In this project, a 10.6L heavy duty diesel opposed-piston (OP) engine was installed in a Peterbilt 579 tractor and was used by Walmart in fleet service starting in December 2021. Measured results that will be reported include:
- In-use NOx, measured by the University of California-Riverside using a Portable Emissions Measurement System showing that the OP engine can meet the most stringent CARB in-use NOx limits and the most stringent proposed EPA in-use NOx limits, with substantial margin to compliance. Kent Johnson of UC-Riverside will describe their test methodology and the results.
- Measured fuel economy (miles per gallon) 10%+ better for the demonstration tractor with the OP engine than a reference 2021 MY tractor with the same routes, loads, and driver.
- Notably, the OP engine only uses conventional underfloor aftertreatment system to achieve ultralow NOx. Fabien Redon of Achates Power will describe the aftertreatment system configuration, and well as the status of the project extensions to measure tailpipe emissions on a transient dynamometer with a fully aged (800,000 mile) aftertreatment system.
- Fabien Redon will also present the results of dynamometer measurements of FTP, SET, low-load, and idle performance and emissions.
- Bill Robertson of CARB will describe the urgent need for NOx reduction from commercial vehicle diesel engines.
- Greg Kolwich of FEV will describe the methodology and results of a cost study that concludes an OP engine capable of meeting CARB 2027 ultralow NOx regulations and EPA 2027 GHG II CO2 regulations will cost less than current model conventional diesel engines of the same power and torque.
The Heavy Duty Diesel Demonstration Program is funded by the California Air Resources Board, the South Coast Air Quality Management District, the San Joaquin Valley Air Pollution Control District, and the Sacramento Metro Air Quality Management District. CALSTART leads the project.