2014 Williams engine cover

Factory teams have an edge when it comes to cooling

F1 technology

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Nico Rosberg, Mercedes, Monza, 2014It’s easy to spot changes to a car’s front or rear wing, but the humble engine cover tends to undergo more subtle changes.

But this area of the car plays a fundamental role in its performance. The way it is designed highlights a key difference between teams who design their own engines – like Mercedes and Ferrari – and their customer rivals.

The new V6 turbo power units introduced this year have much greater cooling requirements than the previous V8s. The new Energy Recovery Systems create some extra heat but it is the addition of the turbo that really ramps ups the cooling requirement.

The turbocharger’s job is to shove as much air into the engine as possible. This mixes with fuel to create more power – the more fuel/air mix in the engine, the more power the unit generates. The turbo has two turbines for increasing air flowing to the engine – one drawing air in, and the second spun by exhaust gasses.

An intercooler (a heat exchange) helps reduce the temperature of this air as cooler fuel/air mix makes for a more efficient engine. This recycling of hot air through the intercooler and engine is what gives right to the dramatically higher thermal footprint of the 2014 power unit.

Given the radically different engine formula most designers chose a conservative cooling route thinking it better to optimise a working package than having to fundamentally redesign an overheating car. This is an equation that Red Bull got wrong to begin with – its pre-season test plans was wrecked by persistent overheating problems.

The basic philosophy of cooling design is to build a ‘base’ solution that delivers efficient aero performance for the majority of tracks. In addition to this design in slots for holes and louvres to allow extra heat to escape. Then at tracks with more extreme cooling needs it is simple to adapt use louvres to vent excess heat. As designers get to grips with the car’s thermal footprint the ‘base’ cooling solution will be revised.

This is the trend we have seen in 2014 and since the halfway mark of the season more teams have introduced ‘shrink-wrapped’ engine covers. The drawing below shows the Williams FW36 from Sochi.

2014 Williams engine cover

The engine cover has shrunk by 50mm, which reduces blockage to the rear wing, improving its performance. The FW36 also features a ‘rear vented’ cooling solution with the bulk of hot air exiting at the back of the engine cover under the rear wing main plane.

This is the most common configuration and is adopted by most teams on the grid. The alternative is to vent air from the sidepods but having excess heat go under the rear wing is less aerodynamically disruptive.

It is not only a better understanding of cooling requirements that has allowed teams to shrink their engine covers. The removal of FRIC suspension has also had an effect. By eliminating the interlinked suspension teams have saved more space around the lower sidepods allowing a tighter design and a smaller coke-bottle areas.

One of the reasons why Mercedes has such an advantage is that they split the turbo between exhaust turbine and air intake which meant the exhaust gasses didn’t heat the air so much meaning the intercooler, and thereby thermal footprint, could be smaller. Not only could Mercedes better balance weight distribution towards the centre of the car, but they could also design tighter engine packaging. This slimmer package allows faster air to be fed to the rear wing/diffuser region, which translates to higher downforce.

This is why it is so beneficial to build the engine and chassis in an integrated way. Mercedes’ customer teams all have the benefit of the best power unit but have not been able to extract the same aerodynamic benefits.

It is therefore hard to see a challenge to Mercedes in 2015 coming from anywhere other than Ferrari, who have always built their own engines and chassis, Red Bull, tied more closely to Renault following Lotus’s defection to Mercedes, and McLaren with their new Honda engine.

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  • 19 comments on “Factory teams have an edge when it comes to cooling”

    1. maarten.f1 (@)
      23rd October 2014, 12:50

      I saw a YouTube movie recently on the Pole Position channel, where Marc Priestley (a former McLaren engineer) talked about this sort of thing. There are three movies there (search for F1 Guru or something), and I can’t quite remember which one it was where he talked about it. But one of things that happened was that Mercedes came with an engine update and it was a much sleeker design, and it left the McLaren chassis with a LOT of unused space. I think it was this movie: http://www.youtube.com/watch?v=YuOKa_VvoIQ but I can’t remember.

      1. @maarten-f1 It was a new cooling solution that they only offered to their customer cars late in the pre-season and Force India responded first with new bodywork as they dropped the orange on the sidepods.

    2. One of the reasons why Mercedes has such an advantage is that they split the turbo between exhaust turbine and air intake which meant the exhaust gasses didn’t heat the air so much meaning the intercooler, and thereby thermal footprint, could be smaller.

      While I don’t doubt that this had some effect, the main reason for this change (I believe) has more to do with the volume of the intake system than the heat involved. The lower the volume of the intake system (between the turbo and the cylinder head) the quicker the compressor can increase the pressure. This reduces turbo lag. In these engines, the turbo lag is compensated for by the MGU-H, so a system with more inherrent turbo lag requires more power input to reduce it.

      By separating the compressor from the exhaust turbine, it can be placed in a more optimal position. This allows the intercooler to be positioned more efficiently without extra pipework. Doing so increases the efficiency of the entire design.

      I will agree, though, that all this helps with both reducing the thermal load and with the overall packaging.

      1. Apprently Mercedes is stronger than their opposition in all crucial areas in terms of PU:

        Energy harvesting
        Cooling
        Turbo lag
        Chassis/PU integration

        I wonder how difficult a task is for Renault and Ferrari to catch up with current engine freeze rule. Honda is still a big ask and despite having spent less time than Mercedes developing their PU, they have a benchmark unlike current suppliers.

    3. Should we expect customer teams making a better job in terms of optimization of chassis/power unit integration? Could Williams be closer to Mercedes next year?

      1. There ought to be something to gain from applying what they’ve learned about the Mercedes design. Particularly Lotus – it’s their first Mercedes-powered car, and the 2014 car belongs in the skip anyway. The other two teams may want to use this year’s car as a starting point. They’ll have to make it work, of course – and Mercedes could have something else up their sleeve for the works team in 2015 – but the customers should be able to close the gap, in theory.

    4. Nice article, thanks.
      I would hope that as the engine formula becomes more mature and staff switch from team to team, that most or all of the secrets for optimising PU’s will be shared about, obviously the Manufacturer teams know more about the PU at the moment, give it 5 years and the teams will learn where they are giving away performance and get on top of it.
      I have high hopes for this engine formula, I can’t wait to compare next season’s lap times and see how quickly the development is progressing. I do think the cars look a little slow in some aspects of the races this year and would love to see them matching 2013 lap times within 2 or 3 more seasons.

    5. Interesting article. Small correction: a compressor is not a turbine. It is a piece of turbomachinery, but the term “turbine” specifically denotes turbomachinery that does the opposite job to a compressor, i.e. what the exhaust gas stage of the turbo does.

      1. Correct. Also need to point out that the thermal footprint of a 2014 engine is lower than previous generations, not higher, this must be so because the cars are more fuel efficient. The heat to exhaust is much lower, because the turbine has extracted energy before it leaves the car. The cooling requirement is however higher because of the need to extract the heat of compression of the intake air.

        The article doesn’t explain why the other Mercedes customer cars haven’t been able to match the factory, it’s quick and easy to increase or reduce the size of an intercooler and the surrounding bodywork to match the requirement and even change manifolding to suit an optimised layout.

        I suspect more and more that the fuel supplied by Petronas has a magic ingredient X, perhaps it’s sold at a few forecourt pumps in Malaysia to make it legal?

        1. I am pretty sure that fuel doesn’t need to be pump grade. There are restrictions on all sort of stuff in the fuel, but Octane rating is free, except for a minimum value.

          1. The fuel in F1 isn’t the same as what you buy at the pumps but it is very similar.

            “The detailed requirements of this Article are intended to ensure the use of fuels which are predominantly composed of compounds normally found in commercial fuels and to prohibit the use of specific power-boosting chemical compounds.”

            http://www.formula1.com/inside_f1/rules_and_regulations/technical_regulations/8700/fia.html

            1. the fuel is important. it is ‘like’ pump fuel but far more sophisticated and refined. a friend of mine worked on some of the formulations that mercedes have used this year – i don’t know the details, but from what he said they are utterly clinical in how they produce the fuels, taking extra, extra care to filter it, remove imperfections and so forth. so in that sense, it is nothing like pump grade fuel. they tested dozens of blends on the dyno as well, so there may well be some variation between the teams who use the same fuel company (eg. Petronas)

        2. Good point to highlight fuel used is also part of the package that makes the Mercedes unit top notch @frasier, but it’s hardly an explanation of the gap between Mercedes and (most of) their customer teams.
          Why? Because all apart from McLaren use Petronas fuel as well to have maximum benefit from the optimised fuel/engine package. That is why Lotus will also be using Petronas next year (that was confirmed by the team press releases)

    6. Love these articles, thanks @john-beamer

    7. Hi John.
      A good read but doesn’t really explain why the actual manufacturer teams have an advantage, just why the Mercedes engine is better, which is a shame because it’s something I don’t fully understand. I guess they just know the shape/weight of the engine first and have more time to design for it?

      1. The manufacturer teams have an advantage when it comes to heat management.
        Mercedes for instance would have run the engines on dynos and then tried out several cooling configurations all the time optimising for aero efficiency and weight distribution.
        Customer teams will be given the energy output and perhaps some heat rejection range for optimal performance. This leaves the customer teams with designing the right compromise without sacrificing too much performance.
        The engine manufacturer cannot be bothered with a customer’s aero efficiency as that isn’t part of their supply agreement and is something that is easily influenced by the aero profile of the car which is the job of the car’s designer.

        1. Also, as far as I understand it, the smaller packaging solution wasn’t brought up until late in the pre-season. Meaning that while Merc had knowledge that it was in development and could develop the chassis accordingly, costumer teams were designing their chassis around the previously available packaging solution. After a certain point in chassis development you can only do so much to change its design and you end up with something optimised for a larger engine than what you got. Yes they managed to reduce the size of the bodywork and have some work done to the actual chassis but I am positive that there is a lot of wasted potential that they cannot change in the current car.

    8. @john-beamer, thanks, I love technical discussions, I miss the days when the engine was all there was between the cockpit and the rear wheels, all shiny cam-covers and induction trumpets gleaming in the sunlight for all to see.

    9. John can you tell us how the coke bottle “sucks” / speeds up air to rear wing diffuser ?

      I have read that the boat-tailing on cars is to reduce the size o the wake and to increase base pressure
      (through pressure recovery) to increase base pressure and reduce drag.
      Is there some misnomer here ? Perhaps the reduced wake size means better airflow to rear wing diffuser
      and hence compared to separated turbulent wake this air is “accelerated” in comparative terms and has more energy ? What is going on in this area ? Great post and I love all your articles in Bernoulli magazine ? An article in an older edition about barge boards is among my favorite. Cheers.

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