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70 mph EV only mode.

Discussion in 'Prius PHEV Plug-In Modifications' started by aminorjourney, Jun 10, 2009.

  1. Flying White Dutchman

    Flying White Dutchman Senior Member

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    and with then new battery packs with high capacity.... where there ... free at last haha
     
  2. drees

    drees Senior Member

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    The ICE is physically connected to the MG1. To let MG1 spin freely to avoid over-revving MG2, you'd have to put a clutch in between the MG1 and ICE.

    I doubt you'd be able to do that and still fit the engine/transmission into the Prius, but it sounds like an interesting conversion to get the engine/transmission into a rear wheel drive car...

    Great diagram and pictures of the Prius engine/transmission here: Toyota Prius Hybrid Car Technical Information
     
  3. Mesuge

    Mesuge New Member

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    It works a bit differently, MG1 spins faster RPMs than MG2, the issue/concern of over-revving relates to MG1. There is some sort of flywheel-damper thingy installed between it and the ICE, check out those Prius tear down sites..

    However, we are discussing rather something else - three basic options for the 70mph hack:
    1/ MG1 spins the ICE during this mode (attached ICE plays no mechanical/load role at all beyond keeping the RPM low for MG1). Therefore all electric Prius conversion is supereasy as per Steve's prototype, which was limited to top safely at 42mph and now it could work <70mph.

    2/ MG1 spins the ICE during this mode
    (but the attached ICE plays some role in the load/torque assembly of the entire MG2-MG1-ICE chain). All electric conversion possible only via connecting in place of ICE some sychronized thingy like <2kW emotor etc?

    3/ Same as previous but for some reason the mechanical interplay of MG1->ICE, sensors and this software hack won't work if we unistall the ICE completely as per #1 a #2 ..

    => So, now this is a quest for any big-brainers out there or Ewerts to shed some light on it..
     
  4. Flying White Dutchman

    Flying White Dutchman Senior Member

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    :rolleyes: i got a prius genius shirt:p:D


    lets see if steve wil remove the ICE at some point.
     
  5. Mesuge

    Mesuge New Member

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  6. Evilshin

    Evilshin Member

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    I thought MG2 was the main drive motor. That's the one whose RPMs is perportional to the vehicle speed. MG1 only needs to be on if you want extra forward torque or if you need to balance the ICE to the right output RPM...

    Anyways, concern regarding over revving a brushless synchronous motor is kind is really over stated. Brushless motors have torque being perportional to current and speed perportional to voltage. The reason why the Prius doesn't allow EV mode above a certain speed has nothing to do with the current limitations of the motor. (The current limitations does however limit torque and therefore acceleration on EV mode.) The issue is voltage. As a synchronous motor increase in speed the back emf increases in voltage. This is the voltage generated by the forward motion of the motor. (In other words a motor spinning becomes a generator, but you already know that, it's what happens when you take your foot off the pedal....) Unfortunately the faster the car goes, the higher the voltage of the back EMF. At some point the voltage equals or is higher than the battery pack. This is when in the past is thought to be the speed limit of motors. But synchronous motors generate AC not DC. So the voltage varies with time. With a bit of software you can phase advance the stators, or run the field coils slightly out of phase with the rotor. This allows the application of power before back emf reaches the pack voltage in its phase cycle. But as the back EMF increase, the more and more out of phase the application of power must be. The more out of phase, the less torque. But generally this gives the motor about 35-50% more range of speed than without this bit of software trickery. For the Prius, phase advance kicks in about 45 mph and reaches it's limit of usefulness around 60 mph.

    To get the motor to continue to torque at hight speeds you need either a higher voltage battery pack (which creates a mess of issues) or some type of higher voltage power supply. A switching power supply can easily provide higher voltage than it's power source. If you phase it with the motor, than you can allow the motor to have full torque up to the switching power supply's max voltage. I suspect that around 70 mph MG2 would no longer be able to produce enough torque to fight air and rolling resistance. Remember that they are increasing the speed range of MG2 not the torque produced.

    Though they don't mention anything about this, but their modification should shave some time off of the prius' 0-60MPH acceleration time. I would love to hear their results on acceleration.
     
  7. Flying White Dutchman

    Flying White Dutchman Senior Member

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    the prius already got a powersupply/switching/inverter..
    the battery pack voltage is going from 201,6 DC to 500 volts.AC ( or was it 600?,mmmm 650 with the gen 3 if i am correct )

    also a new video


    look at how carefull there needs to be accelaration.....
    i think this is nothing more then a bigger pack.. and high soc spoofing. ( kinda )
    and just maybe ICE ECU power cut. ( no fuel pomp cut )
     
  8. Hunter1

    Hunter1 Junior Member

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    Is it possible to make the screen jiggle some more? I was almost able to read the display :eek: I haven't seen a video camera without a steady cam feature for 20 years. But I would never be one to ridicule such innovative engineers over something so trivial as being able to actually see their incredible discovery.
     
  9. hill

    hill High Fiber Member

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    For those posting after July, regarding Nikki's (aminorjourney) incredible 70mph acomplishment, consider her beloved Velma (the PHEV) melted down. During a night time recharge, the battery system caught fire, causing a total loss to the Prius. Thankfully Nikki suffered only minor injuries. We'll never know, I suppose, if high temps in other components naturally created by those speeds played a part in the system failure ... as battery management/cooling was the likely culprit.

    .
     
  10. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    Nikki did not do the 70MPH hack as far as I know. She just reported that someone has done the hack. Her car cought fire during a recharge over night if I remember correctly.
     
  11. donee

    donee New Member

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    Hi Hill,

    As far as I know, I have not heard of any Prius fires in Lombard or Glen Elyn, IL, so it safe to believe the Ewert family Prius is still working.
     
  12. Flying White Dutchman

    Flying White Dutchman Senior Member

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    i can almost do the 70mph
    well on a really flat road i already can and when going easy on te gas pedal

    the way this is done is providing a fake high SOC like 99% for maximum electric use and a warmed up ICE or temp hack to keep the ice off automaticly.
     
  13. hill

    hill High Fiber Member

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    Correct ... and yes, I see it was another PHEV doing 70 ... gotta read more thoroughly

    .
     
  14. miscrms

    miscrms Plug Envious Member

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    This is not the same as being able to lightly touch the pedal on a flat or down hill and get your car to go into stealth mode. This appears to be a plugin-supply like ICE look-out mode with the addition of the increased MG rpm limits from the factory PHEVs and smooth transitions in and out (which the 52mpg plug-in supply/lucious garage version can't do last I knew). Safety/Reliability concerns aside, this is a pretty huge advancement in Prius hacking.

    Unlike warp stealth, this means you can stomp on the pedal and watch the car accelerate from 0 to 70 (eventually) without lighting the ICE. More importantly than being able to get to 70mph, it would likely allow you to run a full commute, which includes a short highway run without ever lighting the ICE even for warmup. I agree, the impact of doing this to a Prius needs to be studied, but that is awesome. Also bear in mind Chris and his brother are the ones that developed the CAN spoofing controller for Cal-Cars / plugin-supply, and have written their own linux based vehicle monitoring software. They've been at this for years, have some of the best in vehicle instrumentation out there, and are well aware of all the issues raised. If they think this is ready for prime-time, I think we can assume its been pretty well flushed out. I'm also a bit disappointed in the price, but can't really begrudge two guys who've given so much to the open-source community making a bit of money on a true innovation.

    Rob
     
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  15. miscrms

    miscrms Plug Envious Member

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    That's a major bummer, sorry to hear about Nikki's car :( Charging of the NimH traction packs is very non-trivial. This has long seemed to me a serious omission in Norm's otherwise brilliant BMS+ architecture.
     
  16. mrbigh

    mrbigh Prius Absolutum Dominium

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    Remember that Norm is not taking over the NiMH charging issue under any circumstance, it is under BMS+ customer's responsability this procedure.
    In Nikki's case, upon the information provided and by personal experience, can be attributed to negligence on properly checking her equipment in a daily manner. Been there, done that in the past 4 years........
     
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  17. NWPriusPlus

    NWPriusPlus Junior Member

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    Thanks! I would really like to be able to go 38 mph on the two miles of 35 mph 4-lane road in the middle of my commute, instead of limping along at 33.5mph.

    I will give it a try tomorrow and see if I can stay in stealth mode while keeping up with traffic. Not sure I'll try for anything over 40 mph, though!

    NW BMS+ Driver
     
  18. Flying White Dutchman

    Flying White Dutchman Senior Member

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    make sure you have the latest BMSplus firmware installed

    and welcome to the club
     
  19. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    I'm just wondering if I can bypass the Hymotion spoofing and use the BMS+ so I can experiment with this %99 SOC. I'm tempted to give Norm some more money to find out. I would like to get a whole new V4+ unit since mine is the original V4 while I'm at it.

    So is this 70mph hack that they are doing really just spoofing the SOC to 99% or are they doing something else with the software? Is there anymore details on this information anywhere?
     
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  20. mrbigh

    mrbigh Prius Absolutum Dominium

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    For the so announced in the past "open source software" that the Ewert brothers made, there is not trace of it anywhere.
    I guest that Plug-In Conversions Co (PICC) has a large piece of the cake in this endeavor and there is not for free :eek: