SuperTruck II Update : Notes from the 2021 DOE Annual Merit Review

This is a continuation of the coverage of the progress made by various participants of the DOE funded SuperTruck II program. Recall that the objectives are two-fold:

(1) Achieve 55% brake thermal efficiency (BTE) for heavy-duty diesel engines; and

(2) Double the freight efficiency, as measured in miles per gallon x freight tons

For the DOE Annual Merit Review presentations, including the SuperTruck II updates, see here: https://www.energy.gov/eere/vehicles/annual-merit-review-presentations

We are moving into the last year of this program, and most participants are close to meeting the goals. The picture here is a summary of the various technologies being deployed on final demonstrations. 

Improvements are made at the engine, transmission and vehicle level, along with model based control of the drivetrain and upgrades to emissions control systems for upcoming low NOx regulations. A few of the common elements include weight reduction (both engine and trailer), improved aerodynamics and tires, mild hybridization, thermal barrier coatings of pistons and cylinder walls, improved turbochargers, and waste heat recovery.

The table below list some more details of the technology pathways for engine improvements being pursued by the participants. Some key updates since 2020 are marked in green, while the striked-through text in red shows a change in 
WHR technology. 

Daimler is now testing a 55% BTE engine and has announced that it is on track for > 115% increase in freight efficiency. The Cummins/Peterbilt team has also hit the 55% BTE mark and expect 170% increase in freight efficiency. Other teams are also well on their way and confident of meeting the goals. This last year of the program will be an exciting one with results from trucks demonstrations to come. 

Further Reading

For the DOE Annual Merit Review presentations, including the SuperTruck II updates, see here: https://www.energy.gov/eere/vehicles/annual-merit-review-presentations