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Toyota Highlander Hybrid

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Comments

  • cdptrapcdptrap Posts: 485
    In CA, chain requirement is not always automatic for a 4WD or an AWD. It depends on where you drive and the road condition. When CALTRAN requires chains on all cars including 4WD with snow tires, it is condition R3 and they normally just close the freeway at that stage.

    R1 and R2 are the most common conditions. R1 is chains required but all cars with snow tires (on all four) are allowed to proceed without chains. R2 is chains required for all cars except for 4WD & AWD with snow tires on all four wheels. Once in a while, R3 happens before they can shut down the freeway, then everyone stops to put on chains, no exception.

    We have seen AWD vehicle with Snow Tires being waved through in R1 conditions in Sierras and up north. We have seen same in R2 condition up in the Redding, Weaverville area. We have driven in R2 condition up in the Sierras but did not pay attention to which vehicle they waved through. We were too busy putting chains :) onto our non-AWD van. We have not encountered any chain control yet while driving our HH.

    We plan on more trips into the mountains this year, so snow tires is in our budget. Nothing beats sound solid traction where the rubber meets the road or snow or ice.

    From experience, CA definition of "Snow Tires" is any tire branded with M+S, Mud and Snow, M/S and MS. I actually will not trust these rating because they normally show up on "All Season" and we have had unpleasant experience taking these tires onto packed snow. We buy real snow tires with the "Snowflake on the Mountain" branding.
  • stevedebistevedebi LAPosts: 3,796
    "I don't think the AWD does you any good in the high Sierra w/o snow tires since they'll require chains for even 4WD vehicles (and this system really ain't 4WD) that don't have snow tires."

    The times I have been up to Yosemite, they allowed me through with all-season tires and AWD. Summer-only or "performance" tires would not be acceptable.
  • terry92270terry92270 Posts: 1,247
    The problem isn't how safe you drive, but the other guy. ;)

    Quite often, in the Winter, on Highway 330 from San Bernardino to Big Bear Lake, CALTRANS will require either chains or 4/AWD cars only. That's in Southern California, and Big Bear Lake is over 6500 feet.

    So, your question is, having kids, should you spend an extra thousand bucks to be safe(r)? :surprise:
  • @ $41000. bucks the ltd. is a steal. what other suv is fastest suv on road except for porsche cayenne and it doesn't make a sound. drive one lately? it's fun, it's funky and it's fast!!! but only until 9/30 can you get tax credit of $2600. ask your dealer about a 'balloon' finance. which means it costs less than a monthly lease except you own the vehicle (so you can take tax credit). you have a large payment due after 4 years, but so what?, it's still less than what this baby's gonna be worth in 4 years (considering an '04 prius is same price as '06)! put together a small down payment (or a trade to save on tax) and it shouldn't cost you more than $4000./yr to drive this hybrid including gas. maybe even less depending on resale. see ya on the pallisades parkway ( & pallisades police patrol i don't mean you!)
  • wwestwwest Posts: 10,706
    http://www.freepatentsonline.com/6588860.html?highlight=5343970

    Wow...Double that, WOW..!

    I have NEVER seen a more direct admission of the hazards of engine braking on a FWD or front biased AWD in my life, never really expected too, from FORD yet. Good-o.

    You should note that the FEH/MMH regenerative braking is significantly reduced ONLY at, near, or below freezing.

    Regenerative braking is instantly reduced to zero if ABS needs to release the brakes to prevent lockup. But what about the ICE itself, does it raise the ICE RPM simultaneously to prevent actual engine braking?

    Now I am very sure, certain, sure, I never want to drive a FWD or front torque biased AWD in wintertime conditions.
  • cdptrapcdptrap Posts: 485
    Thanks for the info, interesting read.

    Regarding AWD or FWD in winter condition, do you mean just hybrid or all FWD, AWD?

    We have driven FWD vans in Winter condition all over Sierras and Michigan without problems. In Michigan, we put on snow tires (not all season). In the Sierras, we used all-season and put on chains only when required. The HH is our first AWD and it has gone to the Sierras as well and ambient temperature hovered around 30-32F at the time. We had only all-season tires at the time. It drove through wet, slushy and also packed snow fine. I do not believe we hit any ice.

    For the HH, Canadian Driver tested the car on frozen (ice) ground (ambient at -10F) and it came out really well braking and cornering with snow tires (not all season). There are also HH owners here and at other forums reporting safe wintertime driving. Can you please elaborate on your concern? it is good to know.
  • wwestwwest Posts: 10,706
    I have long proposed that the 1-2 second engine/transaxle downshift delay/hesitation many FWD or front torque biased AWD Toyota and Lexus vehicle owners are complaining about has to do with the ECU controlling the transaxle being all too willing to quickly upshift at the slightest hint of throttle lift.

    Up until reading the patent I was willing to attribute the quick upshifting technique as much to FE as to alleviating engine compression braking.

    If you happen to reapply foot pressure at the very instant the transaxle begins the upshift sequence then now you must wait for the upshift to complete before the ECU can even command a downshift which will of itself take a second or so.

    Then there is also the issue of the pumping capacity of the transaxle's internal hydraulic pressure pump. Like the power stearing pump, when the pressurized fluid is not be used to do "work" the energy put into driving the pump is consumed, wasted, as heat.

    So to prevent a horrible level of wasted energy the transaxle's internal pump has always been kept as low in capacity as possible.

    Now here we are, with the fluid pumping capacity at an absolute minimum (engine is at idle), needing to complete a double shift sequence as quickly as possible.

    So yes, Toyota and Lexus have been forced to go to the DBW throttle design to prevent premature transaxle failures. Don't allow the engine to build torque until both shifts have been completed and the pump has then had enough time to "rebuild" the fluid pressure to a level sufficient enough to fully and firmly seat the transaxle clutches.

    There is a rumor afoot that a new TSB is out wherein the internal pump will be upgraded to one with a higher volume if owners really, strongly, complain of problems with the downshift delay/hesitation.
  • stevedebistevedebi LAPosts: 3,796
    "
    Wow...Double that, WOW..!

    I have NEVER seen a more direct admission of the hazards of engine braking on a FWD or front biased AWD in my life, never really expected too, from FORD yet. Good-o."

    Wow, a new record. Cross posting in three different forums...
  • jbolltjbollt Posts: 734
    Wow, a new record. Cross posting in three different forums...

    I've seen it in at least six discussions. :mad:

    I think wwest has made his feelings on FWD clear now.
  • cdptrapcdptrap Posts: 485
    Just read the patent file but got to go. A quick note though. The patent filing Background says ...This may undesirably lead to vehicle instability, especially in rear-wheel drive electric and hybrid electric vehicles.

    It seems to be referring to RWD??

    Anyway, I will read it more carefully over the weekend. Thanks.
  • Does any body have an AVERAGE MPG on Speedometer multi-information display on Highlander Hybrid 2WD? My new Highlander Hybrid does not have AVERAGE MPG.

    Please let me know so I can go back to the dealer to have them fix it.

    Thanks,

    John
  • I believe there is a misunderstanding of the problem the patent is addressing?

    Looking at the patent filing, it seems to say the problem is with transitioning between compression braking and service braking right when ABS has to activate in icy condition. This could explain the "surge" we have encountered in the HH. Just as it is transitioning from compression braking to service braking, a bump causes the traction control to think there is a slip and the ABS activates. Unfortunately, the ABS cannot fully activate until the compression braking is completely done and service brakes kick in. That gap means there is no braking whatsoever, no compression and no service braking. If I am right, this means the car is rolling free for that split second until ABS can engage the service brakes. The "surge" we have been reporting is actually the car suddenly rolling freely, correct?

    If I get this right, there is really no loss of traction and no locked brakes. It only means that for a split second, the car is in full free roll until the ABS kicks in. In the worst case scenario, I can see this resembling the problem with a normal ICE rear-wheel-drive (ICE RWD) car hitting a patch of ice. I believe this is why the patent states that it is a problem for RWD hybrid and electric vehicle.

    I believe FWD cars actually already semi-address this problem. FWD is widely believed to be more stable on ice than RWD with all things being equal. I have driven FWD and RWD in snow and driving experience seems to confirm the FWD theory. Modern AWD has even more systems to maintain directional control. In the case of the HH, I believe the VDIM will behave in time to give driver full control. This is probably why Canadian Driver rated HH so high when they drove it on icy surface at temperature ranging from -20 to -10 F. Their "competitive" driver could not get the HH to slide. If I remember correctly, they rated the HH (on snow tires) #2 just behind the #1 Mercedes.

    I can see why Toyota may want to issue a TSB because to many owners, including I, the "surge" is alarming even in the best conditions. I would rather not feel it at all.

    So it is unclear that this has anything to do with FWD and AWD. In practice, if our HH's have snow tires, not all-season tires, and we drive with caution, there should not be any problem with this compression to service brakes transition on ice. It seems then when we drive in icy condition, with all things being equal, FWD and AWD are actually safer than pure RWD.

    What do you all think? Did I get this all wrong?
  • I know you are specifically asking about the 2WD HH, but for your data bank I have the 2006 HH Limited 4WD-i w/Nav system and I DO have an AVERAGE MPG indicater on my Speedometer muti-information display (in addition to the readout on my Nav System display).

    I assumed that all HH's have this speedometer display of MPG AVERAGE and that my Nav System display was just an added bonus for the big bucks. Heck, my wife's 2001 Toyota Avalon has both an instantaneous and average MPG readout. If HH's don't, I'd be MIGHTY disappointed not having it available. In fact, not having it might have persuaded me not to buy the HH. (Sometimes it's the little details that matter a lot!)
  • billranbillran Posts: 113
    Posts in six different discussions. And over and over and over and over and over again. And all this from someone who does not own and has never even actually driven one of the cars that exhibits the behavior being discussed. Has to make you wonder huh.
  • cdptrapcdptrap Posts: 485
    Just read that patent. I did not misread yesterday, it does refer to problems in RWD hybrid or electric vehicle, not FWD or AWD.

    I have to agree with other posters that this seems like the old regular-ICE RWD car on ice problem. It does not seem to have much to do with FWD or AWD. If I were just coasting our HH and my foot were not on the brake pedal, I would not even feel the "surge" (or "free roll"). We only experienced this "surge" when coasting to a stop with very light touch on the brake pedal. We have experimented with pressing the brake pedal more decisively (slightly harder) in areas that used to cause the "surge" and that seemed to have solved the problem.

    We drove on packed snow this past winter and the car felt secure and stable at whatever speed we were doing, probably around 35-45MPH. In slush and loose snow, it had no problem either. I think using snow tires is the best solution if ice is expected and FWD and AWD should prove more secure than RWD as long as we drive with common sense.

    If there indeed is a TSB, I will definitely look into it. Thanks for the heads up, it is good to know.
  • wwestwwest Posts: 10,706
    IMMHO the patent addresses two issues unique to hybrid vehicles but in some sense applicable to any drive scheme.

    Implementation of the patent will result in a lower level of regenerative braking if the local ambient air temperatures are such, ~35F and below, that an icy roadbed might be encountered during regenerative functionally. In effect reducing the effects of the hybrid's form of "engine compression braking" when the potential for loss of directional control due to such braking is present.

    The second use is during ABS activity. When ABS signals a periodic (100 milliseconds{??}) release of the brakes to prevent complete lockup the regenerative braking at that instant might be high enough to prevent the wheel from quickly turning freely.

    So the obvious solution is to "signal" the ECU controlling regenerative braking to STOP regen during that same ~100 millisecond period.

    Obviously the same thing might be true of actual engine compression braking, which if present, cannot be readily overcome within the time frame allotted.

    Since your front brakes are "responsible" for as much as 80% of any braking effort the patent is clearly more pertinent to FWD or front biased AWD.
  • wwestwwest Posts: 10,706
    "However, selectively reducing service brake regenerative braking alone as a function of ambient temperature is not sufficient for some vehicles and conditions. In particular a lift-throttle event that induces (compression) regenerative braking may cause slipping. This may undesireably lead to vehicle instability, especially in rear-wheel drive electric and hybrid electric vehicles."

    Definitions:

    "compression" regenerative braking: regenerative braking that is used to "simulate", instead of, engine compression braking. Lift-throttle but no pressure to the brake pedal.

    "service" regenerative braking: regenerative braking to "simulate" actual braking, the brakes are applied.

    The above quoted patent paragraph simply states that it is not sufficient to remove or lower "service" regenerative braking due to ambient air temperatures, the issue of "compression" regenerative braking must be addressed in the very same manner.

    And yes, it does appear to apply specifically to rear-wheel drive electric and hybrid electric vehicles.

    But doesn't that sentence read to mean electric vehicles of ANY wheel drive configuration?

    I think what the writer was trying to say was that regenerative braking of one axle without the other can be detrimental to maintaining control. And yes, that would be especially true of RWD electric vehicles.

    Do any of those yet exist?
  • cdptrapcdptrap Posts: 485
    Do any of those yet exist? [Question referred to existence of RWD Hybrid]
    Lexus just introduced the GS 450h, V8 RWD hybrid.
  • 8241582415 Posts: 38
    Just experienced the activation of the Brake Assist (BA). A minivan 2 vehicles ahead of me stopped dead on the highway because she did not know what to do after she missed her exit (a scary happening :mad: ). I slammed on the brakes and could feel the sequence of events in a few milliseconds:

    1. regenerative braking
    2. regular braking
    3. brake assist kicked in (my foot was at the same level but I could feel the extra boost without my depressing the pedal any harder)
    4. the expected squeal and burning rubber smell

    It worked fine :shades: .
  • stevedebistevedebi LAPosts: 3,796
    "4. the expected squeal and burning rubber smell "

    You burned rubber? :surprise:

    Take it in to the dealer! The ABS system should have kept the tires from locking up - which is required to "burn rubber".

    Maybe you smelled the brakes overheating instead?
  • terry92270terry92270 Posts: 1,247
    ABS will assist in preventing, but not always stop skids. ;)
  • guestguest Posts: 774
    if you smelled burning rubber when slamming on brakes from highlander hybrid it was burning rubber from tires cause you must've been flying -- highlander hybrid uses a regenerative braking system that recharges elctric engine while you brake and virtually never wears out -- so spped on and don't worry about them brakes!
  • robroirobroi Posts: 5
    I have an early model 2006 HH Limited 4WD-i w/Nav system and it does not have the AVERAGE MPG on the Speedometer multi-information display. It does has the CURRENT MPG.
  • stevedebistevedebi LAPosts: 3,796
    "ABS will assist in preventing, but not always stop skids."

    ABS doesn't stop skids, it prevents skids. I have never had an ABS lock the wheels. That is what ABS is for - to rapidly cycle the brakes. With a properly functional ABS, your wheels will not lock.

    The only way you can skid is if the car is sliding sideways.
  • cdptrapcdptrap Posts: 485
    Hi Eight-Two,
    We had to emergency stop once from around 45-MPH and once from 60-MPH. My wife slammed on the brake pedal both times. The tires did not squeal like normal car and the HH stopped in a hurry. The ABS on this car is really smooth, no funny "kicks" like some domestic models.

    You may want to have the shop inspect the brake pads and discs, they may just need some cleaning or minor adjustment.
    Cal
  • wwestwwest Posts: 10,706
    Your regenerative braking system may have interferred with ABS in a way that prevents ABS from fully releasing the brakes to avoid skidding.

    Ford has recently applied for a patent regarding instantly disabling regenerative braking if ABS activation results in a need to "unbrake" one or more of the wheels during servere braking efforts, say when BA kicks in.

    This is probably, likely, the very same reason many Toyota and Lexus FWD and front biased AWD vehicle owners are complaining of the "too willing" nature of their vehicles to upshift at the slightest lift-throttle movement.

    Save a few lives by alleviating engine compression/(regenerative) braking and thereby allowing the driver to more easily maintain directional control when the roadbed is slippery.

    The same patent describes a techique wherein the level of regenerative braking is significantly reduced when the OAT consistently "hovers" around 35F or below. The idea seems to be to prevent regenerative braking from causing or contributing to a skid when the potential for encountering an icy, slippery, roadbed is high enough to raise the potential for loss of directional control.
  • cdptrapcdptrap Posts: 485
    While safety is foremost concern for me, I am not sure the Ford patent is necessarily related to this.

    Many Highlanders have slugged through snow and ice this past Winter based on owner reports posted in four different forums including this one. There is even an owner in Southern CA who took his HH off-road. Do not forget the FWD Prius, the Taxis of Canada. I was in Boston for a conference and the number of Prius in the parking lot was impressive. That little fast-selling FWD must have seen more ice than all the HiHy on the road today.

    If there had been widespread loss of control issue, it most likely would have shown up already in Canada and northern states.

    I am not discounting safety concern, just cannot make the connection based on our driving experience in snow. If our FWD van with no Traction Control and only ABS can survive snowy road, it seems extremely likely that a well maintained AWD, hybrid or not, with snow tires and Traction Control can do as well or better.
  • wwestwwest Posts: 10,706
    I have been on roadbeds here on the eastside of Seattle so slippery that my then ride, a 1992 Jeep, would not come to a final and complete stop, almost, due to the ABS continuing to operate, release the brakes all the way down to zero MPH.

    I have little doubt that even the slightest bit of engine compression braking, or regenerative braking would have so impeded ABS as to prevent my maintaining directional control of the Jeep.

    Yes, those conditions are rare, but the automotive designers must pay attention to all operational aspects of their designs, not just those that only apply to 99.999% of the populace.
  • I have a 2006 HH and it has current mpg AND AVERAGE MPG on the Speedometer multi-info display. I purchased it on May 11, 2006 in Sarasota.

    Now, having said that, I went to the iGuide at >

    http://www.toyotaiguide.com/iGuide_HighHy.htm

    and looked at the Speedo display readouts and the 2006 has 4 data displays and the 2007 has 5 data displays and guess what the 5th display is >>> AVG MPG ! Maybe my car had later firmware (2007?) installed.

    Good luck.

    Terry
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