New hybrid drives, energy storage and sophisticated power management systems are just some of the technologies that will be key to meeting the needs of electricity-hungry armoured vehicles operational on future battlefields.
Armoured vehicles rely on power derived from various sources to run and operate both main-vehicle electrical systems and peripheral devices and sensors, key to the overall effective operation of the vehicle. From battle management systems, internal/external communications and command and control systems, to the numerous ancillary sensors (such as low-power laser devices, night vision systems, situational awareness sensors and cameras together with the data connections that support them), all rely on an ever-ready electrical power to function. And in the future, higher powered, vehicle-mounted, directed-energy systems/weapons may have to be considered as well. So, there is no getting away from the fact that tomorrow’s battlefield will be more power-hungry than any past battlespace and the armoured vehicles operating therein will necessarily be platforms of power innovation. This will not simply be in terms of the main drives that power the vehicles themselves, but also the innovative power supply systems that will ensure every critical electrical/electronic device in place on these armoured platforms has an uninterrupted and reliable power supply. From generated power to stored power, electrical supply and management architecture will need to be able to intelligently draw on any source of power and distribute it throughout the vehicle to the systems that require it when they need it, without wasting a single amp. The new demand for electricity has pushed the limit of what is available on conventional vehicle platforms – platforms never conceived with the electrical demands of today in mind and, as a result, a fundamental design rethink has been required.
This article, therefore, focuses on the potential move away from the restrictions of the internal combustion engine and traditional driveline components, with the emergence of Hybrid Electric Drive (HED) systems. These offer credible alternatives to conventional mechanical designs, delivering technological advantages, not least of which will be increased onboard power supplies and power availability for future armoured vehicle fleets and all the power-hungry systems they will carry.
The Electrified Battlespace
Traditional vehicle power packs combine a diesel engine with a transmission for both tracked and wheeled vehicles. Electrical power is generated via alternators driven by the engine, or a power take-off from the transmission. These generally operate at 28V and are limited in their power-generation capability, a factor, which, according to QinetiQ in conversations with ESD, limits future power availability for the new defensive systems, weapons and intelligence, surveillance, target acquisition, and reconnaissance (ISTAR) systems carried on the vehicle. Hence, traditional systems are making way for the latest innovations to meet the needs of electrified battlespace and HEDs, such as the E-X-Drive electro-mechanical transmission developed by QinetiQ for tracked vehicles, by operating at higher voltages, enabling a dramatic increase in the availability of electrical power in conjunction with higher capacity energy storage solutions. The E-X-Drive weight range currently addresses vehicle designs in the 10 tonne to 80 tonne range, with demonstrations having been conducted for 18t, 30t and 80t-range platforms. QinetiQ actually conducted concept and design work with BAE Systems for an E-X-Drive variant to retrofit Bradley Fighting Vehicles in the US GCV Programme, although that programme was cancelled in early 2014.
In a hybrid electric vehicle, electric motors housed in the transmission of tracked vehicles and in the wheels of wheeled platforms, draw power from a battery or generator. However, as vehicle design constraints are more flexible than with a conventional mechanical platform, these can be situated almost anywhere on the vehicle.
QinetiQ says that it uses its own “validated modelling tool to size the battery appropriate to the use and duty cycle of the vehicle and locate the batteries flexibly to suit the vehicle architecture”. Not only does this flexibility impact and improve such things as mobility and survivability, it also improves the vehicle’s lethality by enabling it to conduct extended periods of silent watch and silent running, with no main engine, (and, therefore, minimal acoustic and thermal signatures), required to power all vehicle systems. Electrical power is also available in such scenarios for high-power requirements, including rotating the turret.
When not in silent running, the energy produced by an HED’s on-board generator can be stored and used when and where needed, perhaps delivered to the wheels for an added burst of acceleration, or, as mentioned, to power a future directed energy weapon enabling it to fire on and neutralize a threat. Regarding how an armoured vehicle using a HED applies brakes that can hold the vehicle on a substantial slope, QinetiQ eased ESD’s curiosity in relation to its E-X-Drive. Their HED has a foundation brake able to meet European heavy-vehicle, multiple-stop requirements and maintain the hold position on a 60% slope. It also has electrical regenerative braking available, depending on the battery state of charge, and this will be sufficient for most manoeuvres, or for long downhill running.
New Demands Drive Innovation
The increasing emergence and deployment of platform-borne sensors and the subsequent growing reliance on greater amounts of readily available electrical power has led QinetiQ, for one, to recognise that the full electrification of combat vehicles is essential for both wheeled and tracked platforms in the future. The company says that current technology supports the transition from purely mechanical to hybrid electric propulsion systems and that this transition offers significant benefits in vehicle architecture, with associated improvements in survivability, performance, fuel consumption and reliability. As mentioned, the ability to flexibly package and relocate elements of the driveline – those parts of the powertrain excluding the engine – and energy storage systems, radically removes the constraints associated with traditional vehicle architecture.
Possible ‘knock-on’ effects resulting from the transition to HEDs will, according to QinetiQ, include to logistics supply chain, largely due to increased fuel efficiency experienced using HEDs. This will be achieved by being able to run diesel engines at their optimum operating point on the fuel map, due to required changes in torque, changes that are supported by the vehicle batteries smoothing the demand. HED systems, mechanically simpler than traditional drivetrains, also have fewer components resulting in reduced maintenance demands, in turn leading to improved reliability and through-life support costs.
As to the power management in a hybrid system, this is more efficient and effective because all electrical automotive and integrated systems can use the same energy source and a vehicle designed with a sufficient power budget from the outset will be able to accommodate new systems and technologies, as needed, or when available.
While dependent on the platform and installed battery capacity, an example of the sort of power demands QinetiQ’s HED E-X-Drive could accommodate to operate sensors and onboard systems (such as SA, CCTV, NVG, communications, ISTAR etc,) is: a future 50 tonne tracked vehicle with an installed generation power of 800 kW and 200 kW battery capability, which could produce around 1 MW of available electrical power, if a vehicle is stationary.
Research and Development Initiatives
There are several initiatives that address HED as the future for both tracked and wheeled vehicles, including in the US, where the US Congress, as far back as 1992, initiated the ‘Electric and Hybrid Vehicle Technologies (EHV) Programme’, to serve, as it put it, “the needs of the USA’s national defence”. The defence community and government agencies realised then that electric and hybrid propulsion systems, cleaner and more efficient than conventional systems, had a great potential in terms of solving military issues relating to performance, stealth, fuel efficiency and logistics/resupply-of-diesel challenges. Over time, however, the HED’s exceptional ability to deliver substantial electrical power throughout the vehicle for a wide range and increasing number of on-board vehicle systems and sensors, as well as its ability to export power for stationary applications, has also, as with other programmes looking at this tech, been recognised by the US Programme.
As for QinetiQ’s work on HED’s in addition to customer-funded programmes the company has invested significant IRAD funds in developing HED for E-X-Drive (for tracks) and Hub Drive (for wheels). IRAD (Independent Research and Development) funding is an ‘allowable cost’ so that companies can initiate and conduct Research and Development projects of potential interest to the US Department of Defence, funds, which are then reimbursed through overhead cost rates. Looking ahead, including the evolution towards platform-borne directed energy systems, the company told ESD that “Electric drive offers the precision and the control necessary to better deliver autonomous solutions and enables the powering of high power weapon and defence systems” in the future.
Powering Directed Energy Systems
High-powered, armoured-vehicle-mounted directed energy weapon systems will, one day, likely be a standard feature of the battlefield, though one requiring a substantial power supply drawn from any armoured platform on which they are mounted. In the context of a vehicle using an HED, such a future power requirement should not be a problem. However, at this time, directed energy weapons still require more electrical energy to function than is available on a typical, traditionally-powered armoured vehicle, which is not surprising given that to fire such a weapon will require the repeated, rapid drawing of energy either from large batteries/fuel cells, or from a generator capable of rapid re-charge and energy replenishment. Hence, such weapons being used on armoured vehicles (as opposed to naval use, for instance), is still some way off. It is, nevertheless, worth knowing a little bit about how such a system operates and how it will impact power supplies on an armoured platform.
Conducting a mission effectively using a directed energy system will require highly detailed intelligence about any target and its surroundings. This is because the laser beam can and will be attenuated by the operator to ensure an optimum level of energy is used to neutralise a target. This use of an optimum amount of energy per shot will avoid the unnecessary depletion of stored energy and will also avoid potential collateral damage. Hence, detailed intelligence on a target’s structural materials and construct is essential, not only in order to identify vulnerable areas most susceptible to a strike by the weapon, but also to determine the optimum power levels needed against different enemy platforms and installation types. In time, such information and corresponding power requirements will be stored knowledge. However, the key message here is that with the other sensors, ISTAR and communications systems carried on future wheeled and tracked armoured vehicle platforms all requiring effective and reliable uninterrupted power supplies, the introduction of directed energy weapons will only become possible if it is done in tandem with the introduction of suitable novel power systems. HEDs will most certainly play a major part in delivering the power supplies aboard the armoured vehicles of the future to make all of this happen.
Tim Guest is a freelance journalist, UK Correspondent for ESD and former officer in the UK Royal Artillery.