O2 sensor display, w/video

[budgetzagato]

Here's a video of the O2 sensor display I have in my Betone (click on image to jump to the video):

Not rehearsed so I ramble a bit. And I occasionally use "meter" when I mean "sensor", sorry for the confusion.


And some pics of the display, it's very simple and small. This is mounted in a VW switch blank for my Vanagon:

 

[jvandyke]

That's cool.

 

[tfphoenix]

Man that is cool. Thx for makin a vid. BTW is it really pronounced Ber-tony?

 

[ArtBasement]

Awesome vid, and some questions...

Awesome video. Must be entrancing to see the show while you drive. I assume your O2 sensor is not heated and you have a stock exhaust?

Question: why does it fluctuate at idle? I was always told by the FI gurus that the fuel mixture is strictly mapped at idle and does not respond to O2 sensor input. Well here is proof to the opposite. It must be fluctuating because it is in closed loop operation. What purpose does the capped air bypass screw then serve? My O2 sensor read-out does the same btw. It's cool to see it completely go blank on the over run when fuel is shut off.

I love your idea of using the old clock housing. At first I thought you'd found a way have the display and still use it as a clock. Maybe a challenge for Bob Brown, to use the clock to show battery voltage or something like that.

 

[Black-Tooth]

Not in my neck o' the woods...

It's Ber - tone... Ber-Tony must be a "term of endearment" of Greg's...

HA!

 

[Pete Whitstone]

I always wondered about this myself...

It's Ber - tone... Ber-Tony must be a "term of endearment" of Greg's...

HA!

I don't think there are silent letters in Italian (but I might be wrong). So I have always thought that it was Ber TONE uh, rather than BER Tone or Ber TONE ee. Anybody from Italy on the forum?

Pete

 

[Greg (in Conn)]

Bear-tone-ee or bear-tawny

there was a Youtube with Nuccio sister doing an interview...only word I could understand her saying :nod:

 

[Brad Garska]

Generally pronounced Ber-Tone-eh but I most often I hear Ber-tone-e But it seems everyone has their own pronunciation like Ber-tone.

 

[Greg (in Conn)]

Here ya go !!!

Here is one with Nuccio's wife Lilli... 9 secs in :italia:

[ame="http://www.youtube.com/watch?v=0p8EW1A8yFo&feature=related"]YouTube- World Premiere Bertone PANDION Geneva Motor Show 2010[/ame]

 

[bbrown]

Not a challenge...

Maybe a challenge for Bob Brown, to use the clock to show battery voltage or something like that.

Unless it actually requires time. (something I'm running short on these days!)

Greg, that's a great demonstration.
Can you give me the source (specifically) of where you got that meter?
I saw the video but haven't looked up the source.

Pretty clever sticking it in the clock face.
Yes, the clock face can also be converted to show voltage too, but that would be a project.
I haven't planned on. Maybe down the road a piece. (like a long way down the road a piece. Ha!)
The Clock face uses a multiplex display generator (1 digit on at a time, but fast scanning) that can easily be adapted to if someone wants a digital project to build.

But Greg gutted the clock for this project.

Greg's O-2 indicator looks real interesting. Might want to play with that too. :excited:

 

[Robert Mose]

Looks like a simple circuit to me.

 

[Black-Tooth]

My father was Full Blooded Italian (FBI) and...

... he pronounced FIAT as Fee-ah-ta...

Silent letters in Italian... try Bologna...

I think, as the video showed... the "eh" sound for the trailing "e" that is usually assumed to soften the "n" is probably the "most" correct pronunciation.

 

[budgetzagato]

Thanks! And about the signal...

About the singal... The O2 sensor signal looks like that pretty much all the time, but the ECU only uses the signal above idle. This is what I was trying to show; the fluctuating voltage is generated by the special metals in the O2 sensor and is independent of the ECU. The ECU simply uses this information to get an idea of where the mixture is in relation to "lambda" or 14.7:1. So, the O2 sensor voltage and/or display are showing the output of the sensor, not a product of the ECU. This is why it looks like this even at idle.

Unless you have a heated sensor, the sensor is too cold at idle to be accurate. If you use the sensor to adjust idle mixture, you have to rev it to 3K for a minute or so to get the sensor hot enough to give an accurate reading, and it cools off quickly.

The system is open loop at idle, ignoring the O2 sensor, and closed loop above idle. This is why I think making changes to the AFM is folly. Once you are above idle the ECU will adjust the mixture back to lambda using the signal from the O2 sensor.

 

[lookforjoe]

The system is open loop at idle, ignoring the O2 sensor, and closed loop above idle. This is why I think making changes to the AFM is folly. Once you are above idle the ECU will adjust the mixture back to lambda using the signal from the O2 sensor.

I'll take this under advisement when I do my cam/head work.

I'll try using the built it adjustment first.

 

[Pete Whitstone]

Does anybody have definitive data...

This is why I think making changes to the AFM is folly. Once you are above idle the ECU will adjust the mixture back to lambda using the signal from the O2 sensor.

on just how far the o2 sensor/ECU can correct the mixture?

If it has a range of correction of, say, 50%, then I agree, you should not have to mess with anything else, no matter what breathing improvements you make to the engine. But I think it's more realistic to assume that it has a much smaller range, let's say for the sake of this discussion that it's 8%.

If you modify the engine (port intake, port head, add exhaust header and free-flow exhaust), and your modifications yield a 15% peak airflow improvement, then you will need a corresponding 15% fuel adjustment. But if the stock o2 sensor/ECU are only capable of an 8% adjustment, then wouldn't you be forced to "fool" the ECU with air flow meter adjustments to get the rough mixture back within the 8% that the ECU can perform fine adjustments to?

I don't have a good answer for this, I'm just posing the question.

Pete

 

[Dan Sarandrea (Phila)]

Wow!

This youtube has a much much better view of the, er, um, eh, oh yeah the car!

[ame="http://www.youtube.com/watch?v=A-sbHUD9abo&NR=1"]YouTube- Bertone Pandion[/ame]

 

[ArtBasement]

Doesn't make sense to me

The O2 sensor signal looks like that pretty much all the time, but the ECU only uses the signal above idle. This is what I was trying to show; the fluctuating voltage is generated by the special metals in the O2 sensor and is independent of the ECU.

I don't think that's true. When I have the same sensor and same meter hooked up to a carbed engine, it doesn't fluctuate at all. The fluctuation happens because the ECU is adjusting the mixture based on the input from the O2 sensor.

The ECU simply uses this information to get an idea of where the mixture is in relation to "lambda" or 14.7:1. So, the O2 sensor voltage and/or display are showing the output of the sensor, not a product of the ECU. This is why it looks like this even at idle.
The system is open loop at idle, ignoring the O2 sensor, and closed loop above idle.

You don't have me convinced. I do believe the system goes open loop when idle is prolonged and the sensor gets too cold. That's why I installed a heated sensor. Just my 2¢.

 

[budgetzagato]

It doesn't matter...

IF you are using the ECU, AFM and O2 sensor. If you tweak the AFM flap tension, you're just moving the linear fuel "map" a little bit, and the ECU will adjust it with the O2 sensor input.

You're wondering what the effective adjustment ability of the ECU is, a good question. But if you're using the O2 sensor it doesn't matter, either you're using the O2 sensor to adjust the mixture (and it will automatically adjust it to stoichiometric or Lambda), or not. If you unplug the sensor, then you can tweak with actual effect. The only drawback is the linear output of the AFM, a richer mix at low RPM will also be richer at high rpm or vice-versa.

I haven't been able to find a specific number that describes the range that the system covers. Up to 2% CO% is mentioned as an example in once source I have, but not given as a range within which the system can correct. Using the O2 you want an open-loop setting of about .5% CO or about 500mV as measured on a VOM, so the effective range is relatively small.

For max power, the real problem is the limited injector pulse time, at WOT the injectors are basically open full time. Also, the AFM is basically wide open above 4K rpm, and above that the mixture is affected by injector pulse.

Keep in mind the system is designed to balance emissions and power, and to protect the catalytic converter. Modifications for power will affect emissions and the difference between the system's balance of power and emissions and max power is minimal. If you want to run without the O2 sensor and go for max power, remember that your CAT may fail, further increasing emissions.

 

[Pete Whitstone]

I agree to a point...

With these two statements:

You're wondering what the effective adjustment ability of the ECU is, a good question. But if you're using the O2 sensor it doesn't matter, either you're using the O2 sensor to adjust the mixture (and it will automatically adjust it to Lambda), or not. If you want to just unplug the sensor, then you can tweak with actual effect. The only drawback is the linear output of the AFM, a richer mix at low RPM will also be richer at high rpm..

But you still seem to be making the assumption that either the o2 sensor/ECU correction operates in a very wide range (which I don't think it does). I believe it is fairly easy to modify an engine to put it outside the range of the correction available. For a stock engine, what you are saying is true, certainly.

For max power, the real problem is the limited injector pulse time, at WOT the injectors are basically open.

Easily overcome with an adjustable FPR. Within reason, of course.

Pete

 

[budgetzagato]

(new vid) If you stop learning you're dead...

Erwin, thanks for getting me to experiment. I wanted to verify how things worked, so I did some sleuthing (another video):



And I'm not convinced the ECU ignores the O2 sensor at idle. When I was making this video, an audible difference was evident when the sensor is unplugged; the idle speeds up slightly. Perhaps the TPS is only used on overrun, to turn the fuel off at closed throttle over 2K rpm.

Other versions use the TPS to disconnect the O2 signal from the ECU at idle.

Where's John Allen when you need him? He know this stuff inside and out. :confuse2: