Preparation of new hydrogen season

The first hydrogen season is over

First experience with hydrogen fuel cell

We launched the Hydrogen automotive challenge H2AC (racing RC hydrogen cars models ) in January 2019. The sponsor of the historically first hydrogen car team was the Správa informačních technologií města Plzně. Students from Pilsen’s INFIS, SPŠE and SOUEP joined the program. Involved high school students very quickly had to build the first version of a hydrogen powered car. During the construction, the students discovered the key features of the hydrogen-cell electric vehicle (FCEV), where and how electricity is taken from fuel cells in combination with batteries. Understanding the basics and successfully assembling the first version of the car allowed them to participate in their first races in Brno at ISŠA Brno, where they gathered valuable experience and inspiration to improve the model. Hydrogen car races are endurance with a limited amount of hydrogen and batteries. So it is all about saving energy during the whole race. The key to success is maximizing the use of hydrogen in both cartridges and batteries, and according to this state, to plan pit stops correctly.

Knowing the state of hydrogen and battery consumption is crucial

The Horizon Grand Prix (formerly H2AC) final races are 6 hours with a limit of 20 hydrogen bombs and 4 sets of batteries. The team came up with a proposal for remote measurement of both hydrogen and battery consumption, so that they could accurately manage boxing stops and replace hydrogen cartridges and batteries. The SIT Port Garage provides the workspace for the team to do  all improvements. After completing all the preparations, the Pilsdrogen (Pilsen-hydrogen) team set out for the national final – Horizon Grand Prix – in Ostrava. Although the boys were finished at last position, they fought until the last drop of hydrogen. In addition to the jury’s appreciation for the technical solution of remote consumption metering, the guys have gained enormous experience.

Preparing for a new hydrogen season

We organized an exhibition race in Pilsen as part of the Dronfest 2019 at the very end of the season. A total of 5 teams from Pilsen, Hubálov and Kutná Hora secondary schools competed there.

As some of the Pilsen’s team members started their studies at university, it is necessary to add new high school students to the Pilsdrogen team for the upcoming season.

You can see the racing hydrogen car for example at DVT 2019 in Pilsen, where you can also join the team and shine next season.

And now some technical details …

Team members: David Žahour, Jan Kucera, Patrik Vacal, Jakub Kolar and Michal Klecka.
What did the boys learn and create in the project?

Patrik gathered insights from the whole team:

  • 3D designs (hydrogen cartridge holder)
    • We designed the holder in Fusion 360, then we printed this model in the SIT Port Garage on the 3D printer Prusa Mk3. 3D printing allowed us to quickly prototype (we had 3 prototypes) and at the same time relatively simple production of parts.
  • Operation of hydrogen propulsion
    • When designing a toy car, we found out what the hydrogen fuel cell works for and how it works in different situations. Thanks to this we are able to design its optimal use.
  • Creating printed circuit boards
    • To measure consumption we designed our own PCB in Eagle. We measured the voltage and current that we sent via bluetooth. We know how to design and install PCBs.
    • source code can be found here: https://github.com/nvias/HAC_sensor_boardV1
  • Construction of RC cars
    • We learned what the guts of RC cars look like, what we should not forget when building it and how to start such a car. Now we are able to design a car from components that meet our requirements.
  • Calculation of energy consumption using integral equations
    • https://github.com/nvias/H2AC-PilsdrogenMonitor
    • In Python, we plotted graphs from the data received from the measuring PCB and using the integrals we calculated the current amount of energy consumed. These calculations can be used next year for faster development of the new version of the application and also for the consumption figures in other projects.

Finally, our lessons learned, in other words, what to do in the new season:

  • Engine efficiency was poor as expected
    • it was a DC brush motor, now we have a new one
  • As expected, the battery efficiency was poor too
    • NiMH cells have a relatively steep discharge curve, losing up to a quarter of the capacity when consuming more current.
  • The fuel cell is heavy
    • does not necessarily limit us, but every gram counts
  • The fuel cell may be more efficient
    • Reportedly the fuel cell is more efficient the less current it gives, we send less hydrogen to it to produce less, while just maybe carrying just one cartridge
  • The chassis is not perfect for folding the center of gravity
    • At the bottom of the chassis there is plenty of space left to hold the components, which could reduce the center of gravity.
  • The measuring board was unreliable
    • During the testing we forgot the fact that the frequency of 2.4 GHz to which Bluetooth communicates will be disturbed (there were all transmitters / drivers and lots of WiFi networks), but it is also possible that the parameters of the transmitter were incorrectly set in the code
  • The hydrogen transfer tubing was not strong enough
    • During the race, we also fought frequent leaks of hydrogen from tubing, which were more and we could not locate them in time. We’ve lost a lot of precious hydrogen.

 

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