SWEDEN: Volvo announces hybrid bus

By just-auto.com editorial team | 25 September 2008

Volvo has announced that it is launching the world's first commercially viable hybrid bus, the Volvo 7700 Hybrid.

Volvo claims the new bus delivers 30% lower fuel consumption, which means bus operators should get a payback on their investment in five to seven years.

The move is a response to demand for fuel consumption reduction and the need to reduce CO2. CO2 emissions are also 30% lower than comparable vehicles. Particulate and NOx emissions are also 40-50% lower than the diesel version of the bus.

Volvo will use parallel hybrid technology across its range of buses, trucks and construction equipment and aim to achieve economies of scale by using the technology across the group.

Volvo's hybrid concept is called I-SAM and comprises a combined start motor, electric motor, generator and an electronic control unit. I-SAM works together with a diesel engine and Volvo's acclaimed I-shift gearbox. In addition, a lithium-ion battery is used that is charged during braking via the electric motor/generator. This battery then provides energy to the electric motor for drive power.

As a parallel hybrid, the bus can be powered by the electric motor or the diesel engine independently and well as by both engines simultaneously. As a result, the bus could  be equipped with a smaller, 5-liter diesel engine compared with the 9-liter engine in the diesel version of the Volvo 7700. The bus's performance is enhanced, but fuel consumption is reduced.

"Another major benefit with Volvo's hybrid technology is that the diesel engine will be turned off at bus stops and traffic lights," says HÃ¥kan Karlsson, President of Volvo Bus Corporation. "The bus starts moving driven by the electric motor and when the bus reaches 15-20 kph, the diesel engine starts up automatically."

The bus will be on sale from 2009 and mass production will start in 2010.