"Enhanced RPM" parameter on Closed Loop control algorithms

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08-30-2021
pannetron

"Enhanced RPM" parameter on Closed Loop control algorithms

There are two parameters in the latest version of the VCM editor that I'm unfamiliar with: Fuel/Oxygen Sensors/Closed Loop Enable/Enhanced RPM and Simplified RPM. The note mentions that at RPM below the Enhanced RPM limit the ECU uses "enhanced closed loop algorithms" and at RPM over the Simplified RPM it uses O2 sensor rich/lean thresholds. What are the "enhanced algorithms?" A stock ZR1 tune has 3000 and 3100 RPM for those parameters; my 430 HP crate engine E67 has 0 for both values so I assume my ECU never uses those "enhanced" algorithms. Should I care? Maybe my crate ECU lacks those enhanced algorithms?

Back in 2017 there was a forum post (https://forum.hptuners.com/showthrea...t=enhanced+rpm) asking for these two additional parameters among many others.
03-01-2023
Cringer

Quote:

Originally Posted by pannetron

There are two parameters in the latest version of the VCM editor that I'm unfamiliar with: Fuel/Oxygen Sensors/Closed Loop Enable/Enhanced RPM and Simplified RPM. The note mentions that at RPM below the Enhanced RPM limit the ECU uses "enhanced closed loop algorithms" and at RPM over the Simplified RPM it uses O2 sensor rich/lean thresholds. What are the "enhanced algorithms?" A stock ZR1 tune has 3000 and 3100 RPM for those parameters; my 430 HP crate engine E67 has 0 for both values so I assume my ECU never uses those "enhanced" algorithms. Should I care? Maybe my crate ECU lacks those enhanced algorithms?

Back in 2017 there was a forum post (https://forum.hptuners.com/showthrea...t=enhanced+rpm) asking for these two additional parameters among many others.

Did you ever find any more info on Simple vs Enhanced topic?
03-01-2023
pannetron

No, nothing :-(
03-02-2023
07GTS

i noticed on startup i wanted to have it a little richer but it seems to be in an ''OL stoich'' which i found strange, it was using the trims before CL was enabled quite annoying when u need a little more fuel, i thought that enhanced rpm setting might be the cause as it was on might have affected it but seems not but that disabled made it worse, not sure what it does
03-02-2023
verlon

That's not 'enhanced' or 'simplified' algorithm. Calculations and closed loop logic remains exactly the same.
The difference is how frequent closed loop calculation routines are executed.
In 'enhanced' mode (event mode really) routines are executed for every cylinder intake stroke.
In 'simplified' mode (timing mode) routines are executed periodically every 12.5ms (or 80Hz).

If you set both RPMs to 0 you'll get just timing mode only with slightly faster idle CL responce.
03-02-2023
Cringer

Quote:

Originally Posted by verlon

That's not 'enhanced' or 'simplified' algorithm. Calculations and closed loop logic remains exactly the same.
The difference is how frequent closed loop calculation routines are executed.
In 'enhanced' mode (event mode really) routines are executed for every cylinder intake stroke.
In 'simplified' mode (timing mode) routines are executed periodically every 12.5ms (or 80Hz).

If you set both RPMs to 0 you'll get just timing mode only with slightly faster idle CL responce.

That is great info! How did you figure this out? Is it documented somewhere?
03-03-2023
verlon

Quote:

Originally Posted by Cringer

That is great info! How did you figure this out? Is it documented somewhere?

Reverse engineering.
03-07-2023
pannetron

Quote:

Originally Posted by verlon

Reverse engineering.

Wow, good job on reverse engineering and thanks for that info!
11-24-2024
BBA

Did some playing with this. Turns out it runs much better with the enhanced off. This is on a hotcam LS3.
11-24-2024
poulina

maybe because your cam has a bunch of overlap and is giving the o2 sensors a hard time in closed loop.