Impact of Lateral Alignment for Cooling Airflow during Heavy-Truck Platooning

Michael Lammert, Chen Zhang, Brian McAuliffe

Research output: Contribution to conferencePaperpeer-review


A truck platooning system was tested using two heavy-duty tractor-trailer trucks on a closed test track to investigate the thermal control/heat rejection system sensitivity to intentional lateral offsets over a range of intervehicle spacings. Previous studies have shown the following vehicle can experience elevated temperatures and reduced airflow through the cooling package as a result of close-formation platooning. Four anemometers positioned across the grille of the following trucks as well as aligned and multiple offset positions are used to evaluate the sensitivity of the impact. Straight sections of the track are isolated for the most accurate airflow impact measurements and to be most representative of on-highway driving. An intentional lateral offset in truck platooning is considered as a controls approach to mitigate reduced cooling efficacy at close following scenarios where the highest platoon savings are achieved. The truck platooning system was tested at four gap distances from 9 to 23 meters and the following truck was either aligned with the lead or offset with a 25% width (0.65 m) or 50% width (1.3 m) lateral distance. The experimental results clearly show that offset driving is effective at bringing cooling airflow from 56% with an aligned platoon back up to 75%-80% with minimal impact to fuel savings. In addition, the offset driving can also reduce the trailing truck's engine coolant temperature by 2°C and the corresponding underhood temperature rise by 10°C. The test outcomes indicate a plausible controls strategy to mitigate reduced cooling flow during hot-weather truck platooning while still enabling the highest-energy-saving, close-following scenarios.

Original languageAmerican English
Number of pages10
StatePublished - 6 Apr 2021
EventSAE 2021 WCX Digital Summit - Virtual, Online, United States
Duration: 13 Apr 202115 Apr 2021


ConferenceSAE 2021 WCX Digital Summit
Country/TerritoryUnited States
CityVirtual, Online

Bibliographical note

Publisher Copyright:
© 2021 SAE International. All rights reserved.

NREL Publication Number

  • NREL/CP-5400-78553

Other Report Number

  • SAE Paper No. 2021-01-0231


  • connected and automated vehicle
  • cooling airflow
  • Engine cooling
  • heavy-duty truck partial automation
  • heavy-duty truck platooning
  • vehicle alignment


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