New SDS Closed Loop Testing

[Norcalrv7]

I have played with turning closed loop on in my aircraft now below 18" and 1100-2100 RPM. Is there an ultimate limit of allowable % change from closed loop?

My tune is close, but having closed loop to clean up small changes is nice.
Only reason I cant use it below 1100 is my lycoming requires a 12-13:1 mixture to idle nicely.

Caleb

[Randy]

Ross,

For those with split exhaust systems, as in no crossover, do you still plan to use a single sensor, and assume the other side is running the same mixture?

Or, is there a way to incorporate the output from a sensor on each side of the system?

Randall

[rv6ejguy]

Originally Posted by Norcalrv7

I have played with turning closed loop on in my aircraft now below 18" and 1100-2100 RPM. Is there an ultimate limit of allowable % change from closed loop?

My tune is close, but having closed loop to clean up small changes is nice.
Only reason I cant use it below 1100 is my lycoming requires a 12-13:1 mixture to idle nicely.

Caleb

The present closed loop software targets stoichiometric (peak EGT)and can trim mixture +/- 25% maximum.

Once we introduce the aircraft closed loop software, you'll be able to target several different load ranges at different AFRs.

[rv6ejguy]

Originally Posted by Randy

Ross,

For those with split exhaust systems, as in no crossover, do you still plan to use a single sensor, and assume the other side is running the same mixture?

Or, is there a way to incorporate the output from a sensor on each side of the system?

Randall

Since we can trim all cylinders, having a single O2 sensor on one or two primary tubes should work fine. You'll still be able to balance all cylinders with the trim function.

[Toobuilder]

Ross,

Is O2 sensor lead poisoning cumulative, or is it somewhat self cleaning if you predominately run unleaded? I hope to run regular old auto gas in the Rocket locally, but anticipate a primary diet of 100LL going cross country. You say that you have seen up to 300 hours with 100LL... Wondering if my situation will extend that time any noteworthy amount.

Also, is the closed loop feature selectable on the fly? Meaning- I have an established open loop tune loaded as a fallback in case the O2 sensor dies while Im in the middle of nowhere?

[rmartingt]

Originally Posted by Toobuilder

Ross,

Is O2 sensor lead poisoning cumulative, or is it somewhat self cleaning if you predominately run unleaded? I hope to run regular old auto gas in the Rocket locally, but anticipate a primary diet of 100LL going cross country. You say that you have seen up to 300 hours with 100LL... Wondering if my situation will extend that time any noteworthy amount.

Also, is the closed loop feature selectable on the fly? Meaning- I have an established open loop tune loaded as a fallback in case the O2 sensor dies while Im in the middle of nowhere?

I am wondering the exact same thing...

[rv6ejguy]

Originally Posted by Toobuilder

Ross,

Is O2 sensor lead poisoning cumulative, or is it somewhat self cleaning if you predominately run unleaded? I hope to run regular old auto gas in the Rocket locally, but anticipate a primary diet of 100LL going cross country. You say that you have seen up to 300 hours with 100LL... Wondering if my situation will extend that time any noteworthy amount.

Also, is the closed loop feature selectable on the fly? Meaning- I have an established open loop tune loaded as a fallback in case the O2 sensor dies while Im in the middle of nowhere?

We've seen O2 sensor life from 10 hours to 300 hrs. on the Bosch 4.9 wideband sensors when using 100LL. 10 isn't acceptable, 100 + maybe is.

We're having some new sensor bosses made which are longer, so that most of the sensor element is shielded from direct impact of the lead. Other people have noted that this tripled their sensor life on leaded fuels. We're not sure yet how this impacts response time but we'll be testing it this month on our O-200.

Closed loop is easily selectable in a window called Closed Loop, toggle on/off with the +1 button when in the window.

Just be aware right now that the software in place only targets stoich- about 15.2 AFR on 100LL. Not the place to run the engine since this corresponds to peak EGT.

In 2007 I tested a retargeted value of 13.0 on an RV10 in Florida and it worked fantastically. Move the throttle anywhere and within less than .75 second, the AFR went right back to 13.

As mentioned previously, we plan to expand the capability so that the user can define what AFR they wish to target at 3-4 manifold pressure ranges and possibly a couple rpm ranges. Right now, you define closed loop operation with a high and low rpm range and a high and low MAP range. Whenever closed loop is on and you are inside those 4 limits, the ECU automatically jumps into closed loop. It immediately jumps out if any of the 4 limits are exceeded.

We also need to have diagnostics to detect an invalid sensor output, jump the ECU back into open loop when that happens and flash a warning on the programmer letting you know. That code is likely to take much longer to develop and validate than the actual closed loop control which is just a variation on what we've been doing for 20 years already in the automotive field.

This is all planned but we have 4 other development projects to finish off first. I'd hope that we can have beta versions to test sometime in early 2018. Older EM-5 ECUs will be able to be reflashed to have this feature.

[Randy]

https://www.amazon.com/Innovate-Moto.../dp/B000CO9MFI

In my Subaru days I used the bung extender from Innovative Technologies and noticed a definite increase in O2 sensor life. Can give hours of diference but it was certainly noticeable. This extender also helps the sensor run cooler.

Randall

[rv6ejguy]

Originally Posted by Randy

https://www.amazon.com/Innovate-Moto.../dp/B000CO9MFI

In my Subaru days I used the bung extender from Innovative Technologies and noticed a definite increase in O2 sensor life. Can give hours of diference but it was certainly noticeable. This extender also helps the sensor run cooler.

Randall

How is the response time with your extended boss and does the sensor tip extend past the tube wall at all?

[rv6ejguy]

This discussion seems to have prompted some European builders to ask about the future closed loop capabilities. Unleaded avgas, in various forms, has been available in certain countries there for over 20 years and they are keen to be able to use closed loop EFI systems.

In light of this, we will try to accelerate the development of this aspect for our aviation EFI systems.

Some interesting links:

http://www.total.co.uk/en/aviation/g...heretobuy.html

http://www.hjelmco.com/pages.asp?r_id=14663

https://generalaviationnews.com/2013...d-by-lycoming/