Cummins unveiled its 2027 EPA-compliant engine at the Technology and Maintenance Council annual meeting in March. (Seth Clevenger/Transportation Topics)
key takeaways:
- Cummins plans limited production of its model year 2027 X15 and X10 engines starting in January.
- The OEM will continue to offer the current generation engines during the transition to the new models.
- Cummins said production plans could change depending on the differences between the EPA proposal and the final rule.
Cummins plans to introduce two model year 2027 engines meeting stricter emissions standards after reviewing draft Environmental Protection Agency rules announced July 9, and continue production of existing versions, the OEM said July 23.
Columbus, Ind.-based Cummins’ plan to phase out longtime offerings is the first domino to drop after details of nitrogen oxide emissions rules were unveiled, though Volvo Group CEO Martin Lundstedt had already warned on July 17 that the lens on truck sales in the second half of 2026 was bleak due to the rulemaking.
Cummins will continue to manufacture existing versions of the X15 and
CEO Jennifer Rumsey said, “Our long-term product strategy has not changed.” “It’s about improving the transition, not changing the destination. A phased production ramp will allow us to build confidence in our new products through real-world operations and support customers while maintaining our focus on quality.”
Rumsey attended the unveiling of the NPRM on July 9 on the National Mall. Rumsey joined EPA Administrator Lee Zeldin on stage for the launch, along with Daimler Trucks North America CEO John O’Leary and Packer CEO Preston Fite.
The NPRM kept the Biden-era requirement that NOx emissions for heavy-duty trucks be reduced from 200 mg/hp-hour to 35 mg/hp-hour, but manufacturers were offered rebates on implementation, non-compliance, and NOX credits.
From left: ATA President Chris Spear joins Cummins CEO Jennifer Rumsey, Packer CEO Preston Fite and Daimler Trucks North America CEO John O’Leary on the National Mall on July 9. (American Trucking Association)
In another title amendment, the warranty for heavy-duty truck emissions mitigation equipment would be 100,000 miles or five years instead of 450,000 miles or 10 years under the current rule. That decision is expected to cut the price of model year 2027 trucks by up to $10,000.
production plans
Meanwhile, Cummins plans to begin limited production of its model year 2027 X15 engines in January, depending on individual OEM launch plans. The company said production will continue to expand, with full production expected to begin in the fourth quarter of 2027.
However, as part of the amendment to its plans, Cummins expects its current generation X15 engine to remain available.
Similarly, Cummins expects to begin limited production of model year 2027 X10 engines in January, with full production expected by the third quarter, subject to OEM launch plans.
During the transition, current X12 and L9 engines used in truck and transit bus applications will remain available.
That said, Cummins warned that these may not be the last changes. The company expects to continue monitoring the development of the final rule – the draft rule contains at least one big surprise for truck and engine manufacturers – and may adjust product planning and timing if the final rule differs materially from the July 9 NPRM.
Truck makers and Cummins waited as long as possible to introduce their EPA 2027-compliant engines, with the 2027 X15 not being introduced publicly until late March at the Technology and Maintenance Council’s annual meeting.
Citing uncertainty surrounding the introduction of federal tailpipe regulations, Cummins had already delayed the launch once to August 2025.
The EPA 2027-compliant X15 comes with a redesigned, larger selective catalytic reduction system and a dedicated 48-volt alternator for two heaters. There is a heater before the diesel oxidation catalyst/diesel particulate filter and a heater before the SCR section.
DTNA will introduce 6 compatible engines
The diesel X15 is one of six EPA 2027-compliant engines offered by Freightliner and Western Star. Kenworth’s C580 heavy-haul tractor and truck – which was unveiled in March – will come with the X15 as standard.
Meanwhile, Cummins has high hopes for the X10, which is slated for launch in March 2025. It replaces the L9 and X12 engines in Cummins’ North America portfolio and is intended to grow the company’s heavy-duty truck engine market.
“The X10 definitely opens up another market,” Brett Merritt, president of Cummins’ engine business, told analysts and investors during the company’s 2026 investor day. “You will see increased market share in heavy duty through X10.”
While the L9 was seen as a versatile option in the medium-duty market, Cummins is introducing the X10 as a candidate for those fleets and customers with heavy-duty needs.
In March, Mack Trucks unveiled the revival of its Class 8 Granite vocational truck. The X10 for Granite is available in six power profiles. Merit said during its May 21 analyst day that Granite was the first heavy-duty application for the X10.
