Cummins Launches Next-Generation X15 Diesel Engine
The next-generation X15 diesel is part of Cummins' new HELM fuel-agnostic engine platform, which will give fleet access to higher efficiency, lower emissions, and multiple fuel powertrain options.

The Cummins HELM 15-liter X15 diesel engine will be compliant with U.S. EPA and CARB 2027 aligned regulations at launch.
Photo: Cummins
Cummins launched what it called its most efficient heavy-duty diesel engine ever during an online press briefing Feb. 28 as it unveiled its Cummins HELM fuel-agnostic engine platform.
HELM is an acronym that stands for higher-efficiency lower emissions multiple fuel options, according to Jane Beaman, vice president global, on-highway business, Cummins.
The first new product officially unveiled under the HELM banner is the Cummins HELM 15-liter fuel-agnostic platform. This includes the diesel X15 engine, which Cummins said will be compliant with U.S. EPA and CARB 2027 aligned regulations at launch.
“We have applied our decades of experience with the X15 to our next-generation product and believe these investments will serve our customers well into the future,” said José Samperio, vice president, North America on-highway at Cummins.
“With higher efficiency, lower emissions, and multiple fuels, the Cummins HELM platforms give our customers control of how they navigate their own journeys as part of the energy transition," Beaman explained. "They can choose the fuel types that work best for them, their businesses, and their goals.”
This next-generation engine is designed to be able to meet future emissions regulations beyond 2027 without the need for significant architecture changes.
The new engine line will serve customers for the next decade as Cummins continues to fund future research and development in hydrogen and alternative fuel engines, battery electric and fuel cell powertrains, Beaman added.
Integrated Eaton Cummins and Cummins Meritor Powertrains
Cummins said its next-generation diesel X15 will feature improved greenhouse gas and fuel efficiency benefits. The engine will also retain the same ratings of the current X15 (up to 605 horsepower and 2,050 ft-lb of torque).
The new engine will also be optimized for a complete powertrain integration with Eaton Cummins and Cummins-Meritor driveline components.
According to Jonathon White, vice president, engine business engineering, from its inception, the next-generation X15 was developed with Cummins’ fully integrated powertrain in mind. He noted that the X15 architecture uses a belt-driven, high output 48-volt alternator and aftertreatment heater solution, optimized for increasingly stringent emission standards.
Customers taking advantage of EX ratings (requires Eaton Cummins Endurant and GPS look-ahead data) with Cummins Meritor axles, brakes and drivelines will experience additional optimized fuel efficiency and drivability through features such as predictive gear shifting, on-ramp boost, and hill roll out, White added.
Integrated Powertrains and Fuels for Every Application
White said the Endurant HD and XD series are optimized for the next-generation X15 powertrain to work seamlessly, improving efficiency and performance while maintaining driver comfort. It offers transmission lube change intervals up to 750,000 miles as well as remote diagnostic capabilities.
The Cummins-Meritor 14X HE tandem drive axles are designed for performance, durability and fuel economy. They are equipped with a proprietary, advanced Meritor lube management system (MLMS) and feature super-fast ratio options, fuel-efficient bearings and high-efficiency spiral bevel gearing. Cummins-Meritor Permalube RPL drivelines are designed for reduced maintenance and have the ability to handle the high torque demands of today’s downsped engine platforms.
The base engine is built on Cummins’ HELM fuel-agnostic 15-liter engine platform. These new fuel-agnostic engine platforms feature a series of engine versions that are derived from a common base engine, which means they have some parts commonality. Below the head gasket of each engine will largely have similar components. Above the head gasket will have different components for different fuel types.
Each engine version will operate using a different, single fuel. The X15N, the natural gas variant, is the first engine on the Cummins HELM platforms available to customers. The Cummins HELM platforms include the B, X10, and X15 engine platforms.
Aligned with Cummins diesel engine portfolio, the new X15 is capable of using biodiesel blends up to 20% and renewable diesel blends up to 100%. Cummins was an early adopter of renewable fuels and continues to advance use of higher biodiesel blends and renewable diesel.
Digital Capability
The new X15 engine platform also features Cummins' digital products and services. This includes connecting real-time data from vehicles on the road to maintenance and service operations, giving customers the ability to look ahead, streamline operations and minimize downtime.
New features connect in-mission operations directly to maintenance and repair processes for more seamless end-to-end fleet management, Cummins said.
The new X15 is equipped with Acumen, which provides digital connectivity and direct, immediate access to a range of applications and capabilities, including over-the-air calibration, predictive service recommendations, and additional features that help fleets keep their trucks and equipment on the road.
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