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Midsize Sedans 2.0

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  • akirbyakirby Posts: 7,747
    Since Fusion uses a reactive AWD system (rear wheels engage only if slippage is detected in the front wheels),

    Wrong again. Ford's AWD system used in the Fusion, Taurus and Edge will actually predict the need for power to the rear before slippage occurs based on driver inputs (throttle position, etc.). This is far more useful than a reactive only system.
  • captain2captain2 Posts: 3,971
    the only fuel saving technology in the now discontinued Accord Hybrid really was the variable displacement system used to minimize fuel consumption the V6. For 08 this system is now standard on all V6s. As on all Honda 'Hybrids' the electric motors are provided to essentially supplement the gas engine, no to periodically replace it - as on the Toyota system, for example. Since electric motors provide maximum torque at 0 rpm (at startup) the Accord Hybrid is indeed very quick with the additional benefit of that 240hp V6 working on all its cylinders. There is however very little benefit to the system in terms of fuel economy - which I guess is why Honda has had trouble getting folks to pay the extra money for it. The diesel, of course, will change all that and may actually justify an assummed price premium over the standard 4 banger.
  • robertsmxrobertsmx Posts: 5,525
    I will be curious where "again" came from. But as far as Fusion's AWD system is concerned, this should tell you something you might not be aware of. An excerpt:

    The Ford-developed technology is similar in many ways to the Haldex system, Kurrle says, without revealing exactly what changes were made. “This is a ‘slip-and-grip’ system. It detects the slip of the front wheels and transfers torque, similar to the Haldex system.”
  • captain2captain2 Posts: 3,971
    boy, do I have some swampland for you - another case of believing some of that seemingly endless publicity. Perhaps you would like to explain how the car can 'know'
    this and can anticipate that icy spot on the road or whatever, thereby correctly guessing something is going to happen before it does. My God, just think about it. Of course, systems like this are reactive, just like SC systems, and not just Ford's.
  • jeffyscottjeffyscott Posts: 3,855
    Just ask him what his mpg was when he drove a Focus, then you will know it is the type of driving and not the car.
  • akirbyakirby Posts: 7,747
    Maybe THIS will tell you something that you obviously aren't aware of:

    “What’s really impressive about these systems is that they don’t just react to slip,” says Rodrigues. “They usually prevent that slip from occurring in the first place. By predicting slip and preventing it, the driver doesn’t feel the vehicle slipping and responding. The operation is seamless.”
  • akirbyakirby Posts: 7,747
    Perhaps you would like to explain how the car can 'know'
    this and can anticipate that icy spot on the road or whatever, thereby correctly guessing something is going to happen before it does. My God, just think about it. Of course, systems like this are reactive, just like SC systems, and not just Ford's.


    Ok, try to pay attention this time. Of course the system reacts to an icy spot by sensing a loss of traction in the front wheels and transferring torque to the rear. It has to do that. But what it ALSO does is sense when rear torque is likely to be needed BEFORE slip occurs. How does it do this? Simple. The computer knows the steering angle and the throttle position at all times. If you're accelerating into a turn or just accelerating hard then it knows this before slippage occurs and it can compensate.

    It's not rocket science.
  • kdshapirokdshapiro Posts: 5,751
    That is marketing bunk. AWD/4WD vehicles cannot predict slip. They can only react when slip occurs, even before the driver knows it's occuring. How in sam hill for example, can an AWD tell if it's raining and the limits of grip are lower? The obvious answer is they can't. It can only react to a preprogrammed difference in input parameters for the system.

    BMW which IMO has the best DSC type in it's class, cannot predict slip. The system only reacts on inputs so miniscule the driver does not know it.
  • robertsmxrobertsmx Posts: 5,525
    I see more marketing talk there than technical. What is being done to “proactively” counter slip? There is no mention of that. What I do see is that under non-slip conditions, Fusion’s AWD system doesn’t come into effect.

    No AWD can pre-detect slippage. Some may pro-actively engage all wheels during situations that may induce slippage. Honda’s VTM-4 system used in Pilot has an Acceleration Torque Control module to do that. All wheels are engaged whenever the vehicle is accelerated. Otherwise the system remains reactive, waiting for slip detection and fix (“seamlessly” in marketing speak).

    Does Fusion have something similar that engages all wheels by expecting slippage as opposed to functioning only when detecting one?

    Even then, these systems do not put as much drag on drive line as do those that are engaged permanently (that is one of the ideas behind developing such systems). So, they shouldn’t affect fuel economy as much either.
  • captain2captain2 Posts: 3,971
    The computer knows the steering angle and the throttle position at all times.
    exactly, the computer is REACTING to that steering angle and throttle position, and therefore pushing a little power to the rear wheels. As you say ain't exactly rocket science.
  • akirbyakirby Posts: 7,747
    Why is it marketing bunk? Because Ford developed it? Or just because you don't understand it?

    From an engineering standpoint it's quite simple. First, remember that this is an electro-mechanical system, not a mechanical only system. If it was mechanical only then you would be correct. The Fusion has ETC so the computer knows the throttle position. It also knows the steering angle. If you accelerate while turning the computer says "hey - there might be a loss of traction" so it tells the center diff to shift torque to the rear wheels - BEFORE IT ACTUALLY STARTS TO SLIP.

    It has nothing to do with whether the front wheels would actually slip or not - it doesn't matter. It shifts the torque to prevent a POSSIBLE slip.

    If BMW's AWD system doesn't work that way then maybe they need to license the technology from Ford.
  • captain2captain2 Posts: 3,971
    robert - I guess we're kinda on the same page on this, but the only system I know of that proactively does anything is the 'Collison Avoidance' systems on some of the Lexus (MB?) models and even that is tightening seatbelts, disabling throttle and applying the brakes in REACTION to what it (the computer) sees as an impending collison. Dangerous stuff IMO.
  • akirbyakirby Posts: 7,747
    But the point is it shifts the torque BEFORE the front wheels lose traction, so it's not ONLY reacting to front wheel slippage - it's also preventing it under some circumstances.
  • akirbyakirby Posts: 7,747
    Does Fusion have something similar that engages all wheels by expecting slippage as opposed to functioning only when detecting one?

    It does both - shifts torque when slippage is detected AND shifts torque when slippage is expected.
  • captain2captain2 Posts: 3,971
    but you don't concede the fact that this (and many other systems) are really reacting to what some computer programmer somewhere is really guessing to be a problem - in this case your precious steering angle combined with a throttle setting. Think about it - this is Pandora's box - a computer program making driving decisions for us. This does, BTW, go well past silly AWD systems BTW and can be more invasive than simply routing some power to the rear wheels. Of course Ford is well behind the curve on things like SC systems. Since so many folks want these kind of things I wonder how many sales Ford loses simply because it won't add an extra circuit to the brake systems (and a yaw sensor) on the Fusion and therefore doesn't even offer Stability Control - for any price. That's OK I guess, Ford will do it when the government forces them to.
  • akirbyakirby Posts: 7,747
    That's an entirely different argument - whether the computer should be making these decisions for us. The original assertion was that it only sent torque to the rear if slippage was detected and that's not true.

    I'm sure Ford is losing a few sales over lack of SC in the Fusion. But that doesn't mean they're behind the curve from a technology standpoint. SC was available in 1999 on the Lincoln LS (as was manumatic shifting) so the technology is there. They were also the first to put roll stability control on a SUV IIRC.

    You could argue the same thing about the Camcord's lack of AWD. Ford decided to spend the money on AWD while Toyota and Honda spent it on 4 channel ABS and SC. And just because YOU prefer SC over AWD doesn't mean everyone does.

    Next year the Fusion will have both AWD and SC. Where does that leave the Camcords?
  • kdshapirokdshapiro Posts: 5,751
    Why is it marketing bunk? Because Ford developed it? Or just because you don't understand it?

    Because this would make them the first manufacturer on the face of the planet to predict slip "before" it occurs and that ain't so. You cannot predict "slip" any more than you can predict the stock market.

    It has nothing to do with whether the front wheels would actually slip or not - it doesn't matter. It shifts the torque to prevent a POSSIBLE slip.

    They can say whatever they want different systems work differently. But I'll repeat....Slip can not be predicted and therefore proactive shift of torque to prevent slip is an impossibility.
  • robertsmxrobertsmx Posts: 5,525
    Where can I read about that? I haven't found anything on the topic.
  • robertsmxrobertsmx Posts: 5,525
    Acura's CMBS system is another. But we would be digressing from the topic.

    One example of engaging all wheels proactively (as in... no need to detect slippage before doing so) in an AWD system is Honda's VTM-4. But, it doesn't know if a slippage will occur. It will simply engage all wheels when the vehicle is being accelerated. There might be other systems like it, but so far I haven't found anything that suggests Ford's AWD in Fusion/Milan works like that (or engages without detecting any loss of traction). I will now leave that for akirby to provide us with the details.
  • baggs32baggs32 Posts: 3,221
    but you don't concede the fact that this (and many other systems) are really reacting to what some computer programmer somewhere is really guessing to be a problem

    In that case evey AWD/4WD system should be called a "reactive" system. Even a full time system like those in Subarus are reacting to something electronic or mechanical in the driveline. Akirby's point is that 4WD can be engaged in the Fusion without slippage of the front wheels. Our Explorer has the same system, but for RWD, and I do feel the rear wheels slip in snow, ice, and sometimes rain before the front wheels kick in too. What I don't feel is when it might be kicking in going around a bend or something like that. But the part you really need it for IMO, which would be getting better traction in slippery conditions, is totally reactive and you can feel the wheels slip a little at first.

    Does that make a little more sense or am I just adding to the confusion? :blush:

    Of course Ford is well behind the curve on things like SC systems.

    Whoa now captain. They may be behind in offering in on their fleet of cars but all of the SUVs/CUVs, and optional on some cars now, have it standard. And what Ford uses is not the same animal as what other mfrs offer.

    Look up Volvo's SC with RSC system and you'll see the difference right away. Most mfrs are now copying it but I have yet to hear of one that's better than what Volvo and therefore Ford use.
  • baggs32baggs32 Posts: 3,221
    One example of engaging all wheels proactively (as in... no need to detect slippage before doing so) in an AWD system is Honda's VTM-4. But, it doesn't know if a slippage will occur. It will simply engage all wheels when the vehicle is being accelerated.

    That seems really silly to have it work that way. Why not just send a little power to the other two wheels all the time rather than programming it to start from 0% and work up from there each time the accelerator is depressed? Is it a cost savings thing so they don't have to add another clutch or something? :confuse:
  • akirbyakirby Posts: 7,747
    Where can I read about that? I haven't found anything on the topic.

    I posted the link in post 7051. Here it is again:

    Ford Media Article
  • andres3andres3 CAPosts: 5,343
    now that most cars in this segment are very reliable, it's refreshing that I'm not married to a brand anymore and am willing to consider other options.

    Where do you get that incorrect idea, impression, and opinion?
  • akirbyakirby Posts: 7,747
    Because this would make them the first manufacturer on the face of the planet to predict slip "before" it occurs and that ain't so. You cannot predict "slip" any more than you can predict the stock market.

    Slip can not be predicted and therefore proactive shift of torque to prevent slip is an impossibility.

    You are absolutely totally missing the point. Slip is most likely to occur when accelerating briskly or when cornering. Doesn't mean that it will occur - just that it's possible or even likely depending the road conditions. Ford's AWD software senses one or both of those conditions and sends torque to the rear to AVOID a potential slip situation.

    Why is that so hard to comprehend? All you need is a steering angle sensor, throttle sensor, electrically controlled center diff and some softwtare. It's not rocket science.
  • kdshapirokdshapiro Posts: 5,751
    Ford's AWD software senses one or both of those conditions and sends torque to the rear to AVOID a potential slip situation.

    Ok, I understand what you are saying. The Ford system detects acceleration shifts accordingly. That is different than saying it is able to predict slippage.

    As a comparision, Subaru's system has been doing that for years. I posted a description in this thread earlier.
  • backybacky Twin CitiesPosts: 18,784
    Here's a list of mid-sized cars that are above average in predicted reliability according to CR:

    Accord (based on history--current model is a new design)
    Camry I4
    Fusion
    Milan
    Passat V6
    Prius
    Sonata

    Those cover a very large percentage of cars sold in this segment. Several others are at least average:

    Malibu (pre-2008 model)
    Mazda6
    Galant
    G6

    Altima, Aura, Optima, and Avenger/Sebring are too new for CR to have enough data to rate them for reliability. Altima has historically been reliable.
  • robertsmxrobertsmx Posts: 5,525
    That article doesn't speak anything about being pro-active. It does about the system being FWD-only under normal driving conditions. What do you think is "non-normal"? (since the link you provided doesn't talk about it) Thats the missing link.
  • robertsmxrobertsmx Posts: 5,525
    SH-AWD does that with all wheels engaged at all times, and it is an evolution of VTM-4. But like I said earlier, permanent AWD systems come with a cost. Sending power to additional wheels on occasions when it makes no discernable difference does nothing but adds to drive train loss (which equals reduced fuel economy). So, while VTM-4 is capable of sending up to 70% of the torque to rear wheels, it won’t keep any part of it during steady state cruising conditions. 2WD is easier on fuel economy than 4WD with all wheels engaged.

    VTM-4 does allow a lock mode to engage all wheels permanently, and will keep it that way for as long as you choose to drive under 18 mph. :P
  • akirbyakirby Posts: 7,747
    That article doesn't speak anything about being pro-active. It does about the system being FWD-only under normal driving conditions. What do you think is "non-normal"? (since the link you provided doesn't talk about it) Thats the missing link.

    Umm....how about the entire last paragraph? Try this:

    Simple mechanical systems use a clutch to send torque to the secondary drive axle when the primary axle starts to slip. Today’s electronic systems — like those found on all Ford Motor Company cars as well as Ford Explorer and Expedition, the Lincoln Navigator and the V-8 Mercury Mountaineer — use a computer controller that monitors such things as steering angle, accelerator pedal position and engine speed to provide the precise amount of torque, front to rear, as needed.

    “What’s really impressive about these systems is that they don’t just react to slip,” says Rodrigues. “They usually prevent that slip from occurring in the first place. By predicting slip and preventing it, the driver doesn’t feel the vehicle slipping and responding. The operation is seamless.”

    He says on-demand systems create a smooth, confident driving feel in all weather conditions with much better traction. The systems also help balance and improve driving dynamics by sending torque to the secondary axle when it’s most appropriate for handling.

    “On a normal front-drive vehicle, the front wheels have a limited amount of traction available to them,” says Rodrigues. “That traction has to be used for moving the car forward and for steering. If you use all of the torque to drive forward, you don’t have anything left to steer with, and vise versa. An AWD system off-loads some of that drive torque to the rear wheels. The harder you accelerate, the more of that torque that’s going to be redirected to the rear wheels, restoring the ability of the front wheels to steer the vehicle while providing an even higher level of acceleration.”
  • robertsmxrobertsmx Posts: 5,525
    Again, it doesn't tell you anything about the condition(s) that the system sees as having a potential to cause slippage. That is the missing piece.

    The paragraph/link from Ford PR is emphasizing on seamlessness/transparency of the system, not on how it works or when it works.
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