Update and technical details on my PHEV project

Discussion in 'Gen 2 Prius Technical Discussion' started by pEEf, Nov 17, 2010.

  1. hill

    hill High Fiber Member

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    pEEf, to take advantage of the gen III's stronger electric motor arrangement, do you think it would be reasonably do-able to all together supplant the Gen III's hybrid vehicle ecu with the gen II's engine ECM & hybrid ECU?
     
  2. imwoody36

    imwoody36 the prius parts guy

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    [​IMG]I would like to share this demonstration of an on board multimedia interface.
    this unit has windows ce , and allows for a variety of user inputs including usb, micro SD, ipod, and bluetooth.
    [ame=http://www.youtube.com/user/imwoody36#p/a/u/0/vkIDaDaLsDk]YouTube - imwoody36's Channel[/ame]
    I welcome hearing from others who have hacked the chinese 7" multimedia GPS units.
     
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  3. pEEf

    pEEf Engineer - EV nut

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    That would be an insanely complex job, if even possible. The inverter design has been drastically changed in the Gen 3 and would not interface to a Gen 2 HV ECU. I'd say you'd have a more easier time hacking the existing system. Then while you are at it installing a larger boost converter. That would give you 50+kw.
     
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  4. pEEf

    pEEf Engineer - EV nut

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    It would be nice to hack that unit, but it stinks that it's CE based. Linux would be a much better choice. Seems like if you are going to invest the time to hack, you'd be better off hacking the original MFD. Thanks for showing it off Steve!

    I also like your Gen 3 shifter!
     
  5. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    I started down this path a while back with a CE unit. It seems like they're pretty easy to hack the software as long as they have an early enough release of CE (I got a hello world up and running on mine). My problem was getting the hardware working - how do I interface it to the data stream? These things invariably are only USB clients not USB hosts.

    However, I'm with pEEf on this - ditch CE and go Linux. Now that there are a ton of cheap Android devices (7" tablet shipped to US for $123) out there I'd suggest using one of them as your head unit. Android (which is based on top of Linux kernel) development is reasonably straightforward and well supported.

    My suggestion (and what I'm going to be doing) is to have the user interface all done in HTML5 / JavaScript. Then write a custom webserver that provides the data that you want to display. That webserver doesn't have to be on a different device - it can be on the tablet as well. Or, (as in my case), it can be a separate device. Adding a simple wireless web server to something like an Arduino is pretty straightforward. The Android tablet has wi-fi so now I'll have an easy path to get the data onto the device...

    Does any of that make sense?
     
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  6. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    And with 50+kW you would rule the world! Seriously, that would be an awesome basis for a plug-in - I say we should buy pEEf a gen 3 and have him start hacking... :p
     
  7. pEEf

    pEEf Engineer - EV nut

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    From what I've learned so far, the Gen III uses an ECU inside the inverter. To me it looks like there are several discrete CAN Busses (maybe only the CAN physical layer though) that go in and are used to pretty much directly send speed/torque commands. The motor control logic is all inside the inverter now, whereas before it was inside the HV ECU and all the raw drive signals were sent in. This might make hacking actually easier if these comms can be reverse engineered.

    Another option for improving EV performance without screwing with the boost converter would be to add a higher voltage pack. This would still require hacking, but less overall hardware and would result in higher systemic efficiency. If you are going to increase the capacity why not?

    For comparison, The Nissan Leaf EV uses a 403.2v system and has brisk acceleration.
     
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  8. trans-V

    trans-V Junior Member

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    So, can you elaborate a bit on why exactly you chose 240v? Was it only because the stock system will not push a high enough voltage for regen beyond that?

    What would happen if you, say, doubled the pack voltage? Would it work at all? Would it burn the house down? Would it give you more than 20kw to MG2?
     
  9. pEEf

    pEEf Engineer - EV nut

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    Early on, I did some experiments and anything much over 260V set various DTCs while testing. With this pack voltage I come right off charge nudging 260v after a full top balance. When I use EV with the voltage still this high, it's sort of jerky when you take your foot off the brake. This surface charge voltage drops within a few seconds though and then it feels normal again.

    The car doesn't give me any more power when the voltage is high, but it does suck less amps. This probably makes the efficiency a little better. (Especially considering how minimal all the conductors are spec'd!)

    The HV ECU is clearly limiting EV power based on KW, so raising the voltage, at least w/o further hacking, doesn't get you much.

    Having a higher voltage with my battery configuration meant I could use more cells and thus have more EV range.

    I've had zero trouble with this configuration, save for a blown output diode in my Brusa charger. I'm technically over the design limit of the Brusa when I do the top balance and the pack hits about 260v. It was originally rated for a max top of 250v. To pervent this from happening again, I've upgraded the diodes to more modern beefier spec units.

    I suspect I could probably squeeze 30kw out of the booost converter without any trouble using this pack, but it would require a non-trivial amount of effort to hack.
     
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  10. adric22

    adric22 Ev and Hybrid Enthusiast

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    I'm just now stumbling across this thread. This design certainly sounds much better than the Enginer setup I'm currently using. But it sounds like your setup is a long way from a prepackaged kit. However, if it can ever be turned into something that is plug-and-play, and it were cheaper than the PICC kit, then this would certainly have a viable market place. Since the Chevy Volt (and to some degree the Leaf) won't be easily available to people for quite a while, this type of thing is almost a substitute. Only thing I would stress to people is that the EV mode of the Prius doesn't have as much acceleration power as the Volt has.
     
  11. trans-V

    trans-V Junior Member

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    Yes, it seems that pEEf, all by himself, tinkering around in his spare time, comes up with things that are equivalent or superior to the best (and most expensive) commercially available products.

    But, of course, he doesn't really want to make money off us poor saps. He's content to drive around the best car on the planet, that he built himself, and come on here and brag about all his engineering feats.

    Must be that big cloud of smug over Berkeley. :D



    p.s. pEEf, please don't stop bragging about your engineering feats!
     
  12. jdh2550

    jdh2550 Co-Founder, Current Motor Company

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    I've been wondering about that. Do you feel the acceleration is adequate for pulling away from a stop light? Or do you feel like you're holding up traffic behind you? Just curious.

    BTW, I'm a plug-in Prius wannabe and plan on trying to recreate pEEf's awesome design (he's already given us quite a lot of info to go on!)
     
  13. pEEf

    pEEf Engineer - EV nut

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    On electric only the acceleration from a stop is definitely sufficient. I'd say it's better than the average that most traffic does when starting off, so there is some headroom. Acceleration on the highway is abysmal though, it will indeed get up there, but it takes awhile. Of course if you want quick, just use some gas.

    For me, Most of the benefit from the PHEV is local in-town driving, and it works very well for that. Yeah, it might be fun if I had 200kw of acceleration on tap, but then I'd need a bigger battery to get anywhere. (and a stock in a tire company! =)
     
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  14. adric22

    adric22 Ev and Hybrid Enthusiast

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    Well, I drive around in EV mode all the time in town and pulling away from a stop light is certainly no problem. In fact, you can run off and leave the rest of the cars behind. But if you've ever been in one of those situations where you needed to floor it to get across a busy road or something, you might find the acceleration wanting. Also from what I hear, when you are going over 40 mph, it is nearly impossible to pass somebody because the acceleration really drops off the faster you go.
     
  15. pEEf

    pEEf Engineer - EV nut

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    Yeah, it seems to do about a little better than the average of other cars accelerating from a stop. Once you get past about 20 mph though, it starts to feel lacking, but for city driving it's still acceptable. If you like to accelerate hard as I sometimes do, the PHEV still returns around 60mpg though! (conversely about half that w/o plugging in)
     
  16. Flying White Dutchman

    Flying White Dutchman Senior Member

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    just found your topic! and wait a min you replaced the toyota BMS with your own?
    any pics?
     
  17. mrbigh

    mrbigh Prius Absolutum Dominium

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    Leon, he has developed the same concept than Hybrid Interfaces's BMS+. In this case,a modified Batt. ECU for statistics and data spoofing.
    Besides, Mr. pEEF made a Hydrid ECU interrupter to assert (as in a general word and not programming language) certain CAN values to overcome the 34MPH EV limits and pushing both MG1 and MG2 to the 70 MPH electric mark. Also the same principle of the PICC equipment.
    A great accomplishment,:third:
     
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  18. pEEf

    pEEf Engineer - EV nut

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    Thanks H,

    Just one point of clarification; I haven't made a "modified" battery ECU, but an outright replacement for the OEM which is now sitting on a shelf next to the OEM pack.

    It performs all functions as the original, plus controls plug-in charging and a few other things. There have been no wires cut or spliced into in my car, and I could return it to stock in about 30 minutes.

    There is no actual speed limit in EV mode, not even 70mph, but the power is limited to not much over 20kw by the Prius boost converter hardware. Much over 70mph and you really need more than 20kw to sustain that speed. MG1 is never put overspeed, and really it is no different than when gliding in a stock Prius, it's essentially the same as locking the ICE in a permanent glide mode.
     
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  19. KK6PD

    KK6PD _ . _ . / _ _ . _

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    pEEf, from ev nut to ev god! WOW another really great thead, most impressive! Looking foward to more posts!
     
  20. Mesuge

    Mesuge New Member

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    Unfortunately, it looks like all the forthcomming new Toyota hybrid models in mid/lower segment like Yaris/Echo will come only with this new compact gen3 hybrid drivetrain (with smaller ICE engine). So, unless someone cracks this hECU inside inverter cpu boards, that means no DIY/3rd party PHEVs anymore, which would be a real major bummer..

    So far all evidence points to the fact, it's going to be necessary perform changes in that combined hECU/inverter unit, which will be for one thing encrypted/protected and also complex piece of software work with many thousand lines of code.

    Hm, seems Toyota was not happy with people tinkering with their product, although major driver was probably make it from their manuf. point of view simpler/smaller/more robust. :mad:

    There are also other manufs. like Ford (Escape 4WD!, Fusion), who might continue to use the older "legacy" architecture in their hybrids, but their hybrid fleet will not be that large/diverse or volumnous as Toyota announced anyway.

    In terms of that 52-72mph EV mode trick, there seem to 3x solutions presented so far.

    #1 PICC (GoldPeak NiMH pack, + now working on lithium based ver)
    #2 Plug-in Supply (upgraded system into similar seemless functionality at lower price, see new video)
    #3 pEEfs experimental project so far

    Also, there is the Enginer (and Hymotion) option, which are more aimed at the blended mode user, high speed EV performance limited by addon DC-DC converter. Similarly, the last option, CanView + mutli OEM NiMH pack is mostly blended mode only, unless you are living in some low speed residential park.
    Moreover, with the ban on rare-earths and recycling, the older packs might become one day unobtanium, perhaps less pronounced effect on markets, where is Prius weak (Europe)
    http://priuschat.com/forums/generat...olt-plug-in-hybrid-electric-vehicle-plan.html

    However, as more companies and individuals have been lured into this PHEV tinkering madness already, perhaps one day, the gen3 question will be tackled as well..
     
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