From previous experience I decided to try flashing the ECU after which the power was back. I also keep having issues with the TPS. Over time it seems that you have to move the throttle further and further before the TPS indicator gauge indicates an increase. Flashing the ECU resets it so that the slightest touch of the throttle causes a change of the TPS gauge reading. You wouldn't initially think this would make a difference since I'm only using the VE table which relies on the MAP sensor output, but the TPS is used to determine whether the engine is being blipped etc and fuel is added or subtracted depending on throttle change rate. The engine definitely blips crisper when it is reading correctly.

#1 header would glow pretty good on a run right at the top of the run. #2 was not so obvious. The engine also struggled over say 14,500rpm and typically was all over by 15,500rpm. Given that I was lied to about the ECU capability to handle revs, and then they gave me a modified version that theoretically allowed 16,000rpm+ I now suspect that the ECU may be reaching it's limits which may be causing #1 to lean out. The Lambda is in the exhaust plenum so reads the combined cylinder o2 value. I was seeing it lean out up top until I tipped in a heap more. Either way I have no confidence that the engine is being managed properly at revs.

Another problem I had which developed quickly to the point where you couldn't even run the bike long enough to warm it up was the ECU losing it's tune and stopping the engine. I knew the ECU had a problem where a connector or something in the case was shorting to ground, which I fixed way back by rubber mounting the ECU. Anyway, I popped the top off the ECU to check for problems. It looked like the main connector pins to the circuit board had not been cut off short enough so I filed them down and then for good measure put electrical tape over them and a few other bits that stuck out further than I thought they needed to. Turns out I was on the money and it has run fine ever since, apart from the problems above.

So, it has got to the point where I pretty much need a Link Atom to progress. Had a very good chat to one of their guys who seemed confident it would be good. Their web site does claim 20,000rpm capability but I got the feeling from talking to him that nobody had tested that yet. On a twin though it shouldn't be a problem. Evidently Link have experimented with using the MAP sensor to determine where in the cycle the engine is but with the revs I'm going to have to fit a cam sensor.

[Drew]

Am I reading this correctly? From what you're saying I infer that Ecotrons is just shit.

[BASS-TREBLE]

Do you have experience with micro/megasquirt? Is there a reason why you are not considering it if you will replace the ecu? The forums have success stories of 16,000+ rpm, I personally have had no problems up to 11,000

[speedpro]

I have no experience with megasquirt. I'm thinking Link for the support. Local product, help is a phone call away, or email, or go to the web, and in English. The manuals seem readable and make sense, as much as I've read anyway. Trying to puzzle the Ecotrons manuals can do your head in.

Ecotrons for the price is very good. I think for their major market, single cylinder 4 strokes, that they do every thing that is asked of them. They are a budget product. As a consequence some of the bits are not as robust as other pricier products, the fuel pressure regulators springs to mind. My faulty one cost me a year of development time and taught me valuable lessons chief of which was "monitor fuel pressure".

There is bugs which may be fixed with software updates but I'm not giving them another US$250 for support to find out.

I have learnt lots though and I truly don't understand why anybody with a 4T uses carbs, except of course that they work and are reasonably simple.

I may be alone in experiencing some of these issues. The ECU software I am running is unique as far as I know so maybe that has raised issues not found in the regular version.

[Flettner]

I have no experience with megasquirt. I'm thinking Link for the support. Local product, help is a phone call away, or email, or go to the web, and in English. The manuals seem readable and make sense, as much as I've read anyway. Trying to puzzle the Ecotrons manuals can do your head in.

Ecotrons for the price is very good. I think for their major market, single cylinder 4 strokes, that they do every thing that is asked of them. They are a budget product. As a consequence some of the bits are not as robust as other pricier products, the fuel pressure regulators springs to mind. My faulty one cost me a year of development time and taught me valuable lessons chief of which was "monitor fuel pressure".

There is bugs which may be fixed with software updates but I'm not giving them another US$250 for support to find out.

I have learnt lots though and I truly don't understand why anybody with a 4T uses carbs, except of course that they work and are reasonably simple.

I may be alone in experiencing some of these issues. The ECU software I am running is unique as far as I know so maybe that has raised issues not found in the regular version.

My LINK (on the F9) is working well, an ATOM, yes they are a bit dearer but you can consult Simon any time at LINK, he knows EVERYTHING.

Neil

[F5 Dave]

So if you float through the Factorypro website they wibble on about matching injectors. I've supplied and ordered a matched set. Apparently its not uncommon to have one rich, one lean etc. Higher revs would only exacerbate the problem.

[Peiter]

Hi guys,

given the interesting results achieved by all of you with injection, I want to give it a shot too together with a friend.
We are planning to implement the ecotrons system as indirect injection on a rotary 50cc yamaha tz 2-stroke engine.

I was wondering what the pros and cons were to indirect injection, compared to direct injection.
Furthermore, having read that TZ has been fiddling quite a bit with the correct injector size for his engine, could you give me advise on what size of injectors I would need to buy?

Thanks in advance!

Peter

[TZ350]

... given the interesting results achieved by all of you with injection, I want to give it a shot too together with a friend. Could you give me advise on what size of injectors I would need to buy?

Ecotrons would be the best bet for Injector sizing advice but below are my thoughts.

I think the Ecotrons system is great for experimenting with but like most EFI systems it may not be suitable for directly injecting into the cylinder after the exhaust port has closed because the cylinder compression pressures will rapidly become higher than the fuel injection pressure.

Like most, the Ecotrons system is suited for transfer port, crankcase, inlet or semi direct injection.

If you are developing your own EFI CPU Ecotrons would be a great source of injector, fuel pump and other parts at very reasonable prices.



Ecotrons fuel Injector specs.

For a high revving two stroke you will need a staged injector system, smaller injector capacity for low speed, larger capacity for high rpm. But selecting an injector is not like selecting a carburettor main jet because it is not all about fuel volume, it is more about the diminishing time in which to get things done as the rpm increases.

Ecotrons is best placed to advise what injector sizes would suit 50 cc 2T but I am currently getting good results with two 60g's and a 128g injector for a total injection capacity of 248g/min on my 110cc 2T engine that tops out at 13,000 rpm. So for 50cc my guess would be about half that, say two 38g's that then swap to 80g for higher rpm and finally finishing with 156g (38 + 38 + 80, all firing together.) .

You want as small an injector as possible. That way you get the widest range of tun-ability. To get it open and flowing in a controllable sort of way an injector has to be "on" for a minimum amount of time to open properly, at least 1.5ms for the small Ecotrons injectors and for a larger injector 1.5ms will be to much fuel for good low speed running.

Car and other bigger injectors typically take 3.5 - 4.5ms or longer to fully open and start flowing properly and so are far too slow for a 14,000 rpm two stroke engine where you barely have that much time in a complete crank revolution let alone the much shorter time the transfer/inlet ports are open.

The EFI dual injection system CPU swaps to the second larger injector when there is no longer enough time for the first smaller injector to deliver enough fuel. As the rpm gets up and time is even shorter the EFI CPU can run both injectors together.

Remember it is all about time. An injector only needs to be big enough to chuck in the right amount of fuel in the short amount of time available at high rpm and not so big that it floods the engine with its minimum on time when there is lots of time available at low rpm for a smaller injector.

A two stage dual injector system uses the first injector until time runs out to get the business done. It then swaps to the second bigger injector to dramatically reduce the time required to chuck the fuel in there. And when that is not enough it starts to run both injectors together so with two different sized injectors you can get a three tier system.

Bigger two strokes like 250 singles that only rev to 9,000 rpm seem to get away with a single stage injector system but when the rev's go past that then a two stage dual injector system is required. Again it is all about the time available to get things done.

An injector goes through four steps each cycle:- Opening - Injecting - Closing - Resting.

Opening takes time, at least 1.5ms and dribbles fuel in an uncontrolled way while it is is doing so, so you want the smallest size injector possible.
Injecting is the controlled and variable period of time that fuel is flowing.
Closing takes time too, typically 0.5ms for the small injectors.
Resting is the time left over, and in a staged system when the resting time gets to short the EFI CPU moves up to the next (bigger) injector (or combination) because that takes less time in the Injection phase to get the fuel in there but a bigger injector dribbles to much fuel in the opening stage to be useful for good low speed running.

Instead of having the EFI CPU swapping from 38g to 80g as the rpm goes up. It is possible to have 38g and 38g so that when the 80g injector capacity is required because time is running out the system simply runs both 38g injectors together.

Instead of a single 248g high speed injector I have my 60+60 low speed plus 128 high speed arrangement for a total of 248g high speed injection. Having all three injectors firing together spreads the fuel mixing throughout the crankcase for hopefully a better homogenous mixture.



My Ecotrons dual injector two stroke wiring harness came with two injector plugs. One for low speed the other for high speed. You can splice a second injector onto each plug lead if you want to, and it is what I have done.

I currently use 120g (two 60g injectors run in parallel, one in each B transfer port) for low speed and a single 128g injector in the crankcase for high speed. When time has run out to deliver enough fuel with the two 60g injectors run in parallel then the system halves the injector time required by bringing in the the 128g injector for a total of 248g of injector capacity (60 + 60 + 128 = 248g).



My system uses low and high rpm injectors for a staged injector system. For low rpm there are two physical 60g injectors in the B transfer ports like this YZ250 cylinder has. My two 60g injectors are run together as one logical 120g injector for low rpm and the high rpm injector is a 128g unit in the crankcase. To aid mixing all my injectors are currently positioned to squirt against the air flow.



When setting up the map, it is a really big help to have a wide band O2 sensor. On a two stroke the end of the expansion chamber seems the best place to put it. Unlike a four stroke which has them in the header. On a two stroke at the rear you get a good average mixture, in the two strokes header you get a confused reading from all the short circuiting fuel mixture.

Like others, I found the big problem with getting any EFI system going is not so much getting the fuel maps right, they are easy enough but all the options that come with EFI software, you have to sort through them and one wrongly selected option can take a while to find.

My work has all been aimed at outright racing power and very little to do with economy. But I have noticed that the orientation of the injectors and timing of the injection cycle can make a noticeable difference to the fuel demand. A carefully timed shot across the transfer airstream seemed to need less fuel than a general squirt into the crankcase, makes sense I guess.

And squirting the underside of the piston crown through a slot in the piston made very good low speed running but was not so great at max rpm. This was disappointing because I really wanted to use the fuel to cool the underside of the piston crown when making max power.

Good luck and please post your progress on here, I would love to be able to follow your projects success as you go along.

[TZ350]

Some links to YouTube clips of a couple of two stroke bikes modified for EFI.

Yamaha YZ250.

https://youtu.be/hOGZ5llowoU

https://youtu.be/UEQli7nuak4

https://youtu.be/1YG9ko8-Nwk

Kawasaki BigHorn.

https://youtu.be/eleqBGvOM4M

https://youtu.be/ifSEql1X4R0

https://youtu.be/CnIemdISKrM

[Peiter]

Hi TZ,

thanks for the extensive reply, I appreciate it!
Developing our own EFI CPU isn't the goal right now, we are more interested in an off the shelf system like the ecotrons.

From what I read on the ecotrons site, the max RPM of the kit is limited to 16.000.
Is this limitation due to the injection cpu, or does it only apply when one uses the same cpu also for ignition control? I had some mail conversation with ecotrons about this subject but I couldn't get it clear.

I will post regular updates on our project. At this moment, we are designing the 50 cc cylinder which we will first start using / developing on a reed valve tz 50 engine. The next step is then to design and machine rotary valve engine casings.
The design and development of the engine casings will likely be > 1 year of work while the cylinder will be ready in a few months.

Regards,

Peter

[husaberg]

Hi TZ,

thanks for the extensive reply, I appreciate it!
Developing our own EFI CPU isn't the goal right now, we are more interested in an off the shelf system like the ecotrons.

From what I read on the ecotrons site, the max RPM of the kit is limited to 16.000.
Is this limitation due to the injection cpu, or does it only apply when one uses the same cpu also for ignition control? I had some mail conversation with ecotrons about this subject but I couldn't get it clear.

I

Peter

https://www.kiwibiker.co.nz/forums/s...post1130989127

[TZ350]

I will post regular updates on our project. At this moment, we are designing the 50 cc cylinder which we will first start using / developing on a reed valve tz 50 engine. The next step is then to design and machine rotary valve engine casings.The design and development of the engine casings will likely be > 1 year of work while the cylinder will be ready in a few months.

Regards,

Peter

Hi Peter, I look forward to your posts.

From what I read on the Ecotrons site, the max RPM of the kit is limited to 16.000.
Is this limitation due to the injection cpu, or does it only apply when one uses the same cpu also for ignition control? I had some mail conversation with Ecotrons about this subject but I couldn't get it clear.

That is a good point, which is the limiting factor, Ignition or EFI or overheads from the combination? Unfortunately communication with Ecotrons is difficult, and clear communication with the help dept is all but impossible. Maybe it is a language barrier or clash of cultures thing. Or maybe they know their product and EFI so well they just can't understand why we don't.

Speedpro seemed to run into a upper rpm barrier of 16,000 rpm with his twin cylinder 4T running Ecotrons EFI and Ignition. He found Ecotrons help dept a challenge and has since started using a Link EFI CPU. He reports that Link here in NZ has been very helpful and understandable.

I am not sure how much experience Ecotrons has had with high speed two strokes as anything I can see 2T on their site refers to two stroke engines running at less than 10,000 rpm.

My Ecotrons system (same CPU different software to Speedpros) seems reliable to 13,000 rpm which is the physical breathing limit of my 2T engine.

My guess is you would be Ok to 16,000 rpm with a single cylinder 2T but after that "Time" is going to be a very limiting factor, it may pay to do some maths to figure out if the injection cycle can be completed in the time available at the rpm you are thinking of running. Typical pulse widths on my engine are 1.8 to 5 ms at lower rpm and typically around 3ms at max power (bigger injector).

I have heard of someone running a custom 2T EFI system where they alternated between two injectors so that the opening and closing-resting times were overlapping the next revolution and only the injection phase was on the current crank shaft revolution. Clever idea if you are desperately short of time.

[FastFred]

.



Ok, I think I understand it now ... So, when the engine has got a hurry up, it becomes all about the diminishing amount of time to get the good stuff in there.