Current military threats have created a tremendous requirement for mobility for successful execution of missions. Therefore military is now in a rapid transformation to become a lighter, more agile, mobile, networked and more lethal force. To become more lethal and better networked involves new weapons systems and more sophisticated electronic systems, both of which demand more DC and AC power. A vehicle automotive powertrain is designed with adequate power to deliver the vehicle’s needs. While vehicles built for the 2020s have increased power to drive the computers and electronic systems on board, and also to provide spare electrical power for other electronics, there is a limit to that power draw.
Military vehicles are often loaded with energy-hungry mission electronics, such as navigation, communications and survivability systems. On-board devices such as sensors or communication and weapon systems require a continuous power supply. Militaries have traditionally solved this by hauling larger, heavier diesel generators around on a trailer. Some equipment may use a special generator to provide electricity, but some systems, such as Threat Detection, Active Protection Systems and data communications are operating continuously, draining the vehicle’s energy reserve. In order to meet this demand, vehicle designers integrate more powerful alternators, auxiliary power units, energy generation systems and high capacity batteries to increase the energy available on board.
Vehicles typically carry two to eight batteries, which can cost US$4,000 each when life-cycle costs are accounted for. As a result of a lack of confidence in power availability, crews continuously idle their engines to ensure battery banks are charged, thus requiring frequent refuelling of their combat vehicles. While adding more power is a trivial solution, a comprehensive power management approach is likely to deliver the optimal result. Traditional vehicle electrical systems are designed for peak events, but power management systems allow power to flow differently during acceleration, road march, attack/defend mode, and braking. When the vehicle is stationary, power can be provided from an energy storage system to operate in pure electric ‘stealth mode’, also known as ‘silent watch’, with the engine off to reduce the vehicle’s noise and heat signature.
As each combat platform uses different methods of electrical power generation, distribution, conversion, and storage, BAE Systems, for example, approaches a vehicle energy management design with the specific power system architecture of the platform. For example, mechanical accessory packages are implemented differently on each platform. Traditional mechanical auxiliary subsystems, whose unco-ordinated and continuous operations are inherently inefficient, generate waste heat that must be exhausted through already burdened cooling systems. Electrifying and managing power-hungry mechanical accessories, such as pumps and cooling fans, can contribute to heat reduction and fuel saving. Addressing the system, and finding the optimal level of integration, ensures that energy loss and inefficiency are minimised.
OBVP refers to providing an alternative source of AC power on the battlefield that is generated from the vehicle itself which can solve many technical and logistical problems. For example, by providing the HMMWV with a 10 -KW OBVP system supplying continuous AC power, the need to trailer a diesel generator is reduced significantly. In addition, now the HMMWV can negotiate terrain that it could not previously engage while towing a generator, thus leading back to the more agile concept. The OBVP system is compatible with the Department of Defense’s objective of evolving from conducting operations from forward positioned bases, common in Iraq and Afghanistan, to an expeditionary mindset where units rapidly deploy to austere environments and are immediately prepared to begin operations.
The OBVP systems also have potential uses off the battlefield. State and local emergency response agencies could use such systems during natural disasters to power emergency shelters, for example. When daisy chained, such systems could power hospitals, senior citizen homes, water purification plants or other vital infrastructure.
Leonardo DRS experts are focusing on providing power to military vehicles, which increasingly are under pressure not only to support power-hungry on-board systems like high-performance computing, laser weapons, and silent operations, but also to serve as mobile power stations to run deployed command posts and power batteries for the warfighter’s wearable electronics.
DRS’s Aguirre claims that traditional vehicle power systems built around alternators simply are not up to the task. “We need to generate more efficient power than we do today, and that’s where the DOD [U.S. Department of Defense] has not focused enough attention. Every combat vehicle seems to be suffering from what I call a power gap. If we look at MRAPs and Bradleys, we are looking at bigger alternators to generate electrical power, and it’s still not enough.”
As an example, Aguirre points to directed-energy weapons, such as high-energy lasers, high-power microwaves, and similar systems that military planners will depend on to defend forward-deployed warfighters from enemy unmanned aerial vehicles (UAVs), rockets, mortars, artillery shells, and low-flying aircraft like helicopters. Directed-energy systems “are not that efficient today, so that translates into power loss,” Aguirre says. “We need at least 90 kilowatts of power for a counter-UAV laser. So where do we get that power on a combat vehicle? Alternators simply are not powerful enough, and if a belt breaks, we are out of power.” Towing gasoline-powered generators into the field isn’t always a viable alternative because they limit a vehicle’s speed and maneuverability.
“Every vehicle has an engine that spins something,” Aguirre explains. “There is a lot of power being transferred from the engine to the transmission. If I can convert that power into electrical energy, there is a lot of potential to change the dynamic. It might not require an alternator.”
Leonardo DRS has designed a specialised power system known as TITAN On-board Vehicle Power (OBVP). As the permanent magnet generating system is integrated within the transmission, OBVP turns the power train into an efficient electricity generator delivering more energy than a standard vehicle alternator without significant load increase. OBVP is designed to support the increased demand for electricity in command vehicles and command posts, missile launchers and high-energy weapon carriers.
The DRS OBVP system can generate upwards of 120 kilowatts of power inside the transmission, which Aguirre says could power a medium-to-large-size pharmacy, a nursing home, a medical facility, or even a residential neighborhood. The system can generate as much as 55 kilowatts of power when the vehicle is moving, and as much as 120 kilowatts when the vehicle is stationary.
“A group of vehicles could start their own power grid in a forward-deployed area, share power with other vehicles, and as the military logistics tail catches up could go back to their primary missions,” Aguirre says. “I’m hopeful that within the next five to seven years the OBVP could deployed widely.” The system’s benefits could extend beyond military operations to humanitarian assistance and disaster recovery, he says.
Allison broadens onboard electrical power development for army
DRS partners with Allison Transmission Inc. in Indianapolis to provide the OBVP system, which is seeing limited deployment on military vehicles like the U.S. Army’s Terminal High Altitude Area Defense (THAAD) missile battery command and control, and launcher vehicle, which is a version of the Heavy Expanded Mobility Tactical Truck (HEMTT) from Oshkosh Defense in Oshkosh, Wis.
Allison and Leonardo DRS are exploring OBVP uses throughout the full range of wheeled and tracked vehicles. Allison Transmission, in partnership with Leonardo DRS is developing On-Board Vehicle Power (OBVP) systems for the 44-ton Oshkosh Heavy Expanded Mobility Tactical Truck (HEMTT) equipped with Terminal High Altitude Area Defense (THAAD) anti-ballistic missile launchers.
A generator will be fully integrated within the housing of an Allison 4500 Specialty Series™ transmission and installed into the HEMTT’s driveline in its original configuration, without affecting vehicle functionality. In fact, the OBVP will improve agility and reduce logistics costs because the vehicle will no longer have to be equipped with a separate generator. In addition, the OBVP is intended to improve mean time between mission failures.
The electrical loads on vehicles have increased dramatically. It’s getting more and more difficult to produce that level of power with an engine-driven generator/alternator. Allison is proud to be partnered with Leonardo DRS in the development of OBVP technology that will result in innovative and adaptive propulsion solutions that provide capabilities not available today,” said Dana Pittard, Major General (Ret.) and vice president for defense programs at Allison.
TITAN ON-BOARD VEHICLE POWER (OBVP)
TITAN On-Board Vehicle Power (OBVP) vehicles can support a variety of military missions: Mobile Command Posts (MCP), Tactical Operation Centers (TOC), Combat Operations Center (COC), Company Tactical Command Post (TAC), or may be used to power a variety of emergency facilities such as field hospitals, triage units, fueling stations, or any other component requiring clean, reliable power.
The TITAN OBVP system has been designed, tested, and delivered to address the military’s increasing need for more electrical power to support missions. OBVP also reduces the logistical complexity by significantly reducing or eliminating the need for towed or tunnel generator requirements.
TITAN equipped vehicles greatly improve the operational adaptability of the advancing forces by providing mobile, expeditionary power when speed, range, agility, and flexibility are critical to mission success. Whether it’s providing power to a tactical security checkpoint in Afghanistan or emergency power to critical facilities such as medical care or fuel and food distribution centers in time of Humanitarian need, Leonardo DRS’ TITAN OBVP solutions provides Power- Anywhere, Anytime!
References and Resources also include: