[WARNING] Running out of gas (Gen III)

Discussion in 'Gen 3 Prius Main Forum' started by bwilson4web, Jun 26, 2009.

  1. ronhowell

    ronhowell Active Member

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    Re: [WARNING] Running out of gas

    Count me in too on the same side of this argument as Timberwolf.

    If Toyota are guilty of anything in design of the Prius, it is allowing people to conclude that it is an electric car, "in extremis". It is not, and was never intended to be. It is primarily and fundamentally gasoline powered, all the way to a dead stop, when all the stored energy on board (liquid or electrical) is exhausted.

    While I will be the first to admit that Bob has done, and continues to do, seminal work on Priuschat with respect to the Prius characteristics, the experiments listed in this thread demonstrate that Prius drivers should NEVER drive the car to complete fuel exhaustion, as in these experiments.
    It seems to me that inclusion of an EV mode in the G3 Prius is a major error on Toyota's part, fostering as it does the impression that this is indeed an Electric Car, when you want it to be, even if you run the gas tank totally dry of any reserve fuel.

    People need to be made more aware that when the gas gauge starts blinking, they are running on Reserve Fuel. Fill up at the earliest opportunity.
    Or isn't getting 50 miles for every gallon you pump aboard good enough?
     
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  2. darelldd

    darelldd Prius is our Gas Guzzler

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    Re: [WARNING] Running out of gas

    Hmm. If you're *really* concerned about human life and safety, stop driving a car that uses gas. If you run out of gas in your car, it could cause an accident a kill a few people. If you keep putting gas in your car and keep driving it "safely" then you contribute to the 10's of thousands of premature deaths that are directly attributed to gasoline consumption.

    But I digress, as usual...
     
  3. timberwolf

    timberwolf New Member

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    No, the implication of my previous post, was that you shouldn't run out of gas, and gave it to show that in some places they have had to create a law because some drivers appear to not have the common sense or imagination to see that what they are doing by running out of fuel can endanger the lives of other road users.

    My previous post was not addressing the other part of this thread, i.e. that of whether Toyota was right to fix an issue that could damage the HV battery.

    Edit: Shawn you bring out the worst in me, although it's my entirely my own fault for rising to the bait:) Apologies to everyone for my more idiotic posts. I see two sides in this thread so far apart that trying to debate this will just lead to a pointless back and forth. I'm going to try hold my tongue for a bit.
     
  4. fuzzy1

    fuzzy1 Senior Member

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    This isn't bad. My Subaru goes blind with slightly more than 1/4 tank remaining, just over 4 gallons of a 15.9 gallon tank. Well, not quite blind, as the 'low fuel' warning appears about 1 gallon lower.

    I'm another driver who cares about usable fuel capacity. I also desire a fuel range long enough to run a specific trip (for me, 405 miles) without refills, for when 1973-style alternate-day gas rationing returns. And I dislike rewarding vendors who charge tourist trap prices near the very long stretches of roads with no services, or the vendor who demanded a premium to unlock the pump on a holiday when all other stations in the region were closed. (I wasn't the only one to walk out.)

    An accurate knowledge of fuel range is one of several defenses in the consumer tool kit. A fuzzy blanket statement to 'always fill up at 1/4 tank' just isn't good enough for me, especially with that Subaru.

    I've accidentally run out of fuel only once, the very first tank of 'my' first car, which was still reading above E. One more time was deliberate, to see where the next car went dry. I've never had the courage to run a fuel injected engine dry.

    While I'm not as concerned as Bob about the out-of-fuel behavior, as it is no worse than everything else I've owned, I still thank him for running and reporting this test.
     
  5. efusco

    efusco Moderator Emeritus
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    I think it could be a feature to allow the car to run, on battery, after running out of gas. I suspect they built in the "no-go on empty" to prevent folks from running their battery too low.

    But I'm with Bob in that I think it's a shame that they did that. If they could have even built in a conservative battery SOC level that would have helped. IOW, the car would shut down if the battery got to 40% SOC or lower.

    While it sounds so nice to say "it's easy not to run out of gas", the reality is that it happens and it happens every day and to build in an additional benefit of a hybrid to be that you are NOT stranded should that eventuality happen is a good thing, IMO.
     
  6. Midpack

    Midpack Member

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    Fair enough, I shouldn't have tried to quantify but I don't know anyone who has run out of gas (although maybe the few who have won't admit it). I deliberately used 99.9% because I would have thought most readers would recognize it's not a true statistic ("literal minded"). But just for fun, you mentioned 50%, let's be generous and say 100% of us run out of gas twice (since you have) in our lifetimes. Assume most drivers are at the wheel for 50 years and drive every day. Each driver would run out of gas 0.011% of the time - or 99.989% NOT. You can do the math I trust...

    If the finding had been presented as an observation, that would have been one thing. But there has been some mild outrage at Toyota in this thread, and I think it's unfounded, I actually think it's a smart move by Toyota. Evidently we'll have to agree to disagree - and there's nothing whatsoever wrong with that.

    Because no ICE car runs without fuel, it shouldn't be necessary for the Prius to do so either IMO - we'll have to agree to disagree on that one. And while it's certainly technically possible with the Prius (evidently earlier Gen's did), the biggest barrier to greater hybrid sales has been the $ premium. The closer hybrids cost to conventional cars, the more people will buy them. So IMO it would be smart for Toyota to eliminate features that add cost with little value. With running out of gas as rare as I think it is, to add engineering and cost to the Prius for such a feature does not make sense. From what I gather (mostly here), Toyota has subtly de-contented the Gen 3 somewhat to reduce their costs and subsequently MSRP. I would say that's very smart business, and if the running on empty feature was a casualty, makes sense to me. The base Gen 3 is competitively priced (great, a more affordable option and squashing the new Insight possibly), but for those who want more for whatever reason, you can get one well over $30KUS with all sorts of gadgets and options if you to pay for them. Very smart by Toyota IMO, YMMV.

    Your serve...
     
  7. patsparks

    patsparks An Aussie perspective

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    None of you people who think a Prius should run even after it runs out of gas just like every conventional car wont are responsible for providing the warranty for the car. Toyota are and they know that driving a Prius after it runs out of gas MAY harm the traction battery so they made the Gen III Prius behave like a conventional car when it runs out of gas, it stops. Easy solution, fill at 2 bars on the gauge.
     
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  8. efusco

    efusco Moderator Emeritus
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    So you're arguing, Pat, that even if the min. SOC to run the car on battery only if it ran out of gas was 60% that Toyota shouldn't implement it? What about 70%? What about 50%?

    The thing is this, the car is designed to safely tolerate a SOC down to at least 40% without damage to the traction battery on an occasional basis. With the gas running it sometimes achieves this.

    THUS--
    If it is safe to run the battery down to 40% SOC with the ICE running and gas flowing it is also safe to do so without the ICE running--ie, an out of gas situation.
     
  9. fred garvin

    fred garvin New Member

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    1. i have never run out of gas and never will
    2. most i ever pumped into my gen 1 was 10 gallons
    3. 90% of the time i gas at 3 pips (may change in my new, bladderless gen 3)
    4. i appreciate Bob's research that shows 100+miles from flash to crash, as a data point, should i ever find myself in that situation, which will likely be never
    5. Bob - please don't iterate anymore if the test conditions are dangerous
    6. who runs out of gas?
     
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  10. bwilson4web

    bwilson4web i3 and Prime

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    Not to worry, my tests are planned with safety as part of the requirements. So when the second fuel exhaustion occurred, I was fully prepared to glide to a safe place and at 4:30 AM, there wasn't a whole lot of traffic to worry about. BUT I also realized that someone who did the same thing at 4:30 PM would be in a pickle.

    I suspect many accidents turn out badly because of the 'surprise' factor. The astonishment of a new situation 'freezes' some minds, however briefly, and instead of dealing with the situation as it is, many will try to return to a situation that is impossible to return to. It is a question of 'living in the moment.' (Sounds Zen-like, don't you think?)

    I have been married 32 years but in the first couple of years, my wife ran out of gas twice ... and blamed it on me. I recognized that in one respect, she was right:
    • I leave early with time to fix a flat tire or fill-up - she leaves about the time she should be at her appointment.
    I changed my fueling practices and keep her car at least half full so she no longer runs out of gas. As for her always being late ...

    Bob Wilson
     
  11. PriusCrazy

    PriusCrazy Blizzard Pearl for Me

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    Has it been ascertained *for certain* how the G3 would behave if it had a fully charged battery and ran out of gas? Seems we only know for sure how it behaves with a low battery and no gas.
     
  12. Midpack

    Midpack Member

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    True, but at what cost? I don't know either, but I doubt it's ZERO. Some of us wouldn't want to pay anything at all for this feature.
     
  13. Celtic Blue

    Celtic Blue New Member

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    You have no idea if you ever will. A leaky tank or broken/miscalibrated fuel sender can run you out of gas quite easily. A borrowed, rental or company vehicle is the one most likely to bite you. Then there are those GenII's that have run out of gas at 2 pips...
     
  14. Celtic Blue

    Celtic Blue New Member

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    Apparently the cost was zero as this is how it was before they changed it. The beauty of an ECU system is you can program in the behaviour that you want. That's why the battery has such an elaborate management system.

    This car is already designed to operate with the ICE off and to monitor the state of charge and power draw. So the argument you and others are making is false.

    The funny thing is, there is this "protect the battery at all costs" undercurrent, but running out of gas is very rarely going to happen and is much less stressful than many other things that you can already do. One has to be work at it to damage the battery when running out of gas. Whereas some everyday things stress it. Hints: 1. Try a high speed run and watch how depleted the battery becomes. 2. Try sitting idle with the AC running. 3. Do a mountain climb. These are all on the depletion side, but also stressful to the battery are high states of charge and high charge rates so let's add: 4. Mountain descent. 5. A few hard stops followed by moderate acceleration. 6. Bitterly cold weather where it seems to like charging the bejesus out of the battery into double green to warm it up.
     
  15. Celtic Blue

    Celtic Blue New Member

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    Except that we have multiple accounts of GenII's running out of gas at 2 bars.
     
  16. fred garvin

    fred garvin New Member

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    ok - i can't predict the future - you are correct

    i can say that i will never put myself in a situation where it is likely or even reasonably possible that i will run out of gas

    in rentals, i am usually on a business trip where i never use more than a quarter tank anyway

    if a longer rental, i fill up at a qtr tank because i don't know how it behaves

    i had a fiat 128 in 1983 that went from 1/2 tank to zero and i went by miles driven - huge pain in the as on a cross country trip having to fill up every 200 miles. never ran out.

    for me the peace of mind at 3 pips is more important than the incremental time saved by filling up 9 times instead of 10 or eleven over a 3 month period. ten minutes more time for peace of mind.

    but its a personal preference obviously
     
  17. ronhowell

    ronhowell Active Member

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    Re: [WARNING] Running out of gas

    Does the "0 miles remaining" immediately display, or do you have to press buttons to show it? If the former, that should be an immediate indication to "FILL UP NOW"! If you have to press buttons to access it, that in my opinion is a design flaw.
     
  18. efusco

    efusco Moderator Emeritus
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    I'm confident the cost would be ZERO! It's a software/programming function only.
    Hell, they could even make it an advertisable feature...

    "If you should ever run out of gas the car will tell you your approximate range that you can safely drive on battery alone before the car shuts down. Giving you time to get your precious family to safety." [roll dramatic footage of cute kids in a car on a busy highway bridge with no-where to pull off until you get across]
    The display would show "Approximately X.XX miles at 25mph on battery, please pull over and refill as soon as possible."
     
  19. ronhowell

    ronhowell Active Member

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    Multiple accounts!? Just how many, exactly? Maybe some of the early G2 Priuses may have had faulty fuel quantity senders, which would cause this, but I have heard of few cases in recent years.
    Obviously a major flaw which should be warranty covered in any case.
     
  20. PriusCrazy

    PriusCrazy Blizzard Pearl for Me

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    If it is an advertised feature, I can guarantee you the cost will NOT be zero.

    ***** Edit *****
    Everyone,
    Please forgive my ridiculous post to an increasingly ridiculous thread. I am honestly embarrassed to be taking part in this discussion.
     
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