Torque Sensor improves efficiency hydrogen-powered city car

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Eco-Runner Team Delft (TU Delft) is working on building the world’s most efficient hydrogen-powered car. This has been their goal since they were founded in 2005. Each year, a new team takes on the challenge to design and produce this ultra-efficient car and to participate in the Shell Eco-Marathon to compete against many other teams around Europe.

In 2019-2020, the team chose to take on a new challenge: building not just an efficient car but building an efficient city car. This means that more practical aspects have to be taken into consideration. Examples are: making a full stop after each lap to simulate the stopping at city traffic lights, the head- and tail lights, direction indicators, and a wiper. Taking all these new challenges into account, the students started to work towards building the world’s most efficient hydrogen-powered city car.

Eco Runner Team Delft will be competing in the 2022 Shell Eco-Marathon and are continuing to test the electric motor at different rotational speeds and torques:

Improving efficiency

Eco Runner (Team Delft) Car

In order to achieve this goal, every single element in the car needs to be as efficient as possible. Examples are the aerodynamic shape of the vehicle, the need of strong but very lightweight materials for the body and structure, and an ultra-efficient drivetrain. An electric motor is the final part of this drive train, because it is the part where electricity is converted to movement.

The specifications of this motor need to be customised to the team’s needs in order to be as efficient as possible on the track. When the production of the motor is done, tests are being performed to check if the efficiency regions are in line with the initial specifications.

An important part is measuring the torque strength at various rotational speeds.

RWT430 Rotating Torque Sensor

“In order to measure the torque strength at various rotational speeds our sensor partner Althen Sensors helped us by supplying the RWT430 Rotating Torque Sensor of ST Sensor Technology. This sensor is easily connected to our dynamometer on the one hand and a computer on the other hand”.

RWT430/440 series torque transducer with separate electronicsUsing the TorqView software, the team was able to get a good view of the torque strengths of the motor at different rotational speeds. In addition, they could measure the input voltage and current of the motor controller of the motor connected to the dynamometer. Also, the team was able to change the loads on this dynamometer to simulate different stages and conditions of the actual race.

The information of the torque strengths and rotational speeds of the motor, gained with the TorqView software, helped to determine what the actual efficiency regions of the vehicle are. These regions matched the regions that the team calculated beforehand and showed that they had chosen a good motor setup. The strategy departments could use this important information to determine the different speeds needed for an optimal lap!