The turbocharged hybrid era in Formula 1 has underscored one fundamental truth: fuel flow measurement represents both a critical regulatory checkpoint and a sophisticated technical challenge. As teams pushed efficiency boundaries while constrained by fuel load and flow rate limits, the devices monitoring these parameters evolved into some of the most scrutinised instruments in the sport. Now, with 2026’s radical power unit regulations approaching, the technology safeguarding these vital measurements is undergoing its most significant transformation yet.
New supplier brings dual-system integration
After years of Sentronics providing twin flow meters for every car—one accessible to teams, another encrypted exclusively for FIA oversight—Allengra has secured the supply contract for the next technical cycle. This change marks more than a simple supplier switch. The German company has consolidated both measurement systems into a single compact unit, addressing one of the sport’s most sensitive technical areas following the controversies that erupted during the 2019 season.
The integration challenge was substantial. Rather than simply housing two identical sensors in one casing, Allengra’s solution employs fundamentally different architectures for each measurement channel. The fuel passes through pipes with distinct geometries, making mechanical synchronisation between the two systems extremely difficult even when operating at identical frequencies.
“We use different measurement frequencies on the two pipes, combined with anti-aliasing functions, so the teams cannot synchronise with the frequency,” explains Niels Junker, Allengra’s co-CEO. This dual-layer protection strategy creates a formidable barrier against potential manipulation attempts. The varying geometries provide physical security, while the frequency differentiation—enhanced by anti-aliasing technology—prevents signal alignment between the team-accessible and FIA-encrypted channels.
Operating at unprecedented measurement speeds
The 2026 flow meter functions between 4,000 and 6,000 hertz, approximately triple the sampling rate of current sensors. At peak operation, the system captures and processes fuel flow data 6,000 times every second. This dramatic increase in measurement frequency demanded entirely new calibration approaches, as conventional Coriolis sensors typically used by teams during factory development operate at just 300Hz—far too slow to validate the on-track unit’s readings.
Allengra developed a proprietary 20kHz ultrasonic reference sensor specifically to address this calibration gap. The measurement principle relies on ultrasonic time-of-flight technology within a flattened U-shaped flow path. Two opposing transducers continuously exchange signals through the fuel stream, with the transit time providing the key measurement variable.
When fuel flows through the system, it influences signal propagation similarly to how water currents affect a swimmer—accelerating transit in the flow direction while retarding it against the current. By measuring the differential between these two transit times across a known distance, the system precisely calculates fluid velocity. Combined with the pipe’s internal diameter, this yields volumetric flow rate. However, volume alone proves insufficient, as it fluctuates with temperature and pressure conditions.
From volume to mass measurement
The sensor therefore derives mass flow rate through fuel-specific calibration data accounting for density and sound propagation characteristics. This mass flow value, expressed in kilograms per hour, will drop to approximately 70kg/h under the 2026 regulations—a significant reduction from current limits. Yet mass flow represents just one dimension of what the new system will monitor. At the FIA’s direction, Allengra’s sensor will track an additional control parameter that fundamentally changes how fuel usage is regulated.
Energy flow becomes the regulatory benchmark
The 2026 technical regulations introduce energy flow rate as the primary control parameter. Each fuel’s energy characteristics—measured per unit mass—will undergo certification by independent third-party laboratories before reaching any circuit. The flow meter’s mass measurement in kg/h will be converted by the homologated engine control unit into fuel energy flow, using the certified energy density and lower heating value specific to each fuel formulation.
This converted value faces a hard ceiling of 3,000 megajoules per hour. The regulations establish a sliding scale below certain engine speeds: beneath 10,500rpm, for instance, permitted energy flow cannot exceed the figure calculated using the formula EF (MJ/h) = 0.27 × N (engine speed) + 165. This approach fundamentally alters the strategic landscape surrounding fuel development.
Different fuel formulations will require varying mass flow rates to reach the fixed 3,000 MJ/h energy limit. A fuel with higher energy density per kilogram delivers the same total energy from less mass. This difference, though seemingly minor, carries significant implications for vehicle weight distribution and fuel load strategy. Manufacturers developing more energy-dense fuels can carry fewer kilograms aboard while still supplying identical energy to the power unit.
Security architecture prevents circumvention attempts
The dual-channel design with asynchronous measurement frequencies creates multiple security layers that would need simultaneous compromise for any manipulation to succeed. Even if a team somehow synchronised with its accessible flow meter’s frequency—already complicated by the anti-aliasing functions—the second encrypted channel operates on an entirely different, time-varying frequency accessible only to race control in real time.
This architecture directly addresses lessons learned from previous regulatory disputes. The 2019 controversies prompted the FIA to mandate redundant measurement systems, but the previous generation required two physically separate units. Consolidating both into a single device while maintaining complete measurement independence represents a significant engineering achievement, particularly given the packaging constraints within modern F1 power units.
Track validation throughout 2025 confirmed the system’s reliability across varying conditions. The ultrasonic measurement principle offers advantages beyond security—it maintains accuracy across the wide operating range demanded by 2026’s power units, which will derive significantly more output from electrical energy while reducing internal combustion contribution.
What this means for the development race ahead
The shift toward energy flow measurement as the primary regulatory parameter places unprecedented emphasis on fuel chemistry development. Manufacturers and their fuel partners now face a clear development target: maximise energy density while meeting all other regulatory requirements for fuel composition. Success in this area translates directly to potential weight advantages and strategic flexibility during races.
This technical evolution arrives as Formula 1 prepares for its most significant power unit transformation since the turbo-hybrid era began. The 2026 regulations demand substantially increased electrical output while reducing fuel flow limits, creating entirely new optimisation challenges for power unit manufacturers. The flow meter, often overlooked in discussions of engine performance, sits at the centre of this regulatory framework—the instrument that defines what is possible and ensures compliance.
As teams finalise their 2026 power unit designs, the fuel development programmes running parallel will prove equally crucial. The measurement technology ensuring fair competition may operate invisibly during race weekends, but its influence on how manufacturers approach these radical new regulations cannot be overstated. The race to develop fuels that deliver maximum energy from minimum mass has begun, with implications that will shape the entire technical cycle ahead.
