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PRNDL shifter

Discussion in 'Roadster: Technical' started by TEG, Jan 26, 2008.

  1. TEG

    TEG TMC Moderator

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    Apparently in switching from 2 speed to 1 speed gearbox, Tesla has triggered a regulation to need an automatic style "gear selector" instead of the manual type "stick". I don't know what Tesla plans to do. Do they keep the same lever we have seen on prototypes but just make a channel with PRNDx? Do they switch to buttons? I doubt they would consider a "column shifter".

    Here are a few net images of different performance oriented PRNDx gear selectors:

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
  2. TEG

    TEG TMC Moderator

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    Buttons and paddles:
    ferrari2_415x328.jpg left_paddle_a_s.jpg
     
  3. TEG

    TEG TMC Moderator

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    Nissan GT-R:
    nissan_gtr_official_shifter.jpg
     
  4. TEG

    TEG TMC Moderator

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    Original 2-speed Roadster prototype gear selector for reference:
    [​IMG]
     
  5. doug

    doug Administrator / Head Moderator

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    Of course all the paddle shifters and tiptronic related stuff is irrelevant. That first image is from the Audi which I mentioned in another tread. Is there a close-up of the Ferrari center console? It's hard to imagine out how they'll make an automatic style shifter look and feel sporty.
     
  6. malcolm

    malcolm Active Member

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    #6 malcolm, Jan 26, 2008
    Last edited: Jan 26, 2008
    Well hopefully the feel of the car will do a lot.

    As far as the look is concerned, is it legal to rearrange these PRNDx switches into a conventional manual gearbox H-like arrangement?
     
  7. Albern

    Albern Member

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    I didn't notice this until the Road & Track online article but when the main stack is illuminated, it does indicate the gear selection similar to most if not all cars equipped with an automatic transmission; minus the "2" moving forward.

    [​IMG]

    Nonetheless, in looking for a solution I think a variation of the gear selector switches off of a Ferrari 575M Maranello could work best for both the Roadster and Whitestar.

    [​IMG]

    Any thoughts on this?

    Alex B
     
  8. malcolm

    malcolm Active Member

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    Quick mock-up of a PRNDL switchbox
     

    Attached Files:

  9. TEG

    TEG TMC Moderator

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    Thanks, I was thinking of doing something like that but you beat me to it!
    [​IMG]

    (Where L = more regen 'off throttle')
     
  10. doug

    doug Administrator / Head Moderator

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    #10 doug, Feb 1, 2008
    Last edited: Feb 1, 2008
    I listened to the audio of the town hall meeting last night. I found it interesting that there is no neutral, so the rear wheels are always connected to the motor. I suppose there is some effective neutral by allowing the rotor to spin freely.

    Also they plan for the most part to keep the current shifter design, but it was unclear to me if there will be a Park position. Already there is some kind of locking mechanism when the car is off, but handbrake should always be used when actually parking.

    I'm curious how all this will be worked out functionally. Particularly since they plan to have built in creep. If you stop at a light, do you really have to keep your foot on the brake peddle the whole time, or can you put the car in an effective park or neutral? Does the handbrake override the creep? What about when you're stopped facing up a steep hill, like in SF. Can the motor hold you stationary? (That can use a lot of energy.) Is there some kind of hill brake that kicks in (like on some older cars)? Or perhaps you use the handbrake (like most of us do in a manual).
     
  11. WarpedOne

    WarpedOne Mainecoon Butler

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    The rotor may spin freely but it would take quite some torque to make it spin at all. It will show quite some resistance to change its speed. Remember it weighs around 40 pounds and the gear ratio is 8 to 1.
     
  12. tonybelding

    tonybelding Active Member

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    Right. But I'm not clear whether there will be a N position marked on the shifter, or what. Before I always assumed there was an implied neutral position in the middle of the shift gate, just as with other manual transmissions. Now I just don't know.


    That was my understanding also. It implies that there is no P position on the shifter, it's invisible to the user.

    So it seems the whole PRNDL thing that was supposedly required by regulations has been abandoned. All we have left is RD and maybe N.


    Interesting question. Well, that's what you do with an automatic right? Keeping your foot on the brake, I mean.


    I don't mean to offend, but the way you've written that almost sounds redundant. Maybe you could use the handbrake to keep it from rolling. Maybe you could use the steering wheel to steer. Maybe you could even use the mirrors to see what's behind you! :tongue:
     
  13. doug

    doug Administrator / Head Moderator

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    Tony, thanks for your responses. :)


    I realize I was babbling on a bit at the end there, but there is a distinction.

    My point was that using the motor to hold the car stationary on a steep hill can use a lot of energy. (Some types of motors can be burnt out this way.) So I’m curious how this has been implemented. With a manual there a few ways to hold and takeoff on a hill. Some ways are better for your car than others. I was just thinking about my own driving habits and wondering how the Roadster will be different.
     
  14. TEG

    TEG TMC Moderator

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    From listening to Townhall meeting 2 I can offer some suggestions of what I think they plan to do:

    #1: When you take the key out of the car it automatically engages the "P" (park) pin in the gearbox. There will probably be some way to override this if you had to tow it and a flatbed was not available.
    #2: The shift lever plans to offer 3 positions - R/N/D. The old 1st gear position will likely be blocked off.
    #3: The eMotor is always geared to the wheels so "N" will still spin the motor and offer some amount of resistance.
    #4: On hills when you let off the accelerator pedal the car can start to roll backwards. You would need to use the handbrake or brake pedal to prevent it. The massive low end torque makes it no problem to charge up the hill once you decide to take your foot of the brake and tap the go pedal.

    I am still wondering if they will offer any way to pick different regen profiles (like more off pedal coasting for highway cruising versus high regen for twisty mountain roads)...
     
  15. siry

    siry Member

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    TEG - in the town hall I address this question by saying that we (I) definitely intend to offer user customizable regen of some sort at a later date. There has been a lot of discussion about this and there are safety issues to be addressed but they are easily overcome. While the customization may exist initially only in firmware through the VDS (and therefore only settable when stationary), I would like to see a switch or dial at some point that is easily accessible when driving so that you can make adjustments on the fly.
     
  16. malcolm

    malcolm Active Member

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    Cool stuff.

    Since the regen profile is essentially a graph of motor braking effect vs motor revs I'm guessing it's going to be more of a settable-when-stationary option.

    My favourite idea would be a PC or mac application (Tesla Virtual Tuning?) where you can download different profiles from the online Tesla service centre. Select one or create your own (with suitable safety overrides) and download it to the car.
     
  17. TEG

    TEG TMC Moderator

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    Thank DS... I assume you guys will do everything you can to stay on top of this so I will stop mentioning it.

    Question - are the bloggers and forum people giving you any good ideas, or do we just repeat stuff that you have already discussed at length internally?
    Sometime I think that ideas I put forth long ago resurface later, but I don't know if it was something I said or just coincidence.
     
  18. siry

    siry Member

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    I'd say both cases are true. We are always discussing potential ideas internally and we are always reading and listening to what is said in forums like these and other blogs. It is hard to distinguish which ideas come from where after a while. User settable regen goes back to the old EV 1 days.
     
  19. TEG

    TEG TMC Moderator

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    I guess maybe the blogs and forums serve more as a sounding board for you to know how informed the people outside the company have become.

    There is a slow process of having the general public come up to speed as any new technology becomes more mainstream.

    Back in the 70s the average person really didn't think much about the idea of a home computer. That changed in the 80s but people didn't think much about networking their computers, then in the 90s everyone learned about the internet and ethernet.

    Concepts like regen braking were fairly obscure until 2000+ as hybrids (and soon to be Teaslas) make the average person more aware.

    Yeah, it is a big swirl of ideas coming from all over... And you guys are figuring out which ones work and which ones don't.
     
  20. vfx

    vfx Well-Known Member

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    I'm betting that at least 1 idea in 1000 from bloggers or from customers like those met at auto shows is an idea that developers did not think of. And probably only 1 out of 100 of those is actually worth persuing.


    I say. "Blog Away!"
     

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