| Author |
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Turk
| | Posted on Sunday, September 21, 2008 - 07:29 pm: | 
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I happen to adamantly disagree with Mr. Wade's assessment of the limited scope of the sensor. The sensor does in fact just keep the engine running at stoic but in doing so it also provides information as to what is necessary to keep it there. As an example, ever notice how a bike will run differently hot vs. cold? A simple cell value that doesn't react will always be a compromise and that bike will not run as smooth throughout a temperature range as one with the benefit of an O2 sensor to help account for those types of conditions.
I will agree however that the range of the sensor is very limited and the reason is that it does not measure AFR, only rich or lean which I precisely why I have tried to warn some people about trying to tune based on one and why getting a good map based on that alone is akin to waiting for the all the monkeys with the typewriters to finish Shakespeare. |
Id073897
| | Posted on Monday, September 22, 2008 - 03:16 am: |
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Not according to Adam Wade. On page 61, in his Motorcycle Fuel Injection Handbook he flatly states that a narrowband o2 sensor's only purpose is to keep closed loop AFR at 14.7:1 for emissions purposes. It does nothing in helping the bike run smooth.
I haven't read the book, but the statement as quoted previously contains a logical error: if the ECM doesn't pay attention to the O2 sensor, why does running the engine in CL improve emissions?
As said many times before: running CL leads to a given AFR IN AVERAGE. This is a statistical and algorithmical, not a technical question. By modifying the control system the average could be changed (in it's limits of course) also.
Regards,
Gunter |
Swordsman
| | Posted on Monday, September 22, 2008 - 09:38 am: |
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You guys are talkin' WAY over my head, but using just a bit of common sense, I'd have to agree that, if the map is set right, disabling the O2 or locking the AFV isn't going to destroy the engine (as it's been hinted). If it was, every non-fuel injected vehicle out there would have grenaded already, since they also lack the ability to adjust to the environment. Again, that's assuming your map is correct in the first place.
~SM |
Turk
| | Posted on Monday, September 22, 2008 - 11:09 am: |
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Locking the AFV and/or turning off the O2 sensor will not necessarily destroy the engine, but it certainly will not run optimally (or even well in some cases) but it is possible depending on the conditions you tuned in and the conditions that may follow some time in the future. That said, tuning a fuel map based on just a narrow band O2 sensor will certainly result in a map that is too lean in many areas and that can very easily destroy an engine.
Again, they're your own bikes... |
Mmcn49
| | Posted on Monday, September 22, 2008 - 01:45 pm: |
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I happen to adamantly disagree with Mr. Wade's assessment of the limited scope of the sensor. The sensor does in fact just keep the engine running at stoic but in doing so it also provides information as to what is necessary to keep it there. As an example, ever notice how a bike will run differently hot vs. cold? A simple cell value that doesn't react will always be a compromise and that bike will not run as smooth throughout a temperature range as one with the benefit of an O2 sensor to help account for those types of conditions.
} Prior to making these changes, my Buell always seemed to run better for the first couple of minutes after startup. My guess is that cold start enrichment overrides CL and the o2 sensor for the first few minutes.
When the bike warmed up in never ran smooth with the stock maps.
Not according to Adam Wade. On page 61, in his Motorcycle Fuel Injection Handbook he flatly states that a narrowband o2 sensor's only purpose is to keep closed loop AFR at 14.7:1 for emissions purposes. It does nothing in helping the bike run smooth.
I haven't read the book, but the statement as quoted previously contains a logical error: if the ECM doesn't pay attention to the O2 sensor, why does running the engine in CL improve emissions?
The final paragraph under Narrow Band o2 Sensors says:
So in short, narrow band o2 sensors are only useful where there is a requirement to reduce emissions through a catalytic converter, and then only when the engine running conditions, (load and RPM) are close to constant. The vast majority of the time o2 sensor equipped bikes are not paying any attention to the o2 sensor. They are installed for the same reasons as catalytic converters-to cut down on emissions to meet government regulations. Narrow band 02 sensors have no other real use.
I've said throughout this thread that the o2 sensors purpose is to maintain 14.7 in CL. Maintaining 14.7 minimizes HC emissions.} |
Mmcn49
| | Posted on Monday, September 22, 2008 - 02:49 pm: |
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Hi Turk
I guess my bike is the exception that proves the rule.
You’re right saying that data logging with a wideband o2 is the way to go. What is the make and model number of the WB you used when data logging and where did you purchase it? |
Turk
| | Posted on Monday, September 22, 2008 - 10:15 pm: |
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So in short, narrow band o2 sensors are only useful where there is a requirement to reduce emissions through a catalytic converter,Oh? Then why do so many bikes without converters have O2 sensors? and then only when the engine running conditions, (load and RPM) are close to constant. The vast majority of the time o2 sensor equipped bikes are not paying any attention to the o2 sensor. Of course the "vast majority" of the time, most vehicles operate at relatively constant load and RPM with an exception of race vehicles They are installed for the same reasons as catalytic converters-to cut down on emissions to meet government regulations. Except that most if not all O2 sensor equipped vehicles (Buells included) run in closed loop utilizing the O2 sensor well outside of the range that is emissions controlled Narrow band 02 sensors have no other real use. Except things like aiding in temperature compensation, air pressure differences and engine protection, just to name a few.
Maintaining 14.7 minimizes HC emissions. It's way more involved than that.
As for sensors, most of our sensors are Bosch LSU 4.2 and we have a couple of sets of 4.9s. I get them from the shelf in the shop. |
Turk
| | Posted on Monday, September 22, 2008 - 11:07 pm: |
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If it was, every non-fuel injected vehicle out there would have grenaded already, since they also lack the ability to adjust to the environment.
No, carbed vehicles are jetted with margin to account for the lack of adaptation. Chokes or enricheners compensated for cold starting and idle adjustment screws were often readily available to the operator and were frequently adjusted to compensate for different conditions. Even with those knobs to turn, if you took carbed bikes through significant altitude changes, they ran poorly somewhere along the way or they were jetted for a decent compromise and were never optimum anywhere. |
Turk
| | Posted on Monday, September 22, 2008 - 11:14 pm: |
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I guess my bike is the exception that proves the rule.
If it were me, I'd look elsewhere to see why it runs rough, not disabling the O2 sensor. Overall, you will end up with a better running motorcycle. Just my opinion, take it as you wish.
I'll say this, good for you for doing some research (and it seems that you have beyond the internet which is great) and trying to find a solution. I happen to disagree with some of your findings and much of Wade's take on things, but that's me. I could debate this stuff all day, it's actually kind of fun and interesting. |
Id073897
| | Posted on Tuesday, September 23, 2008 - 02:17 am: |
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No, carbed vehicles are jetted with margin to account for the lack of adaptation.
And, additionally, they do adapt. Example: lots of FI fuel pressure regulators are spring loaded, so a constant absolute pressure is reached. Fuel pressure relative to air pressure is therefore changing with air pressure. Using a carb, the same air pressure applies for the float chamber and the venturi stack, and thus "adjusts" the amount of fuel delivered (within limits, of course, but sufficiently for climatic air pressure changes).
The FI system will deliver more fuel when air pressure is dropping, which is exactly the one thing, that should not happen. This is usually adjusted by monitoring a pressure sensor, but in lack of such, the DDFI monitors exhaust O2.
Regards,
Gunter |
Mmcn49
| | Posted on Tuesday, September 23, 2008 - 01:00 pm: |
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WB o2 sensors have to be used with a controller. Does anyone know if the Buell’s ECM will accept a signal from the WB controller’s 0-5V analog output wire?
If so, can the wire on the Buell’s NB o2 sensor be removed and connected to the controller’s wire?
If not will the NB sensors pin have to be pulled on the ECM connector and the WB analog output wire connected there?
Will the data log section of ECM spy operate with a WB sensor? |
Id073897
| | Posted on Tuesday, September 23, 2008 - 02:28 pm: |
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Yes.
Yes.
Yes.
Yes.
Provided a correct configuration of WB controller and ECM. See www.msefi.com and www.megamanual.com
Regards,
Gunter |
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