[quote]ORIGINAL: glens

The SERT users manual states "switching sensors can only control within a narrow range (+/- 0.5 AFR)". +0.5 AFR (from stoich, the center of the range) is 15.2 AFR or -3% fuel [14.7 ÷ 15.2 = 0.97] and -0.5 AFR is 14.2 or +3% fuel [14.7 ÷ 14.2 = 1.03]. That's the limit, which I'm not ignoring. It's also not the function I'm describing. But remember that, the usable reporting range of the O2 sensor is only 3% in either direction from the midpoint.

The SERT manual mentions the VE-New how? It says it's calculated when running closed loop. Does your copy explain how it's calculated? My copy doesn't. Does that mean it's not really happening or does it just mean that it's impertinent to the SERT because it's yet another of the things the SERT cannot touch?

I'll attach an image I picked up from some post here a while back. Note the "VE Front" is 86% while the "VE New Front" is 81.5% (94.8% [=AFV for that cylinder] of the set value) while the "O2 Integrator Front" shows no deviation from setpoint which appears to be 0.56V. That's -5.2% deviation from set VE, almost the total range of "control" available from the O2 sensor! Yet the usable range of control from the sensor in establishing the "VE New" in any direction is only half the total O2 sensor range available, which makes the deviation represented nearly twice the range of the O2 sensor for that direction. How does the VE New get that far away if it's being "controlled" only by the O2 sensor, especially when the sensor is at its CLB value (evidently)? I contend that the sensor is at its CLB value because the VE New, and not the VE, was used to calculate the injector duty cycle. The VE New controls the O2 sensor output, yet the sensor output helps establish the VE New (via the currently-adjusted AFV). None of how that operation takes place is described in the SERT Manual yet it obviously happens.

Look at that again. The VE New is almost twice the distance in percentage of what the O2 sensor can measure in that direction from its midpoint (which it's not even set at; I believe where it's set and the direction of the VE New would result in greater than twice the available range of the O2 sensor in that direction; but even if the "headroom" in the sensor output toward the other direction from its setpoint was used it's still less than the resultant AFV).

You're the one of we two who has a SERT-equipped bike. You could data-log and see for yourself. So far the only instance of that I've been able to scrutinize is included here and discussed above. That's hard data/proof. Though not proof that my specified range limits are correct. But you could easily verify that yourself. I'll leave it to your imagination as to how to go about it. (something like zip-tying some non-flammable fabric around the end of the muffler and data-logging a trip around the block ought to suffice and be harm-free enough)

As I've previously stated, I don't have access to the HD Delphi engineering documentation so I can't provide you with proof that way. I do know, however, from other creditable sources it probably wouldn't do much good to drag into this, that the range is ±15% for

 

I guess I'm not sure I understand which fact I acknowledged At any rate, the the area of change and the information regarding it, while not readily available as official documentation, is somewhat known. I'm trying to help in that regard.

Hell, I don't care. Hahaha!

Really, though, you're quite welcome. It's been a real pleasure. Having to put this stuff into terms which clearly convey the concepts to others has been a great exercise for me, as should be evident I still need work on but feel I'm maybe getting somewhat better at. I have a tendency to imply a great deal with my words and it's not only here that it gets me into trouble sometimes.