LONG BEACH, CA. The second public hearing on proposed truck fuel efficiency and greenhouse gas emissions standards shaped up much like the first: Trucking industry representatives expressed qualified support for the stringency goals and implementation schedule outlined by the Environmental Protection Agency (EPA), while air quality regulators and environmental groups called for tougher restrictions and a tighter timeline. And within trucking there is a divide over exactly how the engine and complete vehicle should be measured.

The big four North American heavy-duty truck manufacturers (Daimler Trucks North America, Navistar, Paccar and Volvo Trucks North America) spoke with one voice Tuesday, as Dan Kieffer, director of emissions compliance for Paccar, delivered a statement on behalf of all.

Calling the Phase II rule “historic in its scope and complexity,” Kieffer noted “a long list of technical and protocol issues” the truck makers will work closely with EPA and the National Highway Transportation Safety Administration (NHTSA) to resolve.

“EPA and NHTSA have set very ambitious goals for this industry, and we will do everything we can to ensure that this regulation will translate into significant real world efficiency gains for our customers, as well as major benefits for society,” Kieffer said. "Our goal is a classic 'win-win' scenario, and we are hopeful we can achieve it.”

He also called on the agencies to adopt a “complete vehicle approach” to the regulation, as opposed to separate vehicle and engine standards. The four points of emphasis were:

  • Engines are best evaluated based on how they operate in the vehicle, considering the engine size and power output, the vehicle power demand, and the driveline characteristics;
  • Truck makers must consider the installation impact of engine-related systems, including space requirements, weight, and cooling demand, all of which can significantly impact the aerodynamic design of the tractor-trailer combination and reduce efficiency.
  • NOx emissions are proportional to engine work, so the more effective the vehicle is as a system, the lower the NOx output. But with engine efficiency improvement, there is a well-documented trade-off between NOx reduction and engine efficiency. Therefore, excessive demands for stand-alone engine efficiency would limit the potential for NOx reduction, especially in urban duty cycles where NOx emissions are most critical.
  • Businesses that rely on trucks are concerned about the incremental investment and operating costs of complex new engine technology. Putting excessive emphasis on the engine as a stand-alone component can result in costly engine technology that would bring little or no benefit in many real world applications. Unnecessarily stringent engine standards will only exacerbate the trend of delaying new truck purchases, prolonging the use of higher emitting vehicles.

“The fact is that vehicle manufacturers must have the flexibility to optimize the complete vehicle design for maximum efficiency at the lowest cost and complexity,” Kieffer said. “Minimizing total cost of vehicle ownership is a top priority for our customers.”

The truck manufacturers’ opposition to the engine standard goes against support from the world’s largest engine-builder, Cummins Inc.