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Natural Gas Vehicle Basics

August 20, 2013 - 9:15am


Photo of a large truck stopped at a gas station that reads 'Natural Gas for Vehicles.'Natural gas vehicles (NGVs) are either fueled exclusively with compressed natural gas or liquefied natural gas (dedicated NGVs) or are capable of natural gas and gasoline fueling (bi-fuel NGVs).

Dedicated NGVs are designed to run only on natural gas. Bi-fuel NGVs have two separate fueling systems that enable the vehicle to use either natural gas or a conventional fuel (gasoline or diesel).

In general, dedicated natural gas vehicles demonstrate better performance and have lower emissions than bi-fuel vehicles because their engines are optimized to run on natural gas. In addition, the vehicle does not have to carry two types of fuel, thereby increasing cargo capacity and reducing weight.

Compared with vehicles fueled with conventional diesel and gasoline, NGVs can produce significantly lower amounts of harmful emissions. In addition, some natural gas vehicle owners report service lives two to three years longer than gasoline or diesel vehicles and extended time between required maintenance.

The driving range of natural gas vehicles generally is less than that of comparable gasoline- and diesel-fueled vehicles because of the lower energy content of natural gas. Extra storage tanks can increase range, but the additional weight may displace payload capacity. NGV horsepower, acceleration, and cruise speed are comparable with those of an equivalent conventionally fueled vehicle.

How Does a Natural Gas Vehicle Work?

Light-duty natural gas vehicles work much like gasoline-powered vehicles with spark-ignited engines. Some heavy-duty vehicles use spark-ignited natural gas systems, but other systems exist as well. High-pressure direct injection engines burn natural gas in a compression-ignition (diesel) cycle. Heavy-duty engines can also burn diesel and natural gas in a dual-fuel system.

Visit the Alternative Fuels and Advanced Vehicles Data Center to learn more about natural gas vehicles.