Fuso Canter Hybrid passes London trials halfway stage with flying colours 30 March 2010

With the UK Fuso Canter Eco Hybrid truck trials now 18 months in, and at the half way mark, Mercedes has released what it sees as encouraging results so far.

Eight London-based fleets, including Parcel force, DHL, Tesco, Ringway, Amey, TNT and John Lewis, have been involved throughout, trialling a total of 10 trucks, all 7.5 tonne gvw, but in a range of configurations from box bodies to a refrigerated box truck and tippers with loading cranes.

Together, they have clocked up more than 260,000km of 'no holds barred' driving, saving an estimated 5,000 litres of diesel and the equivalent (13 tonnes) in CO2 emissions. Impressively, all operators – whose trucks have covered distances varying from 750 to 3,000km per month – report high reliability from their vehicles, including of the hybrid-specific components.

Fumio Akikawa, head of Daimler's Global Hybrid Centre, in Kawasaki, Japan, says the 'hybrid support rate' (the contribution from the on-board electric motors) has been consistently between 13% and 18%, although fuel economy depends on the detailed operation, in terms of distances, speed and stop/start frequency.

"So far there have been no technical issues, despite the Canter Eco Hybrids running at about twice the average speed experienced in our similar trials in Japan – and with heavier loading," says Akikawa.

He also points to data, taken regularly from all of the vehicles' ECUs across the operators, that demonstrates fairly clear correlations between hybrid support rate and average speed and stop/start frequency.

Citing Royal Mail's vehicle, he observes that it has been covering only 5—10% of its mileage with support from the electric motor, due to a high percentage of extra-urban journeys at speeds from 40—60km/h.

"In the stop-and-go traffic of inner-city London, average speed drops to around 20km/h. The support rate [share of mileage covered by the electric motor] then rises to around 15%," he says.

But he adds: "Thanks to the hybrid drive, fuel consumption rises only very moderately from around 15 l per 100km to 17 l per 100 km, despite the extremely demanding operating conditions."

Actual savings recorded across the operators vary from 3.8 to 7.9%, and Akikawa suggests that the data shows that considerable extra savings could be achieved if idling-stop technology was introduced on top of the hybrid engine/transmission.

And with idling in one case recorded at 50.8% of running time, it's not difficult to see the potential for improvement. Estimated savings for TNT, for example, are a further 5.3% from idling-stop, compared with the existing 5.7% derived from the electric motor, itself running at an efficiency of 78.9%.

The hybrid technology used is Daimler's 'P2' parallel drivetrain – in which the diesel engine and/or electric motor can provide propulsion independently. All the trucks are Canter Eco Hybrid LDs, harnessing four-cylinder, 3 litre diesel engines, rated at 107kW and 362Nm max torque at 1,700rpm, matched to automated manual transmissions – with the slimline three-phase permanent magnet electric motor (rated at 35kW max) sitting between the clutch and the gearbox.

That system picks up recuperation energy from deceleration (with the motor acting as a generator), and the trials show the value of using the exhaust brake to maximise efficiency.

"That is the best fit for the truck duties involved," insists Akikawa, also explaining that the batteries are Li-ion technology, comprising 96 cells, and delivering 346V and 5.5Ah – selected to deliver high power, rather than high capacity.

In fact, the hybrid technology switches mode – the electric motor being used to move off, with the clutch to the diesel engine disengaged (making it quiet and virtually zero emissions), while, during hard acceleration, the clutch closes and the diesel engine provides more power. When cruising, the diesel engine takes over completely – although during downhill stretches the electric motor again serves as a generator.

Despite the success of Mercedes' trials to date, hybrids today remain extremely expensive, and Akikawa concedes that, without government subsidies, they are not currently viable.

He points to improvements in fuel economy over the generations of hybrids to date, however, and the potential for globalisation. "In the future, when we reach the 'magic moment', increasing fuel efficiency and reducing system installation costs will mean that operators could get faster payback," opines Akikawa.

That said, no fewer than 1,000 Eco Canters have already been sold, across three continents, and Ian Jones, managing director of Mercedes-Benz Commercial Vehicles, suggests that part of this success is down to Mercedes' infrastructure – including its maintenance training and "very high parts availability off the shelf, throughout the dealerships".

He also alludes to the high take-up of the Vito hybrid, using similar technology, which has resulted in Mercedes taking "20% of new orders and one third of the market".

As for the future, Jones says that ongoing R&D is now set to deliver further improvements in fuel efficiency across a wide spread of operations, not least by using the results of the London trials. He suggests, for example, that higher powered electric motors will be used to deliver higher support rates and better fuel economy.

"Heavy distribution in the London area is already subject to the London LEZ [low emission zone] and congestion charging. These and similar incentives will also drive take-up of electric hybrid trucks," concludes Jones.

Author
Brian Tinham

Related Companies
Mercedes-Benz UK Ltd

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