One team, one dream – the TUfast Eco Team succeeds in Rotterdam

For over one year we have worked hard all day and all night on eLi15. We have spent many nights in the workshop aiming for the 1stplace at the Shell Eco-marathon Europe 2015.

Of course, our success in Colomiers has given a great lift for our hopes. The result should be well known: the overall-win in the prototype category and the Grand Prix, which we have won on the track as well as 3 Off-Track Awards for design, motorization and the technical innovation.

© Marcel Van Hoorn/AP Images for Shell

 

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2015-05-22: People and Off-Track events at the Shell Eco-marathon

On day No.5 at the Shell Eco-marathon we took some time to look around on “the Ahoy” and tried to get an impression of the whole Event and realized that the Shell Eco-marathon is more than just a competition for university student teams.
The Shell Eco-marathon offers young primary students the possibility to discover different things starting from energy production to recycle processes and give a brief insight into the automotive industry, with its Off-Track events. All events cover a broad range of scientific topics and are aimed to increase the interest in technical issues and having fun in exploring something.

Starting with small experiments like building a hot-wire curcuit with clay, building a personal rubber band driven boat, play with optical illusions and laser pointer over to produce high voltage to create lightnings. Every single experiment show the students that science is not only just hard work, but having fun while exploring.

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2015-05-18: the EducEco Challenge in Colomiers, France

This year the EducEco is dated one week before the Shell Eco-marathon. This gives us the chance to drive eLi15 under competition conditions, for the first time. Due to regular test drives, the car as well as our new drivers Julia Hesse and Annkatrin Swanson were well prepared and surprised with reliability and routine.

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2015-05-12: part 3 of our part presentation: the cover

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Based on our decision to make use of GaAs-cells this year, we have adapted our design to the circumstances.

Thanks to the increased efficiency of the solar cells, they we take up even less space this season. In order to avoid unnecessary aerodynamic friction, the solar cells are fully integrated into the car’s shape.

The solar cells are placed in a strip at the very top of the car. This way, the efficiency concerning one-way solar radiation was improved considerably.

A flange is connected to the cover and is supported by its counterpart located at the top of the monocoque. This way, a better placement and a better positioning of the part are ensured. Additionally, the cover is fitted to the monocoque in the back, allowing for it to be fixed against relative motion.

The cover’s edge draws a far lower line towards the rear end of the car than the last years’ cars’ did. This way the powertrain and the rear wheel are easily accessible. This immensely boosts efficiency concerning work in these areas.

Due to differences concerning the regulations, this particular cover will only be used for the Shell Eco-marathon, instead of debuting during the Educ Eco competition.

 

2015-05-02: part 2 of our part presentation: the safety and control board

4 days before our first competition this season, we unveil another secrete of eLi15.

Safety and control board

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The safety and control board supplies all electrical components with power. Voltage regulators set the voltage a.o. to 12 Volts for the horn, 5 Volts for the display, and to 3.3 Volts for the microcontroller. Within, the emergency shutdown circuitry cuts the power, after the emergency-off button is activated.

The board also contains a microcontroller featuring a CAN-connection, hereby allowing for various measurements and switching operations. In order to monitor power consumption, ammeters are placed in the input and output area. In addition to that, the 48 and the 12-Volt rail’s voltages are measured.

If every measuring-point delivers a correct signal and the displaycontroller puts out the starting signal via CAN-interface, a relay that supplies the motor controller with power, is activated.

2015-04-20- start of series: part presentations

Together with the presentation of our vehicle, its appearance was shown off, and the inner workings became transparent. We’d now like to reveal selected components and technical details.

 

Swing arm eLi15

The swing arm is the rear axle’s and motor’s load-carrying component and inherently so a crucial component of the rear axle assembly. It is connected to the body in three points, one being a connection to the rear partition via bent sheet metal, the two other points being screws connected to monocoque side aluminum inserts.Hinterrad-Aufhaengung

Rear wheel bearing

The axle is inserted into the half domes at the bottom and then locked in place through the upper ones. The axial fixation is realized through fitted discs on the insides of the arms.

The positioning of the component within the vehicle is made possible through rotation around a fitted bolt. Guided by the slotted holes, the axle can be adapted to the vehicles’ center line.

To guarantee a possible adaptation of the motor-positioning, a guiding flute is integrated. The motor’s axle and the rear wheel’s axle being parallel, is essential for a high level of efficiency. The fine tuning of the chain’s tension – also important to maintain a high level of efficiency – is realized within the motor’s bearing.

Further additional elements are the rear brake system and a bracket for the RPM-sensor. Extra space and appropriate angles for screwing were considered.

Execution

The most important aspect regarding the construction and building of the swing arm was a lightweight structure, which lead to an aluminum execution. On top of that, the wall thickness has been reduced to a minimum. Only areas in which e.g. screws are placed, deviate. The C-Profile used for the swing arms had proven to be a suitable one for our need for a high stiffness whilst maintaining a low weight. The component’s strength was confirmed through simulation and the following tests with the actual component.

Challenges

Besides the complex mounting relative to the machine, the thin walls causing an oscillation was a challenge during manufacturing.

2015-04-19: Information event

We would like to invite all students that are interested in our project to this semesters information event. We will talk about our project, the organisation and current positions in the team.

Meet us at:
Wednesday, April 22nd at 18:30
in MW 1050 on the Campus Garching, Maschinenwesen (Mechanical Engineering Building).

Or send us an e-mail if you are interested: info.eco@tufast.de

We are looking forward to meet you!