Volvo's concept hybrid powertrain for heavy vehicles, unveiled on Friday, offers fuel savings of up to 35%, the truck maker claimed.

"We envisage opportunities to accelerate developments in commercially viable hybrids for heavy vehicles. This can be significant for both our customers and for the environment," said Volco president and CEO Leif Johansson in a statement.

The Volvo hybrid concept provides maximum fuel-saving effects on routes with frequent braking and accelerations, for example in refuse collection, city bus traffic and city distribution. Calculations indicate that fuel savings can amount up to 35%. Maintenance costs for vehicles can also be reduced through reduced wear on the braking system.

The hybrid concept is designated I-SAM and consists of a combined starter motor, drive motor and alternator, along with an electronic control unit - similar to the technology used in Honda's hybrid cars. I-SAM interacts with Volvo's I-Shift automatic gear shifting system. The batteries are recharged by the diesel engine and whenever the brakes are applied.

The electric motor is claimed to deliver smooth performance at low speeds, supplementing the diesel engine as speed rises. This allows the truck to accelerate under electric power alone and promotes lower fuel consumption, lower emissions and lower noise levels.

Additional features contribute to the lower fuel consumption.

The diesel engine can be automatically switched off when the truck stops to make deliveries, pick up loads or pauses at traffic lights. Auxiliary functions such as the servo pump and air conditioner compressor are driven electrically instead of by the diesel engine.

Efficient interaction between the two power sourcesallows the vehicle to be fitted with a smaller diesel engine without compromising on performance, Volvo claimed.

"The hybrid is a long-term and highly interesting solution for efficient and environmentally-adapted transport activities. We are aware that oil prices for our customers will rise, and therefore, all solutions that reduce fuel consumption are highly attractive", said Johansson.

"The diesel engine in our hybrid solution can also be operated using biofuels, and consequently, transport activities can be conducted without carbon dioxide emissions. This paves the way for interesting developments toward long-term sustainable transport solutions."

Volvo is also participating in the development of a new type of battery - Effpower - based on proven lead-acid technology used in start batteries in today's vehicles. Through this new technology, the power output has been doubled, while at the same time manufacturing costs for the batteries can be significantly reduced compared with alternatives on the market.

With Effpower, the cost efficiency in electrical hybrids can be further enhanced, Volvo claimed.

The new hybrid truck will undergo a wide range of tests, but the predicted it would be on sale "within a few years".

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