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: | PROPERTIES | GASOLINE | DIESEL No. 2 | LPG (HD-5) | CNG | | Physical State | LIQUID | LIQUID | GAS | GAS | | Boiling Range (oF @ 1 atm) | 80 to 420 | 320 to 720 | -44 to 31 | -259a | | Density (lb/ft3) (lb/gal) | 43 to 49 5.8 to 6.5 | 49 to 55 6.5 to 7.3 | 31b 4.1b | 8c 1.07c | | Net Energy Content Btu/lb. Btu/gal. | 18,700 - 19,100 112,000 - 121,000 | 18,900 123,000 - 128,000 | 19,800 82,000 | 21,300a 22,800a | | Autoignition
Temperature
(oF) | 450 - 900 | 400 - 500 | 920 - 1,020 | 1,350 | | Flashpoint
(oF) | -45 | 125 (min) | -100 to -150 | -300 | | Octane Number Range
(R+M) 2 | 87 to 93 | n/a | 104e | 120e | | Flammability Limits (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) | 500 | n/a | n/a | nontoxic | |
