Closing the loop

Aaron Huff is technology editor of Commercial Carrier Journal. E-mail

The bigger your expense, the faster small savings accumulate. With fuel being most fleets’ largest controllable expense, fuel optimization systems are growing in popularity. Such programs determine the lowest fueling cost alternative for each trip. When combined with operations software and mobile communications, fuel optimization becomes an almost automated process.

A vehicle’s beginning fuel level is one of the variables that a fuel optimization system considers. Unlike other variables, such as prices and consumption rate, the beginning fuel level is prone to human error, says Ben Murphy, vice president and general manager of Plano, Texas-based Integrated Decision Support Corp. (IDSC).

Fleets using IDSC’s Expert Fuel optimization software, for example, have drivers input their fuel level through their onboard communications systems once they have delivered loads. A macro prompts them to enter fuel level in eighths, Murphy says. Other systems, such as Prophesy’s FuelLogic, handle fuel level similarly.

When entering his fuel level, suppose a driver underestimates by 25 gallons. Assuming an average fuel consumption of 6 mpg, the optimization system would not factor an additional 150 additional drivable miles. While that variance hardly defeats the benefits of optimization, it does mean that optimization isn’t, well, optimized.

One way to remove human error from a fuel optimization system is with “smart” fuel-level sensors. A truck’s existing mechanical fuel sensors measure the fuel level roughly in terms of fractions of a tank. Janesville, Wis.-based SSI Technologies says a sensor it developed

The Acu-Trac sensor uses ultrasonic waves to calculate the actual quantity of fuel in tanks.

uses ultrasonic waves to calculate actual fuel quantity, in gallons, to within a 1 percent margin of error. This data can be sent back to the host software system automatically through mobile communications, says Larry Reimer, vice president and chief technology officer of SSI Technologies.

SSI Technologies developed the ultrasonic fuel-level sensor to work with Freightliner’s Delphi-produced Truck Productivity Computer. SSI Technologies has since begun marketing the product directly to fleets as Acu-Trac, as Delphi has with the Truck Productivity Computer itself.

Not only does Acu-Trac provide less room for error; it also accounts for times when the fleet might get no data at all, says IDSC’s Murphy. “Sometimes you will get a driver who doesn’t want to play by the rules.”

Acu-Trac allows fleets to run fuel optimization for any truck, any time, and not just when drivers issue an empty call, Reimer says. If a load is not immediately available, the dispatcher may have the driver deadhead until one is found. Or a driver might idle while waiting for another load. In those cases, the fuel level at empty call may no longer be accurate. Acu-Trac allows dispatchers to re-optimize based on an updated fuel level.

The Acu-Trac fuel-level sensor retrofits to existing sensor mounts and automatically configures itself to support existing fuel-level gauges. The sensor ties into the vehicle’s J1708 data bus and third-party onboard communications system to provide on-demand or event-driven data reports that include: truck ID, time, location, fuel level, mpg, idle fuel burned, PTO fuel, fuel added and fuel lost, Reimer says.

A side benefit of the Acu-Trac sensor is that it allows fleets to compare actual gallons added to the tank with daily fuel transactions. A discrepancy could alert fleet managers to the possibility of fuel theft. This is a big issue in Europe, where diesel is substantially more expensive, and the sensor is being used fairly widely there, Reimer says.

Not so in North America. To gain some acceptance in the United States, SSI Technologies currently is running tests with several major carriers. Reimer says the test results show additional annual fuel savings of $300 to $500 dollars per truck. The Acu-Trac sensor is priced under $300 to deliver a payback within one year, Reimer says.

Will a more accurate fuel level change the results of optimization enough to make a difference?

It might, says Bill Ashburn, vice president of Prophesy Software. In four years, however, Ashburn’s customers have not raised the issue. “But maybe people just don’t think about it.”