The 1,000 hp Advanced Combat Engine (ACE), developed by Cummins in partnership with the U.S. Army, will be showcased at Australia’s Land Forces Exposition in Melbourne from Sept. 11-13.

Incorporating advanced technologies not currently available in diesel combat engines, the compact four-cylinder ACE is designed for infantry fighting vehicles and main battle tanks.

The 14.3-liter, two-stroke engine features opposed-piston technology and is equipped with dual Holset® variable geometry turbochargers and a gear-driven supercharger for high power density and peak torque of 2424 lb-ft.

“Compared with existing best-in-class combat engines, ACE provides a 50 percent increase in power density and a 13 percent increase in fuel efficiency,” said Sam Jones, manager of Cummins Asia Pacific’s defense business.

“Being able to debut this engine at the Land Forces Exposition provides a great opportunity for defense personnel and Original Equipment Manufacturers (OEMs) to gain an insight into the performance capabilities of the next generation combat vehicles.”

The engine on display at Land Forces will be the 1000 hp, four-cylinder version, with maximum power delivered at 2600 rpm and peak torque of 2424 lb-ft at 1600-2000 rpm.

ACE’s modular design also allows it to be configured in three-cylinder and six-cylinder arrangements to deliver power ranging from 750 to 1,500 horsepower.

Compactness is an obvious advantage of ACE, particularly crucial for combat vehicles with their restricted installation space. Cummins has collaborated with Achates Power on the opposed-piston technology which eliminates the need for a valve train and cylinder head. Another advantage of the design is low heat rejection which enables a smaller radiator which frees up space and weight in the vehicle.

Whilst being a four-cylinder engine, ACE actually has eight pistons – two in each cylinder that are connected to separate crankshafts and travel towards one another to create compression.

ACE is engineered for operation in full desert conditions using all specified military fuels. Moreover, it is viewed as a facilitator for hybrid electric powertrains in the next generation combat vehicle.

At the US Army’s Yuma Proving Ground in Arizona, ACE recently passed a series of rigorous tests powering the Advanced Mobility Experimental Prototype (AMEP).

ACE is scheduled to go into production in late 2027 and while developed for military applications, its adaptability extends to commercial uses that require high power with limited available space.