Torque Demand, Timing, and GM's new engine run modeling
While looking for information on the new systems I have run into 2 key patents that tell us fairly clearly how to tune these engines. Just takes a keen eye and some thinking to put it into action.
links:
Link One
Link Two
Important Link One diagrams:
http://patentimages.storage.googleap...616-D00010.png
http://patentimages.storage.googleap...616-D00002.png
http://patentimages.storage.googleap...616-D00004.png
http://patentimages.storage.googleap...616-D00005.png
http://patentimages.storage.googleap...616-D00000.png
Link Two Diagrams:
http://patentimages.storage.googleap...224-D00006.png
http://patentimages.storage.googleap...224-D00007.png
http://patentimages.storage.googleap...224-D00000.png
http://patentimages.storage.googleap...224-D00003.png
http://patentimages.storage.googleap...224-D00004.png
The patents also provide Formulas:
Link One:
BTREQ =T ped +T IDLE =T ENG −T Access
BTREQ - Brake Torque Request
Tped - Gas pedal torque request based on position
TIdle - zero pedal torque. iow.. foot off pedal torque
Teng - Engine torque
T access - torque used by accessories
T=f(APC,S,I,E,AF,OT,#)
T- Torque
APC - Air per Cylinder
S - Timing
I - Intake Phaser Position
E - Exhaust Phaser Position
AF - Air/Fuel Ratio
OT - Oil Temp
# - Number of Active Cylinders
Trpm PR = T ZPE + T R + T Ppr + T Ipr
Trpm IM = T AIRACT - T R + T Pim
Trpm PR = T ZPE + T R + T Ppr + T Ipr + T Dpr
Trpm IM = T ZPE + T I im + T Pim + T Dim + T md
T lim = F ( T Ipr )
T AIRACT = T PRCOMM + T ERR
T ERR = T U - T PRACT
T R = T U - T IM
T R = T PR - T IM
T Ppr = f { Δ N }
T Ipr = ∑ x = 0 X T Ipr · f { Δ N }
T Dpr = Δ RPM · K D
Trpm PR - Predicted Torque Request
Trpm IM - Immediate Torque Request
T ZPE - Zero Pedal Torque Request
T R - Torque Reserve
T Ppr - Proportional Predicted Torque. At steady state it equals zero.
T Ipr - Integral Predicted Torque. Equal to F(TIpr).
T AIRACT - Actual Air Torque
T Pim - Proportional Immediate Torque. At steady state it equals zero.
T Dpr - Derivative Predicted Torque. At steady state it equals zero.
T I - Integral Torque
T Dim - Derivative Immediate Torque. At steady state it equals zero.
T md - Torque Differential. At steady state it equals zero.
T Iim - Integral Immediate Torque
T PRComm - Commanded Predicted Torque
T PrAct - Predicted Actual Torque
T ERR - Torque Error
T U - Unmanaged Torque
T Dpr - Predicted Torque Derivative
Kd - Derivative Constant. May be determined from a table based on the ΔN. ΔRPM is a rate of change in engine speed.
Link Two:
Sdes =T −1(Tdes, APC, I, E, AF, OT, #)
S des - Desired Spark
T des - Desired Torque
Seems to me that the key to tuning the torque tables are right here. What we need to do, I think, is log actual torque and whatever parameters will give us some sort of sensor base torque calculation and go from there. The correct data will allow the peak torque tables to be tuned for new mods. On top of that; tuning the VE looks to be the first thing required before the torque management section. We need to figure out which sensors and which torque readings give us meaningful data.
Sorry for the giant google linked pictures.
