CNG - Compressed Natural Gas
What exactly is CNG?
CNG or compressed natural gas is a domestically available, economical, clean burning, alternative fuel source for vehicles.
|Rather than burn gasoline or diesel fuel, a consumer would fuel their vehicle with natural gas. In order to provide enough range, the gas is compressed
and stored on the vehicle in pressurized tanks. Tanks that can hold up to 3,600 psig. |
Sounds a little scary doesn't it? Not when you compare the physical
properties of Natural Gas and gasoline. The fact is that natural gas is a much safer fuel than gasoline. (Ever wonder why the stove in your home doesn't burn gasoline instead of natural gas?) Just take a look at the chart below for some interesting facts:
||DIESEL No. 2|
(oF @ 1 atm)
|80 to 420
320 to 720
-44 to 31
|43 to 49 |
5.8 to 6.5
49 to 55
6.5 to 7.3
Net Energy Content
|18,700 - 19,100|
112,000 - 121,000
123,000 - 128,000
|450 - 900|
400 - 500
920 - 1,020
-100 to -150
Octane Number Range
|87 to 93|
(volume % in air)
|L = 1.4 |
H = 7.6
|L = 0.7|
H = 5.0
|L = 2.4|
H = 9.6
|L = 5.3|
H = 14
Human Exposure Limit For Fuel (ppm)
What is Natural Gas?
Natural Gas is an organic compound that is found deep within the earth. It is a fossil fuel formed over millions of years of geological pressures and changes. Natural gas is primarily methane comprised of hydrogen and carbon. It is a safe fuel source that is commonly used in homes and businesses for heating, lighting and cooking.
How is Natural Gas used for powering vehicles?
This is accomplished by the following steps:
- Natural gas is compressed and enters the vehicle through the natural gas dispenser or fill post
- It flows into high-pressure cylinders that are located on the vehicle.
- When the driver steps on the accelerator, the natural gas leaves the on-board storage cylinder, passes through the high-pressure fuel line and enters the engine compartment.
- Gas then enters the regulator, which reduces pressure from up to 3,600 psi to approximately atmospheric pressure.
- The natural gas solenoid valve allows natural gas to pass from the regulator into the gas mixer or fuel injectors.
- Natural gas mixed with air flows down through the carburetor or fuel injection system and enters the engine's combustion chambers.
Are Natural Gas Powered Vehicles safe?
Natural Gas an ideal fuel source for many reasons, including safety. Refer to the chart above and note the following.
Natural Gas is lighter than air. This means that it will not puddle (like gasoline) or sink to the ground like propane, which is heavier than air. Instead, Natural Gas will rise and dissipate in the atmosphere.
Natural gas also has a higher ignition temperature. This means that it is much harder to ignite. Also the storage systems used for compressed natural gas are infinitely stronger that the gasoline tanks found on cars and trucks today.