Flywheel induction.

Discussion in 'Electrical Systems' started by thudpucker, Sep 9, 2012.

  1. thudpucker
    Joined: Jul 2007
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    thudpucker Senior Member

    The spring time is a booger for starting lawn mowers, Outboards etc when the Gas has set all winter in the Carb.

    I had the idea of making a fuel injector Solenoid valve operated by some Inductance from the Ign Coil magnet in the flywheel.
    This is for a Single cylinder engine. It might work for twins too.

    The most common failure on most newer engines is the Needle Valve.

    I thought an Inductor shown in my photo might be the answer.
    No more sticking needle valves and no battery needed.
    Look at this and tell me if I need to go ahead, and if I do, what info do I need to find out how much energy I'll have to pulse that Fuel Valve.

    Flywheel energy robber.png
     
  2. CDK
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    CDK retired engineer

    Correct me if I'm wrong; I understand you want to throw away the carburetor and install a fuel injector powered by a pick up coil because the gasoline residue makes your engine hard to start.

    There are two issues:

    1. The coil output is a linear function of the flywheel rpm. When you pull the starter the angular velocity is low, so little or no fuel is injected. If you succeed, the injected amount increases and keeps on doing so until the engine blows up.
    That certainly is not what you want, so you need a control circuit metering the amount injected and a small battery to provide power during starting.

    2. The 4-stroke engine requires fuel injection during every second turn, so you also need a control circuit to suppress injection during the power stroke/exhaust cycle.

    All together, you exchange a carb that needs the inevitable spring cleaning with a fairly complicated electronic circuit and a battery.
    The good news is that the coil can charge the battery if a bridge rectifier is used.
     
  3. gonzo
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    gonzo Senior Member

    The sticking needle valve can be easily prevented by draining the fuel. Fuel injection, to work well, has to be metered. In the past they were regulated mechanically, but the amount of maintenance and failures didn't make them popular. With electronics it is possible to regulate the injection reliably.
     
  4. jonr
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    jonr Senior Member

    Add gasoline stabilizer and run the carb dry or drain it. Fill with fresh gas in the spring.
     
  5. thudpucker
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    thudpucker Senior Member

    Thanks gonzo, we've gone over that at the local Small Engine shop. This is just an idea so far.
    I think it it was a Good Idea, you'd see it on all the new B&S, Honda, etc.

    CDK, thanks for the input.
    My idea was to have the fuel supply above the Needle. Gravity flow.
    The Induction pulse from the piston would draw the fuel through the open Needle.
    The amount of Air is still controlled by a Butterfly, same as always.

    At this point, the Needle is open, the fuel will flow, the air is right or close to right, ignition takes place as always.
    The Needle cannot stick, as it is pulsed open, and pulsed shut.
    As opposed to the Float control in a Carb.

    Control.
    Low speed, the Needle opens for a short time.
    Hi speed, the needle is open for a longer time and opens in advance a little.

    Those last two sentences might be a booger to handle without circuitry.

    So what does the idea look like now CDK?
     
    Last edited: Sep 10, 2012
  6. jonr
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    jonr Senior Member

    Sounds like you want to do electronic fuel injection without a fuel pump to pressurize the fuel. Note that at wide open throttle, there is almost no vacuum pressure to pull fuel in and gravity doesn't create much pressure. And that even solenoid valves can get gummed up.
     
  7. Petros
    Joined: Oct 2007
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    Petros Senior Member

    This is not fuel injection but rather a electronically controlled mixture needle in an otherwise normal carb. the problem I see is the crappy federal gasoline will still gum up and corrode the electric needles as much as it does a float and needle valve. You have not really solved the problem. the problem is the fuel sits too long and causes damage to the parts when it breaks down. Best thing would be find a way to have automatic fuel cut off so the carb runs dry, or perhaps a solvent injection that displaces the fuel left in the system when it is shut down.

    Easiest solution is switch to propane, costs less and will not corroded the fuel metering system.
     
  8. thudpucker
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    thudpucker Senior Member

    Thanks guys, I'm still listening.

    Jonr I think in my own little mind that the Intake pulse at hi speed is short, but still very strong.
    Still strong enough to atomize fuel coming off that Nozzle.
    If you think differently c'mon back and tell me what you think.
    Dick
     
  9. CDK
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    CDK retired engineer

    Still not good!
    For any control circuitry you need a power supply, but all you have is the short pulse from the magnet passing the coil. Once the engine is running you could obtain enough electrical energy from it, but how do you get it started?
    And how do you prevent injection during the power/exhaust stroke when the intake valve is closed?
     
  10. thudpucker
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    thudpucker Senior Member

    The Two-stroke engines are not a problem with the injection timing.
    Someone else brought up the mixture problem for two strokes. He said there might be a burned piston etc.

    On a Four-stroke I'd have to put in a trigger off the intake valve or some other movement taking place at the time I needed it.

    I considered a Battery for a pwr supply. It could be a small rechargeable.
    The self-starters have the Battery. All I'd need there is the trigger and timing device.

    For a Six HP B&S single cylinder (mower engine) I thought this way:
    On the first pull it might be slow to start but the Capacitor or Rechargeable would have enough current to pulse the Needle on the 2nd or 3rd turn of the crankshaft.
    That should start the motor if fuel is present.


    I'm going to add a little spring to hold the needle shut. The solenoid windings should pull the needle open as soon as the energy is there.
    The end result would be quick starting even after sitting all winter.
    One pull should do it.
    Also, that problem with the new carb's n' needle valves of leaking gas into the Crankcase would go away.

    I keep thinking there is something even all of us don't see that is keeping the major Mfg's from pursuing this thought.
    Three years ago I sent the idea to B&S and they never even answered me.

    I have an old TV with lot's of 'stuff' inside it that I planned to use in making up this idea.

    I'll work on a circuit.
    Thank you all for the inputs. Keep hammering at me, it'l come together yet. :)
     
  11. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    Uhm, why not go back to the past and use a suction flow carb?
    There is no float, no needle valve to maintain a fuel level.

    I have an old Briggs from 1940 with this carb and it idled and run just fine.
    It has a fuel tank, In the fuel tank is a one way valve to which is attached a small fine copper line.

    The line goes to an adjustable needle valve, some metering holes and butterfly plate.

    I just typed all this in and I dont want to delete it. Cause I suppose it could still clog. I have found however it never has.

    Pic of a very similar engine showing carb, tank, copper line
    https://sites.google.com/site/briggswiengine/home
     

  12. thudpucker
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    thudpucker Senior Member

    That was used from 38 when I was born, to 57 when I graduated from Hi School.
    I certainly will consider that.
    Makes you wonder why they quit using it?
    The whole object is to get a carb that will work when It's been sitting all winter or summer as the case may be.
     
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