Natural gas vehicles or NGVs are an alternative fuel vehicle that use natural gas as fuel rather than the typical gasoline or diesel. Other alternative vehicles include fuel cell vehicles and electric vehicles.
NGVs were first manufactured in United States during the 1930s. They were used during World War II in Europe and interest for these vehicles rose during the early 1950s.
When comparing natural gas versus other fuels, NGVs usually have:
• Lower cost than gasoline and diesel
• High performance similar to diesel or gasoline powered vehicles
• Secure and long lasting fuel supply
NGVs are available from North American manufacturers such as General Motors (GM) and Ford, and conversion kits are available for existing conventional cars. GM offers full-sized compressed natural gas (CNG) fuelled vans for fleet customers. Ford offers many CNG ready chassis body for aftermarket conversion.
Conversion kits are commercially available from worldwide companies. There are three types of natural gas fuels including compressed, liquefied, and adsorbed natural gas.
• Compressed natural gas (CNG) is stored under high pressure of 3,000 psig to 3,600 psig and historically, being the most attractive natural gas fuel. The high-pressure pose safety concerns in design of these vehicles.
• Liquefied natural gas (LNG) is usually stored at -160°C and is best suited for heavy-duty vehicles and natural gas transportation overseas.
• Adsorbed natural gas is stored at a lower pressure of 500 psig to 600 psig in which natural gas is adsorbed by a porous adsorbent. However, there are some technical challenges, which includes the adsorbent (activated carbon) development or deliverability capacity of the gas from the adsorbent.