In Europe, Scania and Siemens have devised an electrically-powered experimental truck with overhead current collectors that resemble the trolley buses of the past but with far more advanced and sophisticated controls.
Systems in the truck use a laser sensor to detect whether there are overhead cables available and then ensure that the truck follows the cables and that the connectors remain in continuous contact with the power supply.
Siemens has built a four kilometre long test track outside of Berlin, Germany. The challenge was not in the building of the overhead cables, but engineering the systems that will allow the truck to be rapidly connected to and from the power supply, for example while overtaking, when the truck is instead powered by its diesel engine.
Scania is hoping to demonstrate the truck on an iron ore mine access road in Northern Sweden once the route is fitted with overhead electrical cables. The Swedish Transport Administration has proposed that overhead cables should initially be placed along a 12 kilometre stretch of the 150 kilometre road in order to gain experience for continued development. In this instance, an overhead conductive power supply is a more realistic solution to using powered rails on the road as the project road is built on bogs and moves up and down.
“Development of our electrified vehicle has to take place on a step-by-step basis,” explained Johan Lindstrom an engineer at Hybrid Systems Development. “We are using electrified gearboxes that were developed in hybrid projects, but then a large electric motor must be added to the power-train in order to drive the 90 tonnes of payload entirely by electricity.”
“This is one of the many different projects at Scania to identify new fuel-saving future alternatives,” said Sara Bengtsson, Manager, Scania Public Affairs.