Honda RA619H power unit, 2019

The hidden challenges of F1’s biggest change to its power unit rules since 2014

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Formula 1’s most dramatic rules changes this year are to the most visible parts of the car. Aerodynamics have been reworked and new, bigger wheels brought in to change the look of what you see on track.

Much less obviously, it’s also switching from 5% ethanol fuel to 10%. But what may sound like a small detail will have a significant effect on power units.

What’s more, the manufacturers need to get their adjustments for the new fuel blend right first time. This is because, following Honda’s decision to withdraw from the world championship as a manufacturer at the end of last season, F1 agreed to implement a freeze on power unit development during 2022.

That will last until the next engine formula arrives, which is currently slated for 2026. While some modifications for reliability are likely to be permitted after the freeze comes in, reliability problems can be disruptive for a championship bid, as Mercedes’ experience last year showed.

The switch to E10 as come about in order for F1 to better reflect what’s happening in the wider automotive industry. F1 uses road-legal fuel blends (even if they’re not identical to those you can buy at the pumps) and many countries are now moving to E10 petrol: It’s the default in the US, Australia, across Europe and now also in the UK.

In theory, this ethanol should be sourced from biological waste products (like food by-products) rather than farmed crops, to limit the negative impact of agriculture on the environment. For a series trying to be both more relevant and greener, it’s obvious why F1 would step from 5% to 10% bioethanol.

E10 fuel is increasingly commonplace on forecourts
Hywel Thomas, the managing director of Mercedes’ High Performance Powertrains, called the move to E10 “probably the largest regulation change we have had since 2014” from the power unit perspective. After F1 declared last season it would put a greater focus on the efficiency of its hybrid power units, the shift to E10 presents a new challenge to teams to maintain that.

Many of the potential problems with using E10 in road cars won’t trouble F1 cars. My 1993 Renault Twingo’s elderly engine would run into trouble caused by the damage E10 can do to rubber connectors and sealants in older cars. But an F1 V6 turbo is rather different from a four-cylinder Cleon Fonté. F1 cars are regularly stripped down, with seals and gaskets replaced, and 2022’s internal combustion engines are designed specifically for the new fuel mix.

However, there is one element that affects both road cars and F1 and that comes down to the energy density of the fuel. There’s about a 1.1% negative difference between the calorific value of 5% ethanol fuel vs 10% ethanol fuel.

Road cars which switch from 5% ethanol fuel to 10% do see some, mostly minor, differences. A study across cars in Finland found that there was a detectable but small loss of fuel efficiency, with cars needing 10.3 litres of E10 to drive 100km but 10.23 litres of E5 – a margin of just 0.07 litres or 70 millilitres. While this would hardly trouble an ordinary motorist, in F1 these tiny margins matter, and engineers have been hard at work optimising their power units to minimise these losses.

Even allowing for more specific, high-energy fuel blends in F1 than at most standard petrol pumps, there will be no way fully around the losses. Ethanol simply contains less energy than fossil fuels, as well as being slightly heavier than petrol. Again, in a normal context you wouldn’t notice that, but this is F1.

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IndyCar currently fills its tanks with 85% ethanol fuel – not a road-use mix, but a replacement for its old methanol fuel. Its cars manage around 1.92 miles per gallon on race pace. But fuel management in IndyCar is less critical as drivers can top up during races.

Alexander Rossi, Andretti, IndyCar, Sebring, 2022
IndyCar fuel contains a much higher proportion of ethanol
Maxed out, IndyCars get through about 375kg of E85 over the course of the Indianapolis 500, which is more than twice the distance of a grand prix. F1 cars have been regulated to use just 110kg of fuel per race since 2019, but whether that number can stand the switch to E10 is a question that has yet to be answered.

Per gallon, E85 is only about 200g heavier than conventional petrol. Of course, the difference with E10 is much, much smaller than that. But there’s still, given the weight limit, a lower volume of fuel, with lower energy density, that will need to carry out the whole grand prix.

That puts some more pressure on the hybrid parts of the power unit to recover energy. It would be possible for the MGU-H and MGU-K to feed more back into the battery, in particular the MGU-K, however, the regulations have not shifted to allow that compensation and remain at the comparatively low 4MJ per lap maximum usage with only 2MJ per lap recoverable from braking.

At the same time, as E10 places a greater efficiency demand on an ultimately smaller amount of available fuel energy, it also puts stressors on the engine components. In a 2017 study Malaysian academics found there was a significant degradation of engine oil viscosity with E10 due to the higher burn temperatures of bioethanol. That means there’s more friction when the piston moves in the combustion chamber – again, not something a lot of people with road cars would notice (let’s be honest, we all know someone who never checks their oil) but an F1 technician definitely will.

Limited testing means teams can’t afford technical trouble
There was also increased acidity in the chambers, as well as greater fuel residue build-up. It’s worth saying this study was with commercially-available blends – not the sort of bespoke fluids that F1 teams get their oil and lubricant partners to make – but when these are all already factors of performance and wear that a team will be managing over an internal combustion engine’s life, any variation becomes significant. Mercedes’ internal combustion engine degradation last year would have been in the margins no roadgoing vehicle would experienced but that’s why F1 is the spectacle it is.

Of course there are not impossible for teams to overcome. The efficiency performance that’s been achieved in F1 is incredible and the technology being used is on a bleeding edge it’s hard to comprehend in meaningful, real-world terms. But underneath all the visible changes, this is a radical shift during a power unit development freeze.

E10 performance will be one of the things it’s hardest to detect, from Barcelona testing next week. Without knowing what fuel loads teams run or how they’re intending programmes to run it’s impossible to say whether there are efficiency issues but reliability problems will immediately stand out – and have costly knock-on effects for mastering all the other changes teams are grappling with this year.

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Author information

Hazel Southwell
Hazel is a motorsport and automotive journalist with a particular interest in hybrid systems, electrification, batteries and new fuel technologies....

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44 comments on “The hidden challenges of F1’s biggest change to its power unit rules since 2014”

  1. So to be more environmentally friendly they are switching to a blend that is less fuel efficient? Sounds about right! :-)

    1. I’m not sure it is actually “less fuel efficient”. It requires a greater quantity of fuel to do the same amount of work, but that’s because the fuel contains less energy. The efficiency (energy in -> work done) is likely to be roughly the same.

      Also, it is* more environmentally friendly because 10% is not fossil fuel anymore, but ethanol, which can be produced by sustainable and environmentally friendly methods.

      * of course, as mentioned in the article, this depends on them actually using ethanol which is produced in sustainable and environmentally friendly ways…

      1. If we work in absolute terms, it ends up being less efficient.
        You have to carry more fuel load to go the same distance which means you then burn much more fuel to carry the extra load.

      2. Biskit Boy (@sean-p-newmanlive-co-uk)
        16th February 2022, 11:26

        Also its debatable whether ethanol is right way to be powering road cars going forward. Its production consumes large areas of land, promoting deforestation and land better used for growing food crops. Water consumption is also a big negative.

        Photosynthesis is about 1% efficient in getting energy from the sun. Photo voltaic cells are about 20-40% efficient. So if we want energy from sun and land, then use solar panels and make electric for PHEVs and BEVs. This is waaaaay more efficient, even when you factor in the need to produce panels and batteries.

        1. Also its debatable whether ethanol is right way to be powering road cars going forward.

          Also its debatable whether Battery/Electric is right way to be powering road cars going forward @sean-p-newmanlive-co-uk.
          Neither battery/electric nor environmentally ‘friendlier’ liquid petrol/diesel replacements (or their respective hybrids) are ideal for every single use case around the world – nor will they be 20 years from now.
          Different cases require different solutions.

          Whatever – it’s in a constant state of evolution.
          Something/s will inevitably replace both of these energy storage forms at some point in the future.
          Whatever is done to improve what we have now until that day comes is an improvement.

          1. Biskit Boy (@sean-p-newmanlive-co-uk)
            16th February 2022, 12:36

            Agree with you 100% regards the constant state of evolution in this area.

            As for

            Whatever is done to improve what we have now until that day comes is an improvement.

            Hmm not so sure. We need to avoid dead end technologies and develop the best available, hence my preference for BEVs. Ethanol production has only made small gains in efficiency over many years, whereas, BEVs are improving rapidly at the moment.

            Within 5 years BEVs will be cheaper to buy than ICE cars, they already cheaper to run and own over their lifetimes. The main real question marks are over, cleaner battery chemistries, range (already fast approaching ICE) and refuel times. Within 10 years BEVs that refuel as quickly as ICE cars will probably be relatively common, certainly within 20 years.

            Ethanol may be part of the equation in the short term yes, but for any energy source to compete with electric in the long term, it will take something special. And perhaps as you say

            Something/s will inevitably replace both of these energy storage forms at some point in the future

            , but again its hard to see anything based on something other than electric which is such a universally fundamental entity.

          2. Ethanol production has only made small gains in efficiency over many years, whereas, BEVs are improving rapidly at the moment.

            Battery tech made little significant gain for a century – but then money, time and effort was suddenly poured into it.
            Give ethanol/bio/synthetic liquid fuels that same attention and resources, and there would inevitably be significant gains there too.

            The main real question marks are over

            Only for a small percentage of usage cases.
            I agree, small electric cars are great for city dwellers – but they don’t do much for those who live in remote or rural areas, nor for those who have industrial usage requirements (trucks and buses, for example). Nor for those who simply can’t afford to go out and buy a new car.

            but again its hard to see anything based on something other than electric which is such a universally fundamental entity.

            It’s not hard when you consider those of us who fall outside of the target/key market for electric propulsion in the near future.

            Limiting or eliminating development of a replacement liquid fuel renders almost every vehicle and non-electric machine on earth obsolete… Think about the effects of that.

          3. Most likely it will be a combination of both, as it will be hard for electric to cover all use cases. It’s just the newest trend. Point is, reducing emissions.

            Now for F1, it is simply doing what it can to stay road-relevant but we can argue that that ship has sailed around the 90s when they banned electronic aids. Aerodynamics are hardly relevant for 98% of road cars, ICEs have 100+ years of development. Maybe the hybrid parts? In the future maybe it swallows FE and we make one exciting hybrid formula.

          4. Biskit Boy (@sean-p-newmanlive-co-uk)
            16th February 2022, 19:46

            Give ethanol/bio/synthetic liquid fuels that same attention and resources

            Well this won’t happen. The US Government has wasted millions trying to kick start it. The potential gains are too small and the cost of the product would almost certainly be too high. The fact is, given the current laws of physics in this universe, this is an intrinsically less efficient way of creating and consuming fuel. BMW amongst others are abandoning this approach, because they have smelled the coffee.

            Limiting or eliminating development of a replacement liquid fuel renders almost every vehicle and non-electric machine on earth obsolete… Think about the effects of that.

            No one is suggesting ICE powered cars are scrapped before their end of life. Where possible it will be better for the planet if when a new car is purchased it be an electric one.

            small electric cars are great for city dwellers – but they don’t do much for those who live in remote or rural areas

            Look I understand the emotional attachment to ICE cars. I miss mine sometimes and there will be niche applications for them in the future I’m sure, but if BEVs of the future have an equivalent range, take minutes to refuel and are cheaper to buy and much cheaper to run than an ICE cars then who in their right mind wouldn’t prefer one?
            And in case you don’t think this is a realistic possibility, then I’m not going to spend anymore time trying to convince you, why not just wait and see. I’m backing BEVs.

          5. @sean-p-newmanlive-co-uk most synthetic fuels are still based around the same Fischer–Tropsch process that was developed nearly a century ago now, and it’s not exactly as if we haven’t been researching that for an extended period of time (just look at companies like Sasol). Similarly, ethanol fuel blends have been in use in places like Brazil since the late 1970s, and the flex-fuel technology to support it is fairly mature technology (now around 30 years old), whilst biofuels are not exactly new technology either.

            If anything, the underlying industrial processes for those fuel sources has been under development for longer and is more mature than the modern lithium battery – commercial lithium batteries didn’t even exist until the 1990s.

          6. Well this won’t happen. The US Government has wasted millions trying to kick start it.

            The world is much larger than just the US.
            Ask Brazil if they think its a dead-end. Actually, stay in the US for a moment and see just how much they are using. Clearly it’s not a complete dead-end, as the US is using more than double what Brazil gets through.

            an intrinsically less efficient way of creating and consuming fuel.

            But outright efficiency isn’t the be-all and end-all if the actual fuel source is cleaner than the current one.
            It’s an improvement over what we have, and may lead to something better afterwards, or better means of production.

            No one is suggesting ICE powered cars are scrapped before their end of life

            But what fuel will they use? Why not provide a cleaner fuel for them to run on in the mean time?
            And what about all the non-car engines that will still require those same fuels for many, many decades to come?

            Look I understand the emotional attachment to ICE cars.

            It’s not just emotional. It’s practical.

            And in case you don’t think this is a realistic possibility, then I’m not going to spend anymore time trying to convince you, why not just wait and see. I’m backing BEVs.

            Of course it’s a possibility. But not universally for at least 50 years.
            As I said, it’s a process of evolution – it will take time, but that doesn’t mean we should be shutting the door on an alternative to/improvement over the current oil based fuels within that time frame.
            But you are, @sean-p-newmanlive-co-uk.

    2. Ethanol is not derived from fossil fuels so that makes it more environmentally friendly in theory. The fuel itself is not less efficient, it’s less energetic. How much energy per liter they can extract from it is gonna be the key. Now how big of a difference is it going to make in the engine construction durability or setup remains to be seen.

  2. Comparing litres of E10 and gallons of E85 is about as useful as a chocolate fire guard!

    Not only are different measurement units being used for both distance and quantity, but, using gallons which is different between UK and US.

    Perhaps rewriting the article so that there is a suitable comparison is in order,

    1. @maddme it doesn’t compare gallons with litres, it uses them as separate measurements in different sections.

      1. @hazelsouthwell. In a roundabout way, it does compare the fuels as it is referencing the consumption of the E85 fuel.

    2. Given it’s a number that comes from IndyCar, I think we can guess which of a UK and US gallon is being referred to, somehow.

  3. In the whole search for better efficiency, I have never understood why they limit the level of regeneration for the battery via the MGU-H and MGU-K. Surely this would have the biggest impact of efficiency increasing the amount of regenerated energy. The amount of energy recovered would obviously be limited by the battery, so each team can only recover the same amount of energy as everyone else (I’m assuming the batteries are the same in each car?), but the speed/efficiency at which energy is recovered surely increases the power units efficiency %

    1. I think it was a holdover from the old KERS regs, with just an increased amount of energy.

    2. Safety perhaps? The driver is sitting on the energy pack and whilst I know little of the chemistry employed, I’ve got to imagine there are limits to the energy flow rate at which it can operate without ‘issues’.

    3. Coventry Climax
      16th February 2022, 10:48

      My thoughts exactly. Yet another way to hamper the imagination and inventiveness of the team engineers. Sounds like yet another example of incompetence with the FIA.
      @Frasier: That sounds like croc to me. Going to space isn’t safe either, but if you just want it badly enough, there’s always a way to make it -at least- acceptably safe enough. We’re talking commercial space travel currently, and our comments are about F1. Pinnacle of … well, something, remember?
      If it was done to preserve some sort of old fashioned fuel burning racing, well, that’s failed already, if you look at how much managing of everything is part of racing nowadays. Could it be budget cap? But that too is rather silly. Who cares what teams and engine manufacturers spend their money on, as long as it’s within budget? Answer to that is -or should be- that only the teams themselves care, as they’re likely to put their money where they think it gives them the most gain. Oh wait, that’s pretty close to the very definition of efficiency, isn’t it?
      I don’t think I will ever understand the FIA. And, mind you, they make no effort to be understood either, as they just like a pair of old Nike’s: Just do, don’t explain.

    4. The reason this was introduced as a limit was pretty much for exactly the same reasons they have strict limits on the exact configuration of the engine SteveM. It means there are less areas where one of them can get it right and others completely wrong, which would have meant even larger differences in performance and more effort/cost for others to catch up.

      The batteries are not actually the same, although they are likely to be quite similar by now because they started off using the storage, replenishment and the pass through with the MGU-H quite differently to start with. It would make sense to change this, but since they wanted to freeze the engines to save cost it would not make sense to have them completely redo their powertrains to get to different levels of regeneration, storage and output per lap.

    5. It was a philosophical decision at the introduction of the hybrid era, in order to make sure that the ICE remained an overwhelming majority of the horsepower.

    6. My understanding is there are discharge restrictions associated with the MGU-K, but not with the MGU-H. So you can do a lot more with the MGU-H, which is useful. I suspect some fuel isn’t completely burnt during combustion inside the ICE, and that it completes burning in the exhaust pipe before it gets to the MGU-H turbine. So the MGU-H turbine isn’t just spinning as fast as the exhaust from the ICE can make it go, it is spinning faster than that because when that unburnt fuel burns you get expansion, which allows you to extract more “to the wheels” energy from the exhaust than would otherwise be the case.

  4. F1 cars are regularly stripped down, with seals and gaskets replaced

    That would mean opening the engine and is not allowed.
    But it is not necessary, the modern seals and gasket are well suited for biofuels.

    1. Coventry Climax
      16th February 2022, 10:56

      But the failed engines are. And the failed parts are examined – and improved. And replaced – for safety and reliablity reasons. Which is how, among the rest of it, the current modern seals and gaskets got to withstand the current load, stress and fuel impact.

      1. That’s not the point.
        Opening an engine means a new engine is mandatory.

        1. Coventry Climax
          16th February 2022, 23:37

          That’s not the point, a new engine necessary means you can open the old one.

    2. I don’t like how Honda supposedly left, but are actually still around will be for the foreseeable future. Red Bull tricked the F1 world into locking in the engines at a time they had the best engine.

      1. It’s al about money and honour Red Bull takes the Bill and Honda had a very good relation wiht the Red Bull group drivers all praised Honda and they find to repay it as the board forced their department to quit but the race department wanted to continue. If you check Honday HQ in Japan he see a Red Bull (of Max) before the front door and I think that Gasly’s car is inside (Alpha Tauri) the lobby.
        So The new Spec will be know in March and is adapted to biofuel thanks to Honda as an leaving present.

      2. Mercedes has still the most powerful but doesn’t live for more then 4 races if used at maximum levels while Honda has the second powerfull engine but more more reiable.

  5. Coventry Climax
    16th February 2022, 11:00

    More than decent article again, @hazelsouthwell !
    I like it when someone’s done the homework and knows what she/he’s talking about!

    1. She is a womsn, no need for she/he

  6. @hazelsouthwell good article…

    It brings up questions..

    How can Indycar easilly use 85% ethanol while F1 worries about 10%?

    Granted F1 is about tiny margins, and to get max power out of an engine nearly everything around combustion changes with fuel.

    I wish F1 engineera would share with us their secrets, did they use new pistons? Will fuel cell be different? Will fuel efficiency improve?

    Would be great to know what they do with it in detail.

    1. One factor Hazel mentions is the regular refuelling, making it rather less important to be able to get as much energy out of a single tank @jureo. Also, Indycar used Methanol fuel before, so they most likely carried over much of the experience from that.

    2. @jureo it’s a matter of differently-designed engines; F1 ultimately runs petrol engines, where IndyCar doesn’t. An engine specifically designed for high-alcohol fuels will be intended to have a higher burn temperature, different air intake requirements for combustion, etc. So it’s a bit like why you can’t put diesel in a petrol car I guess, in terms of a comparison – it’s because the engines are designed for a specific fuel.

      (that’s slightly over-simplistic but hopefully explains it!)

  7. IndyCars get through about 375kg of E85 over the course of the Indianapolis 500, which is more than twice the distance of a grand prix

    Want to compare throttle percentage between Indy 500 and any typical F1 GP too, @hazelsouthwell?

  8. Ethanol does not “burn hotter” as this article suggests — the actual engine temperatures are lower with higher-ethanol content fuels than with lower (or 0 ethanol) blends. Perhaps what’s getting confused is that the flash point, or the temperature required to ignite ethanol, is higher which is actually beneficial in performance applications: this allows an engine manufacturer to increase compression ratios, advance timing, and/or increase the pressure from forced induction. These are all minuscule tradeoffs (lower energy density:lower engine temperature) when the increase in ethanol blends is as small as it is this season. The engine manufacturers will undoubtedly come with an power unit that’s at least as equally powerful as last year and can run a full race distance without problems.

    1. Exactly, was going to post the same information. There is also the stoichiometric air/fuel ratio to consider; E85 requires a 9.75:1 ratio while 10% ethanol/petrol requires 14.04:0, so you have to dump in a lot more ethanol than gasoline to get correct combustion.

  9. ‘While some modifications for reliability are likely to be permitted after the freeze comes in, reliability problems can be disruptive for a championship bid, as Mercedes’ experience last year showed’
    OH! You mean the ‘reliability problems’ that helped Merc identify to what degree they could illegally run the PU exclusively for LH?! How was this ‘disruptive’ exactly? Given it’s what allowed LH to ‘win’ the BRA-QAT-SAU legs??

    1. What? It was a fresh engine, an engine on its first race has more power than an engine on its 5th race, especially knowing you dont have to complete 6 races on it, they can wind it up. Nothing illegal, don’t know where you got that conspiracy theory from, must not like Hamilton.

      1. kpcart, yes, he loves to rant about how much he hates Hamilton and spams the place with conspiracy theories about Mercedes that make it sound as if they are some sort of cross between the Illuminati and Freemasons that have unlimited magic powers – it seems that, to his mind, the illegal thing they are doing is upsetting him by daring to win. That is all that person ever posts – they have never shown any emotion beyond anger or hatred, expressed any passion for anything within the sport that isn’t just bitterness or shown that they even care about the sport or about anybody else at all.

        1. While not ‘illegal’ – it is against the spirit of the regs and the competition to burn through engines in the way that Mercedes did.
          Big props to Mercedes for exposing how utterly useless and ridiculous the ‘penalty’ is for taking engines and systems beyond the allocation, though.

          And as for your personal attack – sorry, review – anon, everyone is allowed to express themselves however they wish.
          That’s free speech – don’t try take it away or deprive anyone of theirs.

  10. Is it just me or does that engine look a bit like a shocked Bernie Ecclestone?

  11. IndyCar currently fills its tanks with 85% ethanol fuel – not a road-use mix, but a replacement for its old methanol fuel. Its cars manage around 1.92 miles per gallon on race pace.

    Maxed out, IndyCars get through about 375kg of E85 over the course of the Indianapolis 500,

    375kg of E85 is around 129 (US) gallons. At 1.92 mpg’s that equals to 248 miles. How does that work?

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