Electric power from the roadway for vehicle operations offers promising opportunities. With conductive electrical transmission through overhead lines or induction through the road surface, vehicles can be completely electrically powered on electrified road sections.
Scania has since the 1980s explored the possibilities of electrifying the powertrain in buses and trucks. Inductive and conductive means of energy transfer offer two exciting future technologies that are presently being tested.
Scania is presently testing two technologies in this field: Scania’s powertrain technology with a hybrid powertrain can be supplemented by conductive electrical transmission through overhead lines, or powered through the road surface using induction, and thus become completely electrically powered on electrified road sections.
In conductivity, Scania and Siemens are operating trials with electrically powered trucks equipped with a pantograph power collector mounted on the frame behind the cab. The truck receives power from overhead lines similar to trains and trams. With this collaboration, Sweden may become the world’s first country with electrified trucks and roads for commercial use.
Connects in motion
Initially, tests will be carried out to ensure satisfactory contact between the pantograph unit and the overhead wires. Unlike trolleybuses, the truck can connect and disconnect to the overhead wires while in motion. The pantograph is as wide as the truck, 2.6 metres, to ensure uninterrupted contact with the overhead wires also when the driver adjusts the vehicle’s position in the lane.
Tests of the truck with the power electrification system as a whole are now being conducted on Siemens’s two-kilometre long test track in Gross Dölln outside Berlin.
“Systems with overhead lines are especially suitable in regular transport routes from point to point, such as between steel mills and ports and between mines and processing plants,” says Christer Thorén at Scania’s Hybrid Systems Development Department.
Power from roads
In parallel, Scania has teamed up Bombardier to test wireless inductive electric charging from roads. Trials with this new technology are presently being conducted at Bombardier’s test facility in Mannheim, Germany. Inductive energy transfer can be an especially appealing solution in cities as a more convenient alternative to trolleybuses and trams.
The test truck has been equipped with a 2×1-metre electric power pickup under the truck, a large power collector that receives electric energy. Approximately 200 kW power is transferred across an air gap of up to 100 mm between the road and truck. In initial tests, Scania primarily seeks to determine the amount of energy losses and how they vary according the vehicle’s position and distance to the road surface. What is the greatest possible distance between the road and pickup and how much can the vehicle deviate from the road centre without incurring energy losses?
Sensors activate energy transfer
Under the truck there are sensors that activate energy transfer from the road. This occurs in close proximity to the approaching vehicle and the energy supply is “turned off” when other traffic and pedestrians are on the road.
These new electrification technologies are being developed as integral parts of Scania’s modular system with standardised interfaces and a limited amount of components that offer customers a wide choice of tailored vehicles. Scania thereby ensures that also its electrified vehicles will be cost-effective, versatile and easily handled and maintained in workshops.