The Green Team Twente won the Shell Eco Marathon in London last weekend with the hydrogen car they presented last year. In doing so, they left dozens of student teams behind, including the team from Nantes in France that won in previous years.
The Shell Eco Marathon is a major European sustainability race in which the aim is for cars to consume as little fuel as possible on a predetermined course. The race is divided into several classes. The main classes are the Prototype and UrbanConcept classes. The subclasses cover the different fuels: petrol and diesel, ethanol, GTL, batteries and hydrogen. The Twente student team competed in the hydrogen class, which is seen as the 'king race'.
Multiple attempts
Each team had several attempts to set the best result, spread over two days. The track of the Shell Eco-marathon was 1659 metres long where each team had to complete ten laps within a time of 39 minutes. Each attempt measured how much fuel was consumed. Green Team Twente won thanks to its third and final attempt where the car, the H2∞ (Infinity), drove an equivalent of 1 litre of fuel on 845 kilometres. This is a new Dutch record.
Hydrogen is the future
The students unveiled the hydrogen car in April last year. The H2∞ can run for three hours on the amount of energy from a Snickers bar. The Green Team Twente students are convinced that the hydrogen car is the car of the future, even more so than battery-based electric cars. This is because of its lighter weight and quick refuelling.
In developing the car, friction was a major challenge. To make the car as economical as possible, there should be as little friction as possible. By putting the right bearings in each component (in collaboration with manufacturer SKF), friction was minimised.
The gearbox is also quite revolutionary. In fact, three motors are connected to the shaft, which can be switched off and on independently.
"This provided a nice basis for optimisation: better material, more efficient transmission and the gears that perfectly overlap form the current gearbox. We modified the gearbox of the hydrogen car to achieve an optimum efficiency of 99.1%. With this, we are theoretically able to drive from Enschede to Geneva with just one litre of fuel."
Among other things, the circuit boards, which provide the peripheral systems, were designed by the team itself. "The reason we design our own circuit boards is because we want to minimise all electrical losses. Almost all PCBs available on the market do not meet this criterion, so we had to design our own highly efficient PCBs. As a result, we are also working on problems that very few engineers have looked at, such as a high-efficiency DC/DC converter with state-of-the-art gallium nitride transistors."
Systems
All electronic systems belong to either the primary system or the secondary system. The primary system starts with the hydrogen fuel cell. This is the part that converts hydrogen and oxygen into water and electricity. Before this is used, the voltage is increased to 48 volts with a DC/DC converter. This is the voltage at which the rest of the system runs. The power is then routed to the motor controllers, which feed the motors, after which the car starts running.
The secondary system, powered by lithium-polymer batteries, powers all systems that are not part of the powertrain, such as the lights and wipers. The H2∞ has a Formula 1-inspired steering wheel. Controls for all functions in the car, from throttle to lights, are located on this steering wheel. The team has also incorporated a system to read real-time data from all components in the car.
By: Kelly Bakker
Source: Green Team Twente
