R1200GS Dual O2 Sensor Questions

[Roger 04 RT]

There were a couple unanswered questions in the recently closed Hilltop ... thread (here), that I wanted to answer.

from F104

Roger 04 RT, I tend to agree with you. I read many of your posts. Years ago I bought a intake temp change module for my2010GS , and it did very little at first, and nothing quantifiable afterwards. I think it comes much down to "I paid for it and I do want it to feel better".

But I also have a ('07 BMW 320d) turbo diesel car, and here the changes with a remap (not tuning box) are very noticeable even at low/part load. I take the difference is the diesel has no closed loop control?

Here's the question: When having access to the maps, why can't the Lambda reference values be raised? I think I understand it reads the value of the sensor, being a voltage, and compares that to where it wants to be. If one could change where it wants to be?

regards,

Martin

Martin,
Good question. In principal, the BMSK could have a software routine, like the one that's built into the AF-XIED, using the O2 sensors in a novel way. That software code is quite different from the robust code the BMSK actually uses to rigidly hold Closed Loop to the center of the Narrowband Lambda sensor.

Since the two jobs of the Narrowband sensor are to:
a) Keep the catalytic converter functioning at high efficiency at Lambda=1 to reduce pollutants.
b) Provide a reference for all fueling (e.g. learn that the amount of Ethanol in the fuel, requires additional fuel across the entire map)

the BMSK has no need of the type of software routine you question suggest. Going a little further, the sensitivity of the O2 sensor is quite high at Lambda=1 and quite low at richer/leaner settings. So the software to do what you suggest would look very different from what is there.

from Bendy Toy (here).

By the looks of it the O2 sensor gives a step change at a particular exhaust oxygen content. Set that value high and the engine runs weak (to allow excess air down the exhaust). Set it low and the engine runs rich. Presumably the fine tuning is done by the ECU map.

That's right, but the BMSK uses the sharp step region to rigidly hold onto lambda=1 and for calculating long term fuel trims. There isn't a place where you can reset the voltages that the BMSK uses, for the reasons I gave in response to Martin's question.

Additional Dual O2 Sensor Info

From some earlier tests by the owner of an R1200GSA Camhead: http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=835682#Post835682

RB