Narrowband O2 sensors vs. Wideband

[Dave at Pelican Parts]

A few months ago, we had a discussion about the wideband versus narrowband O2 sensors, and how they might be useful for tuning.

In the most recent issue of Grassroots Motorsports magazine, they have an excellent article addressing that very subject. They have a comparision of readings from both types of sensor/gauge (both sensors were in the exhaust at the same time) which is quite enlightening about the narrowband sensor, and they mention in the text of the article about how the readings from the NB sensor varied significantly when the mixture was essentially unchanged...

--DD
(Who really needs to get that WBO2 set up on his car!!)

[lapuwali]

Both are very temperature sensitive, and my guess on how the wide-band units work is they're a normal O2 sensor cell with a precision heater and temperature sensor operating in a feedback loop. If you know precisely both the temp and the O2 sensor voltage, you can know the mixture over a much broader range. If you deliberately vary the temperture, too, you can operate the sensor over a wide range of values.

As for needing one, just get ahold of Mueller and put in your share.

[phantom914]

Originally posted by lapuwali
Both are very temperature sensitive, and my guess on how the wide-band units work is they're a normal O2 sensor cell with a precision heater and temperature sensor operating in a feedback loop. If you know precisely both the temp and the O2 sensor voltage, you can know the mixture over a much broader range. If you deliberately vary the temperture, too, you can operate the sensor over a wide range of values.

As for needing one, just get ahold of Mueller and put in your share.

They don't quite work that way. NB sensors are temperature sensitive outside the switch point, which occurs at the stoichiometric A/F ratio. The voltage output of an NB sensor varies with temperature with A/F ratios that are richer or leaner than stoichiometric , but the voltage output at stoichiometric is not very sensitive to temperature. The WB sensor has a NB sensor as well as a catalyst cell that can either consume oxygen if current is pumped through it in one direction or consume unburned hydrocarbons by supplying current in the other direction. A feedback circuit pumps current into the catalyst cell until the NB sensor reads stoichiometric. The polarity and the magnitude of the current signify the A/F ratio.

Andrew

[Dave at Pelican Parts]

Originally posted by lapuwali
As for needing one, just get ahold of Mueller and put in your share.

I've already got one, actually. A buddy of mine wired up a setup for me a few years ago that is akin to the DIY-WB, even including a gauge! I need to route the wires and such, and mount the sucka on my car.

--DD