Natural gas vehicle

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NGV also stands for National Gallery of Victoria

A Natural gas vehicle or NGV is a vehicle that uses compressed natural gas (CNG) or, less commonly, liquified natural gas (LNG)) as a clean alternative to other automobile fuels. Worldwide, there are roughly 5 million NGVs as of 2006, with the largest number of NGVs in Argentina, Brazil, and Pakistan. They are also popular in Italy and Germany.

NGV's have the advantage of being potentially refuelled at home from existing natural gas lines with home refuelling stations that tap into such lines. Honda has pioneered such a system known as "Phill". [1],[2]

While existing gasoline-powered vehicles may be converted to CNG, an increasing number of vehicles worldwide are being manufactured to run on CNG. For example, in Klang Valley, Malaysia taxi companies converted their cars to NGV, greatly reducing the cost of operation. GM do Brasil introduced the MultiPower engine in August 2004 which was capable of using NGV, alcohol and petrol as fuel, since its electronic fuel injection could adapt automatically to any acceptable fuel configuration. This motor was used in the Chevrolet Astra and was aimed at the taxi market.

Although a localized problem, NGV refill stations can be scarce in some places, so cab drivers need to wait in long queues to refill.

1 Chemical composition and energy content
- 1.1 Chemical composition
- 1.2 Energy content
2 Storage and transport
- 2.1 Transport
- 2.2 Storage
3 See also
4 External links
- 4.1 North America
- 4.2 South Asia

[edit] Chemical composition and energy content

[edit] Chemical composition

The primary component of natural gas is methane (C H₄), the shortest and lightest hydrocarbon molecule. It may also contain heavier gaseous hydrocarbons such as ethane (C₂H₆), propane (C₃H₈) and butane (C₄H₁₀), as well as other gases, in varying amounts. Hydrogen sulfide (H₂S) is a common contaminant, which must be removed prior to most uses.

[edit] Energy content

Combustion of one cubic meter yields 38 MJ (10.6 kWh). Natural gas has the highest energy/carbon ratio of any fossil fuel, and thus produces less carbon dioxide per unit of energy.

[edit] Storage and transport

[edit] Transport

The major difficulty in the use of natural gas is transportation. Natural gas pipelines are economical, but are impractical across oceans. Liquefied natural gas (LNG) tankers are also used, but have higher operating costs.

[edit] Storage

CNG is typically stored in steel or composite containers at high pressure (3000 to 4000 lbf/in², or 205 to 275 bar). These containers are not typically temperature controlled, but are allowed to stay at local ambient temperature.

LNG (Liquefied Natural Gas) storage pressures are typically at or just above the local atmospheric pressure (0 to 30 lbf/in², or 0 to 2.1 bar). LNG is stored at temperatures as low as -260°F (-162°C). At these temperature and pressure conditions, natural gas is in a liquid state. Storage temperatures may vary due to varying composition and storage pressure. LNG is far more dense than even the highly compressed state of CNG. As a consequence of the low temperatures, vacuum insulated storage tanks are used to hold LNG. These tanks are often referred to as dewars to credit the early cryogenic scientist Sir James Dewar.