A cooperative project involving 33 institutes at the Fraunhofer research facility is set to change the face of public transport for the better. Its combined applied technologies will come together in an AutoTram a concept that will fuse the very best of design and technology to result in a bus/tram hybrid that will have near zero emissions. Jointed in the middle the ‘bustrolley’, as it is being referred to by its developers, will combine the flexible mobility of a bus while providing the passenger capacity of a tram-type streetcar.

Its exterior appearance and capacity are merely the tip of a technologically blossoming iceberg. Every facet is being explored to make this next generation of city centre public transport versatile, reliable, safe easy to use and maintain and of course as ‘green’ as a tram can be.

The new concept vehicle will be sporting new modules for energy storage, double-layer capacitors and a whole host of other state of the art technologies, tried and tested by departments who have specialised in them for years. The trick will be to combine these ideas effectively into one concept vehicle.

From an entirely practical point the trams are required to be in constant service throughout the entire day. This presents a logistical problem for any electric vehicle, as quite a lot of time is required to recharge even the most advanced Lithium Ion batteries. Previously this process would have required the vehicle to be stationary for relatively long periods. Although this is fine for domestic, electric cars, that are used, on average, less than two hours each day and can be left on charge overnight and when people are at work; the problem with trams is that they are in near constant use. Their power systems will only have a potential recharge time that is between 30 and 60 seconds, just the time it takes for people to board and disembark. What was required was to design fast-charge docking stations positioned at the stops along the route. The trams will eventually be able to re-charge at every third to forth stop. This would still involve solving the problem of delivering 1000 amperes and 700 volts in under a minute. To achieve this they are using double layer super-capacitors or ‘supercaps’ these offer do a high power density but the problem is that they will only take up small amounts of power over such short periods. This will be enough to get them to the next docking station but what if they are delayed in traffic? The answer is to combine the ‘supercaps’ with high performance battery technology giving it the flexibility to function effectively in a city environment with all its little hold-ups.

The battery development alone constitutes some revolutionary advances. There are still measures to be taken to limit the wear on the batteries as they are being recharged and discharged. Different cells discharging at different rates can effect the life-span of the battery and a key design element is to consider the tram’s ecological footprint. By the end of its development the tram will have a fast charging, stable and long-lasting battery systems that will integrate with the ‘supercaps’ to provide seamless power supply to a vehicle in near constant running-time use.

One of the other issues is cost of setting up the infrastructure. Normally trams have tracks and cabling and this can all be expensive and problematic to install in a busy traffic laden environment. This tram will have intelligent sensors and tracking systems that will allow it to follow a white line placed along the roads and highways. This will be relatively easy to install as it does not involve digging up roads or putting in overhead cabling, making the system itself very cost effective.

It is teamwork that will help this project to a successful conclusion, the sensor systems, supercaps and battery technologies are just a few of the innovations being plowed into the tram’s design. Eventually they will combine with hyper-efficient electric motors and a transmission system that offers a new type of engine-generator coupling system that is electrically switchable. All the new technologies are focusing on one main objective to allow passengers to travel safely, economically and as free from exhaust fumes as possible. Zero will be the big number that all the contributing research groups are looking to achieve. It is hoped that once up and running of the new tram will have produce no carbon dioxide emission and will significantly cut down other pollutants.

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