Heavy Duty Trucking Logo
MenuMENU
SearchSEARCH

Class 8 Engines: Is Smaller Displacement the Wave of the Future?

There looks to be a shift away from spec'ing 14L engines in new Class 8 trucks in favor of powerplants that range from over 10L to under 14L in displacement, according to ACT Research and Rhein Associates.

by HDT Staff
August 29, 2019
Class 8 Engines: Is Smaller Displacement the Wave of the Future?

An example of a less than 14L and over 10L engine is the 12.8L Detroit DD13.

Photo: Detroit Diesel Corp.

2 min to read


There looks to be a shift away from spec’ing 14L engines in new Class 8 trucks in favor of powerplants that range from over 10L to under 14L in displacement. And the trend to smaller-displacement engine is expected to continue as diesel’s market hegemony comes “under attack” by alternative power.

That analysis is included in the N.A. Commercial Vehicle On-Highway Engine Outlookreport recentlypublished by ACT Research and Rhein Associates, which predicts that engines over 10L will account for more than 85% of the Class 8 production between 2020 and 2024.

Ad Loading...

“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 for Class 8 trucks and tractors, with an acceleration prompted by new emission regulations expected in 2024,” said Tom Rhein, president of Rhein Associates.

For Class 5-7, he said, "the current metric of interest is gasoline penetration, which continues to see share gains.”

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

Ad Loading...

“Emission regulations are one of the main drivers of alternative fuel adoption, which is why the Engine Outlook includes a section on the commercial vehicle regulatory environment,” he continued.

Vieth also offered a caution. “While many think this is a California-only phenomenon, we would note that Oregon’s legislators recently voted in favor of a bill to regulate diesel trucks in the Portland metro area, and we continue to see reports about various 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.”

The engine report highlights power-source activity for Class 5 to 8 trucks and includes five-year forecasts of engines volumes and product trends. Rhein Associates is a supplier of powertrain information to worldwide clients. ACT Research is a publisher of commercial vehicle truck, trailer, and bus industry data, market analysis and forecasts for the North America and China markets.

More Fuel Smarts

Electric semi trucks parked at a charging station with overhead charging equipment, representing challenges in heavy-duty EV infrastructure deployment.
Fuel Smartsby News/Media ReleaseMay 5, 2026

What Will It Take to Scale Electric Truck Charging? New Electrification Coalition Report Identifies 11 Solutions

A new report from the Electrification Coalition outlines key barriers slowing electric truck charging deployment and offers policy solutions to accelerate infrastructure growth.

Read More →
NACFE Run on Less 2026 findings.
Fuel Smartsby Jack RobertsMay 1, 2026

NACFE: Fleets Need to Recalibrate TCO Strategies as Electric Trucks Gain a Long-Term Edge

NACFE’s Run on Less data has found that recent setbacks aside, electric truck powertrains are trending toward market leadership by 2025.

Read More →
Gray Volvo tractor pulling trailer on open highway
Fuel Smartsby Deborah LockridgeMay 1, 2026

New High-Horsepower Natural Gas Engine Could Expand Fleet Options

Westport and Volvo are demonstrating a 500-hp truck with diesel-like efficiency — one that also offers what Westport says is a better pathway to using hydrogen fuel in trucks.

Read More →
Ad Loading...
Illustration with oil wells silhouetted against red and gold sky
Fuel Smartsby Deborah LockridgeMay 1, 2026

Why Fuel Diversification Matters for Trucking Fleets

Relying on diesel alone exposes fleets to fuel price volatility. Here’s why diversification with electric, natural gas, and renewable fuels can reduce risk.

Read More →
Range Energy eTrailer.
Fuel Smartsby News/Media ReleaseApril 17, 2026

Range Energy Confirms eTrailer Performance in Winter Testing as Commercial Rollout Nears

Range Energy said its production-ready eTrailer system proved it can boost stability, safety, and efficiency in sub-zero winter conditions as the company moves toward scaled deployment.

Read More →
Circles with trucks demonstrating sustainable features and Top Green Fleets logo
Fuel Smartsby Deborah LockridgeApril 16, 2026

Top Green Fleets of 2026: Nomination Deadline Extended

Is your company a leader in sustainability efforts among trucking fleets? If so, Heavy Duty Trucking's editors want to hear from you.

Read More →
Ad Loading...
Youtube thumbnail featuring man in Big-Lebowski-inspired sweater
Fuel Smartsby Deborah LockridgeApril 13, 2026

New Lightweight Wheel Cover Targets Simpler Aero Gains [Watch]

Watch to learn how Deflecktor's new wheel cover design is taking a simpler approach to aerodynamics, with an eye toward making it more practical for both trucks and trailers.

Read More →
Dual truck tires with black aerodynamic wheel cover and a man bending down getting ready to take one off
Fuel Smartsby Deborah LockridgeApril 10, 2026

Deflecktor: Hubbub Aerodynamic Wheel Cover Cost-Effective Even for Trailers

Aerodynamic wheel covers can deliver small but meaningful fuel-economy gains for fleets, and Deflecktor says its latest design aims to make the technology easier and more affordable to deploy.

Read More →
Podcast thumbnail saying "How to Save on Fuel Costs" with diesel pump in the background and photo of the woman guest
Fuel SmartsApril 9, 2026

Cutting Fleet Fuel Costs in a Volatile Market [Listen]

When diesel prices are as volatile as they've been in 2026, it makes it tough for trucking fleets to plan and control costs. Breakthrough Fuel's Jenny Vander Zanden has insights on near-term savings strategies.

Read More →
Ad Loading...
YouTube thumbnail saying "How to Save on Fuel Costs" with woman's photo and a photo of a diesel price pump
Fuel Smartsby Deborah LockridgeApril 9, 2026

Diesel Price Swings Aren’t Over. What Can Your Fleet Do?

Practical steps fleets can take to manage fuel costs, from purchasing strategies to driver behavior.

Read More →