One central criterion for a successful Formula Student season is the reliability of the racing car. The Endurance, a 22-kilometre endurance race with driver change, is by far the most important discipline in terms of points. Together with the efficiency score, which is linked to the Endurance, 425 of the total of 1000 points are tied to the endurance test. Accordingly, a failure is painful and almost always prevents a top ranking. The reliability of the E0711-8 at the decisive moment – the car saw the chequered flag in all four Endurance runs – was the key for the success in 2017.
Overall, the E0711-8 can be described as a successful evolution of its predecessor, explains Philipp Mayer. “There was nothing conceptual that we couldn’t put into practice. One of the reasons for this was that we were able to use well-functioning parts from the old vehicle.” Thanks to countless test kilometres, the team was also able to sort out the initial reliability problems. Although it didn’t really go according to plan, the E0711-8 covered 600 kilometres up to the first competition. But the effort should pay off in the end.
The E0711-7 was the first vehicle in the Formula Student Electric field to rely on a completely oil-cooled accumulator. The oil cooling showed its great potential in the course of the 2016 season, but still needed to be optimised. One of the drawbacks was the excessive oil demand, which the team was able to reduce substantially for the E0711-8. “We use the battery container as an oil container and flood it with oil. In this way, we cool cell tabs and pouch bags at the same time”, explains Max Partenfelder. This solution – a consistent evolution from the previous year – also allows the cells to be pre-treated and the Endurance to be started with less internal resistance. While the battery in the E0711-7 was still divided into two parts and integrated in the two side pods, the team returned to a single battery in the 2017 season that sits behind the driver. The aim of this design change was to reduce the moment of inertia, to enable a more compact package and to reduce the weight at the same time.