Can someone explain these 4 table to me
Can someone explain these 4 table to me and the exact impact in laymens term the effect they have on fueling in a closed loop system
Thanks
Closed Loop Proportional Base vs. Airflow Mode: This table returns the base proportional % fuel change. Proportional base rate table is the primary amount of fuel needed to drive the closed loop fuel control into oscillation. Proportional fuel acts like an on/off switch to keep the fuel moving around the current O2 Rich/Lean vs. Mode table set point. The values on the Proportional Table add or subtract to the base fuel rate depending on the previous fuel condition (i.e. if rich then switch lean, if lean the switch rich). The amount of fuel to add or subtract increases with the airflow mode and should be based on injector size and % fuel switching needed.
Closed Loop Proportional Gain vs. O2 Error: This table returns a multiplier value for the increase/decrease of the base rate table. A multiplier value of 1.000 will have no effect on the proportional base rate. If the difference between the current O2 reading and its desired value from table O2 Rich/Lean vs Mode (the current Fast O2 error) is large the VCM will need to change the proportional fuel a lot. If the error is small, it should change it only a little to continue oscillation without undershoot or overshoot. Undershooting will cause the Closed loop fuel to become sluggish or miss the current O2 Rich/Lean vs. Mode table set point. Overshooting with cause the engine to vary excessively in RPM.
Closed Loop Integrator Delay vs. Airflow Mode: This table returns the base integrator delay.
The integrator is a function of the Slow Filtered O2 Error over time, The integrator handles persistent rich or lean fuel conditions based on the slow O2 error and Rich/Lean vs Airflow mode. The Base Delay vs Airflow Mode table is the minimum time in milliseconds an overly rich or lean condition needs to exist before the VCM is allowed to make a fuel correction.
The integrator is a function of the Slow Filtered O2 Error over time, The integrator handles persistent rich or lean fuel conditions based on the slow O2 error and Rich/Lean vs Airflow mode. The Base Delay vs Airflow Mode table is the minimum time in milliseconds an overly rich or lean condition needs to exist before the VCM is allowed to make a fuel correction.
Closed Loop Integrator Delay Mult vs. O2 Error: This table returns a multiplier value for the increase/decrease of the base integrator time delay. A multiplier value of 1.000 has no effect on the base delay. If the slow o2 error is extremely large the integrator will need to act more quickly. If the error is small the integrator will need less control to keep the closed loop fuel switching closer to the current O2 Rich/Lean vs. Mode table set point.
TECH Addict
Joined: Jul 2002
Posts: 2,261
Likes: 0
Originally Posted by P Mack
I am interested too.
Plain english nuances would be nice
. Seems like I need to make some serious changes when I try closed loop.
On The Tree
Joined: Sep 2004
Posts: 106
Likes: 0
From: Australia
Ken gave one or two answers in this thread on the HPT web site
http://www.hptuners.com/forum/YaBB.p...num=1105454658
http://www.hptuners.com/forum/YaBB.p...num=1105454658
TECH Addict
Joined: Feb 2004
Posts: 2,826
Likes: 0
Originally Posted by P Mack
That helps a little. But do these go into the ltft and stft calculation, or are they in addition to them?
Trending Topics
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
I'd help ya in tryin some of this... but my car doesn't seem to like cold weather... started her up last night (~ 9* F) and when I popped the hood... she was putting on a pretty good light show! seems at least 3 boots musta cracked where the wire plugs into the coil pack... 
TECH Addict
Joined: Feb 2004
Posts: 2,826
Likes: 0
Aha. I may not know how to tune them, but I figured out how the rest of those tables work.
The closed loop proportional base vs. airflow is a value used to add fuel based on airflow mode to keep the O2s oscillating.
The closed loop proportional gain vs. o2 error is a multiplier applied to the values in the closed loop proportional base vs. airflow table. The multipler changes in relation to the mv difference between the actual o2 sensor readings your PCM detects, and the value listed in the o2 sensor vs. airflow mode. Based on the difference between the two it adjusts the amount of fuel to keep the o2 sensors oscillating. Phew.
Well. Now all I have to do is figure out how to tune them.
The closed loop proportional base vs. airflow is a value used to add fuel based on airflow mode to keep the O2s oscillating.
The closed loop proportional gain vs. o2 error is a multiplier applied to the values in the closed loop proportional base vs. airflow table. The multipler changes in relation to the mv difference between the actual o2 sensor readings your PCM detects, and the value listed in the o2 sensor vs. airflow mode. Based on the difference between the two it adjusts the amount of fuel to keep the o2 sensors oscillating. Phew.
Well. Now all I have to do is figure out how to tune them.
TECH Addict
Joined: Jul 2002
Posts: 2,261
Likes: 0
Originally Posted by Another_User
Here is a weird observation. I was comparing some 2003 C5 tunes, and a 2003 C5 Magnusson tune, and the Closed Loop Proportional Gain vs. O2 Error has been halved. I wonder why.
