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

Four men in suits on the National Mall with giant video screen showing capitol building in the background
Equipmentby Deborah LockridgeJuly 10, 2026

EPA Proposal Could Ease 2027 Truck Costs and Buying Uncertainty

The proposal doesn't change the tougher NOx standard, but it would revise key implementation requirements that manufacturers say have driven up costs and complicated fleet purchasing decisions.

Read More →
Illustration showing Paccar MX engine with sketch illustration of DEF fill tank in background
Equipmentby Deborah LockridgeJuly 7, 2026

Cummins, Paccar Ease DEF Derates After EPA Guidance

Updated diesel engine software gives truck operators more time to address emissions-system issues while staying compliant with EPA emissions standards.

Read More →
Illustration with wrenches in background with "Maintenance in the Messy Middle: Biodiesel" text and NACFE Run on Less logo
Maintenanceby Jack RobertsJuly 2, 2026

Maintenance in the Messy Middle Part 3: Biodiesel

Biodiesel can reduce emissions, improve fuel-system lubricity and use existing diesel infrastructure. But NACFE’s Messy Middle maintenance report says fleets must actively manage storage, cold-weather operation, filters and oil drain intervals to avoid problems.

Read More →
Ad Loading...
thermo king heavy duty trucking
SponsoredJuly 1, 2026

Enhance Fleet Performance with High-Efficiency Auxiliary Power Units

Drive sustainable cost savings while increasing driver comfort during short- and long-haul logistics operations.

Read More →
Illustration with wrenches in background with "Maintenance in the Messy Middle: Renewable Diesel" text and NACFE Run on Less logo
Maintenanceby Jack RobertsJune 29, 2026

Maintenance in the ‘Messy Middle’ Part 2: Renewable Diesel Fuel

NACFE's latest Messy Middle Powertrain Service & Maintenance report says renewable diesel gives fleets an opportunity to reduce carbon emissions without changing trucks, fueling infrastructure or maintenance practices. But technicians still need to understand several important operational differences.

Read More →
Illustration messy middle maintenance diesel with wrenches in background
Maintenanceby Jack RobertsJune 26, 2026

The Diesel Engine Enters NACFE’s ‘Messy Middle’

NACFE’s new Messy Middle Powertrain Service & Maintenance report says keeping modern diesel engines running now depends as much on software, diagnostics and data as traditional mechanical service.

Read More →
Ad Loading...
Illustration showing DEF tank and Detroit engine
Equipmentby Deborah LockridgeJune 18, 2026

DTNA Software Update Gives Truckers More Time Before DEF Derates Take Effect

The changes reflect EPA guidance aimed at reducing downtime caused by emissions-system faults while maintaining compliance requirements.

Read More →
Illustration of exhaust aftertreatment system on an AI-inspired blue background and a green fuel pump nozzle in the foreground.
Maintenanceby Deborah LockridgeJune 15, 2026

New Agentic Predictive Maintenance Report Demonstrates How Degraded Aftertreatment Systems Waste Fuel

Questar analyzed a large mixed-class fleet and discovered it was wasting as much as $30 in fuel per vehicle, per day, because of mechanically degraded aftertreatment systems.

Read More →
Amazon electric cargo bike on New York City street
Fleet ManagementJune 15, 2026

New York City's Microhub Project is Delivering Results

Trucking, last-mile delivery companies, and environmental advocates like what they are seeing so far with New York's microhub program.

Read More →
Ad Loading...
Red Kenworth truck pulling Paper Transport trailer
Fuel Smartsby Deborah LockridgeJune 2, 2026

Lessons Learned About Alternative Fuels: Start Small, Stay Flexible

Practical advice on adopting alternative fuels and ZEVs from HDT's 2026 Top Green Fleets, from renewable diesel and natural gas to electric trucks.

Read More →