Lewis Hamilton, Mercedes, Jerez, 2014

Why ‘full throttle’ doesn’t mean ‘full power’ any more

F1 technologyPosted on | Author Keith Collantine

Lewis Hamilton, Mercedes, Jerez, 2014Last week Formula One drivers had their first taste of a radical new generation of engines.

But while much attention has been focused on the downsizing of engines from normally aspirated V8s to turbocharged V6s, the introduction of more powerful and complex energy recovery systems will have the biggest effect on driving technique.

The internal engine plus its heat and electrical energy recovery systems are collectively known as the power unit [PU]. The car’s electronics have to continually balance performance against economy as a driver varies his demands for acceleration over the course of a lap.

The upshot of this is that when a driver puts his foot to the floor at the exit of a corner, he may not get all the power his internal combustion engine has to offer.

“Full throttle no longer means a demand for full engine power,” explained Renault’s technical director for new generation power units Naoki Tokunaga.

“It is an indication to the PU given by the driver to go as fast as possible with the given energy.”

Staying within the maximum fuel allowance of 100kg and peak fuel rate of 100kg per hour will require careful management of the power unit over the course of a race.

“Effectively, once the driver applies full throttle, the control systems manage the power of the PU, with the aim to minimise the [lap] time within the given energy,” said Tokunaga.

How the new power units perform over a lap

Renault energy F1, 2014 F1 engineThe demands on the different parts of the power unit will vary over the course of a lap. Flat-out, the engine will be draining its tank and the turbocharge spinning at up to 100,000rpm.

Meanwhile the Motor Generator Unit – Heat (MGU-H) will be recovering energy from the hot waste gasses and transferring that to the Motor Generator Unit – Kinetic (MGU-K). Depending on the driver’s needs, the MGU-K will use that energy to increase the output of the power unit or conserve fuel.

When the driver reaches a corner and begins to brake the function of the MGU-K changes – it now acts as much as the KERS units of old, recovering energy from braking to story it in the battery.

The MGU-H also performs a different function. As the engine is no longer spinning the turbocharger the MGU-H takes over. This is to reduce the lag which would otherwise occur when the driver came to accelerate out of the corner and found the turbocharger was rotating too slowly.

As the driver accelerates away from the corner the engine is one again able to drive the turbocharger, and the MGU-H reverts to collecting energy from the turbocharger and exhaust.

Although the driver does not have total control over this energy transfer, he can take charge when he needs to.

“Of course, there will be certain driver-operated modes to allow him to override the control system,” said Tokunaga, “for example to receive full power for overtaking”.

“Using this mode will naturally depend on the race strategy. In theory you can deploy as many times as you want, but if you use more fuel or more electric energy then you have to recover afterwards. The ‘full boost’ can be sustained for one to two laps but it cannot be maintained.”

In qualifying the need to conserve fuel obviously does not apply, meaning the drivers will be flat-out. But as they can only recover half as much energy per lap as they can use, drivers will not be able to do two consecutive laps with full electrical boost.

Because of the need to cool down the tyres between qualifying runs this will usually not be a concern. However it may be a consideration in a scenario where qualifying is taking place on a wet but drying track. Drivers also use their boost before crossing the start line and beginning a qualifying lap, to increase their starting speed.

Coping with failures

Daniel Ricciardo, Red Bull, Jerez, 2014While reliability has reached record levels in recent seasons, one component which has caused a series of failures for some teams – notably Red Bull – is KERS. These often caused only a minor loss of lap time and no need to retire the car. But comparable failures with the more sophisticated hybrid power elements in this year’s cars will be much more serious.

“If we lost the MGU-K we would keep the car running,” confirmed Mercedes managing director Andy Cowell in Jerez. With these devices being a major area of development this year he was cagey about the likely time loss, putting it at above one second per lap and less than ten.

“KERS last year [if it failed] it was an inconvenience,” he said. “About 0.3, 0.4 of a second per lap, but you could finish.”

“You lose the MGU-K it’s greater than a second,” he added. But not only would a driver suffer a lack of outright performance, their fuel consumption would also suffer, giving them another headache.

A car would also be able to continue running if its MGU-H were to fail, though turbo lag would also become an additional problem. “Losing both electric machines is bad news,” Cowell added.

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Images ?? Daimler/Hoch Zwei, Renault, Red Bull/Getty

148 comments on “Why ‘full throttle’ doesn’t mean ‘full power’ any more”

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  1. The way this article is written it makes it sound like the software is continually calculating how much fuel it can afford to spend any time the driver asks for full power and using just that amount. I could extrapolate that this would also vary based on position on the circuit – it might be faster to use more fuel in one place (i.e. beginning of long straight) and less in others (end of straight or short connection between corners).

    I hope this is not the case, and what is really being said is that the full power will not always be available due to the current state of battery charge or engine setting and that the driver will have to manage things himself in order to finish the race with the given amount of fuel.

    1. “it might be faster to use more fuel in one place (i.e. beginning of long straight) and less in others (end of straight or short connection between corners).”

      This was my understanding when i first heard about the new engines, but i don’t think so any more. The system doesn’t ‘know’ where it is on the track, so wouldn’t be able to differentiate between a long straight or a short one. It knows the throttle input, and i would guess it knows the average rate of fuel consumption per lap, and number of laps remaining, and will manage fuel based on that.

      However engine modes could be altered by the driver so he can choose when to override the system to give maximum power (for passes or during pit windows) before reverting back to some form of cruise mode to manage fuel until the end. Driver inputs will still have an impact on fuel management of course, short-shifting or coasting if fuel is critical.

  2. kowalsky jose
    6th February 2014, 17:04

    Warning. Do not commit the same mistake i made in 2009. Wait a few years until the engineers bring the performance back. This cars are going to be a disapointment in a tilkedrome. No speed sensación, due to lack of noise, And performance, plus huge distances from grandstands.
    Spend 300 quid at you own peril.

  3. This is hilarious. Imagine the “average” viewer trying to make sense of this complicated mess.
    They say they want to attract casual viewers; yet make the sport more difficult to understand at every turn. Most people just want to see the cars RACE – NOT manage fuel, NOT manage tyres, NOT manage DRS, ERS, MGU-H, MGU-K or whatever gimmick they come up with next.
    The average viewer will surely struggle to get his head around these terms and how they influence what happens on the track! Whatever happened to drivers just racing????

    1. That matches my comment the other day concerning declining TV audience figures. F1 has left the casual viewer behind. The rules and regs are far too complex for anyone but the serious devotee to understand. So when this fabled casual viewer switches channel partway through the race to watch snooker, darts or bowling on the other side, Bernie shouldn’t be surprised.
      “Usain Bolt has five second lead, but remember he’s got to change his running shoes for high heels at the end of this leg of the relay and eat a bowl of Kellogs before hopping the next lap, but his main rivals will only have to drink a Starbuck’s Latte and tie their knees together.”
      Many soccer fans have a problem explaining the offside rule, try explaining ERS and DRS to soccer fan.

    2. Even highly technical F1 oriented gurus don’t understand it fully. I bet even renault/merc/ferrari guys don’t yet. Imagine how painful it’ll be to explain a casual viewer why the one car flew by another one with 30-40kmh advantage.

  4. They can recover 1/2 energy from mgu-k. But that doesn’t mean they can only recover 1/2 over the lap, as they can also recover energy from mgu-h to either directly assist mgu-k, or putting it in energy store. Even Tokunaga himself said: “The ‘full boost’ can be sustained for one to two laps but it cannot be maintained.”

    1. I raised my eyebrows at that bit too, but for other reasons. Was that one lap of Monaco, or two laps of Spa?

      1. Hard to know. No one will share this kind of information I think. Really tricky to predict. MGU-H will harvest most energy while on full throttle, so “stop and go” tracks with heavy breaking will therefore suit this the most, while fast flowing tracks with little braking the least. Silverstone and suzuka will be really bad in that regard. Very little braking and lots of fast stuff, so mgu-h will only be used to directly assist mgu-k and not to store energy at all.
        I don’t think this will be much of a problem because as has been mentioned in the article, drivers tend to either do a cool down lap or simply 1 run. In the wet it will be better to just drive in self sustaining mode.
        This is so complicated I doubt even merc/renault/ferrari themselves know 100% how it’ll work.

  5. It’s like the more we read about the new power units and fuel regs, the less we know about how it will all translate to actual performance over any complete race. Doubtful we’ll know for sure until we get to the finish of each race weekend. I think that could be a good thing because different teams and drivers will have different strategies, likely for each different race. Even as successful strategies are more clearly developed, the strategies that work for one race might not work for another. Add in the potential unreliability for the complete power unit or individual systems and we have a recipe for many different winners and possible instant turmoil for any team or driver at any time during any race weekend. It should be fascinating to see what happens and which teams/drivers can develop any consistency.

    1. And we’ll continue to know nothing about how it works if FOM doesn’t provide EXTENSIVE on screen information of what’s going on with the car. Like kers lightning bolt graphic we had in the past, but much more in-depth. If we’ll just continue to have the same discharge bar, we’ll know absolutely nothing.

  6. For those who know better, what was the fastest year – in terms of full speed and power – so far in Formula 1?

  7. Am I correct that they will run flat out at 15.000 rpm in qualy given they only have to do a handfull of laps within the hour with as much as 100 kg of fuel?

    And second; wil cars spread out there ERS performance over a lap so they have predictable PU torque at each given corner? Or will a CPU control this with the risk of having huge (turbo) lag at the last couple corners of a lap, because a driver failed to harvast enough energy through out the lap?

    I’m confused

    1. 1. They will be flat out in quali, yes. No need to conserve fuel there. However, they won’t run 15k rpm, even in qualifying, I can assure you that much. Due to fuel flow limit max power is achieved around 13500-14000, after that it’s just more friction and power therefore decreases. you’ll only really need those 15k rpm in 8th gear in monza and maybe spa when you’re slipstreaming another car with drs.

      2. They will spread it out yes. There won’t be any turbo lag, engineers will make sure of this with clever mapping. More can not be said at this stage, information is too scarce.

    2. As i see it, drivers will always have predictable PU torque, apart from sometimes at full throttle.

      Example 1, 50% throttle – 50% throttle is say 350hp (approx), engine will deliver 350hp regardless of stored energy levels, it can either be 150hp from ERS with 200hp from the engine, or 350hp from engine with 0 ERS, or anything inbetween. Electronics will decide this depending on engine mode, fuel levels, laps remaining etc.

      Example 2, 100% throttle – engine will deliver as much power as it can depending on what is available. If there is no ERS energy, this would only be say 600hp, or less if in some fuel conservation mode. At full engine mode and with enough ERS charge it will give 750hp (approx).

      So i doubt drivers will be caught out by getting more or less power than they expect. I imagine they only use full throttle when they are sure the car is planted anyway, so a little distance into a straight or on a flat out bend. So the power differences at full throttle won’t matter from a control point of view. Besides, the driver will know engine mode and probably have some graphic for ERS stores so should know what to expect from the PU.

      i’m writing this to try and understand as i go, i might be completely wrong ;)

  8. Zain Siddiqui (@powerslidepowerslide)
    6th February 2014, 22:22

    I thought “full throttle ” hasn’t meant “full power” for a few years now. “Just give me full power, then, give me full power!” – Kimi Raikkonen, Belgium 2012

    1. It doesn’t, no, however Kimi also had kers problems in that race, so it could be that.

      1. Zain Siddiqui (@powerslidepowerslide)
        7th February 2014, 23:06

        James Allison said after that race that if they’re maintaining a good position during a race, they sometimes cut the power/fuel down, so I think power management from the pitlane has been going on for a while.

  9. Fascinating stuff. Many thanks.

  10. A bit whalloped here by people saying they don’t care about the environment.

  11. Sergei Martyn
    7th February 2014, 5:21

    Why F1 bans the productive inventions and concoct stupid counterproductive limitations?
    They tell us they want to use F1 technologies in road cars?
    All the banned F1 inventions made by team engineers – traction control, active suspension etc. are widely used in road cars these days.
    Now imagine offering fast degrading tyres, mandatory stops, 100 kg per month fuel limit, strong unrealibility and (thank you, veeeeryyyy old chap Bernie!!!) double service bills at the year’s end – no matter how much or how loud you babble about environmental friendliness, cutting edge technologies straight from F1, no one buy such cars.
    Same is with F1 – no one wants to buy totally artifical show regulated by stupid gimmicks.
    Goodbye TV viewing figures and true sport principles, hello weeping DNFers and losers weeping in front of the cameras – I was trying to save the planet, you all know that every time F1 car finishes, somewhere a little rabbit dies…

    1. Driving to the shops isn’t a sport though….

  12. “Full throttle no longer means a demand for full engine power,” explained Renault’s technical director for new generation power units Naoki Tokunaga.
    “It is an indication to the PU given by the driver to go as fast as possible with the given energy.”

    This seems to indicate that theoretically if a driver were to change mode of the car for max performance, then they would have a huge advantage over whoever they are trying to overtake or get away from. Of course at the expense of fuel. So it then boils down to whoever saves fuel initially would be a big advantage later. Similar to saving tires which can be used later. Except the fuel advantage will not go away at all, infact it will keep accumulating.

    Will we see races where drivers drive slowly in the first part and make a fewer pit stop so that towards the end they will have a big advantage with fresh tires and a lot of fuel to burn?

    Definitely looking forward to the first few races.

  13. I’m confused. The MGUK can only harvest half the energy it can use per lap, I thought the MGUH could harvest the 2 MJ shortfall?

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