What RFID Can Do for Fleets Today

Audio version
Posted / Last update: 01-05-1999
Publication: Petroleum Equipment & Technology Archive
Issued: May 1999
Author: Stewart Gregory M.

Mobile fueling, RFID
Because the pen-and-paper system creates obvious time-and-error inefficiencies, passive RFID systems have been developed to automate the process. These systems save delivery time because accounting automation is achieved and the delivery driver is able to move directly from one vehicle to the next. The metered delivery ticket prints a detail of each vehicle plus a summary total.

Vendors of the equipment estimate that drivers save a minimum of 30 seconds per vehicle being fueled, with an improvement of delivery efficiency of 20 percent per night. According to the Washington State mobile fueling survey, the average fleet consists of 15 vehicles with 13 visits per month with an average fill of 20.5 gallons.

Here’s how RFID can work with mobile fueling:

The passive system employs a hand-held RFID front-end reader with an RF local area network (LAN) data communicator (DC). The back end RF/DC communicates with a truck computer that operates an electronic solenoid, which controls the valve and meter. A roll printer and electronic register are also part of the packaging.

Each vehicle fuel tank is tagged with a unique passive transponder. The delivery driver takes the hose and nozzle to the first vehicle and scans the bar-code-activating solenoid, which opens the fuel valve on the petroleum delivery truck. Diesel is delivered into the fleet vehicle and, at the same time, the truck computer documents the vehicle being fueled. Once the delivery driver releases the fuel nozzle, additional fuel cannot be dispensed without another passive tag being read. This ensures that each fueling is accounted for properly and minimizes fraud or waste.

Mobile fueling, passive and active
Passive RFID tags have unique identifiers, and improve read rates because passive tags operate effectively in wet or dirty environments. Passive tags do not have batteries and are relatively low in cost. One tag must be attached to each fleet vehicle.

There are two types of passive tags: contact tags and contact-less tags. Contact tags must be touched for the unique identification number to be read by the hand-held device. Contact-less tags, which do not need to be touched, have a read range of one to six inches, depending on the quality of the tag and reader.

Odometer information from each vehicle may be obtained by the installation of an odometer tag mounted in each vehicle. This odometer tag would have an optional active capacity. The odometer information may be retrieved with an RF antenna on the mobile fleet fueling truck. This information may be merged into the computer data for the truck to produce a miles-per-gallon statistic for each fleet vehicle.

Understanding the difference between active and passive systems can be confusing because active systems are sometimes called “passive” for marketing reasons. A simple way to understand the difference between active and passive tags is that active tags have a battery and passive tags do not. Wired into the vehicle’s electrical system, active RFID systems use communication cables, which run together with the delivery hose to a receiver imbedded into the delivery nozzle.

An RF receiver coil is mounted with a unique vehicle identifier as a ring around each vehicle’s fuel tank. Another communication cable may be installed that t connects the RF coil to a vehicle’s data computer, thus recording engine hours and odometer readings.

Activation of the solenoid that controls fuel flow is done automatically when the fuel nozzle is inserted into the vehicle tank. If the fuel nozzle accidentally fails, the solenoid is automatically shut and fuel flow stops. Equipment costs for such a system are more expensive than either bar code or passive RF.

As the market for mobile fueling grows and regulatory authorities create more requirements to safeguard the environment, continuing developments in RFID technology will become more and more important. The days of pen-and-paper delivery control systems are about over. With the recent announcement of the Bluetooth RFID effort (see glossary), we can expect rapid changes in RFID to continue—and even to accelerate. Note: Some RFID applications and methods may be subject to patent claims. A good source of patent information is found on the Internet at


a low cost, short range cellular effort being undertaken by Intel, Toshiba, Erickson and many others. It promises to provide many changes in office automation and vehicle data capture. Bluetooth is expected to complement rather than to replace recent developments in RFID. More information may be found at

“Hall Effect” Sensor:
a component in today’s vehicles that opens and closes a circuit electronically, based on changes in magnetic flux. It is typically used for RPM or position measurement.

Magnetic induction RFID:
An RF system that accomplishes total vehicle identification and secure pump control. Typically, RF devices are installed on each of the fuel dispenser nozzles and hoses. The system requires that a magnetic ring be affixed to the fill of each vehicle and, if odometer information is wanted, a cable from the drive line and onboard computer back to the vehicle fill.

Mobile fueling:
also known as fleet fueling, wet fueling or wet hosing—is the practice of filling fuel tanks of vehicles from tank trucks. This fueling takes place where the tank trucks are driven to the yards or sites where the vehicles to be fueled are kept when they are not in use. Mobile fuelers may only dispense diesel, as mobile fueling of gasoline is prohibited.

A “reader” incorporates an antenna and generates the radio frequency signal. This is transmitted to a transponder. The reader may include an optional computer that allows it to operate on its own without the need to communicate to a central host computer. They are the size of small stereo speakers and are easily mounted on canopies, poles or fuel dispenser tops.

The “transponder,” or tag, is a device that is tagged to an asset or an object. Transponders may be as large as a credit card or as small as a toothpick. The exact size depends on the power supply and antenna. Antenna size is largely determined by the wave length selected for transmission by the readers. Transponders come in a variety of sizes and functionalities. In this discussion, there are three types of transponders (see below).

Passive transponders
obtain power from radio frequency wave energy alone, and do not have batteries or an outside power source. Two-way communication from the reader to the tag is done by reflecting back the energy of the incoming radio wave to establish two-way communication. New passive technology has read ranges in the area of three to six feet.

Active/Passive transponders
have a battery used to power an onboard transponder microprocessor, but it is not used for radio transmission. The return radio link is accomplished by reflecting the same radio wave back that has been used by the passive tags. Read ranges are 12 to 40 feet.

Active transponders
use a battery or outside power source for the transmission of a radio wave back to the reader. These have extended read ranges of greater than 60 feet.


Stewart Gregory M.
Gregory M. Stewart, a Principal in the partnership of Grenley-Stewart Resources, Inc., a company that provides cardlock services.

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