I work at a auto parts store and I seen something wierd the other day.
A man came in asking were he could buy natural gas for his truck. I have heard of propane powered trucks so i figured this was what it was. So i went out to the parking lot to see this truck, and as soon as i walked out the door i seen that the truck was a flexfuel vehicle. So I questioned the mans sight, and ability to read his owners manual, but low and behold i walked around to the drivers side and there were two fuel doors next to each other. The man opened the door and there was a fitting ""like a 3/8 air line quick connect" as if there was a hose that plugged in there. Than i looked in the bed and there was a large tank for the fuel, It was plastic like a water tank. I looked in the fuel door and there was a sticker that had some specifications on it,And a ford part number. i looked in the cab and there was two fuel gauges. like i said ive heard of propane but not natural gas "which was clearly stated on the safety sticker inside the truck".
"that the truck needed to be operated at least every two months on gas to ensure longevity". There was also a large diamond on the tailgate with "cng" in it. I searched and they do conversions but what baffeled me was the ford part numbers. What did i see?
Ford has produced CNG trucks and Crown Vic's for several years now. It is a Ford factory produced CNG vehicle, not a conversion. My brother has owned the Crown Vic, dedicated CNG, not the flex-fuel setup in the truck. As far as I know, they were only sold in a few states. Since your profile shows WI, I dont think he is going to find CNG stations there. The tank is fiberglass reinforced because the fuel is dispensed at up to 3600psi, not at all like LPG systems. The advantages are low fuel cost and extremely clean burning. Downsides are range and availability. They are normally purchased only for big-city fleets with central refueling stations.
There are a lot of CNG vehicles out here in Califiornia, mostly city busses and the like. The fuel is simply highly compressed natural gas which is not a liquid like LPG/propane. The problem is that it does not burn as clean as reformulated gasoline does in the flex vehicles so they have discontinued using most of them around here. Large rigs are setup for CNG around here as it still burns cleaner than diesel. Most heavy CNG vehicles are designed to run on only CNG. Unfortunately, there is a bit of a natural gas shortage around here due to the CNG useage in large fleet vehicles, and the goverment keeps on taxing us so they can afford to by free busses that run on CNG.