Using Fuel Consumption Volume Rate in strategies?
Posted: Mon Jan 16, 2023 3:21 am
Hi,
I am calibrating an N54 PnP S7+ set up. I am finding the DI asynchronous pump set up needs fairly elaborate PWM control. The way the base strategy is set up is basically a generic CLPWM (clPWM01 in the output) controlling DI pump duties against fuelduty1.
The system appears to have non-linearities related to temperature and required DI pump duties independent of calculated fuelfinal1 and these have been successfully dealt with using CMs (ECT v run time acting as adder on CLPWM01 Di output). From cold start I can now have clean stable DIP without the integrator winding up by leaning on P / I and while also having a moderate P term that does not oscillate the pressure under load.
One area that I'm looking at is large DIP variations associated with trqfuelsev requests (gear cut/traction/rev limit). Such requests that happen under load throws off DIP. One would think fuelduty1 would account for these but not sufficiently in may case. Even if I use fuelfinal1 instead it still does not reflect how much duty reduction is needed on the DI pump duty under trqfuelsev situations. However, with trqfuelsev used for ORFC with low demand or closed throttle, the DI pump duty reduction required is larger than under load otherwise DIP overshoots significantly.
I have addressed this with two CMs;
CM311 for for DI pump duty adder using trqfuelsev v RPM (reduced DI duty), this CM also feeds another DI adder map CM304 that takes the CM311 output against TPS. Basically, when throttle open and trqfuelsev has a value (gear cut, traction, revlimit, ALS etc), it takes out some DI pump duty, however when ORFC is active and TPS closed, it takes out even more.
The strategy took some time to calibrate but works surprisingly well and stops massive overshoot of DI pressure when letting off a run and keeps a nice DI pressure when trqfuelsev is active. I can now run the car and enjoy traction cuts, gear shift cuts, launch control etc and DIP remains well behaved.
My query: One thing I have found is that if you log fuel consump vol rate (fuelconsvolrate) it looks to be a far more reliable indication of fuel use when under trqfuelsev versus fuelfinal1 or fuelduty1. It shows a significant variability during trqfuelsev operation and Ideally I would like to be able to map DI pump duties against this, or at least a CM against it to simply my 'nested' CM's. Is there is some way I can turn this fuelconsvol calculated variable into something I can calibrate against?? it does not appear in the CM variable list
Cheers.
I am calibrating an N54 PnP S7+ set up. I am finding the DI asynchronous pump set up needs fairly elaborate PWM control. The way the base strategy is set up is basically a generic CLPWM (clPWM01 in the output) controlling DI pump duties against fuelduty1.
The system appears to have non-linearities related to temperature and required DI pump duties independent of calculated fuelfinal1 and these have been successfully dealt with using CMs (ECT v run time acting as adder on CLPWM01 Di output). From cold start I can now have clean stable DIP without the integrator winding up by leaning on P / I and while also having a moderate P term that does not oscillate the pressure under load.
One area that I'm looking at is large DIP variations associated with trqfuelsev requests (gear cut/traction/rev limit). Such requests that happen under load throws off DIP. One would think fuelduty1 would account for these but not sufficiently in may case. Even if I use fuelfinal1 instead it still does not reflect how much duty reduction is needed on the DI pump duty under trqfuelsev situations. However, with trqfuelsev used for ORFC with low demand or closed throttle, the DI pump duty reduction required is larger than under load otherwise DIP overshoots significantly.
I have addressed this with two CMs;
CM311 for for DI pump duty adder using trqfuelsev v RPM (reduced DI duty), this CM also feeds another DI adder map CM304 that takes the CM311 output against TPS. Basically, when throttle open and trqfuelsev has a value (gear cut, traction, revlimit, ALS etc), it takes out some DI pump duty, however when ORFC is active and TPS closed, it takes out even more.
The strategy took some time to calibrate but works surprisingly well and stops massive overshoot of DI pressure when letting off a run and keeps a nice DI pressure when trqfuelsev is active. I can now run the car and enjoy traction cuts, gear shift cuts, launch control etc and DIP remains well behaved.
My query: One thing I have found is that if you log fuel consump vol rate (fuelconsvolrate) it looks to be a far more reliable indication of fuel use when under trqfuelsev versus fuelfinal1 or fuelduty1. It shows a significant variability during trqfuelsev operation and Ideally I would like to be able to map DI pump duties against this, or at least a CM against it to simply my 'nested' CM's. Is there is some way I can turn this fuelconsvol calculated variable into something I can calibrate against?? it does not appear in the CM variable list
Cheers.