25-10-2016, 05:43 PM
Just thought people would be interested if you take the calibrations of the two different sensors and interpolate the values onto the same axis:
![[Image: gCJ7pu1.png]](http://i.imgur.com/gCJ7pu1.png)
I would debate that the sensors are any different in terms of their maximum mass rate value. I've not actually tested this, but I reckon the larger 2.2 sensor would actually max out at a lower airmass rate than the "maximum" airmass figures people mention when referring to anwLMM_MAX.
I suspect this is a combined reason - it enables the larger sensors to be compatible across 2.2/2.0 HDis without a software change, as I know that some 8v 110s have the larger sensor... It also means that there is much better resolution at low airmass rates which is advantageous... The accuracy is very important for monitoring EGR flow also, not just in terms of providing limitation to prevent smoke.
The reason that we see an improvement in ability to measure airmass when the 2.2 sensor is used is actually a side effect of increasing other values inside the ECU that allow the higher airmass values to be used.
Not to mention - if you go off what the sensor could read at the full 577kg/h it says it's capable of @4000rpm - you could inject enough fuel on an 8v HDi to make about 220lb.ft @ 4000rpm = ~165hp with an AFR of 16.5:1. We just can't use the airflow figure because of what I said above.
I would debate that the sensors are any different in terms of their maximum mass rate value. I've not actually tested this, but I reckon the larger 2.2 sensor would actually max out at a lower airmass rate than the "maximum" airmass figures people mention when referring to anwLMM_MAX.
I suspect this is a combined reason - it enables the larger sensors to be compatible across 2.2/2.0 HDis without a software change, as I know that some 8v 110s have the larger sensor... It also means that there is much better resolution at low airmass rates which is advantageous... The accuracy is very important for monitoring EGR flow also, not just in terms of providing limitation to prevent smoke.
The reason that we see an improvement in ability to measure airmass when the 2.2 sensor is used is actually a side effect of increasing other values inside the ECU that allow the higher airmass values to be used.
Not to mention - if you go off what the sensor could read at the full 577kg/h it says it's capable of @4000rpm - you could inject enough fuel on an 8v HDi to make about 220lb.ft @ 4000rpm = ~165hp with an AFR of 16.5:1. We just can't use the airflow figure because of what I said above.
