Fuel is one of the top three logistics drivers on the battlefield, along with water and ammunition. Fuel powers the vehicles that mobilize troops and keep communications and supply chains running, and is used in the generators that power forward operating bases. Transporting fuel to the front lines, however, has become extremely costly in both lives and dollars.

The Oshkosh Defense ProPulse hybrid-electric drive technology powers the the Mobile Land- Based Phalanx Weapon System (MLPWS), which consists of the Oshkosh HEMTT A3 equipped with Raytheon’s point-defense weapon for detecting and destroying incoming aerial threats.

In Afghanistan, coalition fuel convoys have increasingly become targets for improvised explosive devices (IED) and other attacks. These convoys — many of which are already hauling fuel in from other countries — must travel hundreds of miles across Afghanistan’s unimproved road networks to reach allied forces scattered throughout the country. Even without enemy threats, fuel convoys face the ever-present challenge of traversing severe terrain and overcoming adverse weather conditions, particularly in mountainous regions. The deadly attacks have only made the jobs of the fuel transporters more difficult, creating the need to provide additional armed escorts to accompany them.

The existing levels of fuel usage also have become a financial concern, particularly as Department of Defense (DoD) leadership looks at cuts in defense spending. The 2009 Deloitte study “Energy Security — America’s Best Defense” reports that the military may pay $2 to $3 per gallon of fuel, but that cost jumps to about $15 per gallon once the fuel has reached its final destination. The Pentagon has said, in some cases, the fully burdened cost of fuel in theater can even be as much as $400 per gallon. Additionally, the DoD uses about 4.6 billion gallons of fuel annually, according to a Brookings Institution research paper on the DoD’s energy strategy.

ProPulse Diesel-Electric Solution

During Energy Awareness Month in October 2010, the DoD held the Pentagon Energy Security Event to promote its energy-security initiatives. Oshkosh Defense was among those invited to participate because of the company’s progress in, and commitment to, seeking new and innovative ways to reduce energy demands in the field. Oshkosh’s display at the Pentagon included a promising development in this area, called the Oshkosh ProPulse® diesel-electric hybrid drive system.

The ProPulse technology addresses energy security by improving the fuel efficiency of military tactical wheeled vehicles by up to 20 percent while also providing as much as 120 kW of exportable military-grade power — enough to power a command center, airfield, or city block.

The Oshkosh Defense MTVR with onboard vehicle power (OBVP) can export 120 kW of military grade power while stationary and 21 kW while on the move.

The technology uses a diesel engine to power an onboard electric generator, which delivers power directly to motor-drive axles. This eliminates the need for various vehicle components, including the automatic transmission, transfer case, torque converter and drive shafts, resulting in a vehicle that is lighter and easier to maintain, with much more flexibility in design configuration because of the ease of packaging ProPulse. In place of maintenance-prone batteries, the ProPulse system uses rechargeable ultracapacitors for energy storage. Ultracapacitors can charge and discharge power in seconds, allowing the vehicle to quickly store and release energy, and they can be charged millions of times.

Expanding Army Fleet Capabilities

At the Pentagon Energy and Security Event, Oshkosh displayed the A3 configuration of our Heavy Expanded Mobility Tactical Truck (HEMTT). The HEMTT is a heavy-payload tactical truck that Oshkosh produces for the U.S. Army and National Guard. The original vehicle, introduced in 1985, hauls payloads weighing up to 13 tons and is produced in multiple variants to transport a wide variety of cargo and weapon systems. The A3 is a nonproduction vehicle configuration that is outfitted with ProPulse technology. Incorporation of the ProPulse technology delivers two significant energy benefits to the U.S. Army: exportable power and improved fuel economy.

Delivering exportable vehicle power to the U.S. Army would result in leaner and more capable fleets, and help minimize reliance on fuel-based generators. That would mean less support equipment to haul around on the battlefield and fewer trailer-mounted generators. And while the HEMTT A3’s 100 kW of exportable power could be a valuable addition to support Army forces on forward operating bases and other locations, this integration of onboard energy also allows the vehicle to mobilize and power equipment such as radar systems, IED-suppression technologies, and weapon systems.

An example is the Mobile Land-based Phalanx Weapon System (MLPWS), which is a HEMTT A3 integrated with Raytheon’s point-defense weapon for detecting and destroying incoming aerial threats. The Army currently has fielded a number of trailer-mounted Phalanx that are unable to negotiate some terrain. The MLPWS solves that problem with the weapon, power generation, and transporter integrated into a single, mobile system. The MLPWS underwent a proof-of-concept demonstration in September 2010 and met all demonstration objectives.

In addition to its exportable-energy capabilities, the HEMTT A3 delivers 20 percent improved fuel economy to the HEMTT platform. The vehicle’s diesel engine continuously runs at optimal rpm, which is significantly more efficient than the maximum rpm usually needed for highway speeds and full payloads. The HEMTT A3 also is up to 5,000 pounds lighter than the vehicle’s current configuration due to the packaging benefits ProPulse allows for. These added benefits are provided without impacting the HEMTT capabilities that soldiers in the field rely on today.

The HEMTT A3 provides other benefits as well. Design improvements made as a result of the integration of the ProPulse system include an Enhanced Load Handling System (ELHS), which allows the HEMTT A3 to load and unload flatrack-mounted cargo from a C-130 plane without the need for additional equipment, such as a K-loader.

The Oshkosh Command Zone multiplexed electronics system provides controls for the exportable power on the MTVR with onboard vehicle power (OBVP).

Another example of Oshkosh’s energy-efficient capabilities is the Renewable Energy Mission Module™ (REMM), which Oshkosh is developing under license from Natural Power Concepts. The REMM uses a folding blade wind turbine and photovoltaic solar panels to deliver renewable power for forward operating bases, expeditionary missions, and humanitarian and disaster-relief missions in even the most remote and austere locations. The system also is designed to integrate additional capabilities, including water purification and desalination systems. Designed for rapid deployment, the REMM folds for transport, slides into a 20-foot ISO container, and is easily loaded and unloaded using the HEMTT A3’s ELHS. The A3’s export-power capability provides even greater power-generation flexibility and energy potential in concert with the REMM.

Marine Corps Medium-Fleet Application

The ProPulse diesel-electric drive technology also is being used on the Marine Corps’ Medium Tactical Vehicle Replacement (MTVR) in the form of onboard vehicle power (OBVP) kits for testing and evaluation. The MTVR is a primary mover of troops, materials and equipment for the Marine Corps, hauling up to 15-ton payloads and designed for extensive off-road use.

When equipped with the kits, the MTVR with OBVP will deliver 120 kW of military-grade export power while stationary and 21 kW of military-grade power while on the move. This work is the result of successful OBVP technology-development efforts between Oshkosh Defense and the Office of Naval Research (ONR). The installation of the low-rate initial production (LRIP) kits is expected to be completed in January 2012, and the Marine Corps' evaluation and testing is expected to begin in March 2012.

Looking Down the Road

The Oshkosh Defense MTVR with onboard vehicle power can support critical equipment such as IED-suppression technologies and radar systems.

Beyond the ongoing military testing and evaluation of the ProPulse system, Oshkosh also continues to test the technology using its own time and resources. Most recently, Oshkosh installed it on a prototype named the Light Concept Tactical Vehicle (LCTV). Oshkosh designed the LCTV to incorporate and test next-generation technologies on a light vehicle. The LCTV has been put through various off-road performance and durability tests, and also competed in the 43rd Annual Tecate SCORE Baja 1000 race, which took place in November 2010 in Mexico. Boosted by the ProPulse technology, the LCTV successfully finished the race and reached speeds of up to nearly 80 miles per hour.

Regardless of what military service is using it or what vehicle it’s installed on, the ProPulse technology is designed to give all warfighters the same benefit — the ability to do more with less by increasing fleet capabilities and reducing fuel consumption. That will mean fewer fuel convoys on the road and less equipment for the armed forces to transport, ultimately opening up more resources for combat and other primary operations, offering true combat multipliers.

This article was written by Chris Yakes, Vice President of Advanced Products for Oshkosh Defense, Oshkosh, WI. For more information, Click Here 

RF & Microwave Technology Magazine

This article first appeared in the April, 2011 issue of RF & Microwave Technology Magazine.

Read more articles from this issue here.

Read more articles from the archives here.