Daimler Truck North America (DTNA) has added three new Cummins engines alongside its Detroit Gen 6 diesel lineup to support Freightliner and Western Star models for upcoming 2027 products.
These additional offerings from Cummins complete the 2027 engine lineup and include the new B6.7 Octane gasoline engine, the clean sheet X10 and a redesigned X15. Together the Detroit and Cummins engines are designed to meet upcoming emissions requirements across a variety of applications.
“Cummins is a critical partner for DTNA, and integrating their engines ensures our portfolio covers the full spectrum of applications for our customers,” says Joanna Buttler, general manager of Product Strategy and Market Development for DTNA. “Their next generation of engines strengthen the range of powertrain solutions available across Freightliner and Western Star and support customers as they prepare for upcoming emissions requirements and long-term operational needs.”
The new Cummins B6.7 Octane, the company’s first purpose-built commercial grade gasoline engine, is designed specifically for medium-duty applications and available in the Freightliner M2 106. DTNA states the engine delivers up to 300 horsepower and 660 lb.-ft., of torque, offering performance characteristics traditionally associated with diesel engines while using readily available 87-octane gasoline.
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According to Cummins, the B6.7 Octane leverages Cummins' HELM platform architecture, which enables different combustion systems to share a common engine platform and offers:
- Diesel-like torque response for demanding duty cycles such as hilly terrain and cold environments.
- A simple three-way catalyst eliminates DEF, active regens and diesel aftertreatment hardware.
- Fuel efficiency up to 10 percent better than comparable gasoline engines.
- Extended oil-service intervals of up to 15,000 miles contribute to lower operating costs.
“The B6.7 Octane provides fleets a commercial grade gasoline solution built for tough duty cycles without increasing maintenance demands,” says Jim Nebergall, executive director, Product and Market Strategy at Cummins. “It leverages our established B Series platform to maintain familiar service practices. By combining diesel-like durability with gasoline simplicity, the B6.7 Octane offers customers dependable performance in a footprint they already trust.”
The B6.7 Octane fills a gap for fleets that want the simplicity of gasoline operation without sacrificing the torque response required in vocational, pickup-and-delivery and urban applications. Ordering for the B6.7 Octane opens the week of March 9, 2026, and start of production is scheduled to begin in the third quarter of 2026.
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DTNA adds the X10 and X15 engines represent new developments built on decades of market experience and both will be offered across a range of Freightliner and Western Star products. The Cummins X10 is a clean-sheet design engineered to replace both the L9 and X12 engines. It delivers up to 380 horsepower for medium-duty applications and up to 450 horsepower in heavy-duty applications. This engine uses a 48-volt electrical system to heat emissions-control components quickly during cold starts, reducing emissions and supporting compliance with EPA 2027 requirements.
Finally, the Cummins X15 is redesigned to meet 2027 EPA standards, continuing its reputation as a durable heavy-duty powertrain staple. Cummins previously announced the X15 redesign as part of a broader shift to next-generation combustion platforms.
Several established Cummins platforms also will continue into the 2027 lineup and will be available across a range of Freightliner and Western Star trucks, maintaining their longstanding role in medium- and heavy-duty applications.
- B6.7 (diesel) — long-established medium-duty workhorse
- L9N (natural gas) — reduced-emissions solution with simplified aftertreatment
- X15N (natural gas) — heavy-duty and long-haul option with renewable-fuel capability
Together, the companies state these engines give fleets multiple pathways to align their powertrain choice with duty-cycle needs, fleet strategy and long-term operating goals.
The Cummins engines also expand on DTNA’s total engine availability, which includes the updated Detroit Gen 6 engines, introduced last month in Detroit. Built on a platform with more than 1.2 million engines in service, DTNA says these engines refine the previous generation’s design, providing confidence that the durability and reliability that Detroit is known for continue.
The Gen 6 engines deliver enhanced efficiency designed to help offset the impacts from emissions-related changes. Key updates include a redesigned and simplified fuel system that removes the need for amplified injection and supplies higher, stronger and more consistent fuel flow. Similarly, DTNA says the addition of an asymmetric intake port increases swirl and, combined with new fuel injectors, improves fuel and air mixing for a more complete combustion. The use of Miller timing on the camshaft reduces the work of compression, increases the compression ratio and contributes to overall engine efficiency, the company says.
To meet compliance with stringent NOx requirements included in EPA’s 2027 standards, Detroit Gen 6 engines use a pre-Selective Catalytic Reduction (pre-SCR) system, positioned upstream of the primary aftertreatment system (ATS). This technology, combined with a thermal control valve, helps the ATS to reach operating temperature more quickly, reducing the need for parked regens. The ATS design preserves existing chassis space with no impact to back-of-cab packaging — a key advantage for vocational customers and truck equipment manufacturers.
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The Detroit Gen 6 DD13 and DD15 engines will be available beginning in January 2027, with Gen 6 DD16 production following in January 2028. Through the integration of Cummins engines and its own Detroit Gen 6 platform, DTNA’s multi-fuel, multi-platform strategy ensures customers have access to the powertrain solutions that best support their business needs, whether that means gasoline, diesel, natural gas or emerging emissions requirements.
