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Fuel injection on generators?

Discussion in 'Home Power and Microgeneration' started by N9WOS, Sep 17, 2003.

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  1. N9WOS

    N9WOS Guest

    I am fully acquainted with fuel injection systems
    And how they work.
    And I am acquainted with changing and maintaining them.
    I was just wondering what types of generators
    people have seen with fuel injections systems
    (besides diesel)

    Has anyone tried changing a normal carbureted generator
    Over to fuel injection.
    (ie) Big block v8 running a 100kw generator.
    Taking off the intake and putting on a intake
    with injection harness.
    Mounting the ECU/brain, MAS sensor, MAP sensor,
    And changing out the points or hall effect ignition
    With a TFI ignition system.
    And putting an exhaust system on that has the
    Port for the O2 sensor.

    The idea of active fuel/ignition control for a generator
    is neat to me.

    But I wonder if anyone has any experience with
    any fuel savings that may result, or any cleaner
    exhaust emissions that may result without the cat.

    I have a 1L Suzuki engine out of a GEO.
    The engine is a work of art!
    And the fuel control system is on the dot!
    I was thinking of hooking it direct drive to a
    20 or 30KW 1800rpm generator head.

    The only neat idea I have with regards to
    injected systems is speed control.
    If the car has cruise control, and the throttle actuator
    is controlled by the ECU.
    You could hack the firm ware on the EPROM so
    that the brain will use the cruise control actuator to
    maintain the designated 1800RPM on the engine.

    You could also use the unused outputs on the ECU
    to automatically operate the starter and do weekly
    exercises of the generator.
    (requiring the ECU to be powered all the time)
    And monitor grid power status.
    That would allow it to auto start the gen and activate
    a transfer switch once the gen is operating within specs.
  2. Guest

    Hey Jim got a picture of your hovercraft? I always wanted one for MY
    cabin. I have about 80 ft to the bayou and then the river and bay to
    play in.
  3. Fuel injection ok. Using the cruise control -- I don't think that the
    reaction time is fast enough to prevent severe droop. The best idea with
    gennys that I have is to run them at 3600 instead of 1800 -- more efficient
    and more bang for the buck. I have an incomplete unit (ran out of cash)
    that uses a Ford 460 with a propane set-up to drive a 150kw genny. The only
    component that I'm missing is a PTO. I was building it for my genny
    business when the biz went belly up. I have the engine, genny and other
    components in storage.
  4. N9WOS

    N9WOS Guest

    That is most likely true.
    The reaction time for the vacuum actuators
    is not the greatest thing in the world.
    Ummmm........ no.........

    You can produce the same wattage from a smaller engine when
    you crank it at 3600 rpm but you take a beating on base fuel draw.
    (no load fuel draw)
    And you take a beating on engine life.

    Simple rule.
    When you double the RPM.
    You double the dynamic and atmospheric loads on the parts.
    That doubles the friction and wind resistance/
    Since the parts encounter the resistances twice as many
    times per second, the result is the sum of both.

    Or 2 to the second power, or 4 times the energy loss
    just to maintain the engine speed with no load.
    If you assume that engine efficiency is the same.
    You increase the fuel consumption by 4 times when
    you run it at 3600 rpm instead of 1800.

    Lets say that the peak horsepower of the engine
    at 1800rpm is 1/2 of the 3600 rpm level.
    (which it isn't, it's 2/3 or 3/4 of the 3600 rpm level)
    That would mean that you would have to have
    an engine that is twice as large to produce the same KW.
    If it uses 1/4 of the 3600 rpm level, then it will
    consume 1/2 of the gas that the smaller engine requires
    To run at the 3600rpm level with no load.

    But since you don't need 2 times the size of engine.
    The normal no load fuel draw I see for 3600 rpm
    generators is around 3 times that of the equivalent
    1800rpm generator.

    And since the engine is operating at a more efficient level
    at the slower speed, it's fuel consumption doesn't Go up
    as fast with load increase.

    It requires a larger generator for the same KW output.
    But it is more efficient.
    All the large commercial name brand generators I have seen that
    Use V8 or V6 car engines, are set to run at 1800 rpm.
    I have seen some smaller 20KW 4cyl units that run at 3600
    Namely one that used a ford 4cyl.
    But the no load fuel consumption was horrible for it's size.

    And another side benefit from running at 1800rpm.
    The engine turns half the number of turns per minute.
    The parts encounter half the dynamic forces per turn.
    So the engine life at 1800rpm is usually four times
    the engine life when it is operated at 3600rpm.
  5. Ian Stirling

    Ian Stirling Guest

    Quadruple for some things.
    You have to move things the same distance but in half the time, so
    that means you need four times the accelleration and four times the

    For double the RPM, everything has to move twice as fast
    Err, no.
    Assuming that the "4 times" is correct (it's not), then
    it would be the idle fuel consumption, not the loaded
    fuel consumption.
  6. N9WOS

    N9WOS Guest

    That was my point in stating "Simple rule."
    I wasn't trying to be accurate.
    I was just guesstimating
    I was just basing it on a factor of one increase for each part.
    That was what I was saying.
    you increase the energy loss by 4 times with no load on the unit.
    That will increase the fuel consumption by 4 times when
    you run it at 3600rpm instead of 1800rpm (with no load)
  7. N9WOS

    N9WOS Guest

    Who cares about a freaking topic????
    Not me! :)

    Nice pic.
  8. N9WOS

    N9WOS Guest

    Diesels are preferred for a couple of reasons; they run happily at a lower
    Side note.
    The torque curve on a gas engine is highly dependent on the design.
    intake volume, vs carb bore, vs valve opening, vs displacement.
    The old WD AC tractor around here really cranks at 1000 to 2000RPM.
    And it's can't hold 3600 under load if it's life depended on it.
  9. ben williams

    ben williams Guest

    Both links for video point to firstflight.mpg, can't see the one of the open
    field (according to the description).
  10. Steve Spence

    Steve Spence Guest

    frequency and rpm is a function of the number of poles in the gen head, not
    the engine. lower rpm's make the engine last longer. diesels are built
    better, last longer, use less fuel, and have the advantage of being able to
    burn free waste vegetable oil.
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