US Xpress testing real-world fuel economy

US Xpress testing real-world fuel economy

The PIT Group helps identify most fuel-efficient powertrains

Using six linehaul tractors taken out of regular service plus two pre-production new models provided by manufacturers, truckload carrier US Xpress is just concluding three days of fuel-economy testing on public roads.  The PIT Group, a Canadian-based organization created to conduct unbiased efficiency testing, the project is intended to help US Xpress and other fleets associated with PIT identify the most fuel-efficient powertrain combinations available, according to Yves Provencher, PIT group manager.

“Like most carriers we take fuel economy seriously, and we believe this test will help validate the decisions we make about our equipment,” said Gerry Mead, sr. VP of maintenance at US Xpress.

With US Xpress drivers behind the wheel and support from the fleet’s maintenance staff, the trucks in the fuel-economy run ran a 52-mi. loop that started with a half-mile local access road from US Xpress’ Tunnel Hill, GA, terminal to I-75. They ran south for 25 miles using cruise control as much as possible and then turned around for the trip back to the terminal.  PIT followed TMC Type III fuel consumption test procedures, Provencher said, adding that traffic was light, terrain was rolling hills, and weather was dry and temperate all three days.

The six US Xpress tractors represented a mix of 2016 and 2017 models, engines, transmissions and rear axle ratios currently found in the company’s linehaul fleet, according to Dwayne Haug, consultant working with PIT and a former fleet maintenance manager.  All six had automated or automatic transmissions and were speced with axle ratios and engines set up for low RPM highway operations. The six were as delivered from the manufacturers with no aftermarket items installed, Haug pointed out.

“This is real-world testing, not track testing,” Haug said. That makes the data collected especially valuable to US Xpress and other fleet members of the PIT organization when investigating future equipment purchases that will maximize fuel economy, he added.

Using fleet drivers was also an important aspect of the test, according to Provencher. “We wanted to get real driver input on these new technologies. That will be important for driver buy-in when [fleets] move to implement them later on.”

Basic specs for the six US Xpress tractors were:

Freightliner (MY2017) Cascadia

  • Engine: Detroit DD15 455HP 65MPH Set Speed
  • Transmission: Detroit DT12 DA 1550 12 Speed Direct Drive Automated Manual Transmission
  • Rear Axle: Detroit DA RT 40 Ratio: 2.41  

Peterbilt (MY2016) 579 “6X2”           

  • Engine: PACCAR MX13 455HP 65MPH Set Speed Transmission
  • Transmission: Eaton Advantage 10 Speed Direct Drive Automated Manual Transmission
  • Rear Axle: Dana Econo TREK w/ Bendix eTrac System Ratio: 2.69

Peterbilt (MY2016) 579

  • Engine: PACCAR MX13 455HP 65MPH Set Speed
  • Transmission: Allison TC-10 Automatic Transmission
  • Rear Axle: Dana DSP40 Ratio: 2.69 

Peterbilt (MY2016) 579

  • Engine: PACCAR MX13 455HP 65MPH Set Speed
  • Transmission: Eaton Advantage 10 Speed Direct Drive Automated Manual Transmission 
  • Rear Axle: Dana DSP40 Ratio: 2.69 

Kenworth T680 (MY2017)

  • Engine: PACCAR MX13 405HP 65MPH Set Speed Transmission
  • Transmission: Eaton Advantage 10 Speed Direct Drive Automated Manual Transmission 
  • Rear Axle: Dana D40-155H ADVANTEK40 Ratio: 2.64 

Navistar Prostar ES (MY2017)

  • Engine: Cummins ISX15 450HP 65MPH Set Speed
  • Transmission: Eaton Advantage 10 Speed Direct Drive Automated Manual Transmission 
  • Rear Axle: Dana D40-155H ADVANTEK40 Ratio: 2.64 

The test also included two pre-production new models provided by their manufacturers – an International LT and a new-generation Freightliner Cascadia. The LT had a Cummins/Eaton/Dana powertrain, and the new Cascadia an integrated Detroit powertrain. 

Preliminary results from the three days of testing will be shared with the 50 fleet members of PIT in about three weeks, with a full report to members following in about six weeks, according to Provencher.  Any new members joining the organization will also be given access to the reports, he said.

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