Green Fleet of the Month: Idle time

Addition of APUs boost fuel economy nearly 16% for fleet

Are you interested in getting up to 16% better fuel economy for your fleet? If you are, and you run in colder climates and have not installed an auxiliary power unit (APU) yet, then here’s a lesson you.

Greeley, CO-based JBS Carriers took advantage of a no-risk trial offer by Hodyon of Cedar Park, TX, to test its Dynasys APU. The results were so impressive, Hodyon says, that JBS has already installed the units in about 95 sleepers with plans to outfit the entire sleeper fleet of nearly 700 units within two years. JBS, a 48-state truckload carrier hauling both refrigerated and nonrefrigerated freight with regional operations in some Midwest and Western states, has 1,100 total units.

“The cost of the product was what first attracted [us], but the free, no-risk trial had a huge impact on our decision once we could test other aspects such as maintenance costs and effectiveness in high temperatures,” says Cameron Bruett, sustainability-corporate communications for JBS.

The installation of the APUs in 16 tractor units showed a fuel economy gain of nearly 16%, from 6.04 mpg to 6.99 on the trucks. That translates into a savings of more than $181 per week and $9,417 per year per truck based on a fuel cost of $3.80/gal.

For the average JBS tractor-trailer, which runs about 100,000 mi./year, that results in a return-on-investment for the $8,500 APU of just 11 months, Hodyon says.

The test included measuring mpg prior to installation of the device and then monitoring the vehicles through the onboard ECU and Qualcomm OmniTracs system over 10 weeks once the APU was installed.

Every one of the 16 test vehicles showed an improvement post-install, Hodyon says, with four tractors obtaining more than 7 mpg and six within tenths of a percentage of that mark. The fuel savings, of course, was due to the reduction of idling as drivers no longer needed to run the engine to power heating, cooling or accessories inside the cab. Prior to the purchase of the Dynasys units, JBS had no idle restrictions in place, says Bruett.

One tractor saw its idle percentage drop from nearly 70% to about 20% with 14 of the remaining 15 test vehicles dropping below 10%, and in many cases, dropping into the low single digits.

“Initially, the drivers were skeptical that the units would be able to maintain comfortable temperatures comparable to idling the engine,” explains Bruett. “However, this has now been disproved except [under] extreme conditions.”

JBS is utilizing available grant money from the state of Colorado to help with the install. The APU units should also reduce engine maintenance, Bruett adds.

“We definitely expect to have less maintenance on our truck engines,” he says. “On the other hand, we will add the APU maintenance cost, but we expect those costs to be much less than our current engine maintenance costs.”

As a SmartWay carrier, JBS has been looking at ways to further reduce fuel usage. That includes the implementation of trailer tails, which the fleet expects to improve mpg an additional 4%, Bruett says. Low-rolling resistance tires and fuel optimization software are also in use at the fleet.

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