ECU

[Cliff]

Sorry Cliff,  I wasn't trying to suggest any problem with your system running in closed loop.

 

You're alright, I was primary replying to another post.

 

Just starting to get a little annoyed that some one's supposed argument as to whether closed loop works or doesn't, is based on the assumption that what the OEMs produce dictates the state of the art, or the fact that closed loop gets in the way of what a power commander would like to do and must be disabled, therefore its no good.

 

Realistically how many race teams would have the resourses to pursue this to the level of producing custom ECUs. The majority will just use whatever off the shelf components are available and for most that may mean strapping on a power commander because the OEM ECUs give them little other option. You don't need closed loop to produce maximum power, you just need cheap dyno time.

 

That may work better for race conditions where you can dyno the bike every time you rebuild the motor.

 

For me closed loop means

1) my bike runs reasonably well even if the map is off.

2) it can be used to improve the map - as the map improves so does the closed loop

3) adds an extra diagnostic - if I see large corrections I know I should start looking for problems. If its the o2 sensor I can flip a switch and go open loop.

[luhbo]

.... no "race" bike were using closed loop, since that was a picture of a kitted zx. .......

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Interesting enough, they claimed that picture to be taken from the 2004 Kawasaki Moto-GP bike. (not sure, wether this is a correct english sentence now)

 

Emry, please don't get me wrong, this picture was not meant to proof anything. I just found it interesting in this concern. In contrary to you I know from racebikes only from magazines.

 

Regarding jets and needles: I don't think that talking about carb settings would have brought me over the winter like this EFI stuff actually does.

 

Hubert

[Guest crono33]

hi all

i have spotted this thread and i would post some info. i own a cagiva elefant 900ie and i went for the MyP8 ECU from Cliff.

 

i have ported the original IAW maps on the new ECU just working on paper and a excel spredsheet, and the maps were accurate enough to run the bike from switzerland to UK and back for the elefant meeting in UK with no fueling problems whatsoever.

 

i have run the bike in closed loop using a narrow band sensor for some time

 

i am using now a wide band sensor (www.wbo2.com) and it is a completely different world. fueling is from another planet, literally.

 

if you have a chance, run closed loop using a wide band lambda and you will feel a huge difference. narrow band sensors aim at 14.7 air fuel ratio. best power is obtained at 12.5 or so. narrow band sensors are only good to run catalyzers. not for power, or economy.

 

 

and by the way, Cliff's box is an awesome piece of equipment. forget about power commanders and stuff. i can negotiate roundabouts at less than 2000 rpm just using throttle, and duke engines are not known for being smooth. and it will transform a boring motorway ride in an all-fun tuning session :-)

 

 

gm

[JuhaV]

it isn't your Fi keeping your rev limit so low, its your pistons hitting your valves.

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Yes, that is the case as we both know I was only trying to indirectly point out that the road and race conditions are rather different and especially with the 2-valve Guzzis, we are limited well below 8000 rpm which makes it even simpler for the modern electronics to cope with.

 

I am running closed-loop all the way to the red line (set at 8500 rpm) without problems. It is true that the lambda feedback is not perfectly instaneous because of

 

1) the delay in the lambda sensor response to sniff the exhaust, and

2) the ECU's response in acting based on the sensor reading

 

Let's assume now very realistically that for item 1) the delay is 0.2 s and for item 2) the ECU checks the situation 5 times per second. These values are practical even with the existing probes and ECU electronics.

 

What this means that in a fast changing situation (rapid rpm & throttle change upwards after some steady state driving) in the worst case I am running solely based on the base map because the closed-loop system is not able to make any changes to the fuel injection. Then, if the "situation" remains there even for 1-2 seconds, the closed-loop system is able to tune tune the fuel injection towards more appropriate value than what the base map can provide. The tuning steps may be, for example, a few % of the map value and they can be recalculated 5 times per second.

 

What happens then when the throttle is closed ? It will take a similar amount of time for the closed-loop system to tune the fuel injection "back" towards the original map value, or whatever the value should be.

 

If we prevent that the lambda feedback is not allowed to tune the fuel injection to become overly lean (or rich), then according to my understanding in those situations where the closed-loop is not fast enough to act we just kind of "drop" back to using the base map. On the other hand, in normal situations (maybe 99 % of the time) it takes only less than 1 second to adjust the fuel injection to optimum.

 

The only truly limiting factors here are the lambda probe response time and accuracy.

 

JuhaV

[RacerX]

You're alright, I was primary replying to another post.

 

Just starting to get a little annoyed that some one's supposed argument as to whether closed loop works or doesn't,  is based on the assumption that what the OEMs produce dictates the state of the art, or the fact that closed loop gets in the way of what a power commander would like to do and must be disabled, therefore its no good.

 

Realistically how many race teams would have the resourses to pursue this to the level of producing custom ECUs.

 

Cliff, that first part is obviouly directed at me, so... I'll start by saying, again, that I continually commend you on taking on such a task as developing your own ECU, and having even remote success is well worth commendation. Secondly I'll add, that in the arguement of 02-sensor disconnects... this primarily applies to 90% of the general motorcycling public who cannot control a target a/f ratio for the sensor within the OEM ECU. The words posted elsewhere by Michael Belcher/Dynojet are as stands.

That said, my point has, and still lies in the fact that the current technology (and lets face it, budgets) put constraints on purely 02-sensor driven mapping. I'm pretty sure I never implied that it could *never* work. Just that, at right now at this time, it's not most ideal... as some of the points have been made here (like above) already.

 

Also, race teams... I have spent the latter part of the last 12 years competing in, and around road-racing here in the U.S., and can tell you rules mainly regulate what can be used for F.I./ECUs. There are a great deal of F.I. products/ECU's here Stateside (as I'm sure World-wide too) that are very impressive, but still do not recommend pure closed-loop operation... just yet any way. Most of the upper end drag-racing Moto community strictly use aftermarket style ECUs, which incorporate 02-sensors for data-logging their 5-second 100% throttle runs.

 

My $.02 again,

ToddGuzziTech.com

[Guest Pexi]

Hello all, just registered because of this great thread. I've most probably misunderstood at least half of the technical posts , and also got a headache because of them, thank you very much, but as we have hardcore experts here, I have a question (bear with me, I'm a newbie, this is my first post):

 

I'm wondering why nobody is talking about short term / long term fuel trims? Some say that the closed loop mode is considered too slow at high rpm and that it is used only in partial rpm range, but but but, isn't the long term fuel trim always part of the basic injection duration calculation? Meaning that O2 sensor feedback has "value and effect" even in open loop mode?

 

In my book the fuel injection with O2 sensors works like this:

CLOSED LOOP MODE:

1. O2 sensor output is compared to A/F target map. Difference affects immediately -> short term fuel trim (STFT) is adjusted.

2. STFT affects to long term fuel trim (LTFT) -> LTFT is increased/decreased in small steps when STFT gets over the defined limits.

3. (Fuel map + LTFT) = basic injection duration.

4. (basic injection duration + STFT) + (various environmental corrections) = real injection duration.

5. start again in step 1.

 

OPEN LOOP MODE:

1. (Fuel map + LTFT) = basic injection duration.

2. (basic injection duration) + (various environmental corrections) = real injection duration.

3. start again in step 1.

 

If the above is right, then

- modifying ONLY the fuel map in the dyno will have ONLY short term effect. In the long term ECU will try to compensate with LTFT and return the situation back to target A/F map readings. (As long as we have O2 feedback enabled of cource).

- modifying only the A/F target map, will cause big +/- values in LTFT, and will probably set the MIL lamp. But may be totally sufficient if only small changes are wanted (?).

- blocking the O2 sensor and going 100% open loop, then dynoing and modifying the fuel map for best performance/behaviour (either with PCIII or hacking the ECU) will work well in intermediate term, in given conditions. In long term the sensors for various environmental conditions may deteriorate, causing the fueling to drift away from the dynoed optimum. Even changing any sensor for engine temp/intake air temp/voltage may cause non-optimum state.

 

Have I got it right? Have a nice headache you too.

 

Pexi

 

Terribly sorry for the long premier post.

[Cliff]

Welcome Pexi

 

Another thread you may be interested in

 

http://www.v11lemans.com/forums/index.php?showtopic=4028&hl=

 

I'm about to restate roughly what I said then. This thread is one of those arguments where everyone is agreeing with each other but everyone is arguing different points.

 

The main argument seems to be what is a "closed loop controller" or what is a "full closed loop controller". Perhaps the marketing droids have pencilled in some definitions for us. Lets hope they do better than the "1 bit DAC" boast used on audio CD players.

 

So lets get really technical.

 

In a classical engineering sense a closed loop system is quite simple. One can be easily constructed from an OP amp ( operational amplifier ) and a few resistors. Basically the system has an input and produces an output. The output is fed back as an input in a negative sense ( negative feedback). This negative feedback is used to correct the system ( reduce distortion and non linearities ).

 

Closed loop systems can suffer many problems ( reponse times, stability ) that must be engineered out. - applying the correct amount of feedback and dampening. ( Suspension system has these same issues )

 

In the case of an closed loop ECU the input is the A/F ratio or O2 sensor voltage. There would be none of the current inputs of air temp/pressure etc. There would not even be a throttle input or a map or memory. The ECU would correct the injector pulse based purely on the O2 sensor.

 

Such a "full closed loop" ECU would be difficult if not impossible to achieve today and why RacerX is correct in saying that there a no "full closed loop ECUs" out there.

 

However thats not to say an ECU can not make use of the o2 sensor to improve its output. Probably all closed loop ECUs out there are open loop ECUs that can take hints from the o2sensor. Heck the market droids may call it "fuzzy logic". I've never understood that term fully. Is that the logic you use when you don't know what logic to use?

 

So all closed loop ECUs currently are next generation open loop ECUs. They have a map, they adjust it for barometric variables AND they adjust for O2 feedback.

 

Of course the actual implementation is completely different from one ECU to another. How quickly they respond to barometric and O2 inputs, how much correction is allowed whether that information is reapplied to the map ( short term or long ). You DEFINITELY can't take one and assume it is typical of others.

 

I heard of one car where if you drove up a mountain you had to turn off the engine and restart as that was the only time the pressure sensor was sampled.

 

In summary RacerX may be arguing whether a controller is full closed loop or not, whereas I'm arguing whether the use of a gas sensor can improve a bikes performance ( not necessarily its max power). Definitely not the same argument and they should not be confused.

[Guest Pexi]

I read through the other thread you mentioned, thanks for your reply, Cliff!

 

I also visited your My16M site... amazing! Incredible!

[moto]

There's another problem with closed loop systems, and that is the unreliability of using O2 content derived "A/F ratios" in determining whether the correct amount of fuel is being metered in the first place.

 

The idea is that under perfect conditions (i.e. 100% efficiency), there is some amount of oxygen required to burn a known quantity of fuel with a minimum of leftovers. Unfortunately, that efficiency varies quite a bit. There must be some "average" efficiency then that is used to calculate "A/F ratio" from oxygen content. So, we've arrived at the first problem: There is no direct correspondence between oxygen (or any other gas) content and "A/F ratio". Second, the ideal "A/F ratio" varies from engine to engine and from one rpm/throttle position/load combination to another. Third, I'd like to consider what the goal of tuning is in the first place. Is it to get a particular "A/F ratio"? It's more likely that we would like the engine to make horsepower and be efficient (i.e. get good mileage). Looking at oxygen content has limited use when trying to achieve these ends. However, don't get me wrong, oxygen measurements are actually good for something. Once you have tuned for max power by adding and subtracting fuel, the oxygen numbers can help you to detect an ignition timing or stagger issue. If you go straight to a particular oxygen content, you completely ignore these factors. Even once you've corrected these, the oxygen content can still vary substantially. So it can help to point you in the right direction, but isn't the final arbiter of anything. CO on the other hand can, once a proper value has been established through bracketing, be used throughout a map as a target to set the mixture strength close to optimum for power and mileage. CO is also not the final arbiter of anything, but it tells you much, much more about whether an engines map is in the ballpark than O2. You can hit an oxygen target right off the bat while the engine has the completely wrong amount of fuel and/or wrong timing, whereas with CO, fuel will be close, guaranteed. As an example, there are spots on two Futura dyno charts I have, where the O2 content is 0.2%. One has a CO of 12.6% (this is drowning rich!) and the other has a CO of 3.2% (perfect at this particular throttle position/rpm combination). I'm sure you can draw your own conclusions from this example.

 

The problem with CO for closed loop injection is response time, and I'm not sure if it can ever be improved enough to be useful.

[helicopterjim R.I.P.]

This is so exciting. I have been following this thread on the edge of my seat for some time and I have no response that I feel is worthy. I feel like I am in a university engineering class and all I want to do is listen and learn. I just want to add at this time that this is my most fascinating thread (after the MGS-01 when?) and I have been printing out most of the replies because this is the most amazing stuff.

By the way, I am excited that a newcomer like Moto comes along and has such a strong reply. I do not have a personal response but I can't wait to hear what comes next.

Also I have some of Cliff's gear that I am going to try as soon as the weather permits and all the stuff I printed out just gives me more fuel for the fire. I can't wait till I feel qualified to reply to this thread with something constructive!!!!

[dlaing]

Welcome Pexi

 

snip

Closed loop systems can suffer many problems ( reponse times, stability ) that must be engineered out. - applying the correct amount of feedback and dampening. ( Suspension system has these same issues )

 

snip

 

However thats not to say an ECU can not make use of the o2 sensor to improve its output. Probably all closed loop ECUs out there are open loop ECUs that can take hints from the o2sensor. Heck the market droids may call it "fuzzy logic". I've never understood that term fully. Is that the logic you use when you don't know what logic to use?

 

 

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I have heard people say that regarding suspension, it is damping, not dampening, but I am not sure that is correct since dampen is what your shocks do.

Of course if Guido Webster's dictionary says so, it must be true.

 

My understanding of "fuzzy logic" is that the market droids have misinterpreted the technology and misdefined it as electronic logic that makes it better than traditional mechanical or electrical methods.

I believe fuzzy logic's origins are from math, where they try to define a world of varying shades of grey into terms that could be defined in black and white.

When it got moved over to digital electronics, they took 'fuzzy' grey analog data and digitized it into segments. This is why our ECU's maps do not have infinite points.

In computer graphics, this is why we do not see infinite colors, but a grid of a finite number of colors. So, 256 colors was REAL fuzzy, thousands, less so, and millions, you would have to have superhuman powers to detect the fuzz.

Coincidentally in the 60s, those who enforced laws with Black and White logic, were called "the fuzz"

[JuhaV]

I'm wondering why nobody is talking about short term / long term fuel trims? Some say that the closed loop mode is considered too slow at high rpm and that it is used only in partial rpm range, but but but, isn't the long term fuel trim always part of the basic injection duration calculation? Meaning that O2 sensor feedback has "value and effect" even in open loop mode?

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Terve Pexi,

 

You truly have given at least me some headache with your high level starting post

 

Okay, short term and long term trims ? If I interpret your mail correctly I think that you are referring to well developed automotive ECUs (maybe Alfa Romeo ?) that have the capability to "learn" and also to store what they have learned for future purposes.

 

Therefore, in the long term they are able to refine the fuel map that then becomes the "base map" according to my very non-official terminology

 

This base map is then used during a driving situation and short term trim is applied on those base map values based on instaneous lambda probe readings.

 

I do not know for sure, but I would speculate that those ECUs that are nowadays found in production motorcycles are not able to do this kind of long term learning. In other words, when ever you turn of the power, the ECU is left with the original base map. The base map will not evolve automatically over time. You need to "chip", "tune boy", "powercommand" or "cliff" your ECU very actively to change that map.

 

According to my best knowledge, the only gadget that is able to do this is Cliff's Optimiser, which is a separate tuning & display tool connected to a My15/16M ECU.

 

Did this sound anything like what you meant ?

 

br, JuhaV

[luhbo]

... I do not know for sure, but I would speculate that those ECUs that are nowadays found in production motorcycles are not able to do this kind of long term learning. ....

br, JuhaV

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If you want to learn something, you need some fixpoints to compare that what you have done to that what the fixpoints tell you how it should have looked.

 

Fixpoints could be an A/F target map, the sensor could be a wideband probe. Both is standard actually in cars. The wideband probe sold by Techedge is from a VW Pasat or Golf, the japanese sell them and also GM knows how to deal with such stuff. You find them also in Diesel cars. Every modern EFI-equipement is learning nowadays. Why not?

 

Hubert

[luhbo]

.... As an example, there are spots on two Futura dyno charts I have, where the O2 content is 0.2%. One has a CO of 12.6% (this is drowning rich!) and the other has a CO of 3.2% (perfect at this particular throttle position/rpm combination). I'm sure you can draw your own conclusions from this example.

..............

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The conclusion I draw is that there was a fault at least in the exhaust system of one of the Futuras.

What do you think is the reason for this difference? When you have oxygen in the exhaust gas and everything else is ok the engine runs probably rather lean, or what am I missing?

What did the O2 sensor say at these two Futuras, in terms of Lambda or A/F?

 

hUbert

[RacerX]

I apologize if this has been covered to death, but I can't find anything on the search engine. My service manual says that there is a software package to execute the diagnostics on my 2000 Sport's ECU.  Is this accessible?  Is the hardware cable acccessible?  Is the diagnostic useful?

 

Heh, see what you started Brian.

 

ToddGuzziTech.com