The idea behind the Energy-efficiency-competitions in which the TUfast Eco Team competes in, is best described as follows:
Travel a certain distance within a certain amount of time
and use as little energy as possible, doing so.
The regulations further outline this principle. Specific rules determine the distance, as well as the time, and the average velocity, in addition to describing an obligatory size of the vehicle, power source and security measures.
Until now, the Eco Team has participated in the Shell Eco-marathon and in the Solar Race Region de Murcia and plans to attend other competitions in the future.
The Shell Eco-marathon is an international competition focused on long term mobility, giving student-run teams from around the world the possibility to design vehicles centered around energy-efficiency. It dates back to 1939, when Shell-employees started the first race, which lead to three individual competitions today, being carried out in America, Europe, and since 2011, in Asia.
Within the event, the organizers differentiate between the Prototype and the Urban Concept categories. Whilst the prototype cars are built around the lowest possible energy-consumption the Urban Concept vehicles have to have road traffic capabilities up to a certain degree.
Furthermore the vehicles are split up into groups according to the propulsion methods as follows: In addition to the Internal Combustion Engine and the Electric Propulsion class, the latter is divided into the categories Fuel Cell Powered and Battery Electric, according to the specific energy source.
After a technical inspection, the predominant evaluation of the energy efficiency of the cars is calculated in kilometers per kilo-watt-hour. The vehicle is supposed to travel as far as 16,3 km within a time limit of 39 minutes, carrying a driver weighing at least 50 kg. This results in a minimal average speed of 25 km/h. On top of this, there are several Off-Track-Awards, through which a jury honors teams for excellent work concerning security-concepts, team-marketing, technological innovation, and many more. Teams can enter a maximum of 3 of the before-mentioned categories.
Our first entry in a Shell Eco-marathon took place at the Lausitzring-racetrack in Germany, which we attended with our first vehicle-construction, the H-TU 11. Despite initial problems and no official run, we were able to present a considerably light vehicle.
During the following year, several changes took place. On the one Hand, we had changed our propulsion method from hydrogen fuel cell to battery power, and on the other, the competition didn’t take place at a race track, but rather in Rotterdam, Netherlands, for the first time.
With our completely renewed vehicle, we placed 4th, with an outstanding 570 km/kWh – the equivalent of 5000 km per Liter Gasoline.
In May 2013 the Shell Eco-marathon Europe took place in Rotterdam, once again. By a change in the regulations the former two categories “Solar”, and “Battery-Electric” were combined. We were now able to integrate solar cells with a surface limited to 0,17 m2, in addition to our lithium-ion battery, and therefore increase the optimal range of our prototype. Changes to the electronics and control system, as well as modifications to the running gear and the bearings further improved the performance.
After an exciting competition with a several setbacks, we placed 2nd, reaching a mark of 958 km/kWh, which translates into a distance exceeding 8400 km per liter.
This success marked the last competition for our prototype eLi 12+, which would be replaced by an all new design in late 2013, the eLi14.
SOLAR RACE Región de Murcia
The SOLAR RACE Región de Murcia is a Spanish event, which is attended by students, who develop energy-efficient vehicles with alternative concepts of propulsion.
The vehicles are split up into Experimental Vehicles and Street Vehicles, much like in the context of the Shell Eco-marathon. Common concepts competing within separate classes are bio-fuelled, hydrogen, solar-powered, and electrical plug-in vehicles.
Within the environment of this competition, the vehicles have to complete a series of at last three runs over a distance of 3.479 km at the Cartagena Speed Circuit at a minimal average speed of 25 km/h.
The mentioned track is more complicated than the Shell Eco-marathon-track, because the element of descending and ascending road is added. This is demanding for our vehicle, having been designed for the flat trac in Rotterdam, but with small adaptions and a new driving-strategy, it is ready for the contest.
At the Murcia SOLAR RACE 2012 we reached an average energy-consumption of 1.917 Wh/km or 522 km/kW which resulted in a placement as 3rd. In addition, the integrated construction of our eLi 12+ rear axle was even awarded with the Technical Innovation Award.