Hand Throttle Control Mod, questions

Discussion in 'Gen 2 Prius Accessories & Modifications' started by hojosan, Apr 13, 2012.

  1. hojosan

    hojosan New Member

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    Vehicle:
    2008 Prius
    Model:
    II
    I am considering wiring up a parallel throttle control to mount on my dashboard.

    Since the Prius uses a drive-by-wire system, I figure I can take a duplicate accelerator assembly, pull out the electronics, and mount that on my dash, left of the steering column. With a switch, I can select to let the car see either the standard pedal-mounted sensor (down at the right foot well, obviously connected to the gas pedal) or my sensor up on the dash.

    Why? To allow stable and fine tuned "throttle" settings. Instead of trying to hold my pedal foot very stable, why not use a little knob and just set the sensor to 8%, 10%, or whatever level is required to maintain a (fairly) stable speed over long hauls? I live in the Midwest, with lots of long distance driving, quite flat, no surprises. I think that locking a throttle at a certain position will allow me better control over the fuel economy without the large run up in engine speed that the cruise currently will trigger on certain hills.

    My question is--has anyone already done this? I can't find any threads here or elsewhere that describe it. It seems simple--6 wires to switch from one sensor to another, plus mounting a little hall effect sensor on/through the dash and a 6 pole switch to make the change from one input to the other. Parts from eBay look like around $50-$100.

    Any thoughts? Arguments that this would be a waste of time?

    Related question: If I hit the brake pedal AND the gas pedal, does the computer know to disregard the gas pedal input? I would expect the computer to ignore requests for more speed if the driver is also hitting the brake. This would obviously have some safety issues with regard to my potential mod; I would not want to have to do a panic stop with my gizmo set at 10% throttle, while fighting the car which is trying to engage the engine/traction motor!

    thanks,

    -h
     
  2. Manksgloob

    Manksgloob Member

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    I don't think the throttle cut-off was implemented on the Gen II. Or at least if it was, it's at a certain % and doesn't cut off if it's not depressed a preset amount. I've been able to lightly trigger my brakes while still accelerating but I haven't tried a full bore attempt.

    Having said that, the brakes (supposedly) have more stopping power than the car can provide so if you do have a panic stop you (should) still stop.

    Experiment and see?
     
  3. jpadc

    jpadc Type before I think too often

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    Welcome to PC hojosan.

    My only thought is a legal one. In the state I live in, you must get a special certification on your license to drive a vehicle using hand controls. I know nothing of the laws in other states nor do I know if such a law is enforceable. On the other hand, insurance companies often look for any reason possible to deny coverage on a claim and that might be a big red flag if your vehicle is ever in an accident.
     
  4. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    I would not recommend this mod. The benefits do not outweigh the risks.
     
  5. hep1966

    hep1966 Junior Member

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    I would like to do this mod on my car. Sometimes my students drivers don't push hard enough on the gas pedal.
     
  6. Rokeby

    Rokeby Member

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  7. hojosan

    hojosan New Member

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    Well, you guys have successfully dissuaded me from wiring it up as I had proposed...

    FWIW, my dad (an excellent engineer and mechanic) also voiced similar misgivings.

    I'll keep thinking and tinkering, hopefully to bring something neat-o to the forum :).

    -h
     
  8. Rokeby

    Rokeby Member

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    hojosan,

    You give up/in far too easily.

    I'm going to come clean on this. In the last sentence of one of my posts
    in the 9/'08 thread cited earlier, I said simply,

    "I have been messing with a low pressure air arrangement with variable
    results for a few months now."

    At that time no one picked up on this. At the time it appeared that an
    electronic method would be the most elegant solution and I didn't want
    to divert attention away from that possibility.

    I have built and used a low pressure pnuematic go-pedal "finesse."
    Unfortunately, before I could build a really slick system, there were
    two deaths in my family that caused me to put the system away in a
    "safe place," which of course I cannot now find. I then forgot about the
    whole thing.

    But I'm now looking for it, and I will find it and produce pictures.

    Here is info on the essential parts, the two low pressure pneumatic
    actuators one mounted to the go-pedal, the other hand-held:

    Roughly full size:
    [​IMG]

    Pneumatic actuator - Firestone Industrial

    Specifications

    If you are interested, I can provide a brief explanation of my pneumatic
    finesse and it's operation. (I can't get to making a serious search for the bits
    and take photos until this weekend.)
     
  9. nutmeg

    nutmeg just rollin'

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    when still, the car revs the ICE to charge the batteries if you hit the gas and brake at the same time. Presumably, it does the same when rolling.
     
  10. FederalGnat

    FederalGnat New Member

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    2007 Prius
    Model:
    II
    What about an (A OR B Switch). I'm thinking of buying an extra OEM Throttle. Then having a selector switch that can select Throttle 1 or Throttle 2. Using the OEM Additional throttle I think its possible to switch from 1 --> 2 and back without computer noticing (fingers crossed).

    Need to find a multiple input switch that can switch all continuity to throttle 2 at flip of a switch (multiple connections simultaneously). Could use some sort of solenoid(s) but a (5x3) prong switch would be easiest. Need help finding that tho, not sure if that's available. ( Could be easy to add brake kill switch that reverts continuity to the throttle 1 which would be at zero throttle aka turn off throttle position holder). Brake kill switch probably involves solenoid(s) method (more difficult).

    P.S. I have lots of rolling hills in my area that I've found that if you keep a steady throttle position you can easily save on the mpgs. For simplify I could go without the brake off switch (throttle 2 --> throttle 1 @ zero mph), and just remember to hit switch prior to braking. Its still possible to stop if you forget (fyi).

    *Making a mechanical throttle holder/maintainer for throttle 2 shouldn't be extremely difficult.
     

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  11. FederalGnat

    FederalGnat New Member

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    See attachement
     

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