Resistors for Low Impedance Fuel Injectors

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  brendanm on 29/10/2019 - 17:21

  +1

  What engine are you fitting them to?

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  PPossum on 29/10/2019 - 18:01

  Thank you brendanm
  Not a straight forward application sorry. It is a single cylinder engine running on alternative fuel with a Twin Stroke Compression-less cycle. The engine has been running to about 3500rpm and fires at the top of every cycle. At this stage the duty cycle is be about 75% but that will drop to below 50% as the engine is developed further.

  I would just like to get an idea on what is std with the VE Commodore?

  Thank you

  • 

    brendanm on 29/10/2019 - 18:57

    +1

    Sounds very interesting! It's direct injection then I assume? Using a megasquirt to control it? What impedance does that want to see? Direct injector requires high voltage to open, then lower to hold it.

    Just reading it again, seems it may be indirect injection with that duty cycle?

    • 

      PPossum on 29/10/2019 - 21:05

      Yes it is direct injection. Not using a megasquirt as this is a Twin Stroke engine cycle and I didn't think anything conventional would be suitable. Using an arduino micro controller and mosfet circuits to control the injectors. Please advise if you think different. I could make an open and hold voltage set up if that is the best.

      Any info I can get on the power supply for these injectors would be greatly appreciated.

      • 

        brendanm on 29/10/2019 - 23:22

        -1

        Pretty sure they are 60+volts for the peak and then 12v for the hold. If you need a resistor (not sure what impedance your driver is happy to run), I'd imagine you'd want to be running at least a 25 watt or so resistor, but I'm not 100% on what the actual current draw is from the injectors, I can't imagine it's that high in the hold phase. When you say twin stroke, do you meant two stroke or a different thing altogether?

        Got a link to your project?

        • 

          PPossum on 30/10/2019 - 08:42

          @brendanm: Thank you brendanm Do you know where they get 60 volts from? Our injectors take 1250 micro seconds to open with 12 volts. I was suspicious they might have used less and even dropped the voltage more after they were open. It has been very difficult to find anyone who has this kind of info.

          The engine is a converted 4-stroke that runs as a Twin-Stroke Compression-less cycle on hydrogen and oxygen. It has a full power stroke followed by a discharge stroke. So we ditched the induction and compression strokes (suck and squeeze) and just have - bang blow, bang-blow. There is still work to be done but we will be using waste heat to replace compression and give the cycle its grunt. Just by getting rid of half the cycle we can potentially double the power output without any compression losses. Have had it running to 3500 rpm and it is a pretty kick ass exciting little engine. Especially considering it is zero emission.

          This project is approaching year 4. We have started a BRC Hydrogen Engines Face Book page but have not advertised it yet. I am trying to get the engine to a presentation ready stage so we can get some support. Please fell free to LIKE it all and provide any feedback.

          Thanks for your input - Possum

          • 

            brendanm on 30/10/2019 - 10:59

            @PPossum: They use a dc-dc converter in the ecu to get the high voltage peak, then is dropped back to 12 for the hold. Sounds very interesting, I don't have Facebook but will see if I can view without it, otherwise might have to make a fake account just to look. Might be worth reaching out to the megasquirt guys to see if they have any ideas, adaptronic are also a company that I know (in the past at least) have been very receptive to stuff like this.

            Got a video on YouTube of it going?

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  iforgotmysocks on 29/10/2019 - 19:19

  +1

  Does anyone have any info relating to inline resistors?

  As long as there are no follow up questions - Yes.

  • 

    PPossum on 29/10/2019 - 21:09

    Any info would be greatly appreciated thank you

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  ShannonN on 29/10/2019 - 23:05

  I would just like to get an idea on what is std with the VE Commodore?if in doubt ask on the aussie commodore forums what is std on ve

  • 

    PPossum on 30/10/2019 - 01:41

    Thanks Shannon 8-)