TC and F/awd vehicles.
#1
TC and F/awd vehicles.
Traction Control
Up until this very moment I have always been of the thought that if the brakes are applied, even ever so gently, the engine RPM should automatically drop to idle and not respond to the gas pedal unless the brake pedal is fully released.
No more.
What about a TC "mode" that automatically activates if the gas pedal is depressed, substantially depressed, while the vehicle is stopped and the brakes are applied. The engine's DBW throttle need not respond to the initial gas pedal depression.
This new mode would be implemented via putting both rear ABS/TC braking control solenoids in the "isolate" position, thereby preventing the rear brakes from being functional. ABS would, of necessity, be fully disabled in this "mode".
Driver braking would then apply ONLY to the front wheels thereby forcing the majority of engine torque to the rear. The potential danger for loss of directional control upon the loss of traction on the front wheels common to all F/awd vehicles would then be completely the responsibility, under direct control, of the driver and his/her responsiveness with/on the brake pedal.
It is quite likely that some sort of time/duration limit or engine RPM limit would be required to prevent inadvertent overheating of the front brake rotors. TC would automatically return to "normal" mode once the front ABS sensors indicated a substantial speed were attained, say 5-10 MPH.
There would then be no reason for the TC/VSC disable function.
Up until this very moment I have always been of the thought that if the brakes are applied, even ever so gently, the engine RPM should automatically drop to idle and not respond to the gas pedal unless the brake pedal is fully released.
No more.
What about a TC "mode" that automatically activates if the gas pedal is depressed, substantially depressed, while the vehicle is stopped and the brakes are applied. The engine's DBW throttle need not respond to the initial gas pedal depression.
This new mode would be implemented via putting both rear ABS/TC braking control solenoids in the "isolate" position, thereby preventing the rear brakes from being functional. ABS would, of necessity, be fully disabled in this "mode".
Driver braking would then apply ONLY to the front wheels thereby forcing the majority of engine torque to the rear. The potential danger for loss of directional control upon the loss of traction on the front wheels common to all F/awd vehicles would then be completely the responsibility, under direct control, of the driver and his/her responsiveness with/on the brake pedal.
It is quite likely that some sort of time/duration limit or engine RPM limit would be required to prevent inadvertent overheating of the front brake rotors. TC would automatically return to "normal" mode once the front ABS sensors indicated a substantial speed were attained, say 5-10 MPH.
There would then be no reason for the TC/VSC disable function.
Last edited by wwest; 06-02-2009 at 01:05 PM.
#4
Re: TC and F/awd vehicles.
I don't think ANY modern day TC implementation can be, will be, activated above 15-20 MPH.
And I for one wouldn't want it to be...
"..one rear or front wheel?..."
That would be VSC/PSM/etc, not TC.
And I for one wouldn't want it to be...
"..one rear or front wheel?..."
That would be VSC/PSM/etc, not TC.
#5
Re: TC and F/awd vehicles.
Does not apply to FWD, RWD, or R/awd.
#6
Re: TC and F/awd vehicles.
Because the Ford Escape Hybrid section is an excellent place to find an audience to rant endlessly about the inherent dangers of FWD, FWD-biased AWD, and/or ABS, don't you think?
#7
Re: TC and F/awd vehicles.
#8
Re: TC and F/awd vehicles.
Now read:
http://www.fordvehicles.com/cars/fus...#page=Feature5
"..automatically applies the brakes and modulates engine torque whenever it detects wheel slip..."
That very adequately, succinctly, describes the TC, Traction Control, aspects of Ford's AdvanceTrac ESC (Electronic Stability Control).
So, which comes first, the chicken or the egg...??
See the conflict..??!!
If wheelspin/slip is a criteria for switching engine torque to the rear driveline as stated in your "link", then what is the need (for closing the barn door after..?) because the above clearly states that the engine has just been, or is ALREADY dethrottled, and (front??) brakes are being "modulated".
I just simply do not, cannot believe that the Ford AdvanceTrac design engineers are as stupid as these two linked statements seem to imply.
What SHOULD happen is that upon front wheelspin/slip detection the rear driveline is engaged at the 50% level and ONLY then would TC functionality be activated should wheelspin/slip persist.
On the other hand there is the old "safety" bug-a-boo regarding the need to, as instantly as technically possible, to recover from loss of traction on the FRONT wheels. So it is entirely possible that the initial action is to BOTH activate TC functionality AND route the majority of torque toward the rear. Given that the "normal" torque distribution is only as high as 50/50, TC "Modulation" of the front brakes would certainly move the majority of engine torque to the rear quickly.
Keep in mind that the design engineers cannot know, forecast, just how serious, DEADLY SERIOUS, the circumstance might be when those front DRIVE wheels develop slip. Heading into a uphill right turn, steep drop-off to your left, on a snow covered road up a mountain pass..??
Believe me, you will WANT instant TC activation.
So maybe both statements are correct AND the Ford engineers are not dumb but just stuck with the realities of the potential hAZARDS of FWD and F/awd.
Shame the car doesn't start out with the majority of engine torque to the rear, R/awd.
http://www.fordvehicles.com/cars/fus...#page=Feature5
"..automatically applies the brakes and modulates engine torque whenever it detects wheel slip..."
That very adequately, succinctly, describes the TC, Traction Control, aspects of Ford's AdvanceTrac ESC (Electronic Stability Control).
So, which comes first, the chicken or the egg...??
See the conflict..??!!
If wheelspin/slip is a criteria for switching engine torque to the rear driveline as stated in your "link", then what is the need (for closing the barn door after..?) because the above clearly states that the engine has just been, or is ALREADY dethrottled, and (front??) brakes are being "modulated".
I just simply do not, cannot believe that the Ford AdvanceTrac design engineers are as stupid as these two linked statements seem to imply.
What SHOULD happen is that upon front wheelspin/slip detection the rear driveline is engaged at the 50% level and ONLY then would TC functionality be activated should wheelspin/slip persist.
On the other hand there is the old "safety" bug-a-boo regarding the need to, as instantly as technically possible, to recover from loss of traction on the FRONT wheels. So it is entirely possible that the initial action is to BOTH activate TC functionality AND route the majority of torque toward the rear. Given that the "normal" torque distribution is only as high as 50/50, TC "Modulation" of the front brakes would certainly move the majority of engine torque to the rear quickly.
Keep in mind that the design engineers cannot know, forecast, just how serious, DEADLY SERIOUS, the circumstance might be when those front DRIVE wheels develop slip. Heading into a uphill right turn, steep drop-off to your left, on a snow covered road up a mountain pass..??
Believe me, you will WANT instant TC activation.
So maybe both statements are correct AND the Ford engineers are not dumb but just stuck with the realities of the potential hAZARDS of FWD and F/awd.
Shame the car doesn't start out with the majority of engine torque to the rear, R/awd.
Last edited by wwest; 06-02-2009 at 10:42 PM.
#9
Re: TC and F/awd vehicles.
If wheelspin/slip is a criteria for switching engine torque to the rear driveline
Willard does not have a FEH and is not aware of the "criteria" issue(s) as previously discussed in other threads.
Willard does not have a FEH and is not aware of the "criteria" issue(s) as previously discussed in other threads.
#10
Re: TC and F/awd vehicles.
What does a FEH or owning one have to do with TC/AWD?