trailer world Issue Two 2012

Issue Two 2012 29 University of Bremen to look at energy recuperation in the Commercial Vehicles. mini power station Photo/Illustration:XYQOM For twelve months now, BPW has been involved in a study at the University of Bremen that aims to create a mature system for generating electricity and is intended for future deployment in BPW axles. “Ini- tially, we worked together with Bremen University to analyse the market and ascertain where the main problems are in the vehicles. This resulted in our current approach”, says Rossenbach. “To begin with, we asked: how can we recover energy in the trailer using available technol- ogy while remaining on a financially justifiable level?” Generating electricity in the deceleration phase The aim was for the research team from Bremen to manage deliberately without su- per high-tech, with the whole project geared to swift implementation. Anattempttorecoverenergyduringbrakingmanoeuvreswastherefore swiftly rejected as this proved to be not feasible. “Braking manoeuvres generate high quantities of energy in a very short period of time”, says Rossenbach.“Thebatteriesandcapacitorsneededtorecoverthisenergy are much too big. Anyway, this would entail working with water-cooled generators that weigh several hundred kilos.” It is of course absurd to fit a generator of this size to a trailer axle that weighs no more than 400 kilos. “We tried to take a strictly practical approach, which is why we are now looking at smaller quantities of energy”, explains Bernhard Rossenbach. Development work is currently focusing on a wheel 3. Intermediate storage The 100V HV battery is a Li-Ion battery with 2 kWh for storing energy. The battery has an integrated voltage transformer to convert the energy to 24V for the vehicle electric system. 4. Generators In the wheel hubs of this axle are two generators each with an output of 5 kWh and a torque of 5 Nm. The cables to the voltage transfer run through the cavity in the middle of the axle. Technology

trailer world Issue Two 2012

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