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.
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.
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.
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.
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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