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Prius in reverse: Electric vehicle with range extender?

Discussion in 'Gen 3 Prius Main Forum' started by Hybrid RR, May 10, 2011.

  1. Hybrid RR

    Hybrid RR Junior Member

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    I read somewhere that when a Prius is in reverse it only uses the electric engine, it simply lets the electric engine run in the other direction, the ICE never powers the wheels in reverse, it then only runs as a generator.

    Is this really true? This would mean that you could call a Prius in reverse a pure electric vehicle with a range extender:) not a hybrid.

    And it rises the next question, for how long can a Prius drive in reverse? Would the ICE be able to generate enough electricity so the car is able to drive at max speed in reverse forever? (well, at least untill the ICE runs out of petrol)

    Anyone knows this? Some interesting facts I think, always good to tell at birthday parties:D, another thing that shows how much thought has gone into building this car
     
  2. Maine Pilot

    Maine Pilot Senior Member

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    You are correct about the Prius operating in electric drive exclusively while in reverse. How far you could drive would depend on several factors such as the battery charge, speed, how level the surface, etc.

    As a relatively new Prius owner, I do find operating in reverse a bit disconcerting. First, the vision to the rear isn't the greatest. Then, the sides of the body aren't uniform, leading to an optical illusion when you're using the side-view mirrors. But what bothers me the most is motoring silently backwards into my garage and being startled if the ICE starts up to charge the battery especially as I'm backing up into my garage! That seems to happen even though I'm backing up slowly 10-15 ' and the battery is showing a 3/4 full charge.
     
  3. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    I put it in EV if I need to do a fine maneuver at the end.
     
  4. lucasb7

    lucasb7 GS450h

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    I wouldn't say its an EV since the power is ultimately coming from the ICE.

    There are some significant limitations in reverse if the ICE is forced to turn on. With a good SOC and operating temp, the car will go 25 mph in reverse. However, if the ICE is forced on, the max speed comes to somewhere between 5 and 15 mph. You can see this situation on the simulator at eahart.com/prius/psd/HSD (sorry I don't have enough posts to link)

    On another note, some RXh owners have had issues towing because of the power limitations in reverse. The current HSD solution is perfectly fine in the prius or my GSh but it can be a major detriment in reverse. One owner had to have his car and boat towed up a launch ramp because he got stuck facing the water.
     
  5. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Correct. Prius uses only the HV battery in reverse. Once the charge runs low, the gas engine is used to generate electricity. Gas engine cannot turn in reverse direction so it turns the generator.
     
  6. GSW

    GSW PRIUS POWER

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    ^ Yep, I have to climb a small 45 degree hill to my garage sometimes in reverse and its usually in EV mode, but kicks on the motor if the charge is low.
     
  7. stevemcelroy

    stevemcelroy Active Member

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    To answer the question posed in the original post - I do not think that you could call the Prius in reverse an EV - yes it is running on electric power, but that electricity was generated by gas - either by directly by burning gas to generate electricity or indirectly by regen - either way you start with gas. Of course if you have modified your car with a plug-in kit it would be different.
     
  8. usbseawolf2000

    usbseawolf2000 HSD PhD

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    So you need to charge the battery from a plug to be an EV? What if the grid electricity was generated from oil? Does it matter? Just throwing a bunch of questions to discuss.
     
  9. mikewithaprius

    mikewithaprius New Member

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    You could extend it with regen, but if I remember right there're no amps into the battery when braking in reverse. Or maybe it's because I only reverse at slow speeds, so it's only friction at that speed anyway...I sense a little road test coming up if I get a chance :)
     
  10. stevemcelroy

    stevemcelroy Active Member

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    Just my opinion but I do believe that an EV has to have electricity as fuel source going into the car. I do not believe that the Prius is an actual EV and I get a chuckle when I see cars with the "I am electric" stickers on them. Again just my opinion but I have always viewed the purpose of the synergy hybrid system as a way to make the gas engine more run more efficiently and also a way to recapture energy that otherwise would have been lost. Without gas the Prius can not run.

     
  11. mikewithaprius

    mikewithaprius New Member

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    In case anyone cares, trivia of the day: regen works in reverse over the friction brake speed threshold, just tested it while out this evening.

    Felt like a daredevil going 14 mph in reverse.
     
  12. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Absolutely. Power source defines if it is a hybrid or EV.

    The OP was trying to use Volt's flaw logic to make a statement that Prius operates like the Volt when in reverse. Therefore, it an EREV.

    We know Volt is a hybrid with extended range EV.
     
  13. stevemcelroy

    stevemcelroy Active Member

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    We are really getting down to the fine detail, but I would think that the Volt could be considered an EV - I know that there are a few circumstances where the engine drives the wheels, but it is my understanding that it is only in a few very specific cases and it is to maximize efficiency not because it needs to for power. So - it seems to me that you could actually drive the Volt and be just fine with no gas in the tank and other than the very short range you really would not notice.

    On the upcoming Prius plug-in it does not seem like running with no gas would be possible - even if you could get the car started and thru the warm up cycle you would be severely limited - you could drive around time, but the first time that you had to merge into traffic at speed you would be in trouble without the gas engine.
     
  14. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Prius PHV starts up in EV mode (default) so the ICE does not go through the warmup cycle like the cordless Prius. MG2 feels much stronger with full power from the PHV battery pack.