ECU

[Admin Jaap]

Hey guys, I started this board to exchange information. and now an inferiority complex rears it's ugly head... Thanks... for nothing.

Great to see such knowledgeable people from around the globe discuss this topic.

[Cliff]

Thanks for the link Carl. Thats the best info I've seen so far. I've actually been thinking about how to add this in the past week. That and a simple gas sensor controlling circuit. The cheapest at the moment seems to be over $250.

 

Closed loop ignition control. Thats going to spark an interesting debate isn't it.

[callison]

Closed loop ignition control. Thats going to spark an interesting debate isn't it.

 

Sure, and while we're at it, let's add more fuel to the fire. This is a truly excellent article by the late Gorden Jennings.

 

How you can read spark plugs and select them

 

I'll bet a beer that the Guzzi, with it's hemispherical combustion chamber, is running too much advance and the wrong heat range on the plug. It may even be a safe statement that the Guzzi engine would benefit most from dual plugging. Or not. It would be REALLY interesting to run a dual plug head with one plug running standard timing and the other plug with varying timing to see what the effect would be. One envisions a Guzzi wandering down the road with multiple coils mounted everywhere, a laptop in the top case, various LCD readouts and a chase vehicle - probably an ambulance Okay Speed Channel, we've got your next hot story...

[Guest Pexi]

Just to clarify, the Futura was tuned to within .1 to .2 hp of best power, not to within 1 hp.

 

Just a side note:

0.1 hp accuracy sounds incredible, allowing all those error sources in the dyno, the environment, the bike and the operator himself! Are you referring to a single dyno run or to an average of several sequential runs? Look, 0.1 hp in a 100 hp bike would mean an error margin/variance of 0.1% - not doable IMHO. But I stand corrected.

[Cliff]

Thats an interesting point. The dyno I used was an eddy current type with attached PC. At the lower RPMs ( probably 2000 was the first one I tried ) it was impossible to determine what the bikes output was, let alone maximise it. The dyno literally showed the power pulses of the twin. It might of smoothed out at higher revs to be usable but adjusting the mixture for a given A/F ( or voltage ) was the only measure I had. I think I'll start a new thread is this one is getting a bit long

[callison]

I think I'll start a new thread is this one is getting a bit long

 

Nah, let's stick with it and turn it into a rope...

[moto]

The basic question is : How do I optimise the ignition timing for a given rpm & load condition ? What shoud I measure ? How is the A/F going to affect my ignition timing and vice versa ?

 

The only very basic adjustment that I have done so far is to back of (retard) the ignition timing in those operation points where I experience pinging.  Is the optimal setting close to the pinging limit ?

 

How about knock sensors ? Do you have any experience on those ?  It would be nice to have both lambda and knock sensor on the bike to give feedback both the the fuel and ignition map adjustments.

 

br, JuhaV

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First, you tune for best power at the chosen throttle position/rpm step. If you then have a situation with a multicylinder engine with a common muffler and no individual EGA takeoffs where changes in pulsewidth common to all cylinders don't do much of anything to HP while the CO content is a somewhat high and O2 content is unusually high, you have a stagger issue. If you have control over it, you then try adding or subtracting pulsewidth on one cylinder at a time (if you don't have control over the map for each cylinder individually, it's worth flow & pattern testing and matching the injectors). If HP goes up, CO goes down, and O2 goes down, you are going in the right direction. If O2 is still high once you don't get anymore gains from adressing stagger, the engine can use more advance. Conversely, if HC looks high, you might have too much. As with pulsewidth tuning, the EGA readings help to point you in the right direction, but the final arbiter should be HP. You can use CO2 to check your work, as it will only look good when the proper pulsewidth and timing exist on all cylinders. I think it's a bad idea to try to tune advance without getting fuel right first.

[moto]

But it would be more fun than sitting in the tuning link dyno waiting room as they lug your baby at WOT at 2500RPM, possibly pinging the engine with their earphones on...

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True, but the results will be just as lacking in usefulness.

[moto]

From the graphs, the fact that O2 is 0 until the stoiciometric ratio implies that it is not going to be a good measure below that point.

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How do you know where the stoiciometric ratio is?

Similarly the fact that CO is not produced above that ratio means it is not a good indicator for lean mixtures.

There is measurable CO produced until well below the point where engines start lean misfiring (somewhere around 1%).

The O2 values you quote is just noise around 0.

Could be, but if anything that just serves to further illustrate my point.

Clearly the wideband sensors are not O2 sensors in the same sense as the narrow band sensors. Their construction and chemistry is completely different. These wideband sensors are used in many commercial and open project gas analysers. They give coverage from 11 to 1 to well over 15 - 1.  If as you suggest these wide band sensors are unusable anywhere rich of stioc, then this fact would be public knowledge. We would hear all over the place of this deficiency.

Please provide some links that say these sensors do not work.

Does that mean that the earth was not round until everyone agreed upon it? In any case, I'm not the only one who thinks that tuning to an O2 sensor voltage is a bad idea. See http://66.47.68.116/dyno/dyno_error.html and http://66.47.68.116/dyno/4gasEGAvso2sensor.html. For a list of tuners that are likely to agree, see http://66.47.68.116/dyno/dyno_locs.html.

I don't know how these sensors work or what these sensors measure. I just know that I can set a target voltage and my ECU will produce a mixture (as measured by injector pulse width) that is stable ( within 1% of a mean). I can reduce that voltage and produce a stable mixture that is leaner.  I can increase that voltage and produce a stable mixture that is richer. I have a monotonic and reproducible relationship between voltage and mixture.

Whether or not the ECU makes accurate and repeatable pulsewidth adjustments based on the O2 sensor voltage is not in dispute, but whether or not these adjustments are appropriate is. You can say that you have a "monotonic and reproducible relationship between voltage and pulsewidth" and I will not argue one bit. But you can't say that you have a "monotonic and reproducible relationship between voltage and mixture" unless you have some way that is independent of O2 sensor voltage to verify that. If it's possible to have CO readings that vary from 1.9% all the way to 11.4% with a 0.4% O2 content, I can certainly see how your ECU would be prone to making infrequent changes confined to within 1% of a mean.

I'm at a loss to imagine how a "real sensor" would differ from this behaviour or what more it would provide me.

I never suggested that there was some other better O2 sensor available that would solve the problem.

How is you tweaking the mixture for peak power any different to me tweaking the voltage for peak power (a voltage for each data point not one voltage for all ).

Again, the same voltage can exist at many different mixture strengths.

 

If you dynoed mid winter, six months later is totally different climate wise. You are assuming that the ECU has perfect compensation curves.

I'm not assuming that, but a modern ECU's compensation will be more valid than what can be expected with an O2 sensor driven closed loop system.

If you are using a power commander, Wayne Mcdonald has already explained how its calculation is going to be in slight error.

I'm definitely a believer in native tuning and avoid the use of PCs whenever possible.

Add to that a service were you adjust tappets, balance throttle bodies and adjust TPS. You've pretty much invalidated that dyno session. Unless you're proposing another dyno session.

You would adjust tappets & TPS and balance throttle bodies prior to tuning. Subsequent service would serve to get the engine to once again run optimally with the existing map, not cause it to run worse.

How can I have all those features I mentioned? Because I can specify that any part of my map have any target voltage.

Again, if so many different mixture strengths can exist for a given O2 sensor voltage, what good is it?

I can make my 25% to 50% throttle region track lean.

Again, how do you know how lean it really is and how lean is appropriate?

I can make my 75%+ throttle rich.

Why would you want to do that? Won't you loose power? How do you know how rich you've made it?

I can even go open loop at any point if I want to.

Now that sounds like a plan!

 

As I have mentioned before there is not one type of closed loop controller. As far I know they are all based on an open loop controller and hence have a map that should be adjusted to suit the bike. The gas sensor only gives further hints. Now tts quite possible that you have experience with OEM ECUs that are closed loop. It also would not surprise me to hear that that don't work very well.

The fact that closed loop ECUs use O2 sensors is the problem, not how they do it.

I however have built my own ECU, if you haven't already picked that up, that has optional closed loop behaviour and it does everything I expect it to do and nothing I don't. Not anymore 

What are your expectations of an ECU?

[moto]

Just a side note:

0.1 hp accuracy sounds incredible, allowing all those error sources in the dyno, the environment, the bike and the operator himself! Are you referring to a single dyno run or to an average of several sequential runs? Look, 0.1 hp in a 100 hp bike would mean an error margin/variance of 0.1%  - not doable IMHO. But I stand corrected.

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On the Futura I was able to make minor repeatable changes in mixture that produced in the range of ±.1 to ±.2 hp. That's as good as it gets. My dyno will simply not repeat any better than that. Of course this tuning was done in real time. I think if I had to shut down, make changes to the map, reload and then re-test, the repeatability would not be as good.

[moto]

Thats an interesting point. The dyno I used was an eddy current type with attached PC. At the lower RPMs ( probably 2000 was the first one I tried ) it was impossible to determine what the bikes output was, let alone maximise it. The dyno literally showed the power pulses of the twin. It might of smoothed out at higher revs to be usable but adjusting the mixture for a given A/F ( or voltage ) was the only measure I had. I

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My dyno will measure hp and record EGA data at any throttle position/rpm combination the engine will run reasonable well at. I could see there being a problem at very low RPM and large throttle openings. Still, I was able to tune the Futura (for example) down to 1900 rpm at full throttle. What kind of dyno where you using?

[Cliff]

Does that mean that the earth was not round until everyone agreed upon it? In any case, I'm not the only one who thinks that tuning to an O2 sensor voltage is a bad idea. See http://66.47.68.116/dyno/dyno_error.html and http://66.47.68.116/dyno/4gasEGAvso2sensor.html. For a list of tuners that are likely to agree, see http://66.47.68.116/dyno/dyno_locs.html.

 

Thanks, that was very interesting even if it was written by people pushing 4 gas analysers. I'll certainly keep that in the back of my head and be on the lookout for any anomalies.

 

Are there any cheap and simple CO sensors that can be mounted on a bike instead of an O2 sensor?

 

Whether or not the ECU makes accurate and repeatable pulsewidth adjustments based on the O2 sensor voltage is not in dispute, but whether or not these adjustments are appropriate is. You can say that you have a "monotonic and reproducible relationship between voltage and pulsewidth" and I will not argue one bit. But you can't say that you have a "monotonic and reproducible relationship between voltage and mixture" unless you have some way that is independent of O2 sensor voltage to verify that.

 

Do we have monotonic and reproducible relationship between pulsewidth and mixture? If we do then what I said is correct.

 

I think what you are saying here is that the relationship between mixture and voltage may vary at different datapoints and what I'm saying it will still be monotonic and reproducible.

 

So if I wanted to get maximum performance I would need to determine a voltage level for each data point.

 

If it's possible to have CO readings that vary from 1.9% all the way to 11.4% with a 0.4% O2 content, I can certainly see how your ECU would be prone to making infrequent changes confined to within 1% of a mean. I never suggested that there was some other better O2 sensor available that would solve the problem. Again, the same voltage can exist at many different mixture strengths.

 

Here you are definitely mistaken. Any closed loop system will drift aimlessly with incorrect feedback. If the o2 sensor was not giving me a signal that was related to mixture, my ECU would not produce a stable output.

[moto]

Thanks, that was very interesting even if it was written by people pushing 4 gas analysers.

Even ignoring what was written there, one only needs to look at the charts provided to come to one's own conclusions.

I'll certainly keep that in the back of my head and be on the lookout for any anomalies.

Excellent! If you spend enough time with a dyno, with either an analyzer or a wideband O2 sensor, you will find them.

Are there any cheap and simple CO sensors that can be mounted on a bike instead of an O2 sensor?

You may be able to mount a CO meter of some kind on a bike, but it will not end up being very useful, as you need a certain amount of time at a given throttle position/rpm for CO to stabilize.

Do we have monotonic and reproducible relationship between pulsewidth and mixture? If we do then what I said is correct. I think what you are saying here is that the relationship between mixture and voltage may vary at different datapoints and what I'm saying it will still be monotonic and reproducible.

What you are once again missing is that you can have mixture strengths that vary drastically at the one and the same O2 sensor output voltage, and corrections to the map won't happen until the voltage actually changes.

So if I wanted to get maximum performance I would need to determine a voltage level for each data point.

That would definitely be a step in the right direction, but will still not solve the problem.

Here you are definitely mistaken. Any closed loop system will drift aimlessly with incorrect feedback. If the o2 sensor was not giving me a signal that was related to mixture, my ECU would not produce a stable output.

You said that your ECU was making only minor changes and that they are directly related to O2 sensor voltage. I'm assuming that this is what you mean by saying that the ECU is producing a stable output. Once again, none of that is in dispute. But say that you determine what output voltages should be present at a particular throttle position/rpm. You then let the ECU look for that voltage at that throttle position/rpm while operating the motorcycle. As soon as that target voltage is reached, the ECU will make no further adjustments there until the voltage changes again. It will be just as you say, "stable". The problem is that the ECU can recieve that voltage at a myriad of mixture strengths (not pulsewidths, which as you say are directly related to sensor voltage). Say the target O2 content as established on a dyno is .4% (I don't know what that is in voltage)with a CO of say 3.2%, and the O2 content is currently .5% which is leaner and the threshold for getting to .4% O2 from the lean end is at 1.9% CO, the ECU will stop adjusting when it gets there. Or, lets say we currently have an O2 content of .3% and the threshold for getting to .4% from the rich end is at 11.4% CO, the ECU will once again stop adjusting once it gets there. It will not adjust again until it recieves some other voltage. Will the pulsewidth be related to voltage? Yes. Will the ECU appear "stable"? Yes. Will we have the mixture we wanted? Not likely.

 

That you on one hand argue for the use of closed loop systems on the basis that pulsewidth and mixture (or how an engine runs) do not always correlate and therefore need correction, then on the other hand defend the use of O2 sensors by saying that pulsewidth and mixture (or how an engine runs) are 100% correlated is a bit contradictory.

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[moto]

And some of us may interested in using your dyno services!

Especially if you are open to TuneBoy, TechnoResearch's Direct Link and or DynoJet's PCIII, and  can get anywhere near Tuning Link prices, which start at about $200 for a full map, but higher prices are apparently more typical.

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You can't expect much for $200, no matter who the tuner is or what they might claim, unless they are for some reason willing to work for pennies on the dollar...

[Guest Pexi]

I have to admit that I'm replying to this thread partly because I'm a bit drunk and in that state I know everything better than anyone else . Forgive me.

 

I'm not the only one who thinks that tuning to an O2 sensor voltage is a bad idea. See <a

href='http://66.47.68.116/dyno/dyno_error.html' target='_blank'>http://66.47.68.116/dyno/dyno_error.html

</a> and

http://66.47.68.116/dyno/4gasEGAvso2sensor.html. For a list of tuners that are likely to agree, see http://66.47.68.116/dyno/dyno_locs.html.

 

I made an error and had a look on these links. For an unknown reason the author seems to have a lot of aggression and he either does not know what he is talking about or he wants to mislead readers into the direction that is suitable for his personal commercial mission. Most probably both. Another odd thing is that he doesn't have a decent domain name, but is hiding behind an anonymoys IP address.

 

To keep my reply reasonably short, I'll only argue about the one most annoying text:

 

To properly compare power between different CALIBRATED dynos, all hp must be corrected to "standard air" temps, pressures and humidities..

 

There are a few different "correction factors" and a common one is similar to aviation "standard air" i.e. 0% humidity, 59f/15c and 29.92 in barometer. In the US, we generally use "SAE" correction factors and in Europe... they use DIN correction factors.

 

This chart was given to a customer after the shop worked on the bike and whatever they did - didn't make more power.... So...... they printed out an "uncorrected" chart that the dyno company calls "STD" for some reason. One might assume that STD would be STD corrected"... but... it's not..... If you added in the proper correction  factors, the bike made 3-4 hp less "corrected" to SAE correction factors and they didn't want to show that to the poor customer - They should have figured out what happened and caused the loss in power and fixed it......

 

All magazine tests that I've ever seen and all technical work is "Corrected".

"Corrected" is a nice marketing word. If you know what is behind these SAE/DIN "corrections", you know that it should actually be read as "approximated". Those are nothing more than simple mathematical formulas, which give a theoretical coeffient that is used to approximate the real measured power/torque figures. The idea being that using e.g. SAE correction/approximation you can compare dyno results taken at the 20°C to the result at 40°C environment. Of course, in real life you can't. A dynamometer might be a good device, but it only produces approximate results. Any results shown by a dyno are approximates, they are results of calculations based on inaccurate measurents, averaged and smoothed out as the programmer has wanted.

 

Then, if and when you add a SAE "correction", you have even more inaccurate figure, which has pretty much nothing to do with reality. To claim that SAE or DIN approximated figures are more correct than the real measured figures is utter bullshit. An honest dyno operator should tell you (but he probably won't) that "today, in the current conditions my dyno measured this result. The results will be different if we repeat the session tomorrow."

 

(I have no commercial missions which are related to motorcycles. These are my real and honest opinions. Thanks for reading.)