Fuel-cell race car relies on Bürkert valve technology

With a weight of only 280kg, a length of 3m, 18kW of power (fuel cell only) or temporarily up to 60kW (including regenerative braking power) and a speed of about 120km/h - at first glance the performance data of the Forze V seems modest in comparison with conventionally fuelled race cars; however, this first impression is deceptive, as confirmed by the reaction of Ross Brawn, team leader of the Mercedes AMG Petronas Formula 1 team.

Ross Brawn, impressed by the engineering of the Dutch students, called the Forze V "an outstanding example of genuine innovation". As so often in racing, the reason for this enthusiasm is under the bonnet: as opposed to the overwhelming majority of the race cars at the starting line in Silverstone, this one was powered not by a combustion engine, but by an electric motor. Different again from all other electric vehicles in the race, it was powered by a fuel cell rather than a battery. By finishing in the midfield in Silverstone, the Forze Hydrogen Racing Team proved that it is possible to keep pace in motor sports by using hydrogen instead of petrol in the tank, and with zero emissions.

The rules of the Formula Student stipulate that the teams must design and build a race car in one year, with which they then compete against each other in different events and races. The students are also responsible for the financing of the project, with the aid of industrial sponsors. The team had already competed in 2011 with the Forze IV, the precursor of the current race car of the Delft University team. Jan Jaap Treurniet, team manager of the Forze Hydrogen Racing Team recalls: "We achieved good ratings in the design competition, but were unable to take part in the actual race due to technical problems."

That has changed with the Forze V in 2012. The new race car needed to be more powerful, faster, lighter and above all, more reliable than its predecessor. Since standard solenoid control valves and controllers from Brkert were already in use on the car, the decision to contact the fluid technology specialist for fuel cell specific components and technology was a logical next step.

Racing fever in Ingelfingen

Johann Gunnesch is a motor sports enthusiast and an engineer at the Systemhaus of Brkert Fluid Control Systems in Ingelfingen. He develops customised, highly specific systems for a wide range of applications requested by Brkert customers throughout the world. When his Dutch sales colleague John van Loon approached him on behalf of the Forze Hydrogen Racing Team, he was quick to offer his assistance. After the Brkert executive management agreed to provide the students with products and know-how from the Systemhaus, it was not long before racing fever broke out in Ingelfingen.

After a preliminary meeting at Brkert, the task was soon clear: the student team presented its flow plan for the fuel cell and explained the basic technical requirements. The goal was to find a solution for the hydrogen supply, which had to be as compact and lightweight as possible while making use of standard components from the Brkert product portfolio. In the Brkert Systemhaus Gunnesch and his team developed a proposal for an integrated system. A compact aluminium block, which saved considerably on material, provided room for a safety valve, a solenoid control valve for controlling the hydrogen pressure, a mass flow meter, an overflow valve, as well as temperature and pressure sensors.

Johann Gunnesch explains the function of the low pressure block: "Coming from the tank, the hydrogen first passes a shut-off valve. An integrated excess pressure safety valve has to release the hydrogen in the event of a malfunction. A Type 2833 solenoid control valve meters the hydrogen for the fuel cell by controlling the pressure in the fuel cell. A Type 8711 flow meter measures the supplied quantity of hydrogen and sends this data to the vehicle's electronic control system. The pressure and temperature are likewise monitored constantly by sensors that send their readings to the controller to enable the fuel cell to operate under optimal conditions at all times. Furthermore, there is a Type 6011 overflow valve, which can evacuate the entire system in case of emergency."

After the design phase for the Forze V was completed, the block was adapted to the race car's systems. There were also special requirements such as a mirror-inverted design or the 90 degree shift of a fitting. Finally, the low-pressure block and a second, identical replacement block were manufactured in Ingelfingen and delivered to Delft. Shortly after came positive feedback: all systems go!

Slim and trim

After having found a compact and lightweight system for the hydrogen supply, the Delft Racing Team became increasingly dissatisfied with the existing air supply. Although it functioned perfectly, the size and weight made it unsuitable for racing. The situation was addressed during a visit by Brkert employees to the Delft University of Technology. Johann Gunnesch relates: "At first we had to pass. Our standard components for measuring the flow of gases are just as big and heavy as the components they were using." But then - through a combination of racing fever and experimental spirit - the Brkert team, after having resolved hydrogen supply, joined forces with the students to tackle the air supply problem.

Gunnesch emphasises: "Standard components were out of the question from the start. What we needed was an ultra light, one-of-a-kind component." This was based on a Brkert flow meter for gases, which was reduced to the bare bones, and advanced sensor technology that is not yet available on standard products. The result was an ultra-compact system for measuring the air flow in a compact design weighing several kilograms less than an approach using standard components. The Aerospace and Engineering Department at Delft tested the air flow meter and confirmed its excellent precision. Once it became clear that this approach was not only very lightweight but also functionally outstanding, the enthusiasm spread among everyone involved.

With the exception of the stack, the humidifier, the recirculation pump and the compressor, the rest of the fuel cell technology on the Forze V comes from Brkert. Forze team leader Jan Jaap Treurniet explains: "Thanks to the Brkert we were able to double the performance of the fuel cell in the Forze V in comparison with the Forze IV. At the same time, the weight of the vehicle was reduced by about 10 per cent from 312kg to 280kg. In motor sports, where fractions of seconds make a difference, that is a gigantic step forward."

And that is also exactly what Ross Brawn recognised when he visited the team during the Silverstone event. In an interview about the race, the Mercedes team leader called the Formula Student the most innovative racing class besides Formula 1. There are so many regulations for all the other classes that there is hardly room for genuine innovations.

The Forze V passed its baptism of fire in the Formula Student and cut a good figure in the race. Johann Gunnesch from the Brkert Systemhaus says: "The Delft team race car shows what highly motivated students can achieve in the space of only one year." The race car - "green' in more than one sense - sprints from 0-100km/h in less than five seconds and can run at full speed for about an hour on 600g of liquid hydrogen: in this case, 28 litres at 350bar. The only "emissions' left behind in the environment are about 5L of water. Johann Gunnesch continues: "Working on this project was great fun for all of us. The students' enthusiasm for their racing car was contagious. We are happy that we - as an innovative company - were able to contribute to the progress of a future technology such as the fuel cell drive system."

For more information about fluid control technology from Brkert, please visit their website at www.burkert.co.uk.