© Vladimir RysBulls’ Guide To: Power UnitsEverything you need to know about our Honda Power Unit.
Spa-Francorchampsisapowercircuit.Admittedly,inthemodernera,prettymuchallofthemaretosomeextentbutSpaisoftheold-schoolvarietywithvastreachesoftrackwhere,inthelongstandingsee-sawbetweengrip-limitedandpower-limitedsections,thelatterholdssway.So,let’stakealookatPowerUnits.
Until the start of 2014, F1 cars had engines. They had, over the previous 64 seasons, come in every conceivable shape, displacement and layout, used technologies from gas turbines to superchargers but, in every instance, they were recognisably engines.
What we’ve had since 2014 are Power Units. There’s still an engine in the mix, and that ultimately provides all the power but there’s also… more. F1’s Energy Recovery System is hybrid technology turned up to 11.
Honda Power On Track© Vladimir Rys
When F1 first introduced hybrid technology with KERS, it was very much an ancillary add-on. In 2009 we didn’t fit it; in 2011 we fitted it but sometimes it didn’t work. The RB5 and RB7 won plenty of races regardless. The full hybrids aren’t like that: The two motor-generators are fully integrated with the turbocharged engine. It is all one system. Not an engine with extras but a holistic power unit – though most of the time everyone still calls it an engine, because old habits die hard.
Engine supply in F1 has always come in three distinct flavours. Some teams manufacture their own engines as part of an integrated car design process. Others buy an engine off the shelf, either as a customer of as a works teams, or from an independent supplier. We began life in F1 as customer team using a Cosworth V10, then a Ferrari V8 and then a Renault V8. After that, we migrated to a partnership arrangement, first with Renault, now with Honda in which, rather than an off-the-peg customer engine, they build an engine to meet our needs. Having a partner based eight time zones distant brings with it certain challenges – but making the partnership as close as possible is a hugely important part of the relationship.
“We cannot race with just a PU or just a chassis so it’s been important for Red Bull Racing and Honda to work closely, when designing and building these cars – it is the only way to improve the performance on the track,” says Toyoharu Tanabe, technical director of Honda’s F1 project. “We started the partnership in 2019, and for the 2021 season, we each made challenging demands of each other, but equally worked together very closely to achieve the targets we set.”
Keeping Cool During Sessions© Vladimir Rys
A good example of what Tanabe-san refers to is the cooling requirements of the power unit. While Honda designs the PU, Red Bull Racing is responsible for cooling it. That feeds into car design, with the placement of various coolers but also into aerodynamics, where the size and cross-section of the radiators and airbox are major design features. Engine designers would like over-capacity; aerodynamicists want to draw a missile: between them, they have to develop the most effective compromise.
“It is a fine balance between the two parties’ requirements,” concedes Tanabe-san. “With something like cooling requirements, we have to achieve that balance for meeting the PU’s cooling needs but also not compromising chassis weight, design layout and aerodynamic performance. It is difficult but for 2021 we’ve achieved a good balance and together delivered a good package.”
Our PU programme currently operates across three locations. Power Unit components will be in evidence at our factory, in Milton Keynes, but Honda’s main R&D and manufacturing base is in Sakura, Japan. Additionally, Honda has its own facility in Milton Keynes where they prepare PUs for both ourselves and AlphaTauri.
Tanabe With The Trophy© Vladimir Rys
“Sakura leads the development for the whole power unit, including its concept and design,” explains Tanabe-san. “In terms of development and production of the components, Sakura is responsible for the ICE, MGU-H, MGU-K and Milton Keynes looks after components related to Energy Storage such as the battery. Trackside, engineers work on optimising and calibrating settings for each track and atmospheric and track conditions, in order to get the most out of our package. During the race weekend, trackside members have face-to-face communication with team personnel and the drivers, as well as working with Mission Control rooms in Sakura and Milton Keynes.”
Regarding the trackside team, in the F1 paddock, power units are tended to by their manufacturer, regardless of whether that’s an external supplier or an engine department within the team. Each garage, ours included, will set aside a dedicated workshop space in which the power unit technicians work, preparing the components and carrying out maintenance or diagnostic tests. They’ll bring the components to the car mechanics when it’s time to install them in the car.
Honda’s power unit engineers attached to our team will also have space in our treehouse or engineering office. In total, there’s usually around ten Honda engineers and techs integrated into our trackside team and, in many respects, they simply function as another department, working with the race engineering and car engineering teams through the sessions, briefings and debriefs, like any other group.
Toyoharu Tanabe In The Garage© Getty Images
In common with vehicle dynamics, aerodynamics or strategy, there will be a PU team dedicated to each car, with an engineer on the comms, available to advise the race engineer regarding ERS modes, battery status, potential problems and so forth. They in turn will be backed-up by the wider team of Honda engineers working trackside, but also in Honda’s Ops Room back at the Sakura factory, which receives the same real-time telemetry as our Ops Room in Milton Keynes, planning PU strategy for the remainder of the weekend.
The garage crews disassemble the cars on a regular basis – on a normal Friday evening after FP2, for instance, it’s fairly standard to strip the car and rebuild it, removing various components fitted specifically for practice running. By F1 standards, that process is relatively leisurely but swapping-out power unit components between sessions is rather more pressurised. Rarely is this caused by an out-and-out failure; usually it’s done on a preventative basis, in response to seeing worrying trends in telemetry, or indicative results from oil samples analysed immediately after a session by our garage-based ExxonMobil lab.
Back in 2014, when our knowledge of the hybrid power units was raw, a PU problem would automatically cause the team to shut down for the day. Back then, installing new components usually took the rest of the day and most of the night. Familiarity with the technology, and also the constant push to make it more user-friendly, has reduced this to a task that can be accomplished in the two-hour gap between FP3 and qualifying. Despite the added complexity, it can be done on a similar timescale to that which was normal with the V8s.
Under Covers In The Garage© Getty Images
This late in the season, having to do a rapid changeover isn’t always a cause for consternation. With the number of power unit components heavily proscribed, it’s not uncommon to mix and match older components for practice sessions, maximising their mileage. One of the great achievements of the modern era is that these power units don’t lose performance over their lifecycle due to the Team and Honda managing the operation together carefully. However, the Team still likes to keep fresher components for the business end of the weekend.
The current allocation per car for 2021’s 23-race season is three sets of ICE, Turbo, MGU-H and MGU-K, plus two sets of Control Electronics and two Energy Stores. Should races drop off the calendar this year, the number won’t be reduced, but last year there was a little wiggle room in the permitted allocation when races were being added late.
Post-race, the cars are stripped once again and the power unit components returned to their owners. If there’s a blank weekend following the race, then all the power unit components will be returned to base for analysis and maintenance. As a general rule, teams are not allowed to alter a previously used unit, but there are consumable items that can be swapped out, and taking components apart for inspection is also permissible. There are standard checks – but telemetry from the weekend might indicate particular areas in which the engine technicians may focus.
“The PU goes back to the factory after each race and we check and do maintenance, changing parts where the rules allow, depending on the lifecycle of the individual part,” says Tanabe-san. “At that time, we will also change any parts that have been damaged. Before checking the PU hardware, we first check the data and if we see any cause for concern, we make a physical check and change the part if necessary.”
Hybrids are often described as being a more and more difficult form of technology to work with than the normally-aspirated engines that went before. There are many aspects to that, and it certainly shouldn’t be taken to mean the V8s and V10s were unsophisticated. They weren’t: it’s not like F1 was using tractor spares. The primary difference lies in two general areas.
Hungary For Honda Power© Getty Images
The first is that the development programmes for F1’s V8s and V10s were standing upon the shoulders of giants. Racing engines had a century of development history. Each generation built on the achievements of the last: squeezing out a little more power, revving a little higher, shaving off a little weight, running a little hotter. With the new power units, this wasn’t the case: the specification was developed largely from academic ideas and limited prototypes: no one had ever developed a production PU like these before. This was something new – and new is supposed to be difficult.
The second difference is there was a lot more technology to pack into a new power unit. The litany of components is familiar now: ICE, Turbo, MGU-H, MGU-K, Energy Store, Control Electronics. Each of those – even the ones based on existing tech – comes with its own unique set of complexities, and on top of that making them all play nicely together. This is perhaps the biggest challenge F1 engineers have had to face.
“Compared to the pure ICE car, the modern hybrid PU is very complicated,” agrees Tanabe-san, who started his career in F1 working on the mighty Honda turbo engines of the mid-1980s. “The current PU has extra hardware such as MGU-H, MGU-K and Battery and these components are designed and assembled very precisely. Also, there are now additional control systems to manage the multiple components and energy management, and it requires more complex control logic calibration. Following these changes, drivers need to make more adjustment through the steering wheel.”
It'sNotAllAboutTheHorses…
The contest between engine manufacturers tends to be portrayed as a battle of horsepower, but the reality is that horsepower alone is one factor among many, and it’s not much use having it, if you can’t lay it down. “No, horsepower alone is not the biggest factor,” says Tanabe-san. “You need all areas to work together perfectly to get the most out of the PU package. With only three power units per car per year, it is crucial to strike a balance between performance and reliability.”
Heating Up In Hungary© Vladimir Rys
An F1 engine needs to be lightweight and compact, it needs to be frugal, it needs to be ultra-reliable, have a low centre of gravity and keep going while being shaken around like a tin of nails tank-taped to a jackhammer. Most of all, it needs to be driveable. Driveability is often the overlooked factor in PU performance but it’s worth a lot of lap time. A driver with confidence in his car naturally goes quicker, and a lot of that comes from throttle-response; knowing the engine will deliver precisely the same performance each time he hits the accelerator, lap after lap, with the power coming in smoothly. In the modern era, you can add in the various issues around the ERS, which relies on intelligence in the electronic controls to deliver power in a predictable manner.
Happily, what we have is a thoroughbred, and it brings a smile to everyone’s face when we come somewhere like Spa-Francorchamps because, however much this is an intricate and technical sport, there’s something very, very satisfying about stripping the downforce off the RB16B, and seeing the drivers put the hammer down and take it for a gallop all the way up to 220mph and beyond. Running at full throttle for such a large percentage of the lap puts stresses on the PU – but there isn’t really such a thing as an ‘easy’ circuit for the Power Unit.
Full Throttle In Spa© Getty Images
Each circuit has its own demands, and across the rest of this season, challenges the technology in different ways: Mexico, for instance, with its lower air density, requires the turbo to work harder; afternoon sessions in Abu Dhabi and Saudi Arabia will push cooling to the limit; places like Sochi test energy management because there really aren’t that many heavy braking zones during which the MGU-K can recover energy.
Over the remaining few months with Honda as our engine partner, we’ll be pushing the envelope almost every weekend to drag everything out of the superb RA621H power unit. With both titles in the balance, we’ll need every last erg.
