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Toyota Prius

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  • Thanks for that info. I haven't read the entire manual yet and didn't even check into that portion before complaining to Toyota. I'm still going to question them regarding their response that "3-4 gallons of diminished capacity has been reported and not considered a defect."

    They replied that they would be looking into the matter and would communicate further information to the dealerships.
  • hans000hans000 Posts: 19
    I am convinced the "lurching" (or shrudder) while stopped is caused by AC compressor. When I adjusted the temperature down to the point the blower slows, the shrudder was gone.

    Looks like the AC runs for both warm and cool.

    ===============
    jone1701a wote:
    That lurching while stopped at a intersection during warmup is a bit odd. I've felt it too, and it wasn't there with my classic. The system is apparently doing more than simply moving pistons. It might have something to do with the secondary coolant circulation. After the head of the engine is warmed (using the coolant stored in the thermos), the remaining hot stuff if flushed to the lower part.

    JOHN
  • that is an interesting piece of info. Thanks. I'll test it out tomorrow morning. I will probably shut down the "Auto A/C" mode completely and just run the fans on low to see if this is it.

    If "Auto A/C" is the cause, I wonder if it will do the same in the summer time when I run the A/C to cool the car down? Hmmm...
  • john1701ajohn1701a Posts: 1,897
    Don't forget that motor & invertor have a cooling system. Fluids continue to be pumped through/around them regardless of whether or not the engine is running.

    In my classic, I could very clearly feel when that pump shut off. (In my 2004, it's hard to tell since I haven't driven in any warm weather yet.) A cycling operation when it's needed could easily produce a feel too.

    JOHN
  • ...my battery charge display typically shows 1 to 2 bars below full so I don't believe it's due to low battery capacity.

    Personally, I don't mind the lurch and other quirks of the Prius as long as it is not detrimental to the car.

    On another note, soon the Lexus 400H will be released with HSD, I wonder how much of the quirks Lexus buyers will be able to stand since they are "luxury" minded people. Lexus are known for quiet and smooth operating vehicles. I would think that 400H buyers will be even more picky with their high dollar SUVs than we are with our Prius. I would love to peek into a future 400H forum and have a look at what they have to say about their purchases...
  • hans000hans000 Posts: 19
    The battery was 3/4+. ICE not running for sure. A house window AC unit shrudders. It's electric.

    It's a rocking motion like the compressor is going through on-off cycle every few seconds. Also possible the compressor was running very, very slow. It must also happen while driving, just less noticeable.

    ========
    midnightcowboy wrote:

    The Air Conditioner doesn't run off the engine so there shouldn't be any shuddering under the normal sense of a belt drive air conditioner.

    The only thing that makes sense is that it draws enough current that it causes the HSD to go into a battery charge mode.
  • hans000hans000 Posts: 19
    The battery was 3/4+. ICE not running for sure. A house window AC unit shrudders. It's electric.

    It's a rocking motion like the compressor is going through on-off cycle every few seconds. Also possible the compressor was running very, very slow. It must also happen while driving, just less noticeable.

    ========
    midnightcowboy wrote:

    The Air Conditioner doesn't run off the engine so there shouldn't be any shuddering under the normal sense of a belt drive air conditioner.

    The only thing that makes sense is that it draws enough current that it causes the HSD to go into a battery charge mode.
  • I've seen a picture, not high res, of the 400H speedometer and it has what looks like a traditional analog gauge. The Tach has been replaced by a "juice" meter, showing how much electrical current is put back into the HSD system while you are driving, etc.. it also looks like an analog gauge. I have also seen pictues of the instrument cluster for the Highlander and it does not look too bad. I did not download the pics because they were not high res types.
  • backybacky Twin CitiesPosts: 18,682
    The traditional meaning of a "beta" version of a product is a product that is functionally complete, but may have some unresolved quality issues--including a partial implementation of a rarely-used function. The purpose of a beta test is to test the product through a controlled, actual implementation, and also to allow customers to get a preview of an upcoming product. Based on that definition, there is no way the '04 Prius could be a "beta" version of the 400h. The two vehicles have some similarity due to the design of their HSD systems, but are unlike each other in so many other ways that they are clearly two distinct products--one could not be the "beta" version of the other. However, I would venture an educated guess that Toyota did have "beta" version(s) of the Prius (I mean the "Classic" version) running around before the vehicle was offered to the general public. Perhaps someone (like John) who knows more about the history of the Prius could comment on that.
  • nippononlynippononly SF Bay AreaPosts: 12,687
    happened to get one of these as a rental, and have had it for a couple of days. I can see the big steps Toyota has made with this model versus the first one. As before, my mileage is well below the EPA rating, but I am not surprised. I have done better than the old car, however, and seem to be getting about 46 mpg - 400 miles so far. What are owners averaging in regular round-town driving?

    If I were to buy one, could I put larger (205/60) tires on it, or would there be issues with the power steering unit, or tires not fitting in the wheel wells? I am aware that larger tires would reduce fuel economy.

    The only thing I didn't like in the first one that has carried over is that all the climate controls and the radio display are incorporated in the NAV screen/HSD display. I wish they would have a regular radio at least - I change the station a lot!

    But wow! This one is a lot faster than the "classic"! And the brakes have smoothed out a lot. It is more like a high-tech transportation pod than a car.

    2013 Civic SI, 2009 Outback Sport 5-spd (stick)

  • john1701ajohn1701a Posts: 1,897
    Back in 1999, a few of the Pre-Classic models were shipped over to the United States for evaluation. Toyota changed quite a bit as a result, a whole collection of tweaks in addition to improvement in the hybrid system itself (engine, motors, and battery-pack).

    Anywho, the public in general wasn't involved with any of that, just selected tester families and automotive experts. The intentions were to make it as acceptable as possible for "joe consumer". So things like "should the gear-selector be mechanical or by-wire" had to be considered and "how detailed should the information on the Multi-Display be" are what had to be considered. And now, it's little things like that they are re-evaluating again.

    HSD is well established. Prius broke that ground back in 1997 when sales began, and it has provided the real-word data ever since. Estima (only available in Japan) jumped in 1.5 years ago to provide real-word data about hybrid implementation for 4-wheel drive. So all the system aspects are totally covered.

    What remains now is the interface research. What do SUV owners expect from a hybrid? What do LUXURY owners expect from a hybrid? What do owners that want all the technology hidden expect from a hybrid?

    It basically is just plain old marketing stuff to deal with now.

    JOHN
  • dc8527dc8527 Posts: 12
    "nippononly wrote: "...seem to be getting about 46 mpg - 400 miles so far. What are owners averaging in regular round-town driving?"

    My first 1,200 miles in Minnesota in the past month averaged about 40MPG. The drive between my home and work is similar to EPA's test conditions with 2 exceptions, 5.5 miles, about half of EPA's distance and low temperature, mostly around mid teens above zero F. I got only 33MPG this morning. The temperature was about 20F.

    Toyota said its engineers were investigating into the low MPG concern from the cold climate. The answer would be due by mid Jan. It is about time to call them again.
  • nippononlynippononly SF Bay AreaPosts: 12,687
    I am in California, a lot warmer here, so my mpg is bound to be a bit better than Minnesota! Also, I am judging by gas put in, not the computer, which I figure may be inaccurate - it bounces from 13.2 to 99.9 on a regular basis! :-P

    What's with the gas gauge, BTW? I have stopped for gas twice (after 200 miles each time), because the gauge is down near 'E'

    Does anyone do what I have already done twice - reach for the gear shift in the dark and flick on the wipers by mistake?

    So no-one has thought of changing out their tires for bigger ones yet? The OEM in my case are Goodyear Integritys - not the greatest type either.

    2013 Civic SI, 2009 Outback Sport 5-spd (stick)

  • ...well, I did a test this morning in my Prius while driving to work. Temperature outside was about 49F. I had the "Auto A/C" off as well as fans/blower in off position. The lurching continued as usual. So, fromt this non-scientific test, I would say that the lurching is not due to having the heater or fans on etc...it must have something to do with what John had posted earlier...hot coolant pumping through the engine warming it up etc...
  • I've been doing some research on cold weather fuel mileage and here is what I found. This following article can be found at http://www.startribune.com/stories/435/3799559.html
    <Start of Article>
    When it's colder, engines use more fuel because they're running richer, meaning a lower air-fuel ratio (higher percentage of fuel to air). When engines are cold, a percentage of the vaporized fuel condenses into liquid form on the cold metal parts of the induction system, such as the intake manifold runners, intake valves, pistons and cylinder walls. The colder the engine at start-up, the higher the percentage of fuel that condenses on these parts.
    This condensed, liquid fuel cannot burn. Only fuel in gaseous form can be ignited, so on cold starts the fuel injection system must deliver a richer mixture so that enough fuel in vapor form reaches the combustion chamber, where the spark plug can ignite and burn it.
    As the engine warms up, less fuel condenses as internal parts warm up, so the fuelair mixture can be leaned out progressively. But of course, during the several-minute warmup period, the mixture will be richer than normal. And in the three-mile drive, it may well remain somewhat rich the entire time. In 0 degree weather, it probably would take more than a short warmup period and three-mile drive for the engine, coolant and oil to reach full operating temperature, and fuel-air mixtures to reach optimal levels. <End Of Article> This explains why the Prius has a thermos behind the left front headlight that can keep the coolant warm for up the three days. So why still the bad MPG? Well, if you go to http://www.swri.edu/10light/mile.htm
    they say that cold air is denser, so more fuel is burnt in the ICE, this denser air also offers more air resistance, and the denser air in the tires reduces tire pressure. So all of this explains why all cars get less MPG in cold weather. However, this still does not explain the extraordinary poor MPG performance of hybrids in cold weather. I've lived and driven where it is cold and snows and never really noticed a big hit in MPG when it is cold with a pure ICE. I always checked my mileage after fill ups so I would have noticed. So why the acute affect with hybrids? Well, if you go to http://chemistry.about.com/library/weekly/blbattery.htm
    someone with a Ph.D. in chemistry explains that if a battery is used at a low temperature then less current is produced than at a high temperature because the chemical reactions inside the battery slow down. Since power(watts) = volts multiplied by current, if you have less current, then you will have less battery power. Therefore, the gas engine will have to work harder and MPG takes a dive. This is why on the HCH there is a vent behind the back seat to allow warm cabin air to flow on top of the battery pack. However, there is no fan to blow this warm air down over the battery pack and so it stays cold. This explains why HCH drivers also report poor cold weather MPG. Perhaps someone who lives somewhere cold could perform an experiment by somehow rigging up a contraption that will keep the battery warm and then drive it on a known route to see if it makes a difference. If we can solve this problem the data can be sent to both Toyota and Honda so that they can develop their own battery temperature management systems. If successful, perhaps some kind of after market device could come out of it for existing hybrids?
  • john1701ajohn1701a Posts: 1,897
    > battery is used at a low temperature then less current
    > is produced than at a high temperature because the
    > chemical reactions inside the battery slow down.

    The sweet part of the Toyota design (not sure about Honda) is that it bumps up the voltage to 500 via an invertor. So even if you aren't able to draw as much from the pack due to the cold, you'd never notice. Power will remain the same, regardless of temperature. Overall capacity will be lower though. Fortunately, the pack is big enough to compensate for that.

    JOHN
  • > it bumps up the voltage to 500

    But what if it is so cold that it has to go above 500 volts to maintain the required power? 500 is the max. A better system would have been to keep the battery warm. Then there would be no decrease in power or capacity.
  • > it bumps up the voltage to 500 via an invertor. So even if
    > you aren't able to draw as much from the pack due to the
    > cold, you'd never notice. Power will remain the same,
    > regardless of temperature.

    The given power(watts) that a battery pack can deliver at a given temperature is fixed. Since power(watts) equals voltage multiplied by current, then if power(watts) is fixed and volts goes up, then current must go down. This is the law of conservation of energy. You cannot get something (more power) from nothing. If you could, then you could multiply your voltage with an inverter to a billion, billion volts and power the entire world! I don't think so. The Prius has an inverter because the battery pack puts out DC current and the motor is AC.
  • Did you get rid of the Matrix for the Prius?
  • nippononlynippononly SF Bay AreaPosts: 12,687
    this is a rental that is due to go back soon.

    But the Matrix may go soon, possibly to be replaced by something other than a Toyota for the first time in seven years.

    This new Prius is really neat in many ways, but I have decided it isn't really my thing - not in the market for a Camry-type vehicle. But I was curious to see all the improvements over the "classic" Prius, since I accidentally rented one.

    2013 Civic SI, 2009 Outback Sport 5-spd (stick)

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