Ferrari 4WD Technology | FerrariChat

Ferrari 4WD Technology

Discussion in 'FF/Lusso' started by werewolf, Jan 30, 2011.

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  1. werewolf

    werewolf F1 World Champ
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    goodbye
  2. werewolf

    werewolf F1 World Champ
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    A better description of the technology used to drive the front wheels (that's probably more accurate than my inferences from the patent :( ), can be found here :

    http://www.topgear.com/uk/car-news/ferrari-ff-2011-01-25

    the 4wd technology sounds very compact, and very clever :)

    well done, Ferrari !!!
     
  3. werewolf

    werewolf F1 World Champ
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    i think i've got a thread all to myself :)

    It's really a brilliant execution of compact engineering to fit some form of differential, gear reduction and clutch into a small unit on the front of the motor. I think the basic premise is that the front wheel drive is only used to aid, or supplement, the rear wheel drive ... during times of "need" (i.e. low rear-wheel traction) ... rather than become a true 4WD vehicle for extended periods of time. Certainly this "design premise" allows for some more "compact optimization" than what's offered in a Nissan GT-R, for example.

    When i read about "slipping clutches" in the article above, my first concern was proper heat dissipation. But then i remembered about the clutch packs in standard limited-slip differentials, so i'm thinking that's already a "solved problem" :) So ... clever use of clutch packs, plus limited gear selection, allows a pretty compact unit attached to the front of the motor for limited-use front wheel drive to "augment" the rears.

    Again, well done Ferrari !
     
  4. Russ Birch

    Russ Birch Formula Junior

    Oct 31, 2003
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    OK, although when I first saw the pictures of the red FF, I cocked my head to one side and said WTF?

    That was two weeks ago. I have seen the silver 3/4ths shot and have read more about the car and agree that they have hit a home run. I love it. (still wish they had reworked the hump, though!)

    I can't wait to see one in the flesh and hear that monster v12 shake the neighborhood. -- It may be kinda like puting a roller 427 in a Honda Odessy!
     
  5. werewolf

    werewolf F1 World Champ
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    i like the way you think .... !!!
     
  6. F2003-GA

    F2003-GA F1 World Champ
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    I like the fact that it runs in rear wheel drive only when in Race mode
     
  7. SSNISTR

    SSNISTR F1 Veteran

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    Same here. For a true drivers car, RWD is what you want....glad they gave it that option by turning a knob.
     
  8. Tifosi15

    Tifosi15 Formula 3

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    The 4wd system is nice in that it's not a power sapping system like those that utilize a center diff. I think Ferrari's done it right, also in the fact that it's primarily a RWD system
     
  9. FerrariMC

    FerrariMC Formula Junior

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    Guys, what exactly are "slipping clutches?" By the way, I love the new FF, it's fantastico. Can't wait to drive it and even before that, I can't wait to just see it in person!

    Mark
     
  10. Doctor7474

    Doctor7474 Formula Junior

    Jun 20, 2010
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    They are clutches in an oil bath just like limited slip in most 4wd vehicles. When driving in a straight line they do not slip and apply full power to both wheels (in a diff) or to the front or rear drive shafts (in a center diff). When you turn the outter wheels have to turn faster to cover the same distance than the inner wheels so they have to travel at 2 different speeds, thus you need a mechanical disconnect in the differential to allow this or the axles will bind up and cause sever wheel hop, if anyones drove or rode in a drag car with a spool that connects the axles side to side than you know how bad the wheel hop and loss of traction is when you turn, this is in fact illegal for road use because it is dangerous. Now with limited slips they put a wet clutch in between the axles or drive shafts (in a center diff) and one axle or drive shaft is moving at a different speed than the other the clutches slip to keep them from binding.

    Now some mfg's have developed a gear based limited slip which in my opinion is more reliable but a little heavier than clutches, these clutches will wear out over time and need to be replace, and I don't imagine the Ferrari ones will be cheap....

    How stuff works is awesome:


    http://auto.howstuffworks.com/differential.htm

    Almost all AWD vehicles have a center differential that distributes power between the front and rear wheels and then a differential at both the front and rear so they have 3 differentials and they almost always have limited slip in all 3 differentals that is either viscous based or much more common clutch based.

    Now most 4wd trucks (except Land Rover they use center diffs) use a transfer case, basically these are part time 4wd vehicles. The transfer case only transfers power to the front wheels when it is put in 4wd, these transfer cases almost always do not have any limited slip in them but the front and rear diffs use either open diffs (when turning one wheel does not have any power going to it) or limited slip.

    Hope that helps to explain this.
     
  11. crinoid

    crinoid F1 Veteran
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  12. Tifosi15

    Tifosi15 Formula 3

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    The patent for the 4RM was submitted over 6 years ago, it's been in R&D for at least that amount of time. I think it will be a pretty safe system
     
  13. ingegnere

    ingegnere F1 Veteran
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    From OP of another thread, I love the first sentence:

     
  14. werewolf

    werewolf F1 World Champ
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    from the autocar review :

    "What is particularly interesting about the FF, though, is how it delivers drive to the road, because unlike a conventional all-wheel drive system, there is no centre differential. Instead, for the majority of the time, the FF is effectively a regular rear-wheel-drive Ferrari, with the power directed to the back wheels via a seven-speed, dual clutch transaxle gearbox.

    Only when drive is required at the front axle is power taken directly from the engine into a second gearbox, one with just two forward speeds plus reverse. The fascinating aspect to this system (which Ferrari has patented) is that neither of the two front ratios are a match for those in the rear gearbox. The wheel speed mismatch is then managed by slipping two clutches in the forward gearbox – one for each wheel.

    These clutches also provide the role of the front differential, not only to manage traction but also provide torque vectoring for improved handling. The obvious question here is – don’t the clutches overheat if they are constantly slipping? The answer, apparently, is that in practice drive is being delivered to the front axle only for short periods.

    The main advantages of the system are that it is compact, light (Ferrari claim it adds just 45kg) and that the absence of a front differential means steering feel corruption is minimised.
    "

    It's simply brilliant :)

    And ... aside from true, full-time 4WD vehicles used for extensive off-roading ... it simply obsoletes everything before it.

    WELL DONE FERRARI !!!!
     

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