Students from Delft University of Technology have achieved a new milestone. Their hydrogen fuel cell racer ‘Forze 6’ drove its first meters on hydrogen power at a former airbase in the Netherlands. The students have built five other prototypes and Formula Student vehicles since 2007, competing in various championships. But this car is much larger and powerful. The pioneers are targeting a lap record at at the Nürburgring-Nordschleife track in 2015.
What has happened in the past two months, leading up to their milestone? The team describes:
“Well, the answer is: a lot, but perhaps not everything we hoped for. To give you more insight in how our car works exactly, I will go a little bit more into technical detail in this update. On the 13th of October when we finally made our fuel cell roaring for a long time, still a lot of functionality was missing to make the car truly autonomous or better make it drive on its own without being connected to external wires and hydrogen hoses.
“Our car has the same problem as all the other regular cars out there. You need energy to start it. Hydrogen cars however are a little bit trickier since they have three big systems which have to be powered before the fuel cell can enter nominal operation, namely: the embedded systems, the air compressor and the recirculation pump.
“Since the recirculation and the air compressor need high voltage for operation they cannot be powered by a (small) battery. What we do is the following: First we start all the embedded systems from our 24 Volt startup battery. The embedded systems include the tank solenoid and the complete balance of plant control. We can therefore fill the fuel cell with hydrogen in the same way as in regular operation. Afterwards we use our accumulator to power the air compressor at a low power set point to feed the fuel cell with a small amount of air. At this point the fuel cell has reached its nominal potential and we can start drawing energy for the recirculation pump. Now the air pump and the embedded systems (together with all the fans and pumps) have to be switched over to fuel cell power. And exactly this ‘switching over’ and the tank control took quite some effort to implement. But the effort was worth the time. It worked beautifully in the over 50 fuel cell start-ups we did during the last weeks.
“The award of ‘the most annoying part in the car’ this time goes to our accumulator. It proved not to be oil tight, causing a pretty nasty oil spill and two weeks of delay since it had to be taken apart and sealed: luckily straight forward and only annoying.
“So back to the question: What did we achieve? We had two big testing days one in Valkenburg to test the fuel cell and one at Beek Auto Racing on their dyno to test the gearbox and the accumulator. The test in Valkenburg did not go really smooth. At that day we had 0°C and a wind force of 4 Beaufort, which imposed major problems on our start-up battery and the recirculation pump. We had to warm the car in the trailer which took quite a long time leaving almost no time for testing. However we did manage to perform one clean fuel cell start-up and the magic moment came when the car was finally driving purely on hydrogen. Check the video of our first hydrogen powered meters here:
Check the video to see the first hydrogen powered metres.
“Goal of the second test was to check if our own designed gearbox can cope with high torque and speed. We did 14 acceleration tests with a maximum power of 150 kW. Conclusion: Gearbox holds and accumulator can deliver the power without problems.
Check the video to see the dyno test.
“Now at the beginning of the new release we are going to focus on our DC/DC converter and we will review why our implementation is not 100% working yet. Further the air pump will get some attention as well, so that we can drive on high power as soon as possible.”
· Longest FC run: 31 minutes 54 seconds
· Highest FC power: 14 kW
· Amount of FC start-ups: 54
· Highest accumulator power: 150 kW
· Fastest wheel speed: 181.4 km/h
· Highest combined wheel torque: 1464 Nm
· Number of scrum sprints: 8
Photos in courtesy of Forze Hydrogen Racing Team Delft