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Methane as a substitute for petroleum in combustion engines

  1. Aug 24, 2016 #1
    Dear engineering community:

    For many years now I have wondered why our internal combustion engines have not been adapted for methane in place of the various forms of petroleum products we currently use. Why? (1) Because we have a gargantuan ever-renewing source of methane in human garbage and sewage, and (2) because it seems to me that this could do something about the methane-related carbon emissions into the atmosphere while we work on switching to solar-electric for our vehicles, which could take awhile. Anybody have answers to this? Thanks...
     
  2. jcsd
  3. Aug 24, 2016 #2

    russ_watters

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    There are methane vehicles and they are great except for short range due to having compressed gas as fuel.
     
  4. Aug 24, 2016 #3
    During WWII many vehicles in the UK were converted to methane (coal gas strictly), busses and trucks had large gas bags on their roofs. Carrying enough gas for a decent run is a bit of a problem and keeping it in liquid form would be difficult. I believe it produces carbon dioxide instead of carbon monoxide which is some advantage.
     
  5. Aug 24, 2016 #4
    Germany has been taking it seriously... in a carbon-neutral way.

    Or spray those cars with some solar screen...
     
  6. Aug 25, 2016 #5

    SteamKing

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    This article discusses how natural gas is used to power a variety of different vehicles:

    https://en.wikipedia.org/wiki/Natural_gas_vehicle

    It also discusses why LNG and CNG have not been adopted on a large scale as a fuel for road vehicles.
     
  7. Aug 30, 2016 #6

    JBA

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    The use of CNG for highway freight haulers has recently been gaining popularity and there are some standard highway truck stops around the US that now have CNG fueling for those vehicles.
     
  8. Aug 31, 2016 #7
    CNG and LPG were quite popular here some years ago; the government offered incentives to convert your vehicle and because of the lower running costs many fleet vehicles and taxis were converted. I don't seem to see many around now days though, I don't know what changed maybe the cost of LPG and CNG went up to be comparable with petrol.
     
  9. Aug 31, 2016 #8

    JBA

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    Recently there have also been a number of communities and cities that have started converting their service vehicles, including waste collection vehicles to CNG.
     
  10. Aug 31, 2016 #9
    Whenever gas prices go back up, methane (CNG) will become popular again. There just isn't a very good natural gas infrastructure for the purpose of filling up commuter vehicles.
     
  11. Sep 1, 2016 #10

    1oldman2

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    A very thorough article, I'm surprised they didn't mention methane fueled rocket motors. (I realize the thread concerns internal combustion engines but I was just commenting on the Wiki article)

    https://en.wikipedia.org/wiki/Raptor_(rocket_engine)

    Raptor is the first member of a family of cryogenic methane-fueled rocket
    engines under development by SpaceX. It is specifically intended to power
    high-performance lower and upper stages for SpaceX super-heavy launch
    vehicles. The engine will be powered by liquid methane and liquid oxygen
    (LOX), rather than the RP-1 kerosene and LOX used in all previous Falcon 9
    rockets, which use Merlin 1C & D engines. Earlier concepts for Raptor would have
    used liquid hydrogen (LH2) fuel rather than methane.
     
  12. Sep 5, 2016 #11

    Averagesupernova

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    It is not at all uncommon for methane to be used in internal combustion engines. Maybe not mobile engines but stationary equipment is often powered by natural gas.
     
  13. Sep 7, 2016 #12
    The biggest hurdle at this particular moment is actually oil prices being so low. There was a lot more demand for it in the commercial truck space even as late as last year before the huge drop in oil prices. Infrastructure is growing, and it can be reasonably practical to have a CNG powered car in CA. We have plenty of fill stations around here.

    As for methane formation from our waste, I know one local landfill captures it and feeds it into an onsite power plant. I don't know what the methane output of that landfill is and whether or not it would be enough to make installing a vehicle fill station nearby (in addition to whether or not it is actually a good location for it; the landfill is no longer open for taking in new waste so waste trucks are not driving into it anymore).

    Lastly, NG vehicles tend to be less powerful than their gasoline counterparts. NG expands into the gas volume and displaces the air, so you don't get as much oxygen to burn in the combustion chamber. Gasoline takes up very little volume as it is still a liquid (atomized). Cummins makes a turbocharged motor for Commercial NGV applications which can help get the power back by forcing more air in the engine.
     
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