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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, liquefied 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, Iran, Pakistan and Italy. They are also popular in Germany.

NGV's can be refueled anywhere from existing natural gas lines. This makes home refuelling stations that tap into such lines possible. Honda has pioneered such a system known as "Phill". [1],[2]

Existing gasoline-powered vehicles may be converted to CNG. An increasing number of vehicles worldwide are being manufactured to run on CNG (Honda Civic, Samand). In Klang Valley, Malaysia taxi companies converted their cars to NGV, greatly reducing the cost of operation and many pasengger cars in Malaysia converted their system to NGV. GM do Brasil introduced the MultiPower engine in August 2004 which was capable of using CNG, alcohol and petrol as fuel. The GM engine has electronic fuel injection automatically adjusts 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, with taxi drivers waiting in long queues to refill. This has led to suggestions that taxis should have their own options for fuelling at taxi ranks - a model being tested in Casablanca, Morocco. Here, taxi drivers 'belong' to a base station where they operate from and have priority fuel rights including an account card. [citation needed]

Chemical composition and energy content

Chemical composition

The primary component of natural gas is methane (CH4), 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.

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.

Storage and transport

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.

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.

See also

Wikimedia Commons has media related to Natural gas vehicles.

External links

NGV Network Malaysia

Europe

North America

Latin America

South Asia

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