Garmin G3X Touch Feature Wish List

[BillL]

I would like to see air-fuel ratio readout and some kind of data stream (or output discrete(s))
for A/F, MAP, CHT and OAT to drive an electronic ignition control module. These parameters could allow a controller to give best power timing, but automatically limit advance with high CHT and/or high OAT.

I would not mind doing the work to calibrate the system, but do not want more knobs to twiddle in flight, every flight.

Thanks.

[gfb]

Originally Posted by BillL

I would like to see air-fuel ratio readout and some kind of data stream (or output discrete(s))
for A/F, MAP, CHT and OAT to drive an electronic ignition control module.

Other than air/fuel (which requires an O2 sensor?), MAP, CHT, and OAT are already available on the CAN Bus I believe. You just need to tap in and listen.

[BillL]

Originally Posted by gfb

Other than air/fuel (which requires an O2 sensor?), MAP, CHT, and OAT are already available on the CAN Bus I believe. You just need to tap in and listen.

No, actually, an O2 sensor is not required- We know this because air mass flow can mapped using RPM, MAP, and InManTemp using calibration routine. It is the basis for an open loop speed density fuel system control method. I (as a development engineer) contracted with a controls group to do this on an engine fuel system controller and it was amazingly accurate. In our plane, we could then perform periodic checks at peak EGT to confirm the calibration. It is proven that this is a consistent way of determining A/F with minimal instrumentation.

The O2 sensor can certainly be used for precision, perturbation, drift and changes, but not required.

Fuel flow still has to come from the flow sensor.

Question: Are the Garmin CAN protocols open source or proprietary?

[gfb]

Originally Posted by BillL

No, actually, an O2 sensor is not required- We know this because air mass flow can mapped using RPM, MAP, and InManTemp using calibration routine. It is the basis for an open loop speed density fuel system control method. I (as a development engineer) contracted with a controls group to do this on an engine fuel system controller and it was amazingly accurate. In our plane, we could then perform periodic checks at peak EGT to confirm the calibration. It is proven that this is a consistent way of determining A/F with minimal instrumentation.

The O2 sensor can certainly be used for precision, perturbation, drift and changes, but not required.

Very coo! Don't most engine computers use an O2 sensor though?

Originally Posted by BillL

Question: Are the Garmin CAN protocols open source or proprietary?

It conforms to Bosch CAN 2.0-B and ISO 11898.

[lr172]

Originally Posted by gfb

Very coo! Don't most engine computers use an O2 sensor though?

Most modern systems use RPM, MAT, MAP, and MAF (and CLT for warmup enrichment) for fuel flow and only use the O2 for fuel trimming, which is a fine tuning adjustment. Many only use narrow band O2 sensors, which are only accurate in the near vicinty of stochiometric. They indicate lean or rich of stoch, but no resolution on how much. In these cases, fuel flow outside of the economy range (i.e. acceleration) is purely off of the pre-configured tables.

Without MAF (i.e. speed density), one would have to have a lot of testing and data mapping to build appropriate tables for each engine configuration, but definately doable. It is what I did when I went to a custom EFI for my porsche, though I had wide band O2 to provide testing feedback. This was how early EFI worked.

Larry

[bkthomps]

I've got a simple upgrade that from a developer perspective should be real easy to code

for the SXM Music module, show the elapsed time or time remaining of a song....I had a recent flight where every station my passenger selected, was in the final 15-20seconds of the song, it seems like a simple addition to the code?

Another for the SXM Music Module, can we have a databar display of the song/artist playing?

[Kentsrv7a]

Would like to see the total fuel in each tank without having to go to the engine page. Maybe add them next to "Fuel QTY" like the other graph indicators, Oil PSI GPH, etc. or maybe above and below the graph line. Thanks!

[g3xpert]

Originally Posted by Kentsrv7a

Would like to see the total fuel in each tank without having to go to the engine page. Maybe add them next to "Fuel QTY" like the other graph indicators, Oil PSI GPH, etc. or maybe above and below the graph line. Thanks!

Good Morning,

If you open up the configuration menu on the GDU, and select Engine & Airframe, then select a Fuel Input, there is a selection for Display Options. Change this to Separate and you should be able to display your fuel gauge as described.



Thanks,

Justin

[bjdecker]

On the G3X, Add a Arnav/EI Fuel or Shadin Fuel Flow output format in the RS-232 data stream selection. The would enable us to use Fuel Flow/Endurance calculator in the GTN 650, 750.

If I could use the GTN 650 Fuel flow/endurance planning capability, I could keep the 1/3 of the GDU screen available for things like Traffic, Approach Plate, Maps, etc.

Thanks!

B

[Planecrazy232]

For us manual trim autopilot guys, we get pitch trim commands on the screen. How about giving us roll trim indicators also??