4WD and the FEH
#11
10-01-2009, 12:02 PM
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Re: 4WD and the FEH
Kindly proof-read your post..?
#12
10-01-2009, 12:22 PM
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Re: 4WD and the FEH
C/P from the other thread:
Hmm, good video! The FE/FEH is a asymmetric 4WD but until '09 the FEH didn't have traction control but still neither would perform as good as the Subaru which has symmetric AWD.
Being a asymmetric 4WD, you'd have the steering torque they mentioned in the video. If you have AdvanceTrac(>'09 FEH) and traction at one wheel, you could climb the ramp. Without AdvanceTrac(<'09 FEH), you can't call it AWD either, it's just 4WD!
P.S. Another meaningless post from BillyK.
Hmm, good video! The FE/FEH is a asymmetric 4WD but until '09 the FEH didn't have traction control but still neither would perform as good as the Subaru which has symmetric AWD.
Being a asymmetric 4WD, you'd have the steering torque they mentioned in the video. If you have AdvanceTrac(>'09 FEH) and traction at one wheel, you could climb the ramp. Without AdvanceTrac(<'09 FEH), you can't call it AWD either, it's just 4WD!
P.S. Another meaningless post from BillyK.
No, "4WD", for the majority of us, will always mean 4WD in the traditional sense, as in a locked, fully locked, center diff'l. On the other hand, in the sense that AWD is most commonly recogized as meaning "automatic", switching to and from AWD, or some "rubber bandish", variable coefficient of coupling to the opposite driveline all the FE/FEH F/awd versions have been "AWD".
Were the FE/FEH always primariliy a RWD vehicle then TC activation could be delayed after coupling in the front driveline long enough to determine if the additional drive traction serves to alleviate the loss of trcation with only two wheels being driven.
Given the patently unsafe nature of FWD and F/awd vehicles when front traction is lost that TC delay is not feasible.
The car moving sideways with the front wheels spinning freely, on those rollers need not be the result of torque stear. Once traction is lost on your front drive wheels, as is being simulated, the tires also lose all lateral grip/traction so the car can "drift" on way or another for the slightest cause, sideways roadbed tilt, slightly more traction on one side vs the other, etc, etc.
That's why TC on FWD and F/awd vehicles MUST be so aggressive at recovering those front driven wheels the instant loss of traction is detected.
Besides which the electric power stearing on the FEH can be, should be, "tuned" to negate torque stear.
The Subaru may be able to more easily climb that ramp but the other aspects of symmetrical AWD scare the wits out of me.
Last edited by wwest; 10-01-2009 at 12:26 PM.
#13
10-01-2009, 12:50 PM
Re: 4WD and the FEH
"..it's just 4WD.."
No, "4WD", for the majority of us, will always mean 4WD in the traditional sense, as in a locked, fully locked, center diff'l. On the other hand, in the sense that AWD is most commonly recogized as meaning "automatic", switching to and from AWD, or some "rubber bandish", variable coefficient of coupling to the opposite driveline all the FE/FEH F/awd versions have been "AWD".
Were the FE/FEH always primariliy a RWD vehicle then TC activation could be delayed after coupling in the front driveline long enough to determine if the additional drive traction serves to alleviate the loss of trcation with only two wheels being driven.
Given the patently unsafe nature of FWD and F/awd vehicles when front traction is lost that TC delay is not feasible.
The car moving sideways with the front wheels spinning freely, on those rollers need not be the result of torque stear. Once traction is lost on your front drive wheels, as is being simulated, the tires also lose all lateral grip/traction so the car can "drift" on way or another for the slightest cause, sideways roadbed tilt, slightly more traction on one side vs the other, etc, etc.
That's why TC on FWD and F/awd vehicles MUST be so aggressive at recovering those front driven wheels the instant loss of traction is detected.
Besides which the electric power stearing on the FEH can be, should be, "tuned" to negate torque stear.
The Subaru may be able to more easily climb that ramp but the other aspects of symmetrical AWD scare the wits out of me.
No, "4WD", for the majority of us, will always mean 4WD in the traditional sense, as in a locked, fully locked, center diff'l. On the other hand, in the sense that AWD is most commonly recogized as meaning "automatic", switching to and from AWD, or some "rubber bandish", variable coefficient of coupling to the opposite driveline all the FE/FEH F/awd versions have been "AWD".
Were the FE/FEH always primariliy a RWD vehicle then TC activation could be delayed after coupling in the front driveline long enough to determine if the additional drive traction serves to alleviate the loss of trcation with only two wheels being driven.
Given the patently unsafe nature of FWD and F/awd vehicles when front traction is lost that TC delay is not feasible.
The car moving sideways with the front wheels spinning freely, on those rollers need not be the result of torque stear. Once traction is lost on your front drive wheels, as is being simulated, the tires also lose all lateral grip/traction so the car can "drift" on way or another for the slightest cause, sideways roadbed tilt, slightly more traction on one side vs the other, etc, etc.
That's why TC on FWD and F/awd vehicles MUST be so aggressive at recovering those front driven wheels the instant loss of traction is detected.
Besides which the electric power stearing on the FEH can be, should be, "tuned" to negate torque stear.
The Subaru may be able to more easily climb that ramp but the other aspects of symmetrical AWD scare the wits out of me.
Even so, the Escape is tagged as 4WD but a Fusion which is described in a Ford workshop manual as having the same exact system is tagged as a AWD! The workshop manual's index lists 4WD systems but when you go to the section and start reading, it uses the term AWD.
If you can't at least somehow reduce torque to three wheels, sent it to one, you can't call it AWD and therefore it's a 4WD system.
#14
10-01-2009, 01:52 PM
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Re: 4WD and the FEH
Bill, sorry, but this is a BIG point of confusion. And the manufacturers, at least their marketing departments, aren't helping matters by trying to sell the public sow's ears dressed up to look like silk purses.
Traditionally, historically if I may, 4WD was used, has been used, to denote a vehicle that could engage, via driver manual control, front and rear drivelines simultaneously. FIRMLY engage, generally via a SOLID coupling between the two. Obviously that would mean "part-time" use, either to be used, engaged ONLY off-roading or on a low traction, slippery roadbed, surface. 4X4, generally, meant a 4WD vehicle with a "granny-grunt low, high drive torque, gear ratio.
There is NO full-time passenger vehicle AWD system that can have a continuous solid or even continuously FIRM drive coupling between the two drive lines. The coupling MUST be "rubber-bandish", as with a VC, or be capable of being disenaged virtually INSTANTLY upon brake use, low speed turning, ABS/TC/VSC activation.
I'm not sure where to place the Torsen in this, or for that matter ANY center LSD, except to simply say that these are simply another way of implementing the automatic coupling-decoupling of the two drivelines.
Oh, both of the Jeeps I have owned, an '85 and a '92, had "multi-mode" drive systems. RWD/AWD/4WD/4X4. AWD mode was like the current HL except without TC.
And think about this in the literal sense for a moment, given the constrants, hard physical constrants, could you EVER have a road going passenger vehicle with 4WD full-time,..truly FULL-TIME..??
Traditionally, historically if I may, 4WD was used, has been used, to denote a vehicle that could engage, via driver manual control, front and rear drivelines simultaneously. FIRMLY engage, generally via a SOLID coupling between the two. Obviously that would mean "part-time" use, either to be used, engaged ONLY off-roading or on a low traction, slippery roadbed, surface. 4X4, generally, meant a 4WD vehicle with a "granny-grunt low, high drive torque, gear ratio.
There is NO full-time passenger vehicle AWD system that can have a continuous solid or even continuously FIRM drive coupling between the two drive lines. The coupling MUST be "rubber-bandish", as with a VC, or be capable of being disenaged virtually INSTANTLY upon brake use, low speed turning, ABS/TC/VSC activation.
I'm not sure where to place the Torsen in this, or for that matter ANY center LSD, except to simply say that these are simply another way of implementing the automatic coupling-decoupling of the two drivelines.
Oh, both of the Jeeps I have owned, an '85 and a '92, had "multi-mode" drive systems. RWD/AWD/4WD/4X4. AWD mode was like the current HL except without TC.
And think about this in the literal sense for a moment, given the constrants, hard physical constrants, could you EVER have a road going passenger vehicle with 4WD full-time,..truly FULL-TIME..??
#15
10-01-2009, 02:11 PM
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Re: 4WD and the FEH
Nope! Ford's AWD means All Wheel Drive just listen to any Fusion commercial on TV. A <'08 FEH doesn't have TC, so it's not a AWD system. A '09 FEH or a FE going back how far I don't know far has TC, so it can be called by Ford termnology, AWD.
Even so, the Escape is tagged as 4WD
Probably, maybe, because originally the FE was 4WD. Back then it had a manually or automatically selected 4WD system. If manually engaged by the driver the CAUTION was to NEVER do so on a highly tractive surface. The system would automatically engage if front wheelslip/spin was detected but only for 10-15 seconds. This latter a design aspect taken from the old Aerostar R/awd system.
but a Fusion which is described in a Ford workshop manual as having the same exact system is tagged as a AWD! The workshop manual's index lists 4WD systems but when you go to the section and start reading, it uses the term AWD.
Again, the index use of the 4WD is probably a holdover from the early days.
If you can't at least somehow reduce torque to three wheels, sent it to one, you can't call it AWD and therefore it's a 4WD system.
I'm not sure I fully understand this last/above statement but in my opinion a true 4WD system can be engaged only part time, as was the case with the early FE.
Even so, the Escape is tagged as 4WD
Probably, maybe, because originally the FE was 4WD. Back then it had a manually or automatically selected 4WD system. If manually engaged by the driver the CAUTION was to NEVER do so on a highly tractive surface. The system would automatically engage if front wheelslip/spin was detected but only for 10-15 seconds. This latter a design aspect taken from the old Aerostar R/awd system.
but a Fusion which is described in a Ford workshop manual as having the same exact system is tagged as a AWD! The workshop manual's index lists 4WD systems but when you go to the section and start reading, it uses the term AWD.
Again, the index use of the 4WD is probably a holdover from the early days.
If you can't at least somehow reduce torque to three wheels, sent it to one, you can't call it AWD and therefore it's a 4WD system.
I'm not sure I fully understand this last/above statement but in my opinion a true 4WD system can be engaged only part time, as was the case with the early FE.
Last edited by wwest; 10-01-2009 at 02:14 PM.
#16
10-01-2009, 02:41 PM
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Re: 4WD and the FEH
Here's a question...
Of what good or purpose is the FE/FEH's continuously variable rear driveline clutch coupling if, as described in all the Ford literature, TC is to be activated the instant front wheelspin/slip is detected...?
I suspect that to be the very reason the VC was dropped from the RX330 design. Once TC began to be used to maintain and apportion engine torque a rear driveline coupling VC can have NO PURPOSE. If TC activates as agressively as it seems to. Can't the same be said of the FE/FEH rear clutch system..??
Hmmm....
When the FE/FEH first adopted this new rear clutch system it didn't have TC..??
(are we sure of that..??)
Assuming no TC then in those days the rear clutch ALONE was being used to (potentially) alleviate front wheelspin/slip once it was detected. The clutch then had REAL purpose.
But it was prone to overheating (understandably) if put to continuous or even semi-continuous use. Hmmm.. what to do, what to do..
Ford: Oh, if we reduce the "normal" level of use of rear driveline coupling and then use TC the FE/FEH will be much safer and the rear driveline clutch will NEVER be subject to overheating.
Mazda: If we alleviate overheating of the rear clutch by always using it in a more firm, or fully firm, coupling mode then we may have to find a way to cool the PTO/PTU but then TC only needs to be used if coupling in the rear drive, INSTANTLY coupling in the rear drive, doesn't immediately alleviate front wheelspin/slip...
Anyone know the history of FE/FEH rear drive clutch and/or PTO failures during the period prior to TC adoption..??
Of what good or purpose is the FE/FEH's continuously variable rear driveline clutch coupling if, as described in all the Ford literature, TC is to be activated the instant front wheelspin/slip is detected...?
I suspect that to be the very reason the VC was dropped from the RX330 design. Once TC began to be used to maintain and apportion engine torque a rear driveline coupling VC can have NO PURPOSE. If TC activates as agressively as it seems to. Can't the same be said of the FE/FEH rear clutch system..??
Hmmm....
When the FE/FEH first adopted this new rear clutch system it didn't have TC..??
(are we sure of that..??)
Assuming no TC then in those days the rear clutch ALONE was being used to (potentially) alleviate front wheelspin/slip once it was detected. The clutch then had REAL purpose.
But it was prone to overheating (understandably) if put to continuous or even semi-continuous use. Hmmm.. what to do, what to do..
Ford: Oh, if we reduce the "normal" level of use of rear driveline coupling and then use TC the FE/FEH will be much safer and the rear driveline clutch will NEVER be subject to overheating.
Mazda: If we alleviate overheating of the rear clutch by always using it in a more firm, or fully firm, coupling mode then we may have to find a way to cool the PTO/PTU but then TC only needs to be used if coupling in the rear drive, INSTANTLY coupling in the rear drive, doesn't immediately alleviate front wheelspin/slip...
Anyone know the history of FE/FEH rear drive clutch and/or PTO failures during the period prior to TC adoption..??
#17
10-01-2009, 03:59 PM
Re: 4WD and the FEH
4WD send power to the front wheels or rear wheels and/or a percentage to either. A AWD can send all available power to a single wheel.
#18
10-01-2009, 04:07 PM
Re: 4WD and the FEH
Here's a question...
Of what good or purpose is the FE/FEH's continuously variable rear driveline clutch coupling if, as described in all the Ford literature, TC is to be activated the instant front wheelspin/slip is detected...?
I suspect that to be the very reason the VC was dropped from the RX330 design. Once TC began to be used to maintain and apportion engine torque a rear driveline coupling VC can have NO PURPOSE. If TC activates as agressively as it seems to. Can't the same be said of the FE/FEH rear clutch system..??
Hmmm....
When the FE/FEH first adopted this new rear clutch system it didn't have TC..??
(are we sure of that..??)
Assuming no TC then in those days the rear clutch ALONE was being used to (potentially) alleviate front wheelspin/slip once it was detected. The clutch then had REAL purpose.
But it was prone to overheating (understandably) if put to continuous or even semi-continuous use. Hmmm.. what to do, what to do..
Ford: Oh, if we reduce the "normal" level of use of rear driveline coupling and then use TC the FE/FEH will be much safer and the rear driveline clutch will NEVER be subject to overheating.
Mazda: If we alleviate overheating of the rear clutch by always using it in a more firm, or fully firm, coupling mode then we may have to find a way to cool the PTO/PTU but then TC only needs to be used if coupling in the rear drive, INSTANTLY coupling in the rear drive, doesn't immediately alleviate front wheelspin/slip...
Anyone know the history of FE/FEH rear drive clutch and/or PTO failures during the period prior to TC adoption..??
Of what good or purpose is the FE/FEH's continuously variable rear driveline clutch coupling if, as described in all the Ford literature, TC is to be activated the instant front wheelspin/slip is detected...?
I suspect that to be the very reason the VC was dropped from the RX330 design. Once TC began to be used to maintain and apportion engine torque a rear driveline coupling VC can have NO PURPOSE. If TC activates as agressively as it seems to. Can't the same be said of the FE/FEH rear clutch system..??
Hmmm....
When the FE/FEH first adopted this new rear clutch system it didn't have TC..??
(are we sure of that..??)
Assuming no TC then in those days the rear clutch ALONE was being used to (potentially) alleviate front wheelspin/slip once it was detected. The clutch then had REAL purpose.
But it was prone to overheating (understandably) if put to continuous or even semi-continuous use. Hmmm.. what to do, what to do..
Ford: Oh, if we reduce the "normal" level of use of rear driveline coupling and then use TC the FE/FEH will be much safer and the rear driveline clutch will NEVER be subject to overheating.
Mazda: If we alleviate overheating of the rear clutch by always using it in a more firm, or fully firm, coupling mode then we may have to find a way to cool the PTO/PTU but then TC only needs to be used if coupling in the rear drive, INSTANTLY coupling in the rear drive, doesn't immediately alleviate front wheelspin/slip...
Anyone know the history of FE/FEH rear drive clutch and/or PTO failures during the period prior to TC adoption..??
I don't know when TC was included on the Escape.
Yes, the 4WD and AWD should both be based on slippage instead of "whatever" it's based on now. It sure isn't slippage now!
#19
10-01-2009, 04:27 PM
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Re: 4WD and the FEH
The 4WD part of the system controls torque between the front wheels and rear wheels. The TC can control torque to any of the four wheels.
I don't know when TC was included on the Escape.
Yes, the 4WD and AWD should both be based on slippage instead of "whatever" it's based on now. It sure isn't slippage now!
I don't know when TC was included on the Escape.
Yes, the 4WD and AWD should both be based on slippage instead of "whatever" it's based on now. It sure isn't slippage now!
Other than "spreading" the HIGH FEH torque across more tread surface during low speed acceleration of what good is the electromechanical rear driveline clutch...??
Follow my thoughts...
1. The rear driveline clutch was overheating.
2. As a temporary measure the rear driveline clutch would be fully engaged to reduce internal frictional surface heating.
3. If "2" proved to be non-effective then the driver was "notified" and advised to stop and allow the clutch time to cool down.
4. For how long and how often did "2" work..??
5. When "2" worked, during the time, ENTIRE time, "2" worked the driveline stress was simply "moved" elsewhere.
6. The PTO began to overheat and "blow" lubrication seals.
7. the FE/FEH driveline stress HAD to be reduced.
8. Simple, revise the firmware such that only TC is used to sustain and "re-apportion" engine torque.
Everyone knows that the FE/FEH NEEDED VSC/TC anyway so no big deal.
Like the VC in the Lexus RX series, the FE/FEH's rear drive electromechanical clutch becomes virtually useless.
#20
10-01-2009, 07:53 PM
Re: 4WD and the FEH
But my point is, was, if TC is going to brake the front wheels and dethrottle the engine the instant front wheelspin develops why not use a simple open center diff'l like the Highlander, Sienna, and RX..??
Other than "spreading" the HIGH FEH torque across more tread surface during low speed acceleration of what good is the electromechanical rear driveline clutch...??
Follow my thoughts...
1. The rear driveline clutch was overheating.
2. As a temporary measure the rear driveline clutch would be fully engaged to reduce internal frictional surface heating.
3. If "2" proved to be non-effective then the driver was "notified" and advised to stop and allow the clutch time to cool down.
4. For how long and how often did "2" work..??
5. When "2" worked, during the time, ENTIRE time, "2" worked the driveline stress was simply "moved" elsewhere.
6. The PTO began to overheat and "blow" lubrication seals.
7. the FE/FEH driveline stress HAD to be reduced.
8. Simple, revise the firmware such that only TC is used to sustain and "re-apportion" engine torque.
Everyone knows that the FE/FEH NEEDED VSC/TC anyway so no big deal.
Like the VC in the Lexus RX series, the FE/FEH's rear drive electromechanical clutch becomes virtually useless.
Other than "spreading" the HIGH FEH torque across more tread surface during low speed acceleration of what good is the electromechanical rear driveline clutch...??
Follow my thoughts...
1. The rear driveline clutch was overheating.
2. As a temporary measure the rear driveline clutch would be fully engaged to reduce internal frictional surface heating.
3. If "2" proved to be non-effective then the driver was "notified" and advised to stop and allow the clutch time to cool down.
4. For how long and how often did "2" work..??
5. When "2" worked, during the time, ENTIRE time, "2" worked the driveline stress was simply "moved" elsewhere.
6. The PTO began to overheat and "blow" lubrication seals.
7. the FE/FEH driveline stress HAD to be reduced.
8. Simple, revise the firmware such that only TC is used to sustain and "re-apportion" engine torque.
Everyone knows that the FE/FEH NEEDED VSC/TC anyway so no big deal.
Like the VC in the Lexus RX series, the FE/FEH's rear drive electromechanical clutch becomes virtually useless.
Well, if the ATC starts to heat up, it goes into locked mode and if it still heats up more, it disables it. Just what you said.
