02 wideband sensor
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leftyretro
New Member
And wouldn't you also need a air mass flow meter before you had the variables need to makes a ratio measurement?
Lefty
Lefty
No, you don't need a MAF.
The narrowband 02 sensor generates it's own voltage and the signal is on a single wire. Reading it with the ADC is easy but the question is what does the voltage mean?
The wideband may, as Jaguarjoe said, require some conditioning but I am not sure if that is built in to the unit or separate.
The narrowband 02 sensor generates it's own voltage and the signal is on a single wire. Reading it with the ADC is easy but the question is what does the voltage mean?
The wideband may, as Jaguarjoe said, require some conditioning but I am not sure if that is built in to the unit or separate.
This article explains how the different sensors work and more importantly what the controller for the WBO2 sensor must be able to do:
http://www.wbo2.com/lsu/lsuworks.htm
http://www.wbo2.com/lsu/lsuworks.htm
I have read most of that info but that is an excellent site.This article explains how the different sensors work and more importantly what the controller for the WBO2 sensor must be able to do:
http://www.wbo2.com/lsu/lsuworks.htm
I was looking at the Bosch Bosch LSU4.2 5-wire, wide-band O2 sensor. But again, I don't see a way to correlate the output from the sensor into an AFR. I was hoping to find an equation or a chart.
I also see there are some gauges on the market that use the standard narrowband sensor but I am skeptical as there must be quite a variation in the actual 02 sensors.
Here is one circuit for a WBO2 controller:
http://www.megamanual.com/PWC/
Scroll down on the left side to near the bottom and you'll see the link to the circuit.
http://www.megamanual.com/PWC/
Scroll down on the left side to near the bottom and you'll see the link to the circuit.
harolds1956
New Member
Don't bother with the narrow band sensors. They, in practice, only tell the vechicle computer if the mixture is lean or rich. If you tap into your vechicles computer and everything is functioning properly the o2 sensor waveform looks somewhat like a sinewave centered @.45 volts. .45 volts being 14.7 AF ratio. However this is only in "closed loop" mode. IE cruising down the highway. The wide band will tell you not only if you are @14.7 af ratio when cruising, but more importantly what your af ratio is under acceleration. Under this situation, the vechicle computer then ignores the o2 signal and goes to pre-programed "maps" to set the injector pulse widths. THIS is where the wideband shines and gives the hotrodder/tuner the information to modify the af ratio and make more power.
I know that and the reason I want to make a meter ... so the original question was how to interpolate that voltage into a air/fuel ratio?Don't bother with the narrow band sensors. They, in practice, only tell the vechicle computer if the mixture is lean or rich. If you tap into your vechicles computer and everything is functioning properly the o2 sensor waveform looks somewhat like a sinewave centered @.45 volts. .45 volts being 14.7 AF ratio. However this is only in "closed loop" mode. IE cruising down the highway. The wide band will tell you not only if you are @14.7 af ratio when cruising, but more importantly what your af ratio is under acceleration. Under this situation, the vechicle computer then ignores the o2 signal and goes to pre-programed "maps" to set the injector pulse widths. THIS is where the wideband shines and gives the hotrodder/tuner the information to modify the af ratio and make more power.
harolds1956
New Member
I use the Innovate LC-1 which connects to the bosch wide band sensor and interfaces via software to your computer. You can program the interface to read the sensor and output 2 separate voltage ranges of your choosing. I strap a cheap DVM on my dragbike and read af ratio directly on the 2 volt scale. Example 1.20 volts is 12-1, 14.7 volts is 14.7-1 etc. It self calibrates, data logs and does much more. Check out their website @www.innovatemotorsports.com.
A WBO2 sensor by itself provides no readily useable information. There is no way to interpolate anything with it by itself. It must have the controller circuitry to get a useful AFR signal.... so the original question was how to interpolate that voltage into a air/fuel ratio?
leftyretro
New Member
That was what I was trying to allude to in my earlier post. It seems to me to have a AFR reading one needs access to both O2 level and air flow measurement, so I thought the O2 sensor by it's self would be of little value, wide band or not. A ratio reading implies knowing two quantities, no?A WBO2 sensor by itself provides no readily useable information. There is no way to interpolate anything with it by itself. It must have the controller circuitry to get a useful AFR signal.
Lefty
You mean 1.47 volts for 14.7:1 right? It would take a bit of work to get 14.7 volts from a 12 volt system.Example 1.20 volts is 12-1, 14.7 volts is 14.7-1 etc.
harolds1956
New Member
Yes, 1.47 volts = 14.7 afr when programmed that way. To measure afr one only needs the wideband sensor and associated circuit. The MAP sensor (along with other sensors) gives the engine computer information to determine ignition advance and injector pulse width.
I also have the LM-1 but what you are talking about is the analogue output from that meter ... not from the 02 sensor. It provides a linear output from 0-2 volts.Yes, 1.47 volts = 14.7 afr when programmed that way. To measure afr one only needs the wideband sensor and associated circuit. The MAP sensor (along with other sensors) gives the engine computer information to determine ignition advance and injector pulse width.
So, again what I am trying to do is find the correlation between the 02 output and the actual AFR. Then display that number. However, after reading the link from JaguarJoe I now see there is much more to this than meets the eye. I was hoping for something simple ... lol.
Excelent link ... thanks