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Do CNG cars have a future?

Discussion in 'Fred's House of Pancakes' started by Troy Heagy, Aug 14, 2014.

  1. Troy Heagy

    Troy Heagy Member

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    California thinks so..... they give cash to anyone who buys a Civic GX (natural gas). However I suspect most environmentalists would rather see us drive EVs. Thoughts? Opinions?
     
  2. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Do CNG cars have a future?
    Why Not?
    They're not new.....just immensely impractical for most people.

    My company is tinkering with them but the (un)availability of places to re-fill the vehicle and the EV-like range of many of them make it a lose-lose for most people in fly-over country. There's also the (almost incorrect) perception that in an accident you need a parachute more than you need a seat belt.

    California still thinks that high-speed rail has a future there.....so go figure.
     
  3. PriusC_Commuter

    PriusC_Commuter Active Member

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    According to California Natural gas cars have no where near the same level of practicality as Hydrogen cars...

    On a more serious note, I don't think natural gas vehicles will become more popular here unless there is a significant push in marketing or if more manufacturers start making cars that run on CNG, and price becomes more reasonable. The Honda Civic CNG costs $27,430 base, the Chevy Impala bi-fuel costs $38,210. The cheapest gas station in my area is $3.55 per gallon, whereas the cheapest natural gas is $1.99 per gge. However, if you assume a regular Prius gets you double the gas mileage over most regular cars, on the surface it seems a Prius is cheaper than a CNG to use and buy, so it's a hard sell to most people.
    Natural-Gas Powered 2015 Chevy Impala To Start At $38,210
     
  4. Trollbait

    Trollbait It's a D&D thing

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    Well, CARB has already made their choice regardless.

    No reason why you couldn't have a CNG Prius. :)

    CNG has the same drawback as hydrogen; storing compressed gas isn't as convenient as a liquid. The physics dictate a limited number of tank shapes for the gas. Power equipment, like forklifts, don't travel at high speeds, so external tanks work fine. They might even be a plus be being swappable. Then commercial size size trucks at the other end of the spectrum have plenty of space for bulky tanks.

    Now a CNG car is limited by the space requirements of the owner and safety regulations. That and tanks cost keeps it just large enough for a good BEV range. Longer range is possible, if you don't want a trunk.
    It's a hydrogen ICE but the picture gives an idea of the space these tanks could require.
    [​IMG]

    If need be, we can convert natural gas into methanol or even gasoline. There are conversion loses, but a liquid fueled PHV can have a larger battery than a CNG one.
     
  5. hkmb

    hkmb Senior Member

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    I've been in several Prius taxis in Tokyo - mostly Gen IIs - which said on a sign on the filler cap that they ran on compressed gas. My Japanese isn't up to much - I can get by, but I'm far from fluent - and I was reading the Chinese characters on the filler cap, and the meanings of those characters in Japanese are sometimes not exactly the same as the Chinese. So I'm not sure whether they were CNG or LPG, but they were definitely one of the two.

    I spoke - haltingly - to the drivers about them. After that, I still wasn't sure whether they were CNG or LPG, but the drivers said they were unbelievably cheap to run: one said his fuel costs were about 20-25% of those for a traditional Toyota Crown taxi.

    As for CNG/LPG in general.... In China, it varies from city to city, but there's a fair bit of interest in CNG/LPG for taxis. In Zhuhai, for example, there are lots of diesel VW Jetta taxis. In Shenzhen, there are quite a few BYD electric and PHEV taxis, and lots of Red Flags that run on petrol. In Shanghai, there are lots of CNG and LPG (I've seen both) VW Santana taxis, and some petrol VW Tourans. In Beijing, it's LPG Hyundai Elantras and petrol Citroen ZXs, plus the occasional LPG Red Flag.

    In Australia - at least in Melbourne, Sydney, Perth and Brisbane there's a choice of LPG Ford Falcons or petrol HyCams, and the occasional LPG Holden Commodore. (In Darwin, it's Priuses.) The HyCam is a better bet if you're a passenger: the Falcon is stupid. They put the LPG tank in the spare wheel well, and put the spare wheel in the boot (trunk). This means you cannot get more than one suitcase in the boot of a Falcon taxi, which is completely useless when you're with your family at the airport.
     
  6. wjtracy

    wjtracy Senior Member

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    CNG cars have a huge future especially fleets. But it heavily depends on what Country you are in.
    Back in the 1980's for example, when oil prices were high, New Zealand was trying to convert a substantial portion of the cars to CNG.

    This conversion *can* be done for a several hundred dollars, but in the US it costs $6000-$12000 to convert a car (per 2012 Popular Mechanics). The U.S. mandates a minimum $6000 CNG high pressure tank, so that's why I think the Civic GTX costs a lot to buy. Can you imagine what a H2 tank would cost? This helps explain why Toyota is building its own H2 tanks...apparently the available "robust" tanks on the market are over-the-top expensive.

    So anyways, CNG in the USA is a little like hybrids, EV, or diesel. That is: it's going to cost you $5000-$10000+ over an equivalent gasoline car. If the gov't wants to encourage by subsidies, it can work. If not, well as far as CNG, fleets are the main thing in the US. We also have lots of buses and trucks on CNG in the US, but the topic is cars.
     
    #6 wjtracy, Aug 18, 2014
    Last edited: Aug 18, 2014
  7. Trollbait

    Trollbait It's a D&D thing

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    CNG can work for fleets by spreading the cost of the refueling pump over many vehicles. Most potential private CNG car owners don't have the luxury of a CNG station nearby. So there will also be the cost of a home refueling station to account for, which requires NG service to the home of course. The slow fill time of these pumps make the CNG car even more BEV like.
     
  8. JimN

    JimN Let the games begin!

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    From
    Frequently Asked Questions about Natural Gas Vehicles
    :

    Q. How long does it take to refuel a personal vehicle?
    A.
    Refueling at a public natural gas station takes about the same amount of time as filling a traditional vehicle at a regular gas station. Home fueling appliances have a compressor and fueling equipment that usually involve a time-fill over an extended period of six to eight hours.

    I saw a taxi in Hartford CT that runs on CNG.
     
  9. Trollbait

    Trollbait It's a D&D thing

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    Yeah, the Phil would take overnight to fill a Civic CNG. Residential gas is low pressure, and there might legal/zoning/cost issues with putting in a higher pressure fueling system for faster home refueling.

    A CNG and hydrogen station can refuel at the speeds of a liquid fuel one, but only for a limited number of vehicles for a given time period. These stations are set up like an air compressor used for powering tools. There is a resivour tank that holds the pressurized gas. This allows a better control of the heat generated by pressurizing the gas, and the use of a smaller, cheaper, maybe more efficient over time pump. It works fine up until the resivour pressure runs low, then it might take 20 minutes to fill a vehicle, if it can do so at all. It makes planning a potential station trickier than a liquid one since the costs involve in making it too big or expanding one too small are higher.
     
  10. Troy Heagy

    Troy Heagy Member

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    Hona will void Civic CNG warranties if they find it was fueled at home & the moisture damaged the car (apparently home natural gas is not pure enough).
     
  11. bwilson4web

    bwilson4web BMW i3 and Model 3

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    A couple of years ago, I looked at Ebay injector kits from <some place> for the 1.5L engine. My interest is in co-generation using natural gas feed from the house to the Prius. In effect, plug-in the Prius to provide house power:
    • ~3-7 kW, 120VAC power - easily within the capability of the 2003 Prius MG1 using MG2 power electronics to generate the house power
    • space and hot-water heating - using exhaust heating hot-water tank
    I have no interest in trying to drive on CNG except perhaps a 5 mile range for engine warm-up away from home. Driving in a pre-warmed, Prius is exceptionally fuel efficient and providing an alternate, lower cost, fuel during the warm-up makes a lot of sense.

    There may be a clever hack that would allow bi-fuel use at home without the cost of natural gas injectors. I'll need to test it but the basic idea is use the mass-flow to a fast, natural gas valve, to enrich the intake air with natural gas/propane or other low-cost fuel.

    Bob Wilson
     
  12. hkmb

    hkmb Senior Member

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    I was in Handan yesterday, in Hebei province.

    At the airport, they had this advert. It says that Handan's Xinhua taxis use natural gas.

    IMG_20140901_095348.jpg

    Here is a taxi that I got - the CNG tank is in the boot (trunk).

    IMG_20140901_125225.jpg
    The taxi was a Geely one (Geely is the company that owns Volvo).
     
  13. Trollbait

    Trollbait It's a D&D thing

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    The photo illustrates one of the difficulties CNG cars have in the market. The tank size and required shape mean a are large loss of usable space. Batteries have more options in terms of packaging, and they require some type of cooling. Even a car designed for CNG will need to make more trade offs for the tank than a liquid fuel vehicle. Toyota's FCEV loses the middle rear seat for the hydrogen tanks.
     
    hkmb likes this.
  14. hkmb

    hkmb Senior Member

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    澳大利亚
    Yes, it really is a problem. As I mentioned earlier in the thread, Australia's LPG Ford Falcon's have the same problem: they use the spare wheel well for a gas tank, and put the spare wheel in the boot, so there's nowhere to put your luggage. And in a taxi, that's useless.
     
  15. Trollbait

    Trollbait It's a D&D thing

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    And I bet the Civic CNG lost sales when potential buyers saw its trunk space.
     
  16. goldfinger

    goldfinger Active Member

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    I think its range anxiety that's holding back CNG. With electric you can plug into 120 v in a pinch. With CNG you need a filling station and there aren't enough yet.

    Eaton is developing a single stage liquid piston CNG compressor that will greatly reduce the overall cost of filling station. They've said the home version could cost $500 and fill in one hour. I guess it also cools the gas in some clever way.
     
  17. Troy Heagy

    Troy Heagy Member

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    You're not allowed to use home refueling with the Civic Natural Gas, for the same reason you cannot use home heating oil in your diesel (both fuels are not clean enough). Range anxiety is not an issue in California which has tons of CNG stations for a quick stop & fill. They just installed one directly across the street from where I live.

    I wonder how this problem is resolved with hydrogen cars?

    They too need a big round storage tank to hold the fuel, so a hydrogen Civic would have a small trunk just like a CNG civic. The fuel tank takes-up more room than the battery in my Civic hybrid (which really takes no room at all... it is designed to be the seat back). The pricetag is pretty ridiculous as well, paying about $5000 more over a gasoline Civic.
     
  18. cproaudio

    cproaudio Speedlock Overrider

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    If they are serious about CNG, they need to design a car purely on CNG first not converting existing cars to CNG. Design the car around the tank, not the tank around the car.
     
  19. goldfinger

    goldfinger Active Member

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    Home CNG refueling is currently legal, but suffers a moisture problem. Home heating oil is illegal for road vehicle use because its not taxed enough for the government. If home refueling takes off I'm sure the government will find a way to tax it. Its important to note that heating oil contains too much sulfer for modern catalytic equipped engines.

    Natural gas utility companies typically provide pipeline quality gas at 7 lbs of water per million cubic feet of gas. This is dry enough to avoid problems in their pipes at 60 psi and your home at 0.25 psi. This level of water, however, can freeze at 3600 psi plugging your car's fuel system. Next gen home refueling stations will need to remove moisture.
     
  20. Troy Heagy

    Troy Heagy Member

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    Yes home fueling is "legal" but that doesn't stop Honda from voiding your engine warranty if you use it. (They will claim the engine was damaged by moisture & refuse to provide a free repair.)