time delay relay.

Discussion in 'The Projects Forum' started by black01, Apr 25, 2016.

  1. black01

    Thread Starter Member

    Jun 10, 2013
    31
    0
    Hi
    I am trying to delay the nitrous solenoid on my nitrous system to eleminate a lean spike on my car. The time delay relay is pretty simple, and I can build that with no problems. The problem I'm having is I am using a progressive controller on my nitrous system that pulse width modulates my fuel, and nitrous solenoids to ramp my nitrous in slowly over so many seconds and this can be tuned to any ramp in I need for optimal traction.

    The big question I have is how do I keep the relay delay from delaying everytime the solenoid is activated while the controller is pulse width modulating it to ramp in the nitrous? I just need the very first solenoid activation to be delayed by a few milliseconds so the fuel gets a head start to the spray bars.

    Any help will be very appreciated. Thanks
     
  2. Dyslexicbloke

    Active Member

    Sep 4, 2010
    420
    19
    do you always want the same delay?
    If so you need a mono-stable circuit
    The pulse rising edge would trigger the mono-stable. NotQ would go Lo. The gate then times out causing NotQ to go Hi.
    Your solenoid would open when the driver pulse is high and NotQ is Hi

    Look at NE555, analouge, 74123, TTL or M74HC123 ... probably many others
    If you want quick and dirty drive a darlington transistor with a capacitor charged with a resistor. the transister will turn on when the cap is charged, arrange for it to discharge when the pulse is remloved
    Interestingly if you went this way varying the voltage would vary the time, all be it all far less accurate than a proper timer circuit but it is essentially how a 555 operates.

    Have you considered a small uP you could do all sorts of clever stuff with that

    Al
     
  3. black01

    Thread Starter Member

    Jun 10, 2013
    31
    0
    [​IMG] Screenshot_2016-04-25-17-55-11.png Yes the delay will be the same everytime. I was looking at this, it is exactly what I want but I think when the solenoids pulse width modulate it will delay everytime they are fired.
     
  4. black01

    Thread Starter Member

    Jun 10, 2013
    31
    0
    This is the way the curciut Is wired up. I need to put this on the nitrous solenoid so it fires a couple milliseconds after the fuel solenoid. Screenshot_2016-04-25-18-06-07.png
     
  5. Dyslexicbloke

    Active Member

    Sep 4, 2010
    420
    19
    You should use FET's, or solid state relays if you dont want to build, as mechanical relays cant be relied upon to switch cleanly or at a consistent speed, and they are even worse when opening.

    To be honest I have never actually timed a basic automotive relay but I would put money on them being the wrong choice.

    If you do use any sort of mechanical relay you MUST put a reverse bias diode round it or you will kill almost anything electronic you connect to it. You can get relays with diode built in, just look for automation products.

    I don't actually understand your project, because I have no idea about the application not because you said anything I think is not correct, are these relays switching quickly or just at start up or something, if they are operating along with throttle input you will almost certainly need some form of electronic switch.

    Also you have two lines labeled stage 1 & 2 retard respectively, are you sure the function you want inst built into your controller?
    Just looked it doesn't.... ignore last
    That's 1 expensive piece of kit and given that the instructions show relays I am now amusing that it is designed to work with them, still seems odd though.
     
  6. black01

    Thread Starter Member

    Jun 10, 2013
    31
    0
    The relays just activate the controller via a wide open throttle switch. The controller pulse width modulates the solinoids.
     
  7. black01

    Thread Starter Member

    Jun 10, 2013
    31
    0
    The two stages are so you can have one stage of nitrous at the start of the race and spray another one towards the end. I'm only running one stage so the wiring for the first stage is all that is important.
     
  8. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,018
    1,537
    Sounds more like you need to change the "fuel map" of the fuel injection setup. In a carburetor you would need to give a bigger or longer accelerator pump shot.
     
  9. black01

    Thread Starter Member

    Jun 10, 2013
    31
    0
    That won't take care of the issue. My tuner could Prolly add some extra fuel at wot but they would make the tune rich while not spraying nitrous. I'm running a stand alone and the fuel and nitrous are basically in a race. My fuel pressure is 60 psi and the nitrous pressure is 1000psi. The nitrous will win that race everytime and cause a lean spike because it gets to cylinders before the fuel, unless you give the fuel a head start or make the nitrous travel further. Lots of people are just running longer nitrous lines than fuel lines and compensating for it that way, but I'm trying to come up with a easily adjustable fix to the problem that doesn't involve having having a bunch of extra nitrous hose.
     
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