Air/Fuel ratio display on EMS D10?

[GoMopar440]

Can the EMS D10 be made to display the Air/Fuel ratio on the screen? It would be very useful for setting the mixture correctly while ground tuning or inflight.

There are some simple automotive A/F meter displays that use small LED bar graphs or digital (clock type) number displays but I am going to have to deal with a very cramped instrument panel. I'd like to utilize the EMS to display this info if it would be possible. I am planning on using wide band lambda type O2 sensors to get the A/F reading as accurate as possible.

Could this data be tied into the "Lean Mode" http://dynonavionics.com/docs/D10_Feature_Leaning.html function already on the EMS D10? Maybe make the reading show as a small vertical yellow bar that would slide horizontally across the green CHT bars with some sort of numerical reference at either the top or bottom of the graph? The A/F readings should react faster than the CHT or EGT readings.

Any thoughts? Is this even a workable idea? I was just brainstorming very late at night about this idea so please forgive me If I'm not too clear on the details here. I'll try to explain further if needed.

 

[dynonsupport]

If you use a WBO2 and an external drive box with a voltage output, this would techincally be possible on one cylinder. We could take this input into a general purpose input and use it. We only have three GP inputs though, and they get used for other things in most planes. You'd denfinatley need to use a WBO2 since narrow band O2's are completely worthless away from 14.7:1.

This would take some software and honestly we just don't see the demand. You're the first one to ask, and O2 sensors just aren't generally used in airplanes. Stoich is generally used only for emissions for cars, and O2 sensors are used because car environments are so dynamic. Airplanes tend to go lean of peak and then use fuel flow to determine power since the throttle setting is constant.

We'd be open to hearing more about how you would like to use the O2 sensor in an airplane environment, but at this point adding that feature to the EMS isn't on our priority list.

 

[GoMopar440]

I understand what your saying. I'm coming from an automotive background and am used to tuning engines by A/F. I've still got a lot to learn about what makes these planes tick and am just trying to find out what functions would be useful in one. This KR is my first (full size) aircraft venture and I've still obviously have a lot to learn.

I was thinking of ground tuning the plane with a WBO2 sensor in each exhaust header after the las cylinder comes into it. That would average out all three cylinders on each bank. If there was any drastic side to side variation present then the intake pipes and carb placement could be optimized to balance A/F on both sides. For flight use I would just run one WBO2 sensor since both sides should now read close to the same anyway.

I guess I'll just have to try the small aftermarket car type A/F sytems for this idea then. It is a car engine afterall. LOL!

Thanks for the reply.

 

[Frankh]

Interesting idea but not very practical in the real world I think.

Firstly airplane motors find stoich by pulling the mixture back until peak EGT is found. If done correctly (with instrumentation) this is a very accurate way to find stoich. As our moderator pointed out, one can get go rich of peak for most power or LOP for best economy.

Ths in fact is one of the advantages of using a "proper" airplane engine on an airplane. When I had my Soob conversion on my Zodiac which flew 400 hours I simply had altitude compensating carbs which ran ROP all the time.

The mixture control is also one of the most horribly abused knobs in an airplane and can lead to the early demse of the engine.

More modern auto conversions use EFI systems that automatically adjust to ROP...Normally they don't have a LOP function...shame really.

Secondly, you will eventually fill up with 100LL and leaded gas will kill an O2 over time...i don't know what happens to the accuracy of the sensor when it sees just a little bit of lead.

Depending on what engine you have I would see if you can find a carb that you have full control over the mixture. I believe some of the soob guys were using a Webber carb that they could infinatly vary the mixture. Then install a Cheap EGT sensor in each pipe...better if you have 4 individual exhaust pipes.

Then use the EMS to read the EGT's as normal.

If you have the right carb you can then do the same as the airplane guys and get some serious economy...Note that carbed Lycomings do not normally run Lean of Peak (LOP) due to poor mixture distribution...Thats why fuel injection is poplar because you can balance the mixtures on all cylinders.

Anyway, this s a long message to say why your otherwise fine idea is not likely to be taken up as a standard feature by Dynon.

Cheers

Frank