Class 8 Engine Sizes Shrink As Emissions Rule Changes Loom

The size of engines powering Class 8 tractors is expected to decrease as fleets seek to reduce fuel consumption and meet three rounds of strict federal emission requirements in the next decade.

Engines over 10 liters (L) are projected to account for more than 85 percent of Class 8 truck production between 2020 and 2024, according to a study by ACT Research and Rhein Associates.

"Although the over 14L engine category will remain the largest segment in 2019, there is a trend to smaller displacement engines in the over-10L market segment," said Tom Rhein, president of Rhein Associates. The push is being prompted by federal greenhouse gas (GHG) regulations in 2024, he said.

In August 2016, the U.S. Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) finalized Phase 2 standards for medium- and heavy-duty vehicles through model year 2027. The stricter regulations are intended to improve fuel efficiency and cut heat-trapping GHGs that cause a warming of Earth's surface and the air above it. 

FreightWaves SONAR COMPP.USA data showing CO2 emissions generated by commercial vehicles over a 10-year period support findings by the Global Carbon Project that showed emissions reached an all-time high in 2018 (Chart: FreightWaves SONAR)

Global carbon emissions reached an all-time high in 2018, according to a December 2018 report by a consortium of researchers known as the Global Carbon Project.  

Medium-duty trucks also face tougher standards. Offerings of gasoline-powered trucks are rising. Isuzu Commercial Truck of America and Mitsubishi Fuso, a unit of Daimler Trucks, both introduced gasoline-powered Class 5 trucks in March this year. 

"Diesel power is under attack long-term for use in on-highway commercial vehicles," said Kenny Vieth, ACT Research president. "Alternative power is being developed, tested and refined, even as diesel engines are transitioning to become more fuel-efficient and clean."

The shift to hub-and-spoke freight patterns covering shorter distances to meet demands for faster deliveries could lead to the adoption of smaller-displacement engines, said Bill Van Amburg, executive vice president of Calstart, a clean transportation nonprofit.

"There is also a steadily growing regional goods distribution trend, all of which can make use of smaller bore engines in a Class 8 truck," Van Amburg told FreightWaves. 

"It is not even the emissions concerns as much as the maintenance and engine expense," he said. "While diesel engines last longer, they are more expensive and the after-treatment systems have been a maintenance issue for medium-duty fleets."

Data confirms the move to smaller-displacement engines, said Antti Lindstrom, an analyst with IHS Markit. 

"Fuel economy is better while performance is too, so it's a win-win situation for all," he told FreightWaves.

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California's intention to get diesel trucks off its roads by 2035 gets a lot of attention. But other areas, including Portland, Oregon, are adopting tougher emission restrictions, Vieth said.

"We continue to see reports about state- and federal-level funding for alternative fuel programs that are sending millions of dollars toward these efforts for both commercial and passenger vehicle use," he said.

The U.S. Department of Energy announced $59 million in grants for advanced transportation research projects on August 16, including $7 million for General Motors Co. to develop a low-mass, high-efficiency engine for midsize trucks.

The California Air Resources Board offers matching funds to numerous truck maker efforts to reduce emissions. It announced $205 million in matching grants for clean freight transportation in September 2018.