You may have seen the blue diamond CNG stickers on many mass transit buses and commercial vehicles, so what does it mean?
CNG is Compressed Natural Gas which has been used as an alternative clean burning fuel since the 1990s. It is essentially the same natural gas that is delivered to most homes to use for cooking, heating water, and forced air heat. For use in vehicles, the natural gas is compressed to 3000 or 3600 psi and pumped into the vehicle fuel tank for consumption.
CNG is used mostly in mass transit and large fleet commercial vehicles. It has become mandated in many countries around the world to address both air pollution and the high cost of petrol and diesel fuels. The blue diamond sticker is used mostly in North America to indicate that the vehicle is CNG powered.
CNG fuels an internal combustion engine much like a diesel engine. The engine may have been designed specifically for CNG or converted from diesel to CNG.
CNG vehicles are so clean burning that if you look into the exhaust pipe it is extremely clean with little or no residue, unlike diesel which would pump the black smoke into the air.
CNG is often confused with LNG (Liquid Natural Gas) but they are not the same, the main difference being that LNG is liquefied and therefor requires different production, storage and transportation methods.
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