Durham University Electric Motorsport (DUEM) is a student-run team in the United Kingdom that designs and constructs solar powered cars to compete in international competitions. The team is financed entirely by third party donations and sponsorship.
Contents
Background
Durham University Electric Motorsport is based in the university’s School of Engineering & Computing Sciences, with a small team size of around 20 undergraduate students split broadly across mechanical, electrical, electronic and business sub-teams. The team is also strongly supported by graduates and academics within the department with expertise in the fields of solar technology, racing car aerodynamics, direct-drive electrical machines and electrical/hybrid vehicles. Many concepts and features implemented in the vehicles have been developed as part of final year undergraduate projects.
The team was founded in 2002, and it built its first vehicle in 2004. DUSC’s first competitive event was the 2008 North American Solar Challenge in which they finished 14th out of 26 competitors, earning the “Best Rookie Team” award. They were the only British team to compete. DUSC also competed in the 2011 Veolia World Solar Challenge race across Australia, qualifying in the top ten & then finishing 33rd out of 42 entrants.
DUSC has also participated in local community and awareness outreach events, including touring schools and museum exhibitions to promote science, technology and engineering. In 2010, DUSC ran a successful demonstration event with Cambridge University Eco Racing (CUER).
In 2014 Durham University Solar Car combined with Durham University Formula Student to create Durham University Electric Motorsport (DUEM). DUEM was aiming to develop a new solar powered vehicle to compete in the challenger class of the World Solar Challenge 2015. The new solar vehicle was to be called DUSC 2015, paying homage to the design work carried out while the team was still known as DUSC.
Mechanical design
DUSC 2015 is made of a carbon-fibre monocoque, resulting in a design significantly lighter than a conventional steel chassis. In order to design the monocoque, extensive finite element analysis was conducted upon the structure to ensure its ability to withstand collisions. Furthermore, a series of extensive experiments were conducted in order to verify finite element models of the carbon layup.
The front suspension is an upright forked suspension design ensuring vehicle stability and rigidity. Rear suspension is a trailing arm design manufactured out of carbon fibre to reduce the unsprung mass of the vehicle.
The front suspension is also combined with a steering mechanism allowing the front wheels to turn. The steering rack is the same as the one on vintage mini coopers which was chosen due to its high performance and ease of implementation. Ackermann steering geometries were incorporated resulting in a vehicle which handles superbly well despite its unusual shape.
Hydraulically operated brakes ensure the vehicle is able to stop almost immediately.
Power train
In order to accelerate the vehicle to 69 mph, DUSC 2015 relies upon an in-house designed in-wheel motor. A new brushless DC motor was manufactured. 16 inches in diameter and theoretical efficiency in excess of 90%, the new in-hub motor design ensures as much solar energy as possible is converted into mechanical energy.
Electronics
DUEM have designed their electronics system around the simple idea of being able to capture as much data as possible. To do this, they have designed their very own circuitry which they call sensor nodes. Sensor nodes are designed so they can all communicate to each other across the length of the vehicle as well as each individual node being able to interface with over 20 different sensors each.
Mechanical design
The steel space frame chassis was designed using Finite Element Analysis (FEA) computational packages. The chassis is strong enough to withstand a heavy impact, whilst also being as light as possible. The suspension consists of racing shock absorbers with a conventional double wishbone arrangement at the front and a trailing arm at the rear. Special brake calipers are used which retract to ensure there are no frictional losses when the brakes aren't applied. Specialist solar car tyres are employed to reduce rolling resistance.
Electrical design
A combination of high-efficiency silicon solar cells and maximum power point trackers are used to extract the maximum possible power from the available solar energy and feed it into a Lithium Iron Phosphate battery pack. The vehicle is driven by a specially designed axial flux wheel motor via a custom controller, resulting in higher efficiency and less transmission loss than conventional electric motors.
Electronic design
The vehicle makes use of a telemetry system operating the CAN protocol to communicate real-time vehicle data over a radio link to a support vehicle. Using this data, the driver may make control adjustments to the vehicle to account for the current performance of the electrical package.
Racing as DUSC2008
Substantially the same car was raced both as DUSC2008 across North America and as DUSC2011 across Australia. The major changes between the two are that in 2008 a chain drive was used instead of the in wheel motor, lead acid batteries were used instead of lithium iron, and a commercial solar array was used instead of in-house custom encapsulated panels. There were also numerous other minor changes.
Sponsors
Financially DUEM relies solely on sponsorship and has received support from the Institution of Engineering and Technology, Gurit, Deloitte, Durham University Engineering Society, the Energy Institute, RS Components, C&D Technologies EPSRC & Jaguar Land Rover. The team continues to look for sponsors to develop the car & technology to even greater heights.