Power recycling 07 December 2011

BAE Systems launched its parallel hybrid truck with Denis Eagle at the RWM exhibition. Brian Tinham talked to the developers

RCV (refuse collection vehicles) specialist Dennis Eagle is shipping its first diesel-electric hybrid truck, powered by BAE Systems' new parallel hybrid powertrain. The truck, seen for the first time at October's RWM (Recycling Waste Management) show, at the NEC, is going to an unnamed local authority – one of Dennis Eagle's existing customers – on full fleet road trials.

This vehicle is based on a Dennis Eagle Elite 2 chassis, with a 6x2 rear steer configuration and Olympus 21 smooth body. It is powered by a 300bhp Volvo D7F Euro 5 (and EEV – enhanced environmentally friendly vehicle) engine, with BAE Systems' new clutch and 'electric machine' (motor, electronic controls and batteries) bolted on inline, and matched to a Caterpillar fully automatic transmission.

Andy Graves, technical sales engineer with Dennis Eagle, makes the point that the new hybrid power plant does not impact its existing chassis design – merely requiring movement of front-end cross members to accommodate its slightly greater length. He also explains that the entire unit, including Li-Ion batteries, adds just 350kg to the overall vehicle weight – which, although a factor on the 26-tonner, he sees as more than acceptable for RCV duty cycles.

Most important, Graves insists that, with a price tag for the truck up some £30,000—40,000 (around 20%), compared to Dennis Eagle's conventional equivalent truck, payback for local authority fleet mangers should be within four to five years. That estimate is based on claimed 20—30% fuel savings, on the urban cycle – in line with development work carried out by Dennis Eagle several years ago with Warwick University.

Given a typical seven- to nine-year fleet replacement cycle, that timeframe sounds feasible, and it appears significantly better than many other parallel hybrid truck manufacturers have so far been predicting. Further, assuming success and rising production volumes – which is likely, given Dennis Eagle's claimed high level of interest in the initial vehicle – this current additional capital cost should fall markedly and quite soon.

In fairness, it needs to: Dennis Eagle's existing Fuel Saver pack – which involves conventional diesel RCVs with transmission software changes, better hydraulics and re-optimised engine management – are already just £5,000 more than the standard Olympus vehicle, for example. And with compelling claims for additional fuel economy with this package, payback would be much faster than is currently possible with the hybrid.

That said, Dr Mike Mekhiche, BAE Systems director of programmes, power and energy management systems (who was responsible for the company's parallel hybrid macine), confirms that the on-cost of the hybrid powertrain will quickly result in "no more than a few percent rise in the vehicle price", compared with a traditional diesel unit. In explanation, he comments: "We are a systems house, so there are no special build costs for us." He also points out that the unit launch follows significant work on the supply chain and close co-operation with a growing partner network.

So far, Caterpillar has been named on the transmission side, while the electric motor manufacturer and traction battery developer are as-yet unnamed. BAE Systems is talking off the record of significant global partnership deals to be announced in the next few months. Meanwhile, Mekhiche also nods to the 3,500 series hybrid buses already operating successfully around the world – indicating that experience gained has shaped development this time around.

Crucially, he also observes that the new parallel diesel-electric hybrid offers three times the power and torque of the competing Eaton parallel drive unit, which drives most other truck manufacturers' hybrids to date. And Mekhiche states that it still provides "at least 30% better fuel economy at the same price".

Further, he states that the new electric machine will support anything from a 350bhp to a 650bhp diesel engine, with its 70—100kW variants – making its use in the truck sector even more convincing, and potentially opening the door way beyond RCV operations, certainly into heavy duty multi-drop applications.
"New York City, where we are currently trialling hybrid RCVs, likes to run large engines," comments Mekhiche, adding that BAE-built five trucks in Classes N2 to N3 (construction, RCV, pickup and delivery vehicles) are currently on trial in the US.

Incidentally, expect to see BAE Systems' parallel hybrid engine technology on offer from RCV bodybuilder Crane Carrier next.

Brian Tinham

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BAE Systems
Dennis Eagle Ltd

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