First four paras lifted from longer item at http://blogs.defensenews.com/ausa/.....gd-has-a-plan/

General Dynamics is kicking off a new strategy to sell the Army the infantry vehicles and tanks it (eventually) needs to ferry troops to the next fight, wherever that may be.

More specifically, the company is looking to tweak its existing Abrams tanks, Strykers, and Buffalo route-clearing MRAPs to offer better protection while guzzling less fuel, thereby giving Army formations greater range at less cost, according to a briefing delivered by a group of GD execs.

Mike Cannon, GD’s senior vp for Ground Combat Systems said that the company is “getting away from being platform specific” when it comes to this new strategy, instead focusing on the ground assets of the infantry brigade as a whole.

First up is the company’s plan to install a diesel engine on the Abrams tank, which would result in a 14 percent cost reduction per mile when compared to the turbine engine currently in the tank, while extending its range by 105 miles.
The news release from GD omits mention of two further benefits.

The current gas turbine runs at a high temperature and generates a large volume of hot exhaust gas. The exhaust can be hazardous to accompanying dismounted infantry and even when diverted it serves as a beacon for heat sensors and heat seekers. Also the engine deck is officially assessed as too hot for riders. So one, the lesser volume of exhaust from a diesel engine will substantially reduce the hazard and beacon affects, and also the engine deck temperature. Relative to the gas turbine that diesel is likely to be heavier, require more power to start, vibrate more and have a deeper engine note but generate less high pitched noise.

The current APU with its fuel tank is installed in the Abrams turret basket. When that APU’s light armoured enclosure has in the past been defeated by small arms, heavier weapons or other cause the resultant leakage of fuel has often lead to a fire on the engine cover and subsequent damage to the gas turbine, and in the worst cases loss of the MBT itself. However two, the reduced volume of a diesel engine together with fuel tanks for greater range will still leave sufficient space for installation of an internal APU that has the same level of protection as the main diesel.

The suits and uniforms involved in the original selection of a gas turbine have all hopefully gone to some other place where they will be unable to influence decisions on any engine upgrade.