Formula 1 is set to maintain the DI V6 turbo hybrid power units for the foreseeable future. However, after extensive discussions with the current and some intent OEMs, the next generation, set to arrive in 2026, will contain some crucial recipe changes. One of the most significant is eliminating the turbocharger shaft-mounted e-Turbo-style heat energy recovery system (H-ERS). The H-ERS is a motor-generator unit mounted on the turbocharger shaft of a Formula 1 internal combustion engine. The unit converts the heat energy from the exhaust gases into electrical energy. The electrical energy is then used to power the car’s electrical driveline (either charging the battery or directly deployed to the kinetic energy recovery unit) to boost the power unit’s performance. It’s arguably the most significant performance differentiating system onboard the power unit.
Understanding how this primary performance driver has been eliminated from the regulations is about understanding the parties interested in entering in 2026 – namely Volkswagen Group. The Volkswagen Group’s Porsche Motorsport outfit has kept its eye on Formula 1’s power unit evolution for over a decade. It even developed a current spec V6 before scrapping its Formula 1 entry evaluation program. These efforts were scrapped because Porsche didn’t agree with the turbocharger shaft-mounted e-Turbo style H-ERS. It felt it was hugely expensive to develop and had little road car powertrain relevance.
It began discussions with Formula 1 about scrapping the e-Turbo style H-ERS and running the DI V6 turbo power unit either without an H-ERS or using a style of H-ERS it had developed in its 2014-2017 WEC campaign – specifically, the turbocharged 2.1 litre 9R9 V4 with H-ERS that powered its three-time Le Mans-winning 919 LMP1 hybrid prototype. Porsche recognised Formula 1 and the LMP1 rules had one fundamental similarity – they were both fuel flow-limited formulas, which meant to be powerful, they needed to be efficient. Fuel flow has been the overarching limitation on the performance of Formula 1 hybrids and prototype engines since 2014. But prototype power units had relatively few restrictions when Formula 1 insisted on using gasoline direct-injected 1.6 litre V6 turbo married to an H-ERS on the turbo shaft. People often talk in awe of the efficiency of today’s Formula 1 power units. Still, they demonstrate what is possible only within a type of power unit the FIA prescribed. The relative freedom in exploiting a given fuel allocation seen in LMP1 saw some unique innovations.
A key design feature of the 9R9 engine is its 35kW post-waste gate mounted H-ERS. Located in series with the turbocharger, it uses only waste gated exhaust gas to drive the MGU. The turbocharger is conventional and never receives input from the electric motor element. H-ERS torque load control is done with a variable turbine. Constantly changing the positions of the variable vanes keeps the H-ERS engaged to ensure it is in the most efficient region for harvesting at all times. The engine still operates as a regular ICE if you take away the 9R9’s H-ERS. It is so efficient that there is less than a 0.1 per cent difference in engine power output between regular waste gating compared to the H-ERS in full harvesting mode, and it can switch between those two modes very quickly.
The 9R9 H-ERS configuration means the turbocharger energy to the engine is almost constant without the increased load from the Formula 1 style e-Turbo H-ERS. Although less dynamically responsive than the Formula 1 solution, Porsche’s post waste gate solution is far more appropriate for road car applications. It could even be retro fitted to existing turbocharged ICEs; the 9R9 is a standalone engine in the hybrid 919 chassis with a front axle electrical drive system – making for a parallel four-wheel-drive system with H-ERS charging for range extension – a solution far more akin to what OEMs could use on the road.
Additionally, Formula 1 is considering front axle energy recovery in the framework of the 2026 powertrain rules, though talks about whether it will ever use front driveline deployment are understood to be ongoing. Formula E is adopting a front axle driveline recovery system this year with its Gen3. It, too, will evaluate how the front axle recovery system operated in racing conditions will work and whether it could introduce deployment in further seasons.
The fact that these technologies are on the table and the e-Turbo style H-ERS is off shows how hugely influential OEMs like the Volkswagen Group are to Formula 1, as its technical staff consider their desires.
