Formula 1’s battle over fuel flow monitoring has spilled into the courtroom, with former supplier Sentronics Holdings Ltd launching legal action against the company that took over its role this season.

The British firm filed a patent infringement lawsuit against German manufacturer Allengra GmbH in the US District Court for the Western District of Texas on October 16, just days before Formula 1 arrives in Austin for this weekend’s United States Grand Prix.

Sentronics is demanding a jury trial and seeking financial compensation, along with a permanent ban on Allengra supplying the disputed equipment in the United States.

A change of supplier sparks legal dispute

Sentronics served as the FIA’s exclusive fuel flow meter supplier for Formula 1 from 2018 through 2025, before Allengra secured the contract covering the 2026–2030 seasons in November 2024.

Fuel flow meters are a crucial element of the sport’s technical policing. They measure the rate at which fuel reaches an engine, enabling the FIA to enforce regulatory limits designed to prevent teams from gaining an advantage through excessive fuel delivery and increased combustion-engine power.

At the heart of the dispute is US patent 11,391,609, awarded to Sentronics in July 2022.

The patent covers a method of measuring fuel flow using ultrasonic signals travelling through a fluid in opposite directions. By measuring differences in their propagation times and adjusting their phase, the system can calculate the flow rate.

According to the complaint – reported by website PlanetF1, Sentronics conducted laboratory tests in late 2024 that it says confirmed Allengra’s meters infringed its patent. The British company also alleges that it previously shared technical information with the FIA under a non-disclosure agreement.

Allegations of wilful infringement

Sentronics further accuses Allengra of encouraging the FIA and Formula 1 teams to use the contested meters at American races, specifically naming Austin, Miami and Las Vegas.

The complaint alleges that the infringement was deliberate. Sentronics says Allengra was notified of the corresponding European patent in August 2025, while a formal demand letter sent by Sentronics’ lawyers in April 2026 was disputed by Allengra’s US legal representatives.

The FIA had also acknowledged receiving an earlier notification from Sentronics on September 17, 2025, responding that the contents were “duly noted”, according to the filing.

Sentronics is asking the court to award damages for lost profits and royalties, potentially dating back to 2022. It is also seeking to have those damages tripled on the grounds that the alleged infringement was wilful.

The case now places Formula 1’s current fuel flow monitoring supplier under legal scrutiny in the United States, with the championship’s Austin visit providing an immediate backdrop to the dispute.