The secret 2021 engine targets F1 is working on

Turbo hybrid engines have been both a success story and disaster for Formula 1.

On the one-hand we've had a fresh impetus for cutting edge technology, power units that touch 1000bhp again, renewed interest from manufacturers and new records for thermal efficiency.

On the downside, we've seen engine costs go through the roof, grid penalties reach farcical levels, one manufacturer with a big advantage, criticisms about noise and far too much lifting-and-coasting.

Bernie Ecclestone hated these engines before they ever hit the track, and F1's new owners have quickly come to the conclusion that it cannot continue like this after 2020.

As Ross Brawn, speaking about the current F1 engine, told Autosport at the end of last year: "It is very expensive. It doesn't make any noise. It has componentry that, in order to try to control the number of uses, is creating grid penalties that make a farce of F1.

"Plus there are big differentials of performance between the competitors and we are never going to get anyone else to come in and make engines. So we have the four people we have now and maybe we will lose one or two of them if they continue the way they are. We can't leave it as it is."

Although the current manufacturers accept that things are far from ideal with the way the current rules are framed, they equally do not want to face the task of coming up with an all-new engine concept from 2021.

For that would mean throwing away the hundreds of millions of pounds that have been invested in their power units so far during this rules cycle.

The challenge of finding the right engine solution is going to dominate F1's political landscape for the next few months. There will be the FIA and F1's owners on one side pushing an agenda for change, while the manufacturers kick back to ensure that they are not compromised too much.

Initial proposals last year presented to the teams for the new engines prompted an outcry from Mercedes and Renault, who feared they would be faced with an unnecessary spending war in creating an all-new engine. The renewal of Ferrari's quit threats was also sparked by this, with Toto Wolff recently warning that this must be taken seriously.

But in the end, a counter proposal from the manufacturers was sent back two months ago, and is now being analysed by the FIA's head of engines Gilles Simon to try to find some common ground.

The real issue at stake here is to come up with an engine that means something to fans

While F1 chiefs may hope that a deal can be reached to keep the current manufacturers happy and entice new entrants, there is no illusion that everyone will leave the discussions happy.

As Jean Todt said last week: "If you tell me the 10 existing teams, the commercial rights holder, and the FIA need to agree on each single paragraph of the rules, that will not work."

Compromise will be the name of the game, but having got so much wrong with the current V6 turbo hybrids, it's essential that key elements of this overhaul are not thrown in the bin.

If F1 gets the next rules cycle wrong, it's going to be much harder to bring it back to the right path during a period when F1 will face ever greater challenges - both in terms of audiences and road relevance as electrification gathers pace.

Central to this debate is not ultimately whether we keep the MGU-H, bring more standard parts, open up battery technology or even abandon turbos entirely.

Instead, the real issue at stake here is to come up with an engine that means something to fans. If those sat at home watching on television, or those trackside, are not enthused by the engines - and instead see power units in a purely negative light - then F1 will have failed.

That is why it is heartening to hear that there is a secret working brief that the FIA, the car makers and F1's chiefs are all agreed to, and have been working to for months.

In simple terms, the key targets that F1's 2021 engines must hit are:

- The power unit must be less expensive to develop and produce

- The power unit must be simpler

- It must be road-relevant and it must be hybrid

- F1 must be a power-to-weight related formula

- It must have a better sound

- It must use some standard parts

- It must be used by a driver at its full potential 100% of the time.

Of course some of these targets are of more importance to the manufacturers, and others matter more to F1 itself. But if any of them are taken away, then it will be a big blow for all of us.

A simpler, less expensive engine can still be cutting edge in technology terms. If some parts are homologated, or can be designed/developed to be easily replaced, then that is a good step in the right direction to eradicate the lunacy of grid penalties.

Don't forget that it is only the huge expense of a new turbo, new MGU-H or MGU-K that ultimately created the need to limit the number of components used per season as a means of keeping costs under control.

The over-complication and spending arms race involved with the current engines has contributed to opening up performance between teams, and making it so difficult for those behind to catch up. Heading into year five of these regulations, there is every reason to suspect Mercedes' advantage will be just as big as it has been for the previous seasons.

A more competitive field of manufacturers all within spitting distance of each other, where grid penalties are the exception rather than the rule, is exactly the sort of thing that F1 should be striving for.

But the 2021 engine check list goes deeper than just having good racing, for some of these targets go right to the core of F1's passion and attraction.

Keeping F1 as a power-to-weight related formula will ensure F1 cars are still the fastest and best out there; having louder engines is essential just to stop the subject of noise constantly coming up.

And that final target of having an engine where a driver can push it to its full potential all the time is perhaps the most important of all.

However much 50%-plus thermal efficiency and completing races on 105kg of fuel are impressive achievements from an engineering perspective, F1 should really be about the best drivers pushing the fastest cars flat out all the time.

As Brawn said: "We don't want a driver on fuel consumption pootling around."

Make no mistake, there are going to be table-banging moments between the manufacturers. One is likely to be over whether the MGU-H remains.

While F1's chiefs have been clear that the MGU-H has brought little benefit, and has not offered the road car crossover that was thought possible when the current rules were framed, the car-makers don't strictly agree.

"We [F1] call it the MGU-H, but it is an electric compressor. And these eBoosters are appearing in the road car world" Mercedes engine boss Andy Cowell

On the racing front, remove the MGU-H and you will have to find an alternative way of replacing the power boost it delivers. You would have to increase the revs, but that would lead to an increased demand for fuel - so in the end cars (which are already too heavy) would get much heavier and slower.

The road relevance issue is also not as clear-cut as the repeated argument that the MGU-H has failed because there are no road cars (beyond Mercedes' Project One hypercar that has an F1 engine built-in) that has one fitted.

It was interesting last week to hear Mercedes engine chief Andy Cowell shoot down soundbites that the MGU-H needs to go because it has no future in road cars.

"I think what we are already seeing are eBoosters," said Cowell, referring to one way that the MGU-H technology has started to shift to consumer engines.

"We [F1] call it the MGU-H, but it is an electric compressor. And these eBoosters are appearing in the road car world. Just look at BorgWarner. They are creating eBoosters to help with heavily turbocharged downsized engines - which is exactly what F1 has got."

There are intense technical fights to be had over the specifics of the regulations, and defining the presence and complexity of the individual components that will make up the future turbo hybrids.

But none of those talks and decisions, and none of the eventual compromises, must be allowed to stop F1 focusing on those seven targets for the louder, faster, better, flat-out engine that all fans deserve.

Critically, there won't be a third chance to get the engine rules right if they are not spot on this time.