Diy Haldex controller........Haldex Controller taken apart with pics

Discussion in 'Transmission' started by sambo, May 11, 2013.

  1. sambo Paid Member Paid Member

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    Trying to understand fully how it works and if i can find a way to control it from in car to engage 4wd as and when needed

    I know controllers are available but they are pricey and i want to make my own:)


    Here is a pic of the diagram of internals to show how it works


    [​IMG]


    Basically as and when engine ecu decides it sends signal to haldex controller to engage rear diff. Stepper motor turns and slides spring loaded pin/valve which allows pressurised fluid to pass into clutch pack and engage drive to rear wheels


    I'v removed the stepper motor and tried to figure out wiring and try and control it with stepper motor driver donated by Wayne of Chipwizards :)


    I have managed to get it to work so i'v assembled it back into housing and tried it

    [​IMG]

    [​IMG]

    [​IMG]


    I have found that pin/valve shaft that is actuated by stepper motor is quite stiff and it returns to resting closed position if motor is stopped

    Hard to explain but here it goes

    I dont understand how the motor can keep pin/valve in extended/open position for more then few seconds as it keeps jumping/sliding into resting position for a second or so then sliding into open position again and again if power is applied to stepper motor continuoslly.
    When power to motor is interrupted spring on the pin overcomes stepper motor and returns it to resting open position which means no drive to rear wheels

    Maybe this is how they operate normaly?

    Any input is much appreciated:)

    I have the way to modify the controller and keep pin/valve fully extended manually if i want to but i dont want permanent 4x4 as the car becomes undrivable on road as it wont turn corners! And my car is a daily

    I'l upload video of motor running later on
     
  2. DEX

    Dex Paid Member Paid Member

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    I remember overhearing a bit of this conversation at Curborough - sounds like a pretty fascinating project :)
     
  3. Trev16v

    Trev16v Paid Member Paid Member

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    Could you need a bit of custom electronics for this? That is, something with a basic processor that actuates valves or whatnot under certain input conditions?
     
  4. sambo Paid Member Paid Member

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    Yea it should help out folks out there who, like me, are in need for a such controller to engage 4wd as and when needed and run in fwd mode all other times :)

    Stepper Motor driver is an old tool for testing idle valves and it shuld be easily replicated and built from kit. I am also thinking of tieing it into my ecu to take over switching the unit on/off via few variables like boost, throttle position etc

    Not sure if video will work and is c rap quality but here it is anyway


    [​IMG]
     
  5. sambo Paid Member Paid Member

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    Quite possibly could need to replicate this controller it self unless they could be sourced?

    And maybe other bits and pieces to, i will try and get it work in basic form first once i overcome mechanical operation issues stepper motor side of things
     
  6. Trev16v

    Trev16v Paid Member Paid Member

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    I'd quite like to see if I could advise in any way once you know more about what you need. I'm wondering if there's an off-the-shelf processor board available that possibly has motor drivers and whatever you need already on it (I'm thinking an Arduino-type board). Then making it do what you need it to do is a matter of writing a bit of code.
     
  7. DEX

    Dex Paid Member Paid Member

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    I can hear Trev actually getting a semi at the thought of getting to do an electronic controller project....

    Sambo - I think what he's saying is "please let me join in, please please please"
     
  8. mat-mk3

    mat-mk3 Administrator Admin

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    Is the stepper motor the same one used by VW? I would have thought if you wanted to move a pin and hold it in that position it would have been a servo motor.
     
  9. sambo Paid Member Paid Member

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    Very welcome to join in :)

    Everything i knew about electronics many moons ago i have forgoten about!
     
  10. sambo Paid Member Paid Member

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    It is same as on vdubs

    Yea that is what i thought but spring is stronger then internal rotor resistance on the motor so i guess its a fail safe setup in case wiring is damaged it will return the pin to resting position disabling drive to rears

    I think that maybe haldex controller aplies power to motor to move the pin to desired position and then it reduces voltage to it by amount required to stop motor turning any more but enough to equalize with spring force and keep the pin static?

    Trev, does this makes sense?
     
  11. Dave R

    Dave R Forum Member

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    When the Haldex is applied what's the ratio between front & rear?? Guessing if you saying handling isn't good it's 50:50?? Any way you can alter that and make it 40:60 or 30:70, baised more towards the rear?

    Have this system on my Passat so its nice is know how it works now:thumbup:
     
  12. sambo Paid Member Paid Member

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    Max is ment to be 50-50 but it never is unless you get uprated controller but problems can arise as i said earlier

    If car has full 50% locked to rear then car doesnt want to turn in tight corners due to rear wheels traveling in smaller radius then front which causes rear wheel to drag and hop etc and is only good for straight line max grip

    Even 55-45 ratio is manageable as there is some slip between front and rear
     
  13. sambo Paid Member Paid Member

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    Max is ment to be 50-50 but it never is unless you get uprated controller but problems can arise as i said earlier

    If car has full 50% locked to rear then car doesnt want to turn in tight corners due to rear wheels traveling in smaller radius then front which causes rear wheel to drag and hop etc and is only good for straight line max grip

    Even 55-45 ratio is manageable as there is some slip between front and rear
     
  14. sambo Paid Member Paid Member

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  15. sambo Paid Member Paid Member

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    I think it is doable for someone who knows what they are doing

    Had a play today, experimented with operating bias pin/valve without the spring. I think as it is it will do me for what i want

    Basically pin stays where i want it to

    From in car it will be impossible for me to know where exactly the bias is but i am happy with being able to wind it in fully and unwind so basicaly going from 4wd to full fwd and if need arises for some assistance from rear wheels such as rain/snow i can just knock it back slightly from full 50-50 to give me some slippage between axles and if i feel car is not turning in properly i can just give it further slight adjustment

    Once i put 4wd back on my car i will play about and report on findings

    In mean time does anyone know where to obtain simple stepper motor driver so i can experiment with?

    Needs to be able to drive bipolar motor, 4 wire version
     
  16. Crispy 8V CGTI Committee - Club Secretary Admin

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    It is more or less as I described !!
    Seems bigger than I recall, is it a mk4 type version with a filter as part oils system?
    A 3d map makes sense, prob how the current controller process the info it receives over the network


    Now here's the variable to take into account, the pin doing the control there's amount of systems pressure on the pin, as its not behind it should be minor
     
  17. sambo Paid Member Paid Member

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    Way i see it pin blocks off bleed hole in the 2 port cylinder and hole is sideways on to the pin so i dont think fluid pressure will act onto the pin in any way?
     
  18. Trev16v

    Trev16v Paid Member Paid Member

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    There are just loads of stepper motor driver boards on eBay. An example is this board, which won't do much on its own but it's basically just the stepper motor driver itself which is to be used together with a microcontroller to provide the actual control:

    http://www.ebay.co.uk/itm/Arduino-S...ther_Computing_Networking&hash=item1c2feb9c5f

    That one above is designed to plug onto an Arduino board (a microcontroller board that's very popular with experimenters).

    Another example, again designed really to be used with a microcontroller:

    http://www.ebay.co.uk/itm/SparkFun-...ther_Computing_Networking&hash=item1e78aaee3c

    There are just absolutely loads of boards like this. Many of them are designed as daughterboards for use with microcontroller dev boards such as Arduino, Raspberry Pi, and so on.

    So, some kind of control unit that drives the motor in response to some inputs and perhaps some pre-programmed map (e.g. like cerips suggests) would be quite simple.

    In the meantime though would I be right in thinking that what you actually want is a stepper motor driver that just works on its own without any intelligence, that gives you a manual position control (e.g. a control knob or up/down buttons)?
     
  19. sambo Paid Member Paid Member

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    That is exactly what i have right now and it will do me just fine for now and i bet alot of people out there who use haldex sysytem for drag racing etc will be happy with it

    On the other hand if we could create something more sophisticated that does not cost the earth there will be ample market out there for folk who like to keep to oem controls and fit and forget but who like to have more control over it then oem setup
     
  20. Trev16v

    Trev16v Paid Member Paid Member

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    Having done a bit more searching I haven't yet found a stand-alone stepper motor driver board that lets you adjust the position using manual controls. Such a thing probably exists but I only spent a few minutes looking, and I restricted the search to UK suppliers.

    What I'd personally probably do is obtain an Arduino microcontroller board (e.g. Arduino Uno or Mega) and a stepper motor add-on driver board that's suitable for your stepper motor. Then write a bit of code to give manual control in response to a couple of up/down pushbuttons. Then later on expand the code to give it some intelligence (auto control based on sensor inputs). So for example, these two (though I haven't personally properly checked the suitability of the board for your motor):

    http://www.ebay.co.uk/itm/Sintron-A...ther_Computing_Networking&hash=item257c2a301b
    http://www.ebay.co.uk/itm/Motor-Dri...al_Components_Supplies_ET&hash=item27d257b93c

    Obviously there is some code to be written and soldering to be done.
     

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