|Layout of the I-SAM hybrid system. Click to enlarge.|
Volvo presented an update on its heavy-duty hybrid technology program in a meeting in Brussels. Volvo’s hybrid vehicles can reduce fuel consumption and therefore also emissions of greenhouse gases by about one-third, when compared with conventional diesel-powered vehicles.
In addition to a trial funded by the Swedish Energy Agency, Transport for London and Arriva will conduct field tests with Volvo hybrid double-deck buses on Route 141 in London during 2008.
The Swedish Energy Agency has given Volvo a SEK 9.8m (US$1.4 million) grant for the development and testing of hybrid technology in two vehicles in Sweden. The aim of the project is to achieve fuel savings of up to 30% and the first trucks are expected to become operational within a year. (Earlier post.)
The I-SAM (Integrated Starter, Alternator, Motor) parallel hybrid system comprises a starter motor, drive motor and alternator fit between the clutch and the I-Shift automatic transmission. It supports regenerative braking; electric launch and assist; electrification of power steering, air compressor and airconditioning; and idle avoidance.
The electric motor is used when starting off and for acceleration to about 20 kph (12 mph). At higher speeds, the diesel engine steps in and takes over while at the same time recharging the electric motor’s batteries. When the brakes are applied, the braking energy is harnessed to recharge the batteries. Electric power is utilized when the vehicle is at a standstill, in slow-moving traffic queues and during loading and unloading.
The Volvo Group is also developing hybrid technology for construction equipment such as wheel loaders, in which the fuel savings can be up to 50%.