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Written by TheJudge13 Technical Analyst Lorenzo De Luca
We have already had several occasions to talk about how much more complicated these new F1 cars are – initially during pre-season testing and then during the first race of the season.
But what has really changed under the bodywork ?
Up to last year, the software which ran on F1 cars had “only” two basic functions to realistically deal with. Managing the torque power and the engine maps to provide better traction and to better exploit the exhaust gases in order to gain downforce; both occurred during the braking phase and the very first phase of acceleration.
The old energy recovery system – composed only of the old KERS – was not as sophisticated and the power management was very poor in comparison to the new ones (60Kw vs 120Kw). But not only that – thanks to the new ERS system and fuel restrictions (only 100Kg per hour) the new software has to manage many more parameters at the same time.
Many of us already know, the ERS (Energy Recovery System) is composed of a battery pack (capable of supplying 4MJ per lap) and by two electric motors, the MGU-H and the MGU-K.
As we all know the MGU-K replaced the old KERS and its power supply has doubled compared to last year. The MGU-K can supply 2MJ per lap whilst the amount of energy that can be exchanged between the MGU-K and the MGU-H is unlimited.
In addition – the new MGU-H is connected to the turbocharger of the engine and recovers energy through the heat of the exhaust gases – which can be used to control the turbo, revert to electrical power to be stored in the battery pack or sent to the MGU-K.
All these changes not only introduced a new concept of “engine”, but have also revolutionised the concept of a F1 race. The limit of 100Kg of fuel per hour has forced engineers to focus on how to maximise the power that can be obtained by the ERS instead of that which could be gained from the internal combustion engine (ICE) when pushed to its limit as happened until last year.
The technical complications are even more evident when we consider the huge amount of wiring (about 30Km) and the number of ECUs required by the new ERS system. These in turn must be able to endure continuous cycles of charge/discharge, even over a single lap, that does nothing more than increase the operating temperatures of batteries and cables.
The complexity of the electrical system is also confirmed by the presence of a transformer which converts the DC (Direct Current) to 12, 14, 48 or even 90 V, depending on the needs of use, whilst last year the voltage was limited to only 12V.
This has led engineers to equip each component of the ERS (Energy Store, MGU-H and MGU-K) and their control units with their own cooling systems. These solutions have further complicated the installation of these power trains – into a limited space in which very high temperatures are reached.
A new way to race
If until now we have limited ourselves to a basic explanation of what ERS is, now let’s try to understand how this new technology has changed the way to race in Formula 1.
When we think about F1, the first thing that comes to mind, is the driver pushing the car to the limit in order to finish first. But with the new rules on fuel restrictions (I leave it to you to decide whether if it is a good rule or not) things have changed somewhat. Indeed drivers and engineers now have to take into account that going flat out on every lap is impossible with the imposed fuel restrictions.
This process is assisted in the form of the ERS, in particular the unlimited energy that can be exchanged between the MGU-H and the MGU-K, this mean that having an efficient ERS is crucial if you want to be competitive enough to win races.
These new hybrid systems, have heavily influenced the activities of the drivers during the race and with the help of their track engineers, they not only have to manage their pace in relation to the limits of the tires, but also in the function of the amount of fuel burnt in conjunction with the respective mode of use of the ERS.
With the old V8 engines, a driver tended to push the engine to its limit (18.000 rpm) to gain speed and thus lower his times; with the new turbocharged engines – this is not necessary anymore.
Indeed the power curve of a turbocharged engine flattens out from a certain rotation speed onwards (12.500/13.000 rpm more or less) and this combined with the fuel restrictions have made it practically futile to push the engine to the 15.000rpm limit.
Drivers have begun to use the power collected by the MGU-H and send it to the MGU-K to obtain an over-boost. The methods of use of this new ERS system vary greatly. The MGU-K can slow down the crankshaft under braking and store the energy in the batteries which can then be used during acceleration through the MGU-H – eliminating turbo lag. The MGU-K can also be deployed during acceleration to smooth the torque levels – which at times can reach the monstrous value of 1,000 N/m if the ICE and ERS are both used at 100% – all the while with the MGU-H boosting the turbo-charger.
As you can see by yourselves, the methods of use of the new ERS vary widely; a practical example of what we are talking about could be seen during qualifying.
During last year’s event there was a practice used by all the drivers to exploit the tires more efficiently: slow-fast-slow laps. This year is the same, except that during the slower lap the drivers are not only cooling down the tires but they are recharging the battery pack. This is done for a simple reason because when full ERS power is deployed the subsequent lap times can be lowered by almost 2 seconds.
This trick is also used during the race. There were many team radio transmissions where engineers asked their drivers to play with some switches on the steering wheel. Depending on the situation, the instruction could mean using less power (and then focusing on recharging the battery ) or to use more power in order to overtake an opponent. It becomes easy to understand then, that part of the season will be focused on ERS efficiency, and just in this area will arise early disadvantages/advantages for some teams.
Mercedes PU106 : Less power but more performance
After the Australian GP rumours begun to circulate about what could have been the secret of so much performance and reliability on the Mercedes power unit.
Reliable sources have indicated that the simplified design of the power unit may hold the advantage to the Mercedes PU106. According to these rumours, Mercedes have chosen to give up some of the power of the ERS to have more reliability and a continuous and constant flow of energy. What is it about?
Well, at Brixworth, engineers chose to renounce a part of the energy by reducing battery pack storage capacity (2MJ instead of 4MJ) , the advantages of this would be many. First of all – a much lighter battery pack- around 12/13Kg instead of the 25Kg the competition are running with. The reduced amount of energy translates also into lower cooling needs and in a more clearly defined package.
The reduced weight is a major advantage, which is also reflected in fuel consumption without even mentioning that less stress would be put on the power unit by the reduced loads. In short, simplify to get more performance.
This approach is completely different from its competitors, which could help Mercedes score many points while other teams are still suffering with the reliability of their systems.
It is this reliability that seemed totally lacking for Red Bull yet the Austrian team in collaboration with the transalpine engine manufacturer impressed many people in Australia. Putting aside the controversy about the flow meter, the French giant who has been accused of not being capable to supply a good power unit during the pre-season testing has successfully managed to sort out most of the problems proving once again that the software that has the task to manage the ERS is as important as the mechanical part.
Indeed it seems that the problems Red Bull suffered, and are still struggling with, are related to bad software management of the energy stored in the battery pack, which lead to overheating – first of the wiring and then of the two electric motors (mainly the MGU-K)
Just the two electric motors (MGU-K and MGU-H) seem to be the reasons behind Ferrari F14-T lack of speed. The Prancing Horse has displayed an apparent lack of speed since pre-season testing and this situation has repeatedly manifested itself during the inaugural GP of the season.
During the qualifying session, Ferrari (both with Kimi and Fernando) was unable to do two consecutive laps with the ERS deploying its full power; unlike its opponent. This situation results not only in slower lap times, but also with higher fuel consumption (because of less usable power from the ERS). This forced the drivers to significantly reduce their race pace. The problem seems to lie in the “communication” between the two electric motors and the battery pack, a problem that also affects the brake-by-wire.
Amongst the top teams, the F14-T was the only one that never activated – during the race – the automatic fuel saving function, which is identified by the flashing red rear light. This accounts – more than the alleged heavier weight of the 059/3 – for the high fuel consumption and the lack of performance shown by Raikkonen and Alonso.
It is evident, therefore, that the software will be the key on which teams will focus most of their efforts. The new hybrid systems have opened new scenarios and different ideas for interpretation but all with one purpose: to recover energy in a more efficient way.
Which one will be the best? We are still in the early stages to be able to answer this question. Mercedes’ solution could be the one, which could give more guarantees for the first part of the season, but what will happen when Renault and Ferrari fix their issues? Will it be enough for Mercedes powered cars to run (if rumours are confirmed) with less power but for a longer time?
It’s time to get excited over new F1 technology, rather than distracted by ‘noise’.