Volvo has begun field trials of a new parallel hybrid refuse collection truck out in Gothenburg, Sweden, and plans volume production in around two years’ time. The 26-tonne FE series 6×2 rigid is fitted with diesel and electric power sources and carries a Norba waste compactor body.

Volvo claims this to be an “environmental and carbon-neutral transport”, reducing emissions and cutting noise pollution. Intended primarily for urban collection and distribution duties, the FE hybrid can also run on biofuel and improves on previous prototypes by eliminating the payload penalty incurred by on board batteries by using a lighter lithium-ion type.

Volvo says this technology is more reliable than natural gas/diesel dual fuel vehicles and cites potential fuel savings of 15-20% for distribution work and 15-30% for refuse collection. The FE hybrid uses electric power to start and accelerate to 20km/h – attaining momentum is a major part of fuel consumption. Also for start/stop work, shorts periods of idling and loading/unloading.

Less idle on the street

During electrical operation the diesel unit stops completely – a particular necessity in Sweden where excessive engine idling is illegal. Because electric power has extremely good low speed torque characteristics, a smaller and lighter diesel engine than is usual at this GVW is fitted. Diesel propulsion is better suited to higher and constant speeds – for example, main road running to and from a depot.

The driveline system allows energy to be recovered from braking and the body can be charged from the chassis engine in emergency. Volvo says a hybrid design is required because batteries of the size necessary to run such a lorry on electrics alone couldn’t be carried by two trucks!

Norba – part of the Oshkosh group – built the 8.5-tonne payload body, designed for stand-alone operation and operated by an electric engine fuelled by batteries charged from cheap off-peak power supplies. Norba claims that the stand-alone system has zero CO2 emissions and a 20% fuel saving when used with a conventional chassis, potentially more with this parallel hybrid. Electricity powers the tailgate, compacter and bin lifting mechanisms, the motor’s load sensing using no more energy than necessary.

Waste operator Renova, a leading waste and recycling company in western Sweden, is trialling the truck. Renova operates 200 heavy vehicles, employs 800 people and collected 70,000 tones of waste last year. The company says that because refuse trucks are stationary 60-70% of time, parallel hybrid technology is ideally suited to quiet and smooth operation in urban and residential areas. Renova charges the body batteries with ‘green’ electricity and claims that dual diesel/electric operation reduces overall emissions by up to 30%.

Other operating issues are less certain at this stage, but potential buyers will be keen to assess likely whole life costs, and especially the question of residual values. Battery life on the FE chassis will depend in part on the type of use while early indications are the Norba body batteries will last at least five years.

Pricing structure under review

Volvo reckons it is “too early to say” on pricing for EU and US markets, but this may depend on buyer take-up, economies of production scale and the reduction of unit cost. Permissive legislation is unlikely to encourage purchase if there is a price premium and thus a competitive advantage in conventional technology.

Industry sources in Sweden say enforced emission zone legislation by governments to provide a level playing field coupled with incentives – the Swedish energy authority provided financial support to the hybrid project – is the best way to promote adoption of low carbon footprint vehicles.

Another potential area of difficulty is the length of charging time for the body batteries (up to 15 hours). This could preclude double-shifting and capital optimisation. Regarding reliability, operating experience so far is encouraging, but Volvo points out extensive training requirements. These could form part of forthcoming compulsory driver CPCs, beginning in 2009. For workshop staff the driveline is complex and batteries potentially dangerous if mishandled.

Silent safety concerns

The hybrid’s almost completely silent operation when electrically powered has safety implications for pedestrians who may not hear it approach. The Renova truck viewed at Volvo’s Gothenburg factory had safety cameras at front, rear and on both sides. The chassis can be produced in hook and skip-loader versions and Volvo are also applying the technology to buses, where it claims potential fuel savings of 20-50% and the low emissions suit it to school transport.

Dave Young is a freelance journalist

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