Sun chariot Aachen

Covestro Sonnenwagen during test drives on the Stuart Highway in September 2019

The route for the Sonnenwagen Aachen team and its competitors at the World Solar Challenge in Australia

Huawei Sun Chariot on the Stuart Highway , October 8, 2017

Sonnenwagen Aachen is a student initiative of Aachen students to develop and build solar automobiles to participate in the World Solar Challenge in Australia . The legal entity behind the project is the registered association Sonnenwagen Aachen e. V. with seat in the North Rhine-Westphalian university city of Aachen. In July 2019, the second solar vehicle for participation in the World Solar Challenge 2019 was presented in Aachen. The racing car for the 2019 competition, powered solely by solar energy , is officially called Covestro Sonnenwagen , named after the main sponsor, Covestro AG . The 3022-kilometer race from Darwin in the Northern Territory to Adelaide in the state of South Australia took place from October 13-20 , 2019. The Sonnenwagen team came in sixth.

backgrounds

The World Solar Challenge is considered to be the toughest race for solar vehicles. It has been held in Australia since 1987, every three years until 1999, and every two years since then. The race takes place during the day on public, open roads . The route essentially runs through the Australian outback and largely uses the Stuart Highway .

When it was first held in 1987, one of 13 teams was German-speaking ; it came from Switzerland . In the years 1990 and from 1996 to 2007 a private German team competed without reaching the top positions. From 2003 the Bochum University took part regularly; The greatest successes were a second place in 2013 and a third place in 2015, each in the more thinly occupied, somewhat more practical “cruiser” class. In both 2013 and 2015, Dutch teams won the two most important classes. Since 2013 the race has been officially called Bridgestone World Solar Challenge , named after the tire manufacturer and main sponsor Bridgestone .

In 2017, the event celebrated its thirty-year anniversary with the fourteenth edition. A team from Aachen started for the first time; In the field of over forty, it was the only German team in the strong, extreme "Challenger" class.

The Sonnenwagen Aachen e. V.

The main building of RWTH Aachen University, where most of the members of the Sonnenwagen Aachen e. V.

To legal transactions independently as a legal entity to occur, founded students on September 21, 2015 Aachen the club Sonnenwagen Aachen e. V. , which was entered on January 26, 2016 under the association register number VR 5554 at the Aachen district court . According to the state in June 2017, he has 40 active members, mostly male and a few female students at the RWTH Aachen (RWTH Aachen University) and the University of Applied Sciences in Aachen (FH Aachen - University of Applied Sciences).

The Sonnenwagen Aachen team

The Sonnenwagen Aachen team designed and built the racing car and used it as a team in the Bridgestone World Solar Challenge 2017 in Australia. As of the beginning of October 2017, it comprised 45 Aachen students from various departments as well as additional assistants in the race on site.

Eleven prospective engineers dealt with the mechanics , five of them with the supporting structure and six with the chassis . Twelve prospective engineers worked in the field of electrical engineering , specializing in solar cells , batteries , electric motors and the cockpit . Seven people from the fields of aerospace , production and energy technology, as well as computational engineering, took care of the aerodynamics . Two team members looked at the driving strategy including the weather forecast . The non-technical department comprised ten people for project management and information technology , sponsoring and marketing, as well as logistics and travel planning. In addition, there is the three-person board of directors for coordination and representation. The proportion of women in the team was around 10%, including an aerodynamicist and the head of the electrical engineering department.

The solar cars

The Huawei solar car after a test drive in Australia

Huawei Sun Chariot (2017)

The first solar car of the Sonnenwagen Aachen team was designed and built as a thoroughbred racing car especially for the "Challenger" class of the Bridgestone World Solar Challenge 2017 . The regulations comprised a total of 45 pages. According to the specifications, the vehicle is four-wheeled. As a closed monoposto , it only offers a single seat for the driver in order to keep the vehicle mass as low as possible and to be able to design the shape to be particularly aerodynamic. Based on the results of the two previous events in 2013 and 2015, in which four-wheeled vehicles were required for the first time, the Sonnenwagen Aachen team also decided on a concept that is reminiscent of a catamaran : the wheels are almost completely covered in the two longitudinal hulls . They are hung on parallel wings , the front ones are pushed, the rear ones pulled. On the upper side, the two hulls are connected by an approximately rectangular, slightly curved plate on which the solar cells are located. On the right-hand side, the plastic cockpit hood protrudes upwards, under which the driver, protected by a roll bar and in accordance with the regulations, sits comparatively upright.

The self-constructed vehicle chassis is made of tubular steel. The light and aerodynamic body is a lightweight construction with parts made of fiber composite material . Air and rolling resistance are as low as possible in order to enable higher speeds with the same performance. The photovoltaic system generates the electricity that directly drives the electric motor; a battery storage system with lithium-ion cells with a total mass of 20 kg serves as an energy reserve. The sun car met the requirements of the regulations, which stipulated a maximum length of 5 meters, a maximum width of 2.2 meters and a maximum solar area of 4.0 square meters. It weighs 200 kg empty. As expected, the reduced solar area compared to previous events contributed to the fact that the average speeds did not increase any further and that exceeding the maximum permitted speed was avoided as far as possible.

There are 260 silicon solar cells on the top of the body . The in-house developed 135 volt wheel hub motor achieves an output of 1.4 kilowatts (around 1.9 hp ). With the low-resistance body, this is enough for a top speed of 135 kilometers per hour. However, this is more of a theoretical value in terms of range and Australia's speed limits. At an average speed of 70 to 80 km / h, one battery charge lasts four hours and a good 300 kilometers. The aim was an average speed with problem-free operation and depending on the intensity of the solar radiation and the route profile of 80 to 90 km / h. The converted solar energy is comparable to "the performance of a hair dryer".

In order to get the support of the main sponsor Huawei , the racing car, initially called Sonnenwagen Aachen , was renamed Huawei Sonnenwagen , but the previous team name was retained. During the race, the vehicle was numbered “70”. The finished vehicle was presented in Berlin on July 20, 2017 in the presence of Federal Environment Minister Barbara Hendricks .

Covestro sun car (2019)

The Covestro Sun Chariot during a test drive in Australia

The second solar car of the Aachen team was developed and built according to the regulations of the "Challenger" class of the Bridgestone World Solar Challenge 2019 . In contrast to the previous vehicle, the decision was no longer made for a catamaran concept with two longitudinal hulls, but instead used the maximum permissible length of 5 meters and built a very narrow vehicle. The shape of the vehicle causes a small amount of air resistance and is designed like a vertical aerodynamic wing . This makes it possible to use cross winds to sail like a boat and thereby further reduce drag. On top of the vehicle is the 2.64 m² solar cell surface, consisting of 890 highly efficient multi-layer solar cells with a nominal output of approx. 1 kW. A battery consisting of 420 lithium-ion cells enables the temporary storage of solar energy. With a capacity of 5 kWh and a cell weight of 20 kg, the battery enables a range of 500 km at a driving speed of 90 km / h without using the solar cells. A four-wheel steering also makes it possible to steer the rear wheels. The rear wheels can be steered in the opposite direction to the front wheels, but also in the same direction (crab steering), in order to align the vehicle while driving depending on the cross wind and to increase the sailing effect.

The Covestro Sonnenwagen is named after the main sponsor, Covestro AG , and was presented on July 22, 2019 in the presence of North Rhine-Westphalia's Prime Minister Armin Laschet .

The name

The project is named - in addition to the common place of study for the club and team members - after the literal German translation of the English term “solar car”; the German-language term creates a reference to the internationally highly regarded German engineering. At the same time, connections to the sun chariot are created as a chariot- like mythological representation that depicts the journey of the sun across the sky. Most famous is the sculpture of the Trundholm sun chariot from around 1400 BC. Chr.

The partners

The budget of the project for 2017 was made available by numerous partner companies, partly in the form of production grants, and also by providing infrastructure for planning, development and production.

Main sponsor for 2017 was founded in 1987, Chinese telecommunications company Huawei , based in Shenzhen and European headquarters in Dusseldorf , a company with approximately 170,000 employees worldwide and a profit in 2015 of around 5 billion euros . One of the so-called “gold” sponsors was the German materials manufacturer Covestro AG from Leverkusen , a subsidiary of Bayer AG , formerly known as Bayer MaterialScience AG ; The second "Gold" sponsor was the automobile manufacturer Porsche AG from Stuttgart - Zuffenhausen .

“Silver” partners were the Swiss weather forecasting service and specialist for solar power forecasting Meteoblue as well as the US software developers ANSYS, Inc. , developer of the finite element software ANSYS , and Autodesk, Inc. , developer of the design software Autodesk Fusion 360 . There were also eleven other “bronze” partners, 21 other partners and additional departmental sponsors, many of them from the Aachen area, in particular research companies and university institutes in an advisory capacity.

The history of origin

Several students in a shared flat in Aachen came up with the idea for the Sonnenwagen team in the summer of 2015. The desire to build their own solar car and thus take part in the World Solar Challenge in Australia in 2017 quickly materialized . The first members founded the registered association Sonnenwagen Aachen e. V. and started with computer-aided drafts for the vehicle and the development of organizational structures, especially to finance the project. They have been running their own blog since August 2016 , in which the current state of development was often documented several times a month.

Four members of the association gained their first experience with electric vehicles in competitions at the event e-CROSS Germany , which from September 1st to 4th, 2016 led in the style of an emission-free rally and skill drive from Bielefeld via Düsseldorf to Aachen. Among 34 business and 19 private teams, a team of two from the Sonnenwagen team won on a Twike 3 ; a second team took part in an electrically powered Kia Soul EV.

On November 18, 2016, the team presented the project publicly in the auditorium of the main RWTH Aachen building . In the presence of the then North Rhine-Westphalian Science Minister Svenja Schulze and Professor Jörg Feldhusen , Dean of the Faculty of Mechanical Engineering, the vehicle concept was unveiled and Huawei presented as the main sponsor. Covestro AG has supported the project since June 2017, and Porsche AG since July 2017 .

Participation in the race

Typical racing scene: the Huawei sun car south of Darwin with two support vehicles

Preparations by the Sonnenwagen Aachen team for an overnight stay in the Australian outback (next to the Stuart Highway)

The race preparation

On 4 August 2017, the team sent large pieces of equipment in a 40-foot container by sea to Australia, including a six-meter trailer, tools, camping equipment and spare parts. The expensive battery was also included, as it was not allowed to be sent as air freight . In order to be able to test the vehicle further, the team only sent the Huawei Sonnenwagen by air freight from Amsterdam via Kuala Lumpur , Sydney and Adelaide to Darwin on August 30th . The Sonnenwagen Aachen team is represented by 38 people in Australia. They arrived in four groups between September 7th and October 2nd, 2017.

The Huawei Sonnenwagen has had temporary Australian road approval since September 28th . The team uses them for extensive test drives on the Hidden Valley Racetrack in Darwin and the Cox Peninsula . On October 4, 2017, the car passed the official technical and the first part of the practical vehicle inspection . The last part of the "Dynamic Scrutineering", the test drives for the race acceptance, was the qualifying on the curvy Hidden Valley race track on October 7, 2017. The Aachen team completed the lap with the fifth-fastest time of 38 participating teams; With a lap time of 2'15.9 ″ and an average speed of 76.0 km / h, it was right behind the co-favorite and last year's winner Nuon Solar Team from the Netherlands with the Nuna 9 .

The race

The actual race started on Sunday, October 8th in the morning and officially ran over 3,022 kilometers. About halfway the highest point was reached with almost 750 meters above sea level . In order to be considered, the vehicles had to arrive in Adelaide no later than Sunday, October 15th. Vehicles of the "Challenger" class such as the Huawei Sonnenwagen were only allowed to use the electricity that was currently generated by solar radiation or that could be stored in the regulated battery before, during and after the day segment. In contrast, the more practical multi-seat vehicles of the “cruiser” class were allowed to be recharged on the go via external collectors.

On the first day of the race, the Sonnenwagen Aachen team covered 493 kilometers, although as a newcomer to the WSC it started with deliberate care. A technical problem temporarily caused an unusually low battery level, so that the second day of the race was also concluded with 14th place in the “Challenger Class”. In the course of the third day of the race, the Huawei Sonnenwagen, like many competitors, got into a large bad weather zone with heavy cloud cover, while a top group of five was able to break away even further. The solar area, which was reduced by 20 percent in 2017, only allowed low speeds without being able to continue charging the battery. After nine teams dropped out by the end of the second day, another six dropped out on the third day. The Aachen team was the only remaining “newcomer” at that time.

On the night of the fourth day of racing, a large thunderstorm front with storms and intermittent rain broke out in the Australian outback near Alice Springs , which determined large parts of the day of the race. Alice Springs could be reached with the last battery reserves within the time corridor extended by the race management. Further south it cleared up again and allowed continuous high speeds. On the afternoon of the fifth day of the race, the checkpoint in Coober Pedy had to be reached at kilometer 2187 . Due to the extensive bad weather zone, the Sonnenwagen Aachen team lost too much time to be able to catch up to Coober Pedy: The control time was exceeded by a few minutes, which led to the elimination from the "Challenger Class". From then on, the Aachen team could “only” continue the race in the “Adventure Class”. The Huawei Sonnenwagen reached Port Augusta on the afternoon of the sixth day of racing and Adelaide on the morning of the seventh day.

In its thirty-year history, it was the World Solar Challenge with the lowest proportion of sunshine and the highest proportion of clouds and rain. The Aachen solar car covered the full distance of 3,022 kilometers, making the team one of the best "newcomers" in WSC history ; Despite the bad weather zones, the average speed of the Aachen car was 60 km / h.

Web links

Commons : Team Sonnenwagen Aachen - Collection of images, videos and audio files

The website of the Sonnenwagen Aachen team at www.sonnenwagen.org , accessed on September 27, 2017.
Klaus-Achim Peitzmeier: "Sonnenwagen", report on the Sonnenwagen Aachen and the cooperation with Porsche including technical details from September 29, 2017, published in the Porsche customer magazine Christophorus No. 383 , accessed on October 7, 2017.
“With solar power through the outback: Huawei becomes main sponsor of the Aachen solar car”, report on the Aachen solar car and the cooperation with the main sponsor Huawei on the web portal finanzen.net from November 18, 2016 , accessed on October 4, 2017.
“Economical, light, streamlined: Students build solar racing cars”, report on the Aachen solar car on the heise.de web portal from November 18, 2016 , accessed on October 4, 2017.
Ruth Herberg: "Solar student project: With the sun car through the outback", report on the sun car Aachen e. V. on the web portal of the trade journal Wirtschaftswoche on September 20, 2016 , accessed on October 4, 2017.
"World Solar Challenge in Australia: Project Sonnenwagen", report on Sonnenwagen Aachen on the Spiegel online web portal from November 18, 2016 , accessed on October 4, 2017.

Individual evidence

↑ The history of the World Solar Challenge on the official web portal of the organizer , accessed on October 5, 2017 (English).

↑ Overview of previous events and the podium finishes at the World Solar Challenge on the organiser's official web portal , accessed on October 5, 2017 (English).

↑ Overview of the teams participating in the Bridgestone World Solar Challenge 2017 on the official web portal of the organizer ( Memento of the original from October 6, 2017 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed on October 5, 2017. @1@ 2

↑ Presentation of the Sonnenwagen Aachen project with backgrounds to the World Solar Challenge on their web portal sonnenwagen.org , accessed on October 5, 2017.

↑ The Team Sonnenwagen Aachen and the Huawei Sonnenwagen on the official web portal of the organizer worldsolarchallenge.org ( memento of the original from October 7, 2017 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed on October 7, 2017. @1@ 2