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Toyota Prius



  • wwestwwest Posts: 10,706
    First, I didn't say the driver did.

    What I said was that I'm the only one to see, and I'm the ONLY decision maker, as to whether or not I wish the car to be slowing down.

    If the hybrid system suddenly, or even "seamlessly", decides to throw in a little regenerative effort I would most likely suspect that a head wind just came up and I need to apply more throttle to maintain my speed....

    If I'm going downhill and lift my foot from the throttle to conserve fuel and the system starts applying the "brakes" my instincts will be to get back on the gas. Even if I don't get back on the gas immediately then I will still need to do that earlier than otherwise due to the increased "drag" of the regenerative effort.

    Like a heavilly loaded trucker coasting, speeding, downhill to conserve fuel but then throwing a dragchute out.

    On the other hand a light foot on the brake pedal (or in "cruise") to maintain a set speed downhill and the system using that as a signal to charge the batteries for "boost" on the uphill pull makes a lot of sense.
  • john1701ajohn1701a Posts: 1,897
    > The net loss can be really serious as is indicated
    > by the Prius' poor hwy MPG

    A 51 MPG highway rating is poor?

    No other gasoline powered vehicle that size can compete with efficiency so high. Since the end result is *BETTER*, it is a *GAIN*. How can you claim a net loss?

  • wwestwwest Posts: 10,706
    I would be willing to bet you a brand new 04 Prius that I can BEAT the hwy mileage of any 04 Prius in that same Prius if I could prevent the batteries from being needlessly used on a run from Seattle to Portland.

    Watching the dash "gauges" it was my experience that no matter how lightly I feathered the increase in throttle position the electrics would come FULLY on line. I was willing to settle for a slow acceleration rate using just the ICE but the system wouldn't let me settle for that. The result was about 30 to 40 needless discharge/charge cycles in 150 miles.

    Yes, 51 MPG is pretty damn good. But if one could avoid needlessly discharging (supercharging the "weak" engine) and then recharging the batteries in a continuous cycle for a 150 mile reasonably flat freeway drive the mileage would be even better.
  • wwestwwest Posts: 10,706
    I have read all three references, all good reads, especially the latter, but I can find no statement implying the batteries are automatically charged during coasting.

    Would you mind directing me more explicitly to same?
  • john1701ajohn1701a Posts: 1,897
    > ...flat freeway drive the mileage would be even better.

    That has absolutely, positively nothing to do with a "net loss".

    It is still a gain no matter how you analyze it. What did I miss?

  • wwest,

    It works a similar way in the Civic hybrid. Lifting off the gas causes the regen feature to kick in.

    To maximize opportunities to recharge the batteries, I guess the computers assume that when you're not on the gas, you don't need thrust, so that spinning drive shaft can be used to turn the generator (electric motor). I use it all the time to maximize charging.

  • wwestwwest Posts: 10,706
    I was not referring to the "overall" design or execution of the Prius design, only to the detail of the NET LOSS resulting from the needless discharging of the batteries resulting in the losses via the use of the ICE for recharging.
  • john1701ajohn1701a Posts: 1,897
    Quite a number of times now, definitions of words have changed as discussions continue. No hard feelings on this side. I've grown used to it.

    For our next topic, how about discussion winter efficiency? Lots and lots of people aren't aware of those cold weather factors that cause MPG to drop.

  • wwestwwest Posts: 10,706

    You "restated" my position on NET LOSS so explicity in post 1096 that I see no way it could have been misunderstood to be more "global" than I intended.
  • Graham's site pretty well describes the charging
    while coasting.

    You can really notice the difference between the
    regenerative braking while coasting, vs. no
    regenerative braking, by throwing the Prius into
    Neutral while coasting. Instead of slowly slowing down,
    you just sort of glide along. Unfortunately, by
    going into Neutral, the battery no longer gets
  • In a normal car, any excess power from the ICE
    that isn't used for motive force is wasted. (Think
    about coasting or going downhill - the engine isn't
    doing much work to keep you going...)

    In a Prius, the eCVT keeps the ICE at the most
    efficient (cleanest) RPM. In some cases, there is
    more power coming from the engine than what is
    needed to move the car (uphills, usually), and this
    excess power is routed to charging the battery, or
    the electric motor.

    Strange, but usually a Prius gets better MPG going
    through hills than if it took the flatland route!
  • I placed an order for a 2004 Prius in mid-October with a Fairfield County CT dealer. Yesterday I spoke with the salesman, who said that I was 15th on their order list and they anticipated getting 1 or 2 a month starting this month. And only two option packages - everything or almost nothing. When I go online to for Ft. Lauderdale, where my daughter lives, the availability list goes on for pages, with lots of different option packages. I could cancel my CT order, order the car in Florida and ask her to drive it north, and maybe I'd even have some bargaining power on price. Does anyone have any thoughts on whether this makes sense? And why is there such a demand - supply imbalance?
  • john1701ajohn1701a Posts: 1,897
    I've grown tired of constantly having my words twisted here. That doesn't happen elsewhere.

    Those that are interested in assistance with Prius know where to find me. And I'd much rather help them than just put out all the fires you keep setting.


  • wwestwwest Posts: 10,706
    coming from the engine than is what needed to move the car (uphills, usually)....

    Why would the engine produce more power, using MORE fuel, than is required to move the vehicle, especially uphill? I would think, assuming the batteries have some reserve left, this would be a very important time to use the batteries to boost the net output power and conserve fuel.

    As a matter of fact that's the exact way my 03 seems to work. I'll have to pay more attention now, but I don't think I've EVER seen the batteries being charged in this circumstance. Absent starting out virtually fully discharged, maybe.
  • wwestwwest Posts: 10,706
    Without admitting that it actually does....

    How or why is it an advantage to use regenerative braking during "coasting" (no throttle or brake application) to recharge the batteries?

    Without this "braking" (however slight) the car would coast farther and thereby use less fuel overall.
  • john1701ajohn1701a Posts: 1,897
    > Without this "braking" (however slight) the car would coast
    > farther and thereby use less fuel overall.

    The primary purpose of HSD is to REDUCE SMOG-FORMING EMISSIONS.

    Since using less fuel is secondary, opportunities to do save are sometimes not taken for the sake of being CLEANER OVERALL.

  • I have had the '04 prius in my garage for 1 week. Averaged 46.3 mpg over first 400 miles, without trying. I love this car. Handles better and rides more smoothly than old Prius (my daughter has an '01). The fold down rear seats were a necessity for me. The blue is a very nice shade, was kind of hard to tell exactly what you were going to get from the web site. I got the first one from my dealer. My only complaint to date is the faint green line on the windshield at night from reflections from the speedometer display- any suggestions? I haven't tried to create a "blocker" about the display yet.
  • seem well pleased with their new Prius, as it should be.

    I am eager to see how it compares to other vehicles when there are independent test reports available.
  • lsinclsinc Posts: 270
    My husband and I are considering purchasing an '04 Prius sometime in the future. Currently my husband commutes 350 miles in 5 days and we are looking for fuel economy. We also need a car that is reliable and good in snow. Can anyone give me information on

    1. Fuel ecomony ratings
    2. Overall Reliability
    3. Handling in rain and snow


  • Masshockey...I've post this issue previously and from other owners, all you have to do is turn down the dimmer switch/wheel to the left of your steering wheel. This should take away the glare. Happy driving. Tony.
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