Achates Power and Cummins teamed up to develop a 14.3 L twin-charged diesel flat-four for the U.S. Army’s Advanced Combat Engine (ACE) program. The motor uses an opposed-piston design with eight pistons (two in each cylinder), two crankshafts, and no cylinders heads or valves. It uses a 130 mm (5.12 inch) bore and 135 mm (5.31 inch) stroke. The two-stroke motor produces 1000 horsepower at 2,600 rpm with two HE500 VGT turbochargers and a gear-driven supercharger.
Source: Janes and Achates Power via Piotr
Tts not twin charged or a supercharger. Its a low pressure blower and the engine MUST have it just to operate, the engine cannot move air without it.
Cummins calls it a “gear-driven supercharger”.
Except its not a supercharger.
Having read a more detailed on the engine, they refer to a gear driven Roots style supercharger, as well as a pair of Holset turbos. Not sure which bit is the supercharger.
https://www.thedrive.com/news/35330/how-cummins-designed-a-14-3l-flat-four-with-eight-pistons-no-valves-and-1000-hp