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  • LNG to CNG

    anyone know how to convert a LNG car to run on CNG? I assume you would need to replace the LNG tank with a CNG 3600 psi tank of course. Perhaps a regulator to reduce the pressure from 3600 to at least 50-60 psi. Then use the LNG components from there.

  • #2
    Re: LNG to CNG

    LNG CAR? I never heard of one.
    LNG is used on trucks and buses.
    BLUE 09 GX


    • #3
      Re: LNG to CNG

      Perhaps he means LPG?


      • #4
        Re: LNG to CNG

        No, I mean liquid natural gas not Liquid propane gas. I have seen a LNG bronco. small truck with a small engine. I really meant pickup when I said car. sorry.

        But there is no reason they could not do it. The tanks are about the same size. But, the stuff gets warm and vents if you do not drive a lot.
        I am checking with impco to see if they have a regulator that will drop the 3600 PSI CNG pressure down to LNG levels. They do have one that will drop it from 3600 to 150 PSI. But I still need to do more home work and see if there are any more safety devices to install. The cost of the regulator is about 208( 35% off full list).
        Last edited by Idarusskie; 05-22-2008, 07:01 PM.


        • #5
          Re: LNG to CNG

          LNG on a Bronco. The LNG system is worth 1000 times more than what the Bronco is worth even if it's a classic collectable. You mean LPG (propane) LNG requires special training to handle the stuff, ever see the terminator when the guy freezes? Yeah that's what it can do to you. Not to mention where you getting the LNG from. The re-frigerate system required to keep NG at 150 below would take up the entire Bronco. You can get a high pressure regulator from just about anywhere for $250-$500 for a CNG system, sounds like what you were quoted.
          Last edited by CNG MOTORS; 05-22-2008, 07:09 PM.

          2003 Hummer H2 bi-fuel
          2000 GMC Yukon XL bi-fuel
          1999 International 4700 dual-fuel
          2007 Chevy Avalanche bi-fuel

          FMQ2-36 Fuelmaker w/ 24 GGE cascade


          • #6
            Re: LNG to CNG

            I do not know why people keep saying propane when I say LNG

            No, it was absolutely a liquid natural gas bronco. We have a bunch at the lab where I work. The guards use them because they idle their rigs a lot. I read the tank up close. it read refrigerated methane max pressure 256 psi. Also had the blue diamond tags on the bumpers and at the fill spout that read LNG
            (not CNG not LPG).

            As for it being 1000 time more then the bronco. perhaps in this case. It was all smashed up.

            here is an example of the tanks they use. There is no refrigerator on board LNG vehicles. This one was smaller then what they have posted. maybe custom made. the tanks hold the -260 degree F gas for 5 days. The vacuum around the bottle gives it an R5000.

            yes you have to be trained and yes you have to wear personal protect equipment or you will end up like the terminator. its is hard to get. that is why would like to convert it.

            I believe besides the tank and the heat exchanger the system is not that much different then a CNG or propane system with SS steel lines. Different pressures and relief valves.


            • #7
              Re: LNG to CNG

              Good luck with that, there are not too many LNG refueling stations.
              BLUE 09 GX


              • #8
                Re: LNG to CNG

                Well it seems to me like you need to figure out the pressures / states of your LNG system through the various points in the system. Do you know where in the system it changes state from liquid to gas? Is it right off the tank? I would tap in and check the pressure at the final lower pressure regulator in the engine compartment on the inlet fitting, and if it is like 150psi say, then you just need configure the CNG supply system to bring 150 psi to that same point. I would think you need to replace the tank, and high pressure regulator and any other components that lead up to the final regulator. I call it the final regulator and not the secondary regulator because perhaps LNG has more than 2, I don't know. I would just figure out what the pressure is up to that last one, and get the same pressure/state up to that point


                • #9
                  Re: LNG to CNG

                  You are right I still need to do some more home work.

                  LNG can be a gas in the tank or in the line leading from the tank. But would normally change to a gas after it goes through a heat exchanger. This heat exchanger would have to be bypassed. I would expect there to be pressure relief valves which will have to be checked for rating.

                  Thanks for all the comments


                  • #10
                    Re: LNG to CNG

                    I believe on CNG high pressure regulators, the pressure relief valve should be built in to the regulator and vent to atmosphere like a PRD per NFPA 52.
                    Regulators from GFI or Conoflow are used to supply factory Fords and Dodges at 125-150psi.
                    Your Friendly Nazi Squirrel Administrator


                    • #11
                      Re: LNG to CNG

                      thanks for all of the resposes.

                      This is a truck I got from DOE fro 1000.00 and I have not gotten in my hands yet but look forward to checking out soon.