By Mary Catherine O'Connor
Apr. 1, 2009—Vehicles that run on compressed natural gas (CNG) carry steel cylinders to store the gaseous fuel. At filling stations, the fuel is dispensed at higher pressure than that in the tank, thereby enabling a speedy refueling process. If a vehicle carries a non-standard natural gas cylinder, however, or if it has not been inspected prior to refueling, this can cause an explosion during the refueling process.
Viridis, a Toronto-based provider of vehicle-fuel dispensing systems for CNG, as well as hydrogen, has developed an
RFID-based system for ensuring safety and accurate billing when refueling CNG vehicles.
Viridis sells its CNG dispensers to companies or individuals that operate CNG fueling stations around the world (Viridis' CEO, Ian Patterson, estimates that the company is among the top five worldwide manufacturers of such dispensers). Once a dispenser is sold, Viridis has no means of ensuring that the fuel will be dispensed appropriately—that is, that employees will check that a vehicle's fuel cylinders meet safety and inspection standards—but Patterson says the RFID system his company has developed will change that.
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Viridis' RFID-enabled CNG fuel dispenser includes a nozzle fitted with a reader antenna (the inner white ring).
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Viridis' RFID-based system comprises
Texas Instruments passive
low-frequency (LF)
ISO 11785-compliant tags and interrogators, a customized reader antenna designed into the fuel-dispensing nozzle assembly and specialized software to manage tag data. The
RFID tag is to be attached, using a strong epoxy, near the vehicle's fueling valve, and within the tag's four-inch
read range. Viridis software collects that tag data and controls the dispenser, so that it will only begin dispensing fuel when a valid RFID tag is read.
The exact data encoded to that
tag will be determined by the regulatory body in each country. Typically, however, the tag data would include the vehicle's serial number (such as a VIN), the
license plate number, the owner's name and the fuel cylinders' latest inspection date. In cases in which a vehicle has been converted to run on CNG (as opposed to being originally manufactured as a CNG vehicle), the date of conversion would be encoded to tag data, along with the party that converted the vehicle.