U.S. Army Will Soon Have the First Fleet of All-Hybrid Vehicles
Hybrid Electric Engines Increase Fuel Efficiency in Manned Ground Vehicles
 By Susan Benson, Hypertronics - BAE Business Manager

The United States Army’s Manned Ground Vehicles (MGV) is a family of eight vehicles that is distinguished as the first operational Army suite of ground combat vehicles to use hybrid electric engines. BAE Systems is working with General Dynamics, Boeing Co., and Science Applications International Corp. on the creation of the hybrid electric drive system for the Future Combat Systems Program (FCS). The hybrid electric drive uses a diesel engine to generate electrical power for mobility and all other vehicle subsystems. An electric motor drives the tracks that propel the vehicle, as well as run all internal systems, drawing power from batteries charged by the diesel engine.

The engine, which is located on the left rear side of the vehicle, is about three-quarters the size of the Bradley armored vehicle engine, so it is much smaller than previous engines. Electric engines offer both energy and environmental benefits by providing better fuel economy and lower emissions. An additional benefit for military use is the considerable noise reduction of electric engines compared to fuel engines, creating an obvious advantage in tactical maneuvers.

Fuel Costs Will Decrease Significantly
Since World War II, fuel supplies have been the primary limiting factor for army strategic mobility. Since then, fuel economy has only improved by 20 percent, based on an average of 0.6mpg for the M1A2 Abrams tank. Fuel efficiency is important for strategic sustainability. The impact of fuel use is enormous, and the shift to hybrid electric engines offers a tremendous savings in fuel cost. For example, in 2008 the U.S. military consumed about 1.7 million gallons of gas a day in Iraq. Hybrid engines could save the U.S. Army up to a billion dollars a year in Iraq alone. Fewer fuel trucks and fewer refueling breaks are added benefits of using hybrid electric engines.

The U.S. Army's Tank-Automotive Research, Development, and Engineering Center (TARDEC) recently announced that its new diesel-electric hybrid propulsion system is moving into the “hot buck” testing stage, a realistic simulation environment that is the last stop before full-on field testing. The first use of the hybrid electric drive technology will be in the Non-Line-of-Sight Cannon (NLOS-C)—the lead FCS ground combat vehicle.

The achievement of this milestone was made possible in part by the Power & Energy System Integration Lab (P&E SIL) located in Santa Clara. The lab is an $80 million science and technology initiative administered by the U.S. Army’s TARDEC, and managed by Science Applications International Corporation (SAIC) and BAE Systems. For the past eight years, the P&E SIL has allowed the Army and industry to jointly solidify the foundation for hybrid electric combat vehicle technology of the future.

Features and Benefits of Electric Drives
By exploiting the benefits of hybrid power, power management, and power sharing, it will become possible to design future combat vehicles with advanced weapons and protection systems, while reducing logistical requirements, increasing efficiency, and reducing overall weight and volume. Its advanced energy storage, electric traction drive, power generation, regenerative braking, and integrated power management technology all serve to provide our combat soldiers with increased performance and unprecedented flexibility.

The traction drive systems of the new manned ground vehicles are designed to enhance longevity. This further reduces costs, because it is designed to allow for future improvements by decoupling the power generation unit from the drive train architecture. The existing power generation unit can be replaced by a fuel cell, for example, once this technology matures, to further improve fuel consumption, acoustic signature, and mobility performance.

What This Means to Connector Manufacturers
There were several design challenges unique to hybrid electric engines when developing the interconnect system. Due to the high current requirement in electric engines, all components must maintain their integrity in very harsh thermal environments. There are also considerable constraints on size and weight of the components, which need to increase their performance on smaller form factors. In order to conform to the technology requirements of the hybrid electric engines for Manned Ground Vehicles, MA-based connector manufacturer, Hypertronics Corporation developed a custom interconnect system to supply the higher power required in a more compact form factor. Designed to operate under the harshest conditions and withstand shock and vibration, while supplying high voltage, this rugged blind-mating, self-aligning connector system ensures signal reliability. The design features the simplicity of a lock-and-load system that is easy to access, and creates cost savings through reductions in maintenance crews and vehicles.

While COTS establishes readily available military standard products, customized products for military and aerospace applications are frequently the only solution. “The Hypertac group of companies specializes in early-stage collaboration with manufacturers that often begins at the design stage,” said Garry MacDonald, vice president of business development for Hypertronics Corp. “In the early design stage, we work directly with the manufacturer’s engineers to establish material selection, footprint specifications, and military standards for the product. Then our in-house engineers design a unique configuration that meets the technical specifications for that application and optimize the system.”

Often custom designs become a global, multi-country effort, such as in this case, where Hypertac Ltd., London, England, provided technical expertise during the development stage. “Being a part of Smiths, a global company gives us a wide range of expertise to tap into during the product development phase,” adds MacDonald. “While we offer many standard products, we specialize in the ability to create highly customized solutions tailored to fulfill the customers unique design challenges.” In the case of the design for the MGV, TDS, there were also multiple teams of engineers who all contributed to the design.  Expertise in working with large-scale design operations from prototype to final production is essential for a manufacturer to succeed in designing custom products.

Hypertronics’ Hypertac advanced wire basket socket contact system is distinguished by its unique design. The shape of the contact sleeve is formed by wires strung at an angle to the socket’s axis. When the pin is inserted into this sleeve, the wires stretch around it, providing a number of linear contact paths, therefore extending the contact area around the pin to 360 degrees. The low mass and resultant low inertia of the wires enable them to withstand the most abrupt or extreme excursions of the pin without loss of contact—a critical factor for ensuring electrical integrity in harsh environments and demanding applications.

As new technologies like electric engines emerge, it affects all of the components and part suppliers who interface with the manufacturers. “A large part of our business is in custom products, across all industries, including medical, where unique system configurations and form factors are often required,” adds MacDonald. Technology agreements are often established to ensure customer privilege. Custom designs allow the manufacturer to create the model best suited for their design. To offer customers the opportunity to design products themselves, Hypertronics provides their 3D configurator on their website, but customers are always welcome to work directly with their in-house design engineers.

Features/Benefits of Electric Engines

• Increased power for integration of high-efficiency electric drives, sensors, and computing systems

• Exportable electric power that reduces logistics burden of towed generators

• Enhanced low-speed maneuverability

• Smaller overall vehicle profile for concealment

• Low acoustic signature and quiet ride

• Embedded diagnostics/prognostics permitting maintainers to directly determine the source of faults and advanced planning for unscheduled maintenance

• Designed to produce high amounts of electrical power—equivalent to the demand of 300 typical American homes and more than 10 times that provided by a current force vehicle. There is sufficient electric power to enable the use of future high-power technologies.

• Electric engines also make it easier for fuel sharing, which helps greatly with logistics.

Susan Benson is the BAE business manager for connector manufacturer, Hypertronics. Email Susan at susan.benson@hypertronics.com. 

For more information:
http://asc.army.mil/docs/pubs/alt/2007/4_OctNovDec/articles/36_Army_
Transitions_Hybrid_Electric_Technology_to_FCS_Manned_Ground_Vehicles_200710.pdf.
http://www.army-guide.com/eng/article/article.php?forumID=783
http://findarticles.com/p/articles/mi_m0FZX/is_12_73/ai_n21175774