Northrop Grumman ANd Oshkosh JLTV Features Leapfrog Diesel-Electric Drive Design

The diesel-electric design intentionally excludes the large, high-voltage battery pack often found in hybrid solutions, mitigating the logistics burden of battery disposal. With the weight of the batteries removed, the vehicle can also carry more valuable payload.

by Staff Writers
Oshkosh WI (SPX) Jun 06, 2008
The Joint Light Tactical Vehicle (JLTV) family of vehicles offered by Northrop Grumman and Oshkosh features diesel-electric drive, a unique approach that provides more power, enables higher performance, provides better protection and is easier to maintain.

Company officials presented details of the team's JLTV at the National Press Club in Washington, D.C., on May 16. The JLTV will replace the Humvee for the U.S. Army and U.S. Marine Corps.

The Northrop Grumman-Oshkosh diesel-electric vehicle-propulsion approach opens the door for numerous design advances, reduces the logistics footprint, lowers life-cycle costs, and provides surplus exportable electrical power, all based on proven technology. Although no vehicles in the military's fleet use diesel-electric drive today, railroads and mining equipment have been powered by the technology for decades.

"This vehicle is of such importance that the Department of Defense wisely reached out to create an acquisition process -- including Technical Development and System Design and Development phases -- to harvest the best ideas that industry could bring to the table," said Joe Gray Taylor, vice president of Ground Combat Systems at Northrop Grumman's Mission Systems sector. "Our team had some very good ideas that enable us to leapfrog current capabilities by offering greater flexibility to cope with unexpected future combat requirements."

"Diesel-electric drive is a time-tested and proven technology -- simple in theory but complex in capability -- that allows us to meet and exceed the customer's requirements for protection, payload and performance," said John Stoddart, Oshkosh Corporation executive vice president and president, Defense Group. "What is new is the ability to take that proven technology and package it so that its vast power reserves can be exploited in very intense areas like battlefields."

Oshkosh also demonstrated the technology during relief operations in 2005 following Hurricane Katrina, powering pumps around the clock to remove millions of gallons of water from Louisiana State University Health Services Center-Charity Hospital.

Northrop Grumman and Oshkosh believe the design gives them an enormous power advantage. Noting that specifics are competitive sensitive, Taylor said: "This technology provides not only exportable power but also a great deal of power to the vehicle, which means agility, performance, and the ability to deal with payloads, such as the C4ISR systems it carries."

The design also offers more flexibility and modularity and the ability to tailor engineering solutions. Since diesel-electric power eliminates the need for a transmission and conventional drive train -- the so-called "doghouse" and drive shaft hump -- engineers can tailor and create a more spacious and efficient crew compartment with optimal armor protection.

By reducing the number of parts, the Northrop Grumman-Oshkosh JLTV reduces the likelihood of a complex mechanical failure. Fewer parts also mean less burden on maintainers, higher reliability and lower life-cycle cost.

The diesel-electric design intentionally excludes the large, high-voltage battery pack often found in hybrid solutions, mitigating the logistics burden of battery disposal. With the weight of the batteries removed, the vehicle can also carry more valuable payload.

"Because the diesel electric design itself is inherently modular, it allows for a family of vehicles made up of a small number of common modules. In practical terms, the military can modernize or repair this design far more simply than traditional designs," Stoddart said. "This design allows efficient manufacturing, crew maintenance, battle damage repair and eventual refurbishment."

Stoddart cited as examples the easy replacement of the front or rear drivetrain module if it sustains combat damage and the engine with a fuel cell if the military decides to move to new power systems. Hybrid technology -- "once it matures" -- could be integrated in the design, and the crew compartment module could readily accept new base armor and add-on armor technologies when available.

Diesel-electric powertrains are made up of a diesel engine connected to an electrical generator, which creates electricity to power an electric traction motor driving each axle to move the vehicle. The components that form this design include a high-horsepower engine, high power-capacity generator, high power-rated motor, motor controller and a power inverter, all proven technologies that have been demonstrated in military trucks.

The Defense Department is expected to decide next month which industry competitors will continue into 27-month Technology Development phase for this $40 billion program.

Northrop Grumman and Oshkosh Corporation joined forces to compete for the JLTV program on Jan. 8. If selected, Northrop Grumman will be the prime contractor and systems integrator. Oshkosh Corporation's Defense Group will be responsible for designing, engineering and manufacturing the vehicle, including the armor system.