FR19 - a Formula Student race car by "Elefant Racing"

Who we are and project "Formula Student"

We are a Formula Student Team called "Elefant Racing Bayreuth" and we are building an electric racecar each year. This project would not be possible without sponsors though.

Let me introduce you to Formula Student (if you haven't heard of it already). By definition, it's a student design competition for students where each team's goal is to build a race car. These vehicles are made by a lot of other teams from around the world and we compete against each other in several events at the end of each season. Formula Student is not just about winning at these events though, it's more about being able to work as a team and being able to build a racecar in under a year from scratch (excluding gathered knowledge and lessons learned).

We are currently at the beginning of a new season and start with design and concept evaluation. Once we are done construction time begins where we design PCBs and make CAD models. The next step is manufacturing. Some components are sponsored by companies (dampers e.g.) and others are self-manufactured (carbon fiber monocoque).

After assembly our racecar we are using our test track intensively to adjust and tune our vehicle. The last (and most fun and thrilling) thing of a season is competing at events.

One part of events are dynamic (longitudinal and latitudinal acceleration, fast lap, long distance) and the other part rea statically (concept evaluation, cost report, business plan). Due to these different competitions, it isn't necessary to build the fastest car but to have innovative ideas, clever designs, and a solid implementation of our concepts.

This happens throughout a year and we are collecting knowledge and experience with which we are able to improve from season to season.

FR18 - our latest car

A more technical look at the FR19 (our car)

The FR19 will be a four-wheel driven vehicle powered by four self-developed wheel hub motors, each with a maximum power of about 35 kW. The power comes from our accumulator which should pack about 7 kWh and a bit under 600V maximum voltage.

The up-rights have to withstand more forces than before and do not only need to have enough space for the motors but also for our self developed planetary gear set. These units are attached to our carbon fiber monocoque chassis which should weigh less than 20 kg.

There are some other major things to consider like packaging, cooling and added forces on suspension, caused by wheel hub motors.

New opportunities come along as well like torque vectoring and thus being a lot faster than a rear wheel powered car or being able to recuperate more energy.

As we are working with a high voltage accumulator special safety features are required. For example, there are three shutdown buttons, a crash sensor, a battery management system (monitors voltage and temperature of the accumulator) and more to ensure safety for our drivers.

As a board computer, we use a Raspberry Pi in combination with a self developed PCB with an ARM processor which functions as a co-control unit and increases safety by redundancy.

Apart from that, we have a lot of other PCBs which are mostly designed by us.

BMS-Master

This PCB receives all cell voltages and temperature via ISO-SPI and checks if those values are ok.

BMS Slaves

These PCBs are mounted on top of each cell pack in the accumulator and measure voltage and temperature of each cell. Then they send their information via ISO-SPI to the BMS-Master

CCU

The co-processing control unit (featuring an ARM processor) helps the Raspberry Pi by doing certain tasks and is designed so that it can be simply stacked on top of the GPIO pins of the Raspi. Both can restart each other if one fails.

Safety Circuit

As the name suggests this PCB is checking if it is safe to draw current from the accumulator by checking signals from BMS-Master, IMD (insulation monitoring device), ECU (Raspi + CCU) and some other sources. It controls the so-called TSAL (tractive system active light) which has to be flashing red if the tractive system is active.

Sensor Nodes

These PCBs are made so that you can plug in a variety of sensors, read their values and send those via CAN to the onboard computer.

And more

We use many PCBs more that are mainly used to ensure driver's safety.

EBox - some of our last car's PCBs

Why your support is important to us

As I already mentioned at the beginning we could not build a race car without our sponsors. They support us by manufacturing components, giving us advice or financial support. PCBWay could help us a lot by producing (and maybe assembling) the PCBs we need.

This would save us money and more importantly time. We are a small to medium sized Formula Student Team which appreciates any help we can get!