Wide Band Air Fuel Ratio (AFR) Indication

[Dynon101]

Has anyone setup an AFR indication on their Dynon SV?

I would love to have two AFR indicators on my screen.  Would be most helpful when yu have an engine roughness you can see what side has a stuck injector/ intake leak/ bad plug/ etc.

I am looking at various aftermarket units and since I want an indication for each side of the engine I would need to buy two units and then have to drill two huge holes in my panel (or mount them under the panel in a gauge cluster) and that would just suck.

IF...only IF Dynon had this kind of feature available I would buy a second EMS (already ran out of inputs) and install two O2 sensors (one on each pipe) and make it happen the clean and high tech way.

The wide band O2 sensor would be the way to go since it can measure a greater AFR range.

https://www.brakeandfrontend.com/wideband-oxygen-sensors-vs-narrowband-understanding-the-differences/

I cant imagine that it would be too tough to do???

 

[mmarien]

Been done. Search for AFR or try here:

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1381941973/54#54

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1268164287/29#12

 

[Dynon101]

mmarien

Thank you for your reply.

I did a search of afr and absolutely nothing came up. Just now I realised that the automatic option of replies this week had been selected and therefore I was surprised that only my post in your response popped up .

Looking through some of the other posts I see that you have an afr system on your airplane.

What type of oxygen sensor did you use?

Any issues with lead fouling?

Was there anything in particular you needed to do as far as setting up the sensor I see that there is a lot of specialised programming that needs to be loaded in or is it as simple voltage = colour?

THANKS

 

[mmarien]

I used the PLX device. It uses the Bosch o2 sensor:

https://www.plxdevices.com/ProductDetails.asp?ProductCode=897346002726

I've been using the same sensor for a few years and it still works. I run LOP (AFR 15+) and there is little lead in my exhaust. I believe if you run 300+ CHT it burns the lead off but there are all those times before your CHT get to 300+ so there is some lead buildup. I've been told lead fowling will just slow the sensor.

You have to add a sensor definition. It's the the *.sfg file when you export your settings files.

; my sensor definition for the PLX oxygen sensor.
sensor={
     id=AIR FUEL RATIO
     function=PRESSURE
     pins=C37_P8 C37_P22 C37_P23 C37_P31
     name=AFR
     min_val=10.0
     max_val=20.0
     resolution=1
     round=1
     is_piecewise=0
     low_coeff={
           c_x4=0
           c_x3=0
           c_x2=0
           c_x1=2.0
           c_x0=10.0
           }
     low_resistance=NONE
     low2high_cross=0
     high_coeff={
           c_x4=0
           c_x3=0
           c_x2=0
           c_x1=0
           c_x0=0
           }
     high_resistance=NONE
     high2low_cross=0
     window=.2
     shift=3
     age=16
     }

Once you add the sensor definition, you can use the normal Skyview Sensor Input Mapping functions to add the sensor to a pin. The EMS pin you use must be an Enhanced General Purpose pin d37p8, d37p22, d37p23 or d37p31. The function is PRESSURE. Skyview doesn't have a generic unit yet. You can suppress the units with the SHOW UNITS = NO. The ranges I use are:

      c37_p31={
            valid=1
            name=AFR
            id=AIR FUEL RATIO
            alarm_type=OFF
            range={
                  max_display=17.5
                  min_display=10
                  range1_valid=1
                  range1_top=20
                  range1_bot=17
                  range1_name=R1
                  range1_color=YELLOW
                  range2_valid=1
                  range2_top=17
                  range2_bot=14.7
                  range2_name=R2
                  range2_color=GREEN
                  range3_valid=1
                  range3_top=14.7
                  range3_bot=13.5
                  range3_name=R3
                  range3_color=RED
                  range4_valid=1
                  range4_top=13.5
                  range4_bot=12
                  range4_name=R4
                  range4_color=GREEN
                  range5_valid=1
                  range5_top=12
                  range5_bot=10
                  range5_name=R5
                  range5_color=YELLOW
                  }
            show_units=0
            }

Looks like this (upper left corner of ENGINE page):

The LOP is a regular Skyview INFO item.