Formula One and the FIA have outlined proposals for the next generation of power units (PU), aimed at improving noise, reducing costs and making the sport a more level playing field.

The plans - intended to come into being in 2021 - were announced at a summit in Paris, attended by the FIA, F1 owners Liberty Media and representatives from current and potential manufacturers.

An FIA statement explained: "In line with the objectives outlined by the FIA for the future of these regulations, which include a reduction in cost, maintaining road relevance with hybrid technology and improving the sound of the cars and the appeal for the fans, manufacturer representatives were presented with a roadmap for the development of the next generation of regulations.

"The proposals shared today have been developed jointly by the FIA and by F1 using data and input from teams, power unit suppliers and outside experts, and the overall framework for the 2021 power unit definition will be in place and published by the FIA at the end of 2017.

"In order to uphold the objective of cost reduction, work will continue over the next 12 months to define certain elements of the power unit, but the design and development of the complete power unit will not be possible until all the information is released at the end of 2018. This aims to ensure that manufacturers continue to work on the current specification power unit.

"During the remaining part of 2017 and 2018, the FIA and F1 will also work with the teams to establish power unit test and development restrictions as well as other cost containment measures."

The reduction in noise has been one of the main criticisms of F1's hybrid era, with some fans believing the sound of the cars to be a major part of the sport's appeal.

"We've carefully listened to what the fans think about the current PU and what they would like to see in the near future, with the objective to define a set of regulations which will provide a powertrain that is simpler, cheaper and noisier and will create the conditions to facilitate new manufacturers to enter Formula One as powertrain suppliers and to reach a more levelled field in the sport," said F1 motorsports managing director Ross Brawn.

"The new F1 has the target to be the world's leading global sports competition married to state of the art technology. To excite, engage and awe fans of all ages but to do so in a sustainable manner.

"We believe that the future power unit will achieve this.

"The 2021 power unit is an example of the future way the FIA as regulators, F1 as commercial right holders, the teams and the manufacturers as stakeholders will work together for the common good of the sport."

Key features of new proposals:

- 1.6 litre, V6 Turbo Hybrid
- 3000rpm higher engine running speed range to improve the sound
- Prescriptive internal design parameters to restrict development costs and discourage extreme designs and running conditions
- Removal of the MGUH
- More powerful MGUK with focus on manual driver deployment in race together with option to save up energy over several laps to give a driver controlled tactical element to racing
- Single turbo with dimensional constraints and weight limits
- Standard energy store and control electronics
- High level of external prescriptive design to give ‘Plug-And-Play’ engine/chassis/transmission swap capability
- Intention to investigate tighter fuel regulations and limits on number of fuels used