Project Electronic Fuel Injection

[mono]

Doesn't seem like something useful to me. I've never heard of any application of such a thing to improve performance or efficiency in any way - I'm pretty sure that it's meant as a restriction...

I guess it has something to do with the EU homologation system to make some versions of their exhausts legal for road use in the whole of the EU...

Is there a mark with an "E" in a circle, followed by a number like "15" or something, imprinted somewhere on the exhaust ? An unrestricted tuning part will never have this mark, while this mark is kind of mandatory with a road legal one in the EU...

Whatever the reason is and whether it's shipped the same way to other countries, I wouldn't hesitate for a second and rip this silly cone out of there immediately...

(but then again, I tend to switch back and forth all the time from being impulsive to trying to do the wise thing....   )

[baddi]

Doesn't seem like something useful to me. I've never heard of any application of such a thing to improve performance or efficiency in any way - I'm pretty sure that it's meant as a restriction...

I guess it has something to do with the EU homologation system to make some versions of their exhausts legal for road use in the whole of the EU...

Is there a mark with an "E" in a circle, followed by a number like "15" or something, imprinted somewhere on the exhaust ? An unrestricted tuning part will never have this mark, while this mark is kind of mandatory with a road legal one in the EU...

Whatever the reason is and whether it's shipped the same way to other countries, I wouldn't hesitate for a second and rip this silly cone out of there immediately...

(but then again, I tend to switch back and forth all the time from being impulsive to trying to do the wise thing....   )

Yes, for some reason they've got it approved in Luxemborg. On the Type Approval it sais that it is approved to have low noise and a good exhaust gas filtering system.. How they got it approved is still a great big mystery to me!

[streido]

I havent had time to take mine off yet to check it but from memory the end of mine looks different to yours 

Maybe im wrong tho. Im def going to have a look as soon as i get some free time, had a lot on lately, maybe try at the weekend. Will post a pic when i do to compare them. If it is there then its getting drilled out before the exhaust goes back on tho 

[baddi]

I havent had time to take mine off yet to check it but from memory the end of mine looks different to yours 

Maybe im wrong tho. Im def going to have a look as soon as i get some free time, had a lot on lately, maybe try at the weekend. Will post a pic when i do to compare them. If it is there then its getting drilled out before the exhaust goes back on tho 

Drilled?  Forget that!

Just take a flat screwdriver and a hammer and hit the weld a couple of times. And don't be drunk while you do it, you will hit your hands.

[zombie]

I missed your point about the closed loop temp/cold start. It sounds like once you re install the pipe all you have to do is shorten the duration of the pulse across the board. I'm sure the program has access. I still don't understand the oscillation in rpm... Perhaps just a by product of running rich. Sounds like you pretty much have it.

[mono]

Is it possible that the oscillation is caused by the injector being too large to spray fuel in the extremely small amounts needed at idle ?

I can imagine that it's only dripping instead of spraying at idle, which means that it will take more time for the fuel to atomize, the control unit will then see a lean condition because of this delay and it will increase the amount of fuel, which will be too much of course - and when all of the dripping fuel has eventually reached the cylinder, the control unit will detect a rich condition, starting the loop all over again and again....

Is it possible to switch off the control loop below a certain rpm and use a fixed setting at idle rpms ?

[baddi]

Is it possible that the oscillation is caused by the injector being too large to spray fuel in the extremely small amounts needed at idle ?

I can imagine that it's only dripping instead of spraying at idle, which means that it will take more time for the fuel to atomize, the control unit will then see a lean condition because of this delay and it will increase the amount of fuel, which will be too much of course - and when all of the dripping fuel has eventually reached the cylinder, the control unit will detect a rich condition, starting the loop all over again and again....

Is it possible to switch off the control loop below a certain rpm and use a fixed setting at idle rpms ?

I don't think so, since this is the smallest injector sold, and it have succesfully been used for engines down to the size of 25cc, but there were some problems with it being rich at that little motors. :p

The loop goes like this: Idle is stable at something high during warm-up. Then the fuel is cut a little down when warming up, and the idle slowly falls to 2200-3000rpm. Then at some point, when the warm-up process is done, the lambda sensors output slowly raises from 0,46v (rich) to around 0,9v (still rich), and when the voltage signal comes up here, it starts to try to correct the fuel real-time, by cutting one forth of the fuel away. On the way, dropping from no fuel cutting to that, the rpm raises, and when the fuel is cut to 75% of normal, the rpm quickly hits 4-5000 rpm, where it forcefully cuts all the fuel untill the rpm are at 2200-3000 again and the loop goes back. :/

[mono]

What size is the throttle body ? Airspeed could also be a factor in atomization...

[mono]

I don't think so, since this is the smallest injector sold, and it have succesfully been used for engines down to the size of 25cc

The number of cc's of the engine might not be the dominant factor that it seems to be....

The amount of fuel and air needed at idle for any engine will be determined by the amount of power needed to keep that specific engine at it's idle rpm, which will depend on factors like the sum of all friction at all moving parts, external loads like alternator and drive belts, and also very important and very engine-type specific : the efficiency of that engine at that rpm...

It might well be that your engine is more efficient at lower rpms and/or sees a smaller mechanical load - and therefore needs less fuel at idle - than the 25cc ones they are talking about.... (what kind of application is that anyway ? 25cc doesn't sound like a regular kind of vehicle to me, and are they talking about two stroke engines here ?...)

[baddi]

The number of cc's of the engine might not be the dominant factor that it seems to be....

The amount of fuel and air needed at idle for any engine will be determined by the amount of power needed to keep that specific engine at it's idle rpm, which will depend on factors like the sum of all friction at all moving parts, external loads like alternator and drive belts, and also very important and very engine-type specific : the efficiency of that engine at that rpm...

It might well be that your engine is more efficient at lower rpms and/or sees a smaller mechanical load - and therefore needs less fuel at idle - than the 25cc ones they are talking about.... (what kind of application is that anyway ? 25cc doesn't sound like a regular kind of vehicle to me, and are they talking about two stroke engines here ?...)

My bad. It's 35cc radio controlled cars and garden tools that are the smallest they've fitted it on. :p

Well, right now, i'm just waiting for the money to do a cylinder-leak-test, since it would give the engine more air, so too rich mixture still would give high rpm. My line of thought could also be that the raise in rpm when the fuel is cut down is that it gets closer to the optimum AFR, but still gets too much, so it gets high rpm. The problem with this is, that it seems imposible to get the fuel mixture right by cutting down on the global fuel enrichment (fuel is always multyplied by that factor, so when it is normally 1, it doesnt make any difference, but around 0,65 it goes from being rich to being lean, without being right at any point).

Yes, the resistance in idle are very low on any engine, but with the throttle closed and the air bypass screw fully screwed, it shouldn't have enough power to keep idle at all


By the way, the last 3 loads of fuel have given me the result of 30 km/l, which is really not much, so the high idle rpm and the rich mixture have really hit the fuel economy... But that will hopefully get much better when i get it all figured out.

[zombie]

Maybe try some different resistors on the Lambada line. If you can lower the voltage it will fool the ecu. I've done that on Marine engines where there was NO EGT sender. I forget the math for figuring voltage/resistance but that's on the web.

[mono]

Now that's a clever hack that someone with my background in electronics can appreciate !!  

[jprestonian]

My Project Electronic Fuel Injection: Plunk down $3700 for a Honda PCX. Done in minutes!  :lol:
.

[mono]

Done in minutes ? I would like to take over your job then for a while, since I certainly wouldn't be able to make $ 3700,- in a few minutes in my line of work...

[baddi]

Maybe try some different resistors on the Lambada line. If you can lower the voltage it will fool the ecu. I've done that on Marine engines where there was NO EGT sender. I forget the math for figuring voltage/resistance but that's on the web.

Then i would loose control of the engine and could as well just remove the O2 sensor, but even without it, the rpm are oscillating.
I want to find and fix the source of the problem, not just fix the symptoms, so fooling the ECU by getting readings from the sensors, that the ECU aren't calibrated with, would be against the whole purpose of this project. 
The purpose of this project is to get a scooter to self-tune by sensors and a computing unit, but if i mess up the sensors, this wouldn't really be possible, and it would read right when the AFR is wrong and wrong when its right.

I accidently broke a piece of plastic that leads fuel again, so now i'm carburated again untill it is fixed. As a coarse fix, i'm making a plastic-glue of acetone and lego to fix the crack, untill i can get a replacement plastic part. If it doesn't work, i will be carburated for 2-3 weeks. :p

My Project Electronic Fuel Injection: Plunk down $3700 for a Honda PCX. Done in minutes!  :lol:
.

Swapping between Fuel injected and carburated takes 20-30 minutes, where the most time consuming part is to dismount the fuel tank and mount the other one.
In complete darkness at 2 in the night, it takes about an hour.