Fuel efficiency for engine-driven accessories addressed in NACFE Confidence Report

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Updated Feb 27, 2017

Screen Shot 2017 02 26 At 5 41 39 Pm 2017 02 27 07 38The North American Council for Freight Efficiency (NACFE), Carbon War Room and Trucking Efficiency have determined variable engine-driven accessories have emerged as minor fuel-saving strategies for long- and regional-haul fleets.

The announcement was made Sunday when the groups released their newest Confidence Report on such accessories at the Technology & Maintenance Council (TMC) Annual Meeting in Nashville, Tenn.

Unlike some past Confidence Report studies that uncovered significant freight efficiency benefits, Mike Roeth, operations lead at Trucking Efficiency and NACFE executive director, says the advantages of engine-driven accessories appear minimal but, in specific cases, have the potential to grow.

“Variable engine-driven accessories present relatively small opportunities for gains in fuel efficiency, but they may provide better payback with further development,” he says.

In building its new report Roeth says Trucking Efficiency’s team defined engine-driven accessories as products that consume fuel but don’t help move a vehicle down the road. Typically, these accessories use about 3 to 5 percent of the overall fuel consumed by Class 8 tractor-trailers. Trucking Efficiency concludes current fuel prices make justifying the added cost for variable engine-driven accessories hardware that improves fuel economy difficult, and the added complexity of these systems creates concerns about their reliability.

“The fuel economy gains are pretty modest,” and for some technologies are actually declining due to other technology advancements, Roeth says.

The new report provides details on 2-speed/modulating cooling fans, variable speed water pumps, clutched air compressors, high-efficiency alternators, smart air dryers, dual displacement power steering pumps, electrically driven A/C compressors, and electrically driven accessories. It also explores some of the challenges presented by these technologies.

Ultimately, Roeth says proactive fleets should continue to review these accessories and watch them emerge, and monitor possible improvements driven by greenhouse gas regulations. He also says higher voltage systems will enable additional payback, but accessories will not be the driver for higher voltages. He says NACFE will continue to monitor developments and update this work as it warrants.

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This is the second time Trucking Efficiency has released a Confidence Report on an emerging technology. The report is an effort to provide a foundational understanding of variable engine-driven accessories because current and upcoming greenhouse gas regulations are likely to push at least some of the technology choices related to engine-driven accessories from optional to standard equipment on new truck orders.

To read an executive summary or download this Confidence Report, please CLICK HERE.