Detroit rolls out Gen 6 engine portfolio for Freightliner and Western Star trucks

“At a moment in the marketplace where customers are particularly focused on value, their capital, where they utilize their capital, then the next decisions about stepping into 2027 are really focused on what do I get on my investment? Is it just an emissions change, or is there more value there?” said David Carson, senior vice president of sales and marketing at Daimler Truck North America. “There’s a tremendous amount of value in this product.”

The engines will be available for all heavy-duty Freightliner and Western Star trucks. DD13 and DD15 will be available beginning in January 2027, with Gen 6 DD16 production following in January 2028.

“Freightliner and Western Star customers depend on Detroit to operate reliably, efficiently and powerfully, and we’re honored by the trust placed in both the Detroit brand and the DD13, DD15 and DD16 engines to help navigate past transitions as well as this next one,” Carson said. “With our Gen 6 engines, we have a successor that builds on years of proven performance to be prepared for 2027 and beyond.”

This is the sixth generation of Detroit’s Heavy-Duty Engine Platform. Detroit first introduced it in 2007 as a clean-sheet design. More than 1.2 million of these engines now run across North America and global markets.

Detroit completely redesigned the fuel system. The company switched to an oil-lubricated high-pressure pump that delivers 2,500-bar common rail pressure with simplified non-amplified injectors. It also added Miller cam timing and an electronic variable-displacement oil pump to cut parasitic losses.

“Our customers can’t always control the quality of the fuel that they have access to,” said Steve Collins, director of field sales engineering for Detroit. “A robust fuel system improves efficiency and reliability.”

Engineers added an asymmetric intake port to increase swirl. They combined this change with Miller cam timing. As a result, the engines improve combustion and raise compression ratios. Detroit projects a 3 percent improvement in real-world fuel efficiency.

To meet the tougher NOx rules, Detroit added a pre-Selective Catalytic Reduction (pre-SCR) system upstream of the familiar aftertreatment system. It uses the same proven technology fleets already know.

“It became very clear to us that once 35 milligram was decided on, the pre-SCR strategy was the best way to go,” said Greg Braziunas, head of powertrain engineering for North America. “This known technology delivers familiarity, robustness and the best value for customers.”

The thermal control valve, once available only on the DD13, now comes standard on every Gen 6 engine. Braziunas said it has greatly reduced or even eliminated the need for parked regens on many vocational trucks.

Detroit kept most familiar Gen 5 power ratings. However, it added three new options: a 505-horsepower, 1,750 pound-feet torque DD13 for vocational customers and two DD15 ratings at 425 and 455 horsepower with 1,900 pound-feet of torque for more downspeeding.

The company tested the platform for seven years and more than 8 million real-world miles in temperatures from minus 40 to 130 degrees Fahrenheit. Oil maintenance and diesel particulate filter ash-cleaning intervals remain the same as Gen 5.

All Gen 6 engines are built at the Redford Township plant. That facility recently received a $285 million investment supported by Michigan Economic Development Corp. incentives