Announcement

Collapse
No announcement yet.

dome light

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • dome light

    some friends and I were sitting around and studying how to make cng safer and got to door switchs for the dome light these are mostly open contact to ground one would not know if the car was full of gas from a leak if outside the car and open the door and could have a spark from the door switch so we unhooked the door post switchs and just use the switch inside on the head light switch as sitting in the car one would smell the gas and would know not to turn anything on or off

  • #2
    Re: dome light

    Your comments make some sense Cowboy, but I think it is a little overkill. Remember that CNG need a mixture of between 5% and 15% cng in the air to be within flamablility limits (go boom). You would probably detect a leak in your system, inside the vehicle, long before the CNG got within flamability limits. There is suppose to be enought mercaptian (odorant) in the gas to notice the smell when it reaches about 20% of the lower flamability limit (1% gas in air).

    I would be more worried about gas building up (within flamability limits) under the dash or behind the kick pannels in close proximity to interior light door switch. You still have a spark when you use the headlight switch or dimmer to turn on the dome light. There is less chance for a flamable mixture to disapate from under the dash than from the interior of the vehicle. What about under the power seats. Power seat motors use brushes (spark). Or maybe a vent blower motor in the air duct system, or the blower motor switch under the dash??

    Just a few other consideration. It is great that you are thinking safety

    Larrycng

    Comment


    • #3
      Re: dome light

      our thought was that say on a windy day one would not smell it walking up to the car as the doors and windows are closed but the car is full of gas but once one was to open the door and get in or start to one would at that point smell the gas and no spark prior to that cowboy

      Comment


      • #4
        Re: dome light

        Good point.

        Also after spending some time around the mecaptian they say you become de-sensitized the wreched stuff; I have somewhat.

        Larrycng

        Comment


        • #5
          Re: dome light

          What Cowboy is illustrating is the prime reason all CNG fittings, tanks, valves, and filling connectors are isolated from the passenger compartment and trunk and are vented to the exterior of the vehicle.

          The encapsulation may be a "simple" bag with clamps over the tank valve and fittings to an elaborate device which fits the tank and tubing via a fabricated duct and hose.

          At one time, one of the European standards required a pressure test of the ducting or bag to prove it was gas tight. This standard may still exist elsewhere.

          Franz
          Last edited by Franz; 12-16-2008, 05:49 AM. Reason: clarification

          Comment


          • #6
            Re: dome light

            Yes, this is way overboard in the safety department. Maybe you should disconnect the starter and push start it every time
            02 GX
            01 GX
            03 Crown Vic
            06 GX
            Home Fueler

            Comment


            • #7
              Re: dome light

              Originally posted by freedml View Post
              Yes, this is way overboard in the safety department. Maybe you should disconnect the starter and push start it every time
              ok a flash fire under the hood is not near as bad as in the pass compartment but if you will come and push when im ready to go some where I will pop the cluch and we will be off hope you can run fast the van is a auto transLOL

              Comment


              • #8
                Re: dome light

                Two possible safety methods:

                1) Use magnetically-closed switches enclosed in vacuum - so-called "reed switches", old technology but effective. Switch goes in the chassis, small magnet in the door.

                2) Use solid-state switch actuated by a proximity detector. More modern, probably more reliable.

                In either case, no mechanical contacts exposed to the air.

                Comment


                • #9
                  Re: dome light

                  If your that worried about "what ifs", instead of reverse engineering a band-aid, why not just install a methane detector (like the ones in marine engine compartments) that would kill the main battery power or activate a brushless/explosion proof, spring loaded, powered roof vent to exhaust the fumes.
                  It would also come in real handy after a hard night of beer drinking and chili eating!
                  Your Friendly Nazi Squirrel Administrator

                  Comment


                  • #10
                    Re: dome light

                    As stated, if the tanks are installed properly, it would be VERY unlikely that you would get any significant methane in the passenger compartment. The tank containment should ensure that any leakage is routed to the outside, and is isolated from the passenger compartment.
                    1997 Factory Crown Victoria w/ extended tanks ~~ Clunkerized!
                    2000 Bi-Fuel Expedition --> ~~ Sold ~~ <--

                    Comment

                    Working...
                    X