The transition to hybrid power was formally announced by the FIA to replace the 2.4-litre V8 formula used from 2006 to 2013. While an initial proposal for four-cylinder turbocharged engines was considered, a compromise led to the adoption of the 90-degree V6 configuration. The new 1.6-litre engines featured a fixed bore of 80 mm and a stroke of 53 mm.
Unlike previous eras that limited boost pressure, the hybrid era introduced a fuel flow restriction of 100 kg/h. This regulation fundamentally changed engine development, making thermal efficiency a primary competitive factor. Forced induction returned to the sport for the first time since 1988, with all manufacturers opting for single-stage turbochargers.
The hybrid power unit is composed of several distinct systems regulated by the FIA:
Internal Combustion Engine (ICE): A 1.6-litre V6 reciprocating engine with four valves per cylinder and a maximum mechanical compression ratio of 18:1.
Motor Generator Unit–Kinetic (MGU-K): An electric motor connected to the crankshaft that recovers energy under braking (up to 2 MJ per lap) and can deploy up to 120 kW (160 hp) of power.
Motor Generator Unit–Heat (MGU-H): An electric motor positioned on the common shaft between the exhaust turbine and intake compressor. It recovers energy from exhaust gases and can either drive the turbocharger to eliminate lag or send power directly to the MGU-K.
Energy Store: A high-voltage lithium-ion battery system, often paired with supercapacitors, weighing between 20 kg and 25 kg.
From 2014 to 2025, power outputs steadily increased despite the fuel flow limits. In 2014, Mercedes, Ferrari, and Renault were the sole manufacturers, with Honda joining in 2015. By 2015, the Mercedes engine reached approximately 870 hp (649 kW). By 2019, Renault claimed its engine had reached 1,000 hp in qualifying trim.
Efficiency gains were significant during this period. The Honda RA621H engine used in 2021 generated over 100 kW (130 bhp) more power than the 2015 RA615H while using the same 100 kg/h fuel flow rate. Manufacturers achieved these gains through lean and rapid burn techniques, enabling an air/fuel ratio much leaner than the traditional 14.7:1.
In 2022, the FIA implemented a "freeze" on power unit specifications, locking the design of the ICE, turbocharger, and MGU-H until the end of the 2025 season. This was intended to control costs as manufacturers shifted focus to the upcoming 2026 regulations.
The hybrid era engines operate at lower rotational speeds than their predecessors. Although the regulations allow for 15,000 rpm, engines rarely exceed 12,000 rpm in practice. The use of the turbocharger and lower rev limits significantly altered the exhaust note compared to the previous V8 and V10 eras.
To manage the complexity of these units, all teams use a standard FIA Electronic Control Unit (ECU). This system manages energy recovery, deployment strategies, and fuel injection pressures, which are limited to a maximum of 500 bar.
A new set of regulations is scheduled for 2026, marking a change to the power unit configuration. While the 1.6-litre V6 ICE will be retained, the MGU-H will be banned to simplify the technology and reduce costs. To compensate for the loss of heat energy recovery, the MGU-K's output will increase. The ICE’s power contribution will be reduced, and the cars will run on fully sustainable fuels.
New manufacturers confirmed for this upcoming cycle include Audi and a Red Bull-Ford partnership, while General Motors (Cadillac) has been confirmed as a power unit supplier starting in 2029.