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As part of the driving training I do to complement taking my F Type R AWD on the track I've been working on a simulator model of the car.
My instructor took the car out for a few laps recently and he believes that the only feature of the model that is now noticeably different to the real world car is that our model is RWD and my car is AWD.
Is anyone able to point me at any technical details of the F Type's AWD implementation they could share?
In the first instance we're interested in any information about how the torque is split between front and back.
From what I've read the AWD is predominantly RWD until the car detects that a bit of a pull from the front would help. Doubtless someone will be along with a definitive explanation.
Here’s how the transfer case on the XE works, I assume the F-type’s is similar. Pretty simple - a clutch pack grabs onto the driveshaft. With it off, 100% of the torque goes to the rear. While this doc doesn’t say explicitly, with it on, it should be 50/50 torque split as far as I can tell. I don’t see how it could do more than 50% to the front. https://www.dropbox.com/s/0wqmbes7k5...0Case.pdf?dl=0
Does the F-Type R AWD have a "Drive Information" menu screen like the AWD F-Pace models do? It doesn't display any measurable units, but it features a real-time display (like bar graphs) of the torque distribution. On my AWD F-Pace, I've noticed it's RWD the majority of the time in normal driving (cruising) but will gradually apply more power forward with each commensurate degree of additional throttle angle. It will send "max" (whatever figure that is, 50%?) forward at WOT.
It's 100% RWD until it detects slip and then the clutch pack transfers up to 50% of available torque to the front. Switching it into Rain/Snow mode locks the split at 50/50.
A while ago, to reply to a similar forum query, I found a piece in the Jaguar Owner's website that claimed that, normally, 90% of the torque goes to the real wheels. With the IDD that's part of Jaguar AWD, that torque changes automatically with driving conditions. And when you turn on Rain/Snow/Ice, the torque is directed to both the front and rear equally.
Unfortunately, none of that information is readily apparent on dashboard displays or even iGuide. Too bad. I have mixed feelings about whether the car smugly acts smarter than I do.
Sorry to add a different perspective, but I had learned differently. Yes, I concur than unless demanded (and not sure of the algorithm that detects/delivers demand - i.e. torque - up front), but rears always until the trigger then engages the front wheels. I read some technical discussion somewhere that stated each of the front wheels can deliver up to 100 ft. lbs. With nominally 500 ft.lbs. available, that's 300 or more to the rear wheels, and up to 200 to the front wheels.
Sorry to add a different perspective, but I had learned differently. Yes, I concur than unless demanded (and not sure of the algorithm that detects/delivers demand - i.e. torque - up front), but rears always until the trigger then engages the front wheels. I read some technical discussion somewhere that stated each of the front wheels can deliver up to 100 ft. lbs. With nominally 500 ft.lbs. available, that's 300 or more to the rear wheels, and up to 200 to the front wheels.
inmainlanier,
I'd be interested in your sources. I did some research on Ford's "Intelligent AWD" after I bought my F-150 (presumably, specifics of which would have been available to the JLR engineers), and a bit more on Jaguar's Intelligent AWD and the "Intelligent Driveline Dynamics" (IDD) systems. But nothing I found included anything about actual torque measurements. Thanks.
FWIW, generic "Intelligent AWD" typically reads sensors on wheels, steering angle, yaw rate and sends those to Electronic Control Unit. That computer (i.e. your "trigger") would read those and might then send instructions for power to be sent AWAY from wheel(s) with traction loss and TO wheel(s) with most traction.
inmainlanier, ... I'd be interested in your sources.
The problem with being at Medicare age is memory. I've learned to carefully qualify anything I can't at the time verify, but along those same lines I am NEVER inclined to analy extract miscellaneous caca to try and impress people. My vague recollection was a ZF publication as the source. No promises, but if intrigued enough I'll try and find the source.
Jaguar is introducing a new All-Wheel Drive (AWD) system to its 2013 Model Year XF and XJ saloon cars for selected markets powered exclusively by a new 340PS (335 hp, 250 kW) 3.0-liter V6 supercharged gasoline engine, a ZF eight-speed automatic transmission, and Stop/Start technology.
Jaguar AWD. Click to enlarge.Jaguar AWD operates intelligently, continuously monitoring grip levels and driver inputs to both pre-empt and react to wheel-slip, enabling maximum traction in all conditions.
Feed-forward torque distribution allows the system to actively anticipate wheel slippage and prevent it occurring, therefore providing greater driver confidence and vehicle stability in low-grip scenarios. Torque split can be up to 50:50 front/rear. At speed in normal grip conditions the AWD system is rear-wheel drive-biased.
The longitudinal engine installation means Jaguar’s engineers were able to retain the rear axle as the primary drive path, with a multiplate clutch within the transfer case apportioning torque to the front axle as dictated by grip conditions and driver inputs.
Providing the power for the All-Wheel Drive system is Jaguar’s new all-aluminium 3.0 V6 S/C 340 gasoline engine, which delivers 450 N·m (332 lb-ft) peak torque output produced from 3500-5000 rpm, with 400 N·m (295 lb-ft) available from just over 2000rpm for low-down pulling power.
The 3.0 V6 S/C 340 utilizes dual independent variable cam timing (DIVCT) and spray-guided direct injection (SGDI), allied to new spark plug orientation that aligns the electrode precisely within the combustion chamber for enhanced efficiency. These features, along with a compression ratio of 10.5:1, optimize power, torque and economy throughout the rev range.
The latest twin-vortex Roots-type supercharger is mounted in the V of the engine and features electronically managed boost control which offers operating efficiencies of up to 20%. A system of counter-rotating front and rear balancer weights devised by Jaguar’s engineers ensure the V6’s refinement matches that of the marque’s 5.0-liter gasoline V8s.
Utilizing a twin solenoid starter, the Jaguar Intelligent Stop/Start system is able to restart the engine in less time than it takes for the driver’s foot to move from the brake to the accelerator.
The All-Wheel Drive system utilizes the eight-speed automatic gearbox, standard on all XF and XJ models for the 2013 Model Year, but modified to accept the fitment of a transfer case with an active coupling which directs torque to a new front propshaft, front differential and halfshafts as required.
The multiplate wet clutch coupling directs torque through the front propshaft as dictated by the Transfer Case Control Module (TCCM), which monitors grip levels and driver inputs, apportioning the torque front and rear as appropriate.
In order to accommodate this All-Wheel Drive hardware in both the XF and XJ, a new front subframe, cross member, engine mounts and exhaust system have been engineered. The system has been optimally packaged with the front driveshafts running through the engine sump for a lower centre of gravity. The engine itself receives a recalibrated ECU to allow it to communicate with the active transfer case while under-bonnet modifications have been carried out to the fuel lines, hoses, air intake and exhaust to accept the new systems. A new engine undertray and heatshield incorporates a transmission tunnel acoustic pack to ensure refinement is identical to the rear-wheel drive models.
In dry road conditions, the All-Wheel Drive system operates in such a manner that all the dynamic qualities of the rear-wheel drive models are preserved by prioritizing torque delivery to the rear axle. The exception to this is on pull-away from rest when a pre-load torque is always applied to the front wheels to ensure smooth initial acceleration.
This is governed by the feed-forward element of the control algorithms, whereby situations in which wheel-slip might occur are predicted and accounted for by delivering torque to the front wheels as a pre-emptive measure to eliminate the possibility of a loss of grip. Because it is an active, rather than passive, torque delivery method, feed-forward allows the car to offer all-wheel drive security entirely unobtrusively while retaining dynamic rear-wheel drive handling characteristics.
The system constantly monitors road conditions, throttle and steering inputs and should any slip be detected between the front and rear axles, the TCCM will automatically apply reactive feed-back torque to negate any difference in front and rear wheel speeds. The maximum torque split is 50:50 front to rear.
When operating in Winter mode—selected by using the Jaguar Drive Control buttons—the feed-forward function is strengthened to pre-empt the possibility of wheel-spin. In addition, the Dynamic Stability Control system constantly monitors wheel-slip across each axle and uses the anti-lock braking system to selectively brake each of the four wheels as necessary to prevent wheel-spin.
Jaguar Drive Control also offers the driver the option of Dynamic mode in which throttle response is sharpened and the gearbox is instructed to upshift more quickly and at higher revs. Dynamic mode also firms up the damper settings in vehicles equipped with Adaptive Dynamics to deliver more precise, controlled body movements to enhance handling. In Dynamic mode, the All-Wheel Drive system operates in the same manner as in Normal mode.
This sounds like the XE transfer case, about which I posted technical info earlier. And the AWD display in the XE agrees with what you posted. At a stop, it shows RWD. As you pull away, it show some torque going to the front. Putting it in snow is similar, thought I’m sure if it detected a slippery surface, it would behave direct more to the front. Like the snow mode on my RWD F-type, it does make the throttle much less sensitive.
This sounds like the XE transfer case, about which I posted technical info earlier. And the AWD display in the XE agrees with what you posted. At a stop, it shows RWD. As you pull away, it show some torque going to the front. Putting it in snow is similar, thought I’m sure if it detected a slippery surface, it would behave direct more to the front. Like the snow mode on my RWD F-type, it does make the throttle much less sensitive.
Agree, just sharing. Likely the same systems (a company would be super silly to have different systems across cars given their numbers...same tranny, likely same ecu, sensors, network, tcu, transfer case tech, even brake calipers.... Just how you do things these days to make things reliable (and manage spare parts/repair training, etc.). HP, mass, and other things just change the model but I suspect the code is pretty similar across the whole of the product lines.
Found this at "Green Car Congress" via google....2012 so pretty much the system that came with the F-type's launch date once awd happened:
The system constantly monitors road conditions, throttle and steering inputs and should any slip be detected between the front and rear axles, the TCCM will automatically apply reactive feed-back torque to negate any difference in front and rear wheel speeds. The maximum torque split is 50:50 front to rear.
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I looked a bit with no luck. My memory on stuff like this is pretty good - if I would have read 50/50 (on the V8) I would have remember that. An oddity like 100 ft.lbs. limit each front tire (and the overall being around 40%) I would think would stick with me. As I recall the front wheel torque delivery is through electronic clutches, yes? I would think they have a maximum limit, which tends to support my recollection. Oh, well. I'll try one more time.
I looked a bit with no luck. My memory on stuff like this is pretty good - if I would have read 50/50 (on the V8) I would have remember that. An oddity like 100 ft.lbs. limit each front tire (and the overall being around 40%) I would think would stick with me. As I recall the front wheel torque delivery is through electronic clutches, yes? I would think they have a maximum limit, which tends to support my recollection. Oh, well. I'll try one more time.
not to worry, inmanlanier. Your earlier post led me down a ZF tranny rabbit hole.
For example, if you believe Wikipedia, the ZF 8HP70 unit put into F-type (V6/V8) produces about half again as much torque as the 8HP45/50 units put into XF's and XE's
Woo hoo!
(hmmm.... to be pedantic, some of the 8-speed XE & XF V6/V8's have the 8HP70 or 8HP75 units, not the 45/50's)
<Also, FWIW, I'm not trying to impress. It's just that I seem to be genetically cursed with sucking up miscellaneous semi-useless info --- over thirty years in IT, plus my 90+ year old mother (a former XK120 owner) still takes only a day or so to complete the NY Times Sunday crossword puzzle. Go figure... I guess I just gotta do something to keep the brain from going stale.>
For example, if you believe Wikipedia, the ZF 8HP70 unit put into F-type (V6/V8) produces about half again as much torque as the 8HP45/50 units put into XF's and XE's>
I thought the engine produced the torque, the tranny just has to be able to cope with it? The "70" in 8HP70 indicates 700Nm of torque capacity, so presumably the 45/50 will cope with 450/500 Nm.
I though the engine produced the torque, the tranny just has to be able to cope with it? The "70" in 8HP70 indicates 700Nm of torque capacity, so presumably the 45/50 will cope with 450/500 Nm.
Mea culpa. Obviously, you're right, and I apologize for the misstatement and oversimplification.
As far as your presumption as to model names & torque units, that pretty much jibes with the list of ZF models in the Wikipedia article... with a few minor exceptions.
FWIW, according to that article, it appears that the Alfa Romeo Stelvio rental I had in Honolulu earlier this year had an 8HP50. Humph.... No wonder that it was a far better driving experience than the Camaro I had rented later. (don't ask)
R AWD - technical details?
Jaguar AWD. Click to enlarge.Jaguar AWD operates intelligently, continuously monitoring grip levels and driver inputs to both pre-empt and react to wheel-slip, enabling maximum traction in all conditions.