VEHICLE POWER REQUIREMENTS REACH CRITICAL LEVELS
By Julian Nettlefold
One of the core drawbacks with modern military vehicles; is their ability to supply adequate electrical power at the right times, with an ever increasing load demand. With limited current generation often possible (for example from relatively small vehicle alternators), it’s absolutely critical that power is distributed correctly and stored effectively so that it’s available when required.
Ricardo makes this point in their research. ‘The maturity of hybrid systems and technologies are ahead of expectations. However, system cost reduction is a critical area of activity. This is underway within the civilian automotive sector. This learning is being carried over indirectly to military vehicles through manufacturing and technology improvements developed for COTS systems. This implies that over the next five years, truly competitive and robust hybrid systems can be made available to the defence sector. These vehicles will bring significant benefits to their roles in the ever-changing military landscape.’
In this feature we review new technologies developed by a number of manufacturers to overcome these problems.
DRS Test and Energy Management
“The added power requirements caused by the addition of complex C4I, IED-defeat and EO systems on today’s battlefields have reached critical levels,” Gary Smith, VP & General Manager of DRS Test & Energy Management Inc. told BATTLESPACE at this year’s AUSA. “We know of one particular vehicle type which actually experiences brown-outs during combat when all its systems are in use.”
There are a number of key programs being initiated in the USA to meet this challenge for legacy and new vehicle fleets. Both the Joint Light Tactical Vehicle (JLTV), in the USA, and the Operational Utility Vehicle System (OUVS), in the U.K., have mandated an on-board generating requirement of 30kW of 120/208V (in the USA), 3-phase utility-grade power.
Toward this end the Navy’s Office of Naval Research awarded the On-Board Vehicle Power Program (OBVP) to DRS Test & Energy Management Inc. DRS offered a combination of a 30Kw generator embedded within the bell housing of the Marine Corps M1123 HMMWV’s existing transmission thus saving space and minimizing the impact of this generating capability to the existing vehicle design. Prototype hardware has already been built and extensively tested in DRS’s System Integration Laboratory (SIL). The equipment has now been installed in the required M1123 HMMWV where it will continue to be tested as a fully integrated system. The specification requires the system to generate a total of 30 kWatts of exportable electric power while the vehicle is stationary and 11Kw while the vehicle is moving (power is restricted due to engine capability and mobility requirements). The ONR requirement also stipulates that the unit must provide either AC and DC power for specific missions. One of the key applications of the system, also recognized by the U.K. MoD, was the system’s ability to provide battery charging for tactical radio batteries and soldiers.
DRS displayed its transmission embedded solution at this year’s AUSA which generated great interest. The solution provided by DRS offers:
* Flexibility. The system can be forward-fit into new products such as MRAP, JLTV and OUVS or retrofit into existing HMMWV and Land Rover-type products.
* Reliability. The DRS solution provides the embedded generator design with no extension in overall driveline length. This is a very important feature when retrofitting existing vehicles. Mounted totally within the stock transmission envelope, it is possible to integrate the 30 kWatt generation capability by simply removing the existing transmission and replacing it with a modified unit. Power management and conversion electronic LRU’s can then be mounted in convenient locations around the vehicle. Installation of the equipment does not impede the operation o