F1 | The secrets of the 2026 fuel flow meter: more complex and decisive
From 2026, the way fuel is measured in Formula 1 will become even more complex. But how will it work? We spoke with Allengra, the company that won the tender and will supply the new, advanced fuel flow meter this season. Beyond the mass flow, from this year the FIA will also calculate the energy flow of the fuel.
The importance of the fuel flow meter
If there’s one thing the turbo-hybrid era has taught us, it’s how critical and complex the fuel flow meter’s role is. This device monitors the flow of fuel from the tank to the engine, ensuring that FIA limits are not exceeded. Starting in 2026, with the arrival of the new Power Units, this element will undergo a deep evolution, both in measurement and in supplier.
After years where Sentronics supplied each car with two flow meters—one for the teams and one encrypted for the FIA—the contract will now go to Allengra, the company that won the tender for the new technical cycle. This is a major responsibility, as the flow meter handles some of the most sensitive parameters in F1, especially considering what happened prior to 2020. For this reason, a more advanced and functional unit was needed, precisely what Allengra developed.
Why the new sensor is a generational leap
To understand why the new sensor represents a real generational leap, it’s necessary to look at the changes. Until 2025, each team used two separate units. From 2026, there will be a single redesigned device. Allengra has managed to integrate two units within the same compact structure: one for the teams and one encrypted, accessible only to the FIA.
Advanced architecture for security
“You could say it’s like two units in one. A major advantage is that the tubes have different geometries, making it mechanically difficult to synchronize them perfectly at the same moment, even using the same measurement frequency. However, we use different measurement frequencies on the two tubes, combined with anti-aliasing functions, so teams cannot synchronize their readings,” explains Niels Junker, Co-CEO of Allengra, in an exclusive interview with Motorsport.com. He is the visionary behind the project to bring Allengra into Formula 1.
This architecture is not a simple technical detail but one of the main reasons the FIA approved it. The two fuel flow tubes have different geometries—a first level of protection making it mechanically hard for teams to synchronize measurements. A second level of protection comes from each tube using its own measurement frequency, further safeguarded by anti-aliasing functions that prevent any signal alignment.
The two units do not measure flow at the same frequency, which varies over time. This is crucial: even if a team hypothetically synchronized with its own flow meter, it could not replicate the encrypted unit’s readings, accessible only to the FIA in real time. The result is a multi-level security system designed to prevent synchronization attempts or manipulation of recorded values.
A system that measures 6,000 times per second
The Allengra flow meter operates between 4 and 6 kHz, roughly three times faster than current sensors. This means the detection process is repeated up to 6,000 times per second. Such a fast system cannot be calibrated with a classic Coriolis sensor, often used by teams in factories, which operates at only 300 Hz. That’s why Allengra developed its own internal ultrasonic reference sensor at 20 kHz, capable of validating the measurements obtained.
To understand why the FIA chose this new generation of flow meters, tested on track during some 2025 sessions, one must consider the device’s core. Imagine a flattened “U”-shaped structure: fuel enters one side, follows a set path, and exits the other. Two opposing ultrasonic transducers exchange a signal, and the “time of flight” it takes to cross the system is the key parameter. In static conditions, the system has all the data needed to determine this travel time.
When fuel flows, the signal is accelerated in the flow direction, like a boat carried by waves, and slowed in the opposite direction. Measuring the difference between the two travel times and knowing the distance between transducers allows precise calculation of the fluid velocity. Using the internal tube diameter, volumetric flow is then obtained. To account for variations due to temperature and operating conditions, mass flow is measured. Through specific calibration for each fuel, considering density and sound velocity, the flow meter calculates the regulatory flow in kg/h. In 2026, this limit drops to just over 70 kg/h, reducing fuel consumption.
From mass flow to energy flow
Mass flow data is essential but represents only the first step. The Allengra sensor will continue measuring mass flow, but from 2026 the FIA will also control the energy flow of the fuel. The energy content per mass of each fuel, certified by an independent third party, will be used to convert the kg/h readings into energy flow. The system ensures that the total energy flow does not exceed 3,000 MJ/h. For example, below 10,500 RPM, the allowed energy flow is calculated with the formula EF (MJ/h) = 0.27 × N (RPM) + 165.
What does this imply? Depending on the energy density of fuel developed by each manufacturer, differences in required mass flow to reach the 3,000 MJ/h limit may arise. Energy density becomes a strategic variable: denser fuel requires less mass to deliver the same energy. This also provides a potential weight advantage—less fuel onboard for the same energy. This is why the fuel war is so critical, and why costs are rising in pursuit of sustainable additives. And this is only the first part of the story…
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