Tucked away in the back of L-3's exhibit at the Association of the US Army show in Washington last week was the current configuration of the company's OPOC (opposed piston, opposed cylinder) heavy fuel engine. OPOC, as reported here a year ago, was originally intended as a powerplant for the A160T Hummingbird UAV but is currently being promoted as a compact, fuel-efficient vehicle powerplant.
Road tests on a Family of Medium Tactical Vehicles (FMTV) truck, sponsored by the Army's Tank-Automotive Research, Development and Engineering Center (TARDEC), are due to start in 2009. L-3 acknowledges some delays, caused by the development of an electrically-boosted turbocharger - OPOC needs some boost to start. However, the company still believes in its benefits, including modular design: the basic two-cylinder 325 hp block can be assembled in a two- or three-pack configuration, the latter yielding a 975 hp Bradley-sized engine, and L-3's even talking about a horizontal-H six-pack engine for re-engining tanks.
At AUSA, the OPOC demonstrator was connected to a novel integrated starter-generator (ISG) from L-3's German subsidiary, Magnet-Motor. The company's ISGs are being acquired "for almost all" the Joinht Light Tactical Vehicle (JLTV) programs, according to general manager Manfred Hegg. The 65 kW version here is the baby of the family - JLTV versions are rated at 120 kW and there are 2000 and 400 kW units in the works. Advantages include a lot of electrical power for a small net weight increase - since the ISG displaces the conventional alternator and starter - and a design that involves only a small increase in drivetrain length, making it easier to retrofit.