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EV's need a "Trim Tab"

Discussion in 'Technical' started by woof, Apr 23, 2012.

  1. woof

    woof Model S #P683 Blue 85 kWh

    Apr 30, 2009
    I would like to have a "Trim Tab" on my next EV. This would be a physical slider or vertical thumb wheel on the steering wheel that would do the following:

    When pushed to the "up" position it would add power to the accelerator input. If the car were on level ground and the trim moved up, it would "creep" without pedal input. If on a hill, the trim tab could be positioned to add enough power to hold the car still. At highway speeds the tab could be used to maintain a steady power input, letting the driver move his foot off the accelerator to rest without triggering regen.

    When pushed to the "down" position, it would add reverse power/regen. When going down hill the amount of regen could be adjusted to maintain steady speed. When stopped on a hill the trim tab cold be positioned to add enough regen/reverse power to hold the car still.

    And there would be a center position, that if held down would zero out the power, to put the car quickly into neutral for coasting.

    Pressing the brake or significant change of accelerator angle would override any trim input instantly.

    The slider could be spring loaded so it returns to center without pushing on it, allowing for fingertip speed adjustments. Or it could be "sticky" like the controls on an audio equalizer, acting more like a standard "trim tab" on an aircraft, but instead of adjusting pitch it adjusts accelerator power. It could even be two push buttons, one for increasing trim, one for decreasing, and resetting to 0 on brake input.

    After a month of driving the ActiveE with regen on the accelerator, I've come to enjoy the single pedal control of an EV, but find that my leg tires due to the very fine adjustments needed to deal with hills and traffic. If I could make those adjustments with my thumb instead of my foot, I think I'd like it even better.

    On Acuras/Hondas, the cruise control speed up/slow down is on the wheel, easily reached by the right thumb. This has trained me to use my thumb for fine speed adjustments. However, after reading all the arguments for/against creep, for/against adjustable regen, and those hyper-milers who want to use neutral, I think a single "trim tab" concept could be a way to implement all those features and everyone would get what they want in a simple easy to use thumb control.
  2. rabar10

    rabar10 FFE until Model 3

    Dec 3, 2010
    Indianapolis, IN
    The solar car we built in college (avatar) had its throttle/regen control as a spring-loaded thumb slider on the steering wheel for this very reason -- easier to make fine adjustments and less difficult to hold position for long durations.

    Seeing as cruise controls with speed up/down adjustments have been standard for years, I wonder if there would be any regulatory issues with this. So long as precautions against exiting a powered vehicle are put in place (a common reason cited for 'creep'), I could see it working well.
  3. vfx

    vfx Well-Known Member

    Aug 18, 2006
    CA CA
    Pretty much what I have been asking for for years. The Ebox has it. I just asked for it to be a second stick on the steering wheel. (either side) Up down push away or back in for control.

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