Cummins’ Advanced Combat Engine Revolutionizes Diesel Combustion

It’s no secret that Cummins does more than just six-cylinder engines for Ram trucks. The company even provides a wide variety of off-the-shelf engines and generators for military applications. But as vehicles are expected to meet new more stringent government requirements, have more power density, and increase fuel economy, Cummins is quick to adapt.​ In fact, did you know that Cummins is also involved with building engines that will help protect our freedoms?

For the last several years Cummins has been working to fulfill an $87M contract awarded by the U.S. Army to complete the development of the Advanced Combat Engine (ACE). If you watch the video above, things have progressed nicely. This new modular and scalable diesel engine uses opposed-piston (OP) technology to provide leap-ahead capabilities in power density and heat rejection not available in the current marketplace.

The Other Transaction Authority (OTA) contract builds upon a competitive multi-year effort from the U.S. Army’s Ground Vehicle Systems Center (GVSC) to develop transformational powertrain technology that is power dense, thermally efficient, modular, scalable, and affordable enough to enable the toughest mobility, survivability, and lethality vehicle requirements. Furthermore, the OTA allows for transitioning the new technology into the next generation of vehicle programs ahead of the programs’ launch dates.

advanced combat engine

The Cummins Advanced Combat Engine (ACE) has flexible layout options that allow the engine to be configured in three-, four-, and six-cylinder arrangements to deliver power ranging from 750 to 1,500 horsepower. With twin-turbocharging this 14.3-liter engine uses a design that has two pistons in each cylinder working in opposition of each other, sharing the same air/fuel mixture and resulting combustion. When playing with a cubic-inch mathematical equation, if our math is correct, that means it could have a bore in the neighborhood of 5.25 inches and a stroke of 5.00 inches or a multitude of other combinations.

“Coupling our opposed-piston technology with Cummins’ robust engine design, manufacturing, and new product introduction capabilities allows us to create a high-performing and reliable engine for military operations,” says Dave Crompton, president and CEO of Achates Power. “Achates Power is pleased to continue to support Cummins as a key technology partner in creating the next generation of engines for combat vehicles.” Achates Power is the opposed piston technology partner of Cummins for ACE and a recognized expert in opposed-piston engine technology.

Each side of the Advanced Combat Engine has its own crankshaft, and the pistons face each other building enough compression as they meet to complete a power stroke. Also, the pistons move between top dead center (TDC) and bottom dead center (BDC) uncovering holes in the combustion chamber that allow air in and out which means no valvetrain is required.

Each crankshaft is connected via gearsets which turn a single output shaft for vehicle propulsion. Ace is fueled by number two diesel and utilizes a two-cycle operation versus the traditional four-cycle.

The modular configuration of ACE affords the ability of the engine to be integrated into hybrid architectures that will enable commonality. This will eliminate the expensive logistical burden of having multiple combat powertrains. I will also facilitate the incorporation of new electrified technologies.

“We are excited to continue our valuable partnership with Cummins on the development of the Advanced Combat Engine (ACE); what’s under the hood of the Army Ground Vehicles is also what drives our team’s efforts at enhancing capability development,” says Alfred Grein, executive director for research & technology integration, U.S. Army DEVCOM Ground Vehicle Systems Center. “This project is a key part of our research and development work, and we see ACE as a potential enabler for both traditional and hybrid electric powertrains applicable to current and future combat vehicles.”

Cummins engines are in more tracked combat vehicles today than any other brand. As a major supplier of diesel engines and gensets for defense purposes throughout the world, Cummins understands the needs of the U.S. military. In every mission, Cummins-powered equipment has served with distinction, earning the highest commendation for durability, dependability, and performance, and the Advanced Combat Engine is a continuation of that service.

“ACE offers the U.S. Army rock solid Cummins engine performance coupled with a configurable, flexible architecture to support their complete portfolio of combat vehicles,” said Norbert Nusterer, vice president and president of Cummins Power Systems. “ACE also offers the option to integrate into hybrid architectures and leverages Cummins’ expertise from investments already made in the commercial space. We are excited to expand and deepen our longstanding relationship with the U.S. Army and contribute more cutting-edge technologies that support the current and the next generation of combat vehicles.”

All I can think of is what could we swap this into. The possibilities are endless.

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Randy Bolig

Randy Bolig has been working on cars and has been involved in the hobby ever since he bought his first car when he was only 14 years old. His passion for performance got him noticed by many locals, and he began helping them modify their vehicles.
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