|Scania truck with a pantograph on the roof (“trolley-truck”) . Click to enlarge.|
Scania and Siemens have entered into a partnership which involves the integration of Siemens’ trolley-assist technology with Scania’s expertise in the electrification of powertrains in trucks and buses.
Scania has for a long time explored the possibilities of electrifying the powertrain in buses and trucks, while Siemens has developed trolley-assist systems for heavy duty trucks and is selling its SIMINE trolley-assist system for mining trucks to that industry. At EVS26 in Los Angeles in 2012, Siemens described its ‘eHighway of the Future’ concept for the electrification of on-road commercial trucks and select highway lanes via overhead electrified wires. (Earlier post.)
Full-scale demonstration of electrified road sections can quickly become a reality through this partnership. Fuel savings made possible by electrification are huge, and this project is a foundation stone for fossil-free road transport.—Henrik Henriksson, Executive Vice President and head of Scania’s sales and marketing
Scania’s powertrain technology with a hybrid powertrain can be supplemented by electrical transmission through a line in the air (conduction) or powered through the road surface (induction), thus becoming completely electrically powered on electrified road sections.
The eHighway. Siemens’ eHighway concept for the electrification of road-freight traffic has three core components:
- Diesel-electric hybrid technology
- Power supply via catenary lines and regenerative braking
- Intelligently controllable pantograph for energy transmission
In normal operation, eHighway HGVs draw electric energy from a catenary system using an adaptive pantograph to establish contact with the overhead wire. Wherever there is no overhead line, the eHighway HGVs automatically switch over to their diesel-hybrid drive system. This means that they can be used just as flexibly and universally as conventional HGVs.
The catenary systems are designed as two-pole systems for two-way electricity transmission (infeed and outfeed); unlike railway technology, the current return circuit cannot flow via the road. The overhead wire is fed from a container substation. The substation used at Siemens’ testing site is equipped with:
- Medium-voltage DC switching system
- Power transformer
- Rectifier 12-diode array
- Controlled inverter (for the feedback of the electric energy generated by the vehicles’ regenerative braking)
An intelligent pantograph is used for direct transmission of electric power from the overhead wire to the eHighway heavy-duty truck. The actively controllable pantograph can be easily connected to and disconnected from the overhead line at speeds of up to 90 km/h (56 mph). Depending on operating mode, connection is made either automatically or manually at the push of a button.
The pantograph automatically compensates for any shifts in position within the lane. Moreover, the mobility of the pantograph minimizes the risk of selective wear on the current collector, substantially extending its useful life.
(In the mining truck application, the catenary is installed only on the uphill portion leading to the unloading zone; in the unloading zone, on the way down, and in the loading zone, the win due to the save of fuel or the increase in speed would be negligible.)
Siemens’ e-Highway technology is being tested in Germany, with pilot projects planned for the ports of Los Angeles and Long Beach to connect to cargo centers.