At the Shell Eco-Marathon 2025, the Ecogenium Team achieved a specific range of 2,647 km/kg H₂ with their hydrogen prototype vehicle Hydraix II, placing them in second place worldwide. In order to achieve this level of efficiency, it was necessary to measure the hydrogen mass flow accurately, reproducibly, and dynamically stable throughout the entire driving cycle.
The use of the red-y smart series mass flow meter enabled hydrogen consumption to be precisely monitored and systematically optimized. The high data quality and measurement stability contributed significantly to achieving a range of 2,647 km/kg H₂ and second place worldwide in the Shell Eco-Marathon. This application exemplifies how precise mass flow measurement in hydrogen systems contributes to maximizing efficiency and reproducibility—even under real and dynamic operating conditions.
Real-time hydrogen flow
The red-y smart series mass flow meter from Vögtlin Instruments was integrated into the vehicle’s hydrogen supply system to continuously measure the mass flow directly in the supply line. The measurement data was transferred to the control system in real time and was used both for consumption monitoring and for downstream analysis to optimize the control strategy and driving profile.
Due to the limited installation space in the vehicle, the measuring device had to be compact and easy to integrate into the existing system, both mechanically and electrically. At the same time, a high level of measurement stability was required in order to provide valid and noise-free signals even at very low flow rates.
Precision under extreme conditions
The competition placed high demands on the measurement technology. The aim was to achieve the most constant hydrogen mass flow possible and a stable supply to the fuel cell, which feeds its energy into capacitors in order to minimize efficiency losses due to load peaks.
During the journey, so-called purge processes occur at regular intervals. These involve the brief opening of valves to release nitrogen deposits from the fuel cell. These processes are accompanied by a short-term increase in hydrogen mass flow and must be reliably recorded by measurement technology.
In addition, elevated ambient temperatures of over 30 °C and mechanical influences from driving had an impact on the overall system. Under these conditions, drift-free, temperature-stable, and fast-responding flow measurement was crucial in order to obtain reliable data for system optimization.
Stable data at minimal flow rates
The red-y smart series met these requirements thanks to its high measurement accuracy at very low gas flow rates and its fast sensor response time in transient operating conditions. The stable and reproducible measurement of the hydrogen mass flow enabled precise quantification of energy consumption over the entire driving cycle.
In addition, the mass flow meter was used intensively in stationary test series to determine the consumption and optimal operating point of the fuel cell at different power levels. The digital readability of the measured values proved to be a decisive advantage both in the development phase and in competition.
The compact design of the device facilitated integration into the vehicle, while the high data quality provided a reliable basis for software adjustments and performance analyses between individual runs. The red-y smart series thus made a measurable contribution to increasing the efficiency of the overall system.
