KERS - Actual Stats on its impact

[Liam.Owens]

Hi guys, I recently posted a question based on the engine regulations for 2014 season and the response was awesome.

I am including KERS on my EPQ and looking for statistics on:
- Fuel Saved,
- Efficiency,
- etc

I understand it's benefits towards power input and increase of speed with the additional 160bhp for 2014 but what I am not seeing is the benefits towards fuel efficiency and carbon emissions which was the idea behind Max Mosely when he pushed for it to be introduced in 2009.

Thanks for any responses.

[Tim.Wright]

Well there won't be any stats in the public domain, its likely you will need to do some calcs yourself.

Firstly I'd say that KERs is not saving any fuel, its only giving a slight increase in performance using the same amount of fuel. In fact, I'd even guess that the fuel economy has become worse, because the minimum weight was raised at the same time that KERs came in to account for the extra systems. The extra weigh of the KERs system, needs more fuel to push it around the track.

If you do a basic calculations using the fuel energy content and efficiency of the engine, you could see how much extra fuel (and hence CO2) you would need to increase the lap performance to the level of a KERs car but using only an IC engine.

Then you could do another calculation to find out how much energy is required to push the extra 20-30kgs of battery, motor and ECU around the track. And then using the fuel engery content again, calculate how much fuel this requires.

If the first calculation gives you a bigger number than the second calculation, then KERs is effectively saving fuel. If the second number is bigger then you would have just proved to yourself that KERs was brought in purely for politcal reasons.

I'd actually be interested in the results of the calculation

[Liam.Owens]

Thanks for that, I am not too sure how to do those calculations. Would you be able to help me out?

Cheers.

[WhiteBlue]

You can use 46 MJ/kg of fuel for the thermal energy content of petrol and 29% for break thermal efficiency of the engine. Weight difference due to KERS is at least 30 kg.
Here we go:
30 kg * 46 MJ/kg * 0.29 = 400 MJ per race equivalent mechanical energy from the engine
§ 5.2.3. regulates a maximum of 400 kJ/lap of energy output from KERS
400 kJ * 70 laps = 28 MJ
=> if the weight difference for KERS was carried in fuel there would be 14 times more mechanical energy available
=> KERS isn't efficient under pure racing considerations

That doesn't tell us whether KERS will save any fuel, but it is a very strong indication that it will not. You would have to go into a performance analysis to answer the question. It is generally believed that 10 kg will give you 0.5 s per lap. So a difference of 30 kg will mean you add 1.5 s to an average lap.
http://www.formula1.com/inside_f1/under ... /8763.html

KERS lap time benefits range from approximately 0.1 to 0.4s.

So even if we use the optimistic figure of 0.4 s we get almost four times the performance from not carrying the KERS weigt around.
=> from both comparisons that KERS is a political statement!
The purpose was simply to bridge a gap and show the commitment to energy recovery technologies until the new engine formula could kick in. The 2014 formula was much too difficult to implement quickly in 2008, so they went for KERS to bridge the gap.

The history of KERS and minimum weight:

• 2008, 605 kg, no KERS
• 2009, 605 kg, KERS possible but not feasible due to performance deficit
• 2010, 620 kg, KERS increasingly used
• 2011-2013, 640 kg, KERS is essential to all teams
• 2014, 690 kg, ERS is mandatory with kinetic and heat recovery

Having a look at 2014:
If we consider that the new power train weights in at 80 kg more than the 2008 V8 engines and saves carrying 40 kg of fuel we still have to make up 40 kg of extra weight by the ERS system. So lets have a look at those figures. The new system is supposed to keep the performance level or exceed it. So we can positively say that the system will save 35% of the race fuel.
The MGU-K can deliver 120 kW to the power train and theoretically itwould be legal to feed as much as that power from heat recovery and kinetic recovery. The figure is a bit unrealistic but we can use it for a back of an envelope style computation. We would assume that 120 kW would be delivered for 65% of the race duration of 90 minutes.
120 kW * 5400s = 648 MJ
40 kg * 46 MJ/kg * 0.29 (old engines without ERS) = 534 MJ
So our calculation shows that the new 2014 systems makes sense in every respect. It saves fuel and will earn the additional weight that it costs to implement in terms of energy recovery. Naturally such a system would also have been better in 2009 but at the time it was impossible to implement.

[Pierce89]

Good post WB. The only issue is the increasing KERS uptake in 2010. That did not happen because there was a gentleman's agreement not to use KERS in 2010. As an aside, is minimum weight really going up to 690kg next year? That's way too heavy for F1.

[WhiteBlue]

Good post WB. The only issue is the increasing KERS uptake in 2010. That did not happen because there was a gentleman's agreement not to use KERS in 2010. As an aside, is minimum weight really going up to 690kg next year? That's way too heavy for F1.

OK, my memory about 2010 may have been a bit shaky. The 2014 tech regs published in the second edition in December 2012 say the minimum weight is 685 kg. The WMSC said last Friday that this value would be increased by 5 kg again.

[Paul]

I don't think evaluating KERS based on potential energy of fuel of the same weight is fair if the target is using less hydrocarbons, not just being more energy efficient, disregarding the source of that energy. As it was proposed earlier, it makes sense to evaluate it by comparing if added benefit of KERS is more than the extra energy it takes to move the weight of KERS together with the car.

Then there is the issue of minimum weight, so it might actually come down to KERS vs blocks of tungsten.

[WhiteBlue]

I don't think evaluating KERS based on potential energy of fuel of the same weight is fair if the target is using less hydrocarbons, not just being more energy efficient, disregarding the source of that energy. As it was proposed earlier, it makes sense to evaluate it by comparing if added benefit of KERS is more than the extra energy it takes to move the weight of KERS together with the car.

Nicely said, but more difficult to do. I think you need the engine consumption over lap performance curve for that. For instance the amount of fuel you save when you tune the engine down by an amount that lap performance goes down by 0.4s. I have never read details on engine mappings that would give you such values. Do you have the figures and can you give us a computation?

[timpane22]

thank you very much for this valuable information. it's really helpful. Keep updating us
=D> =D>

[H2H]

In verge of the TC ying yang thread and the discussion about KERS and the EBD blowing under braking I tried to collect some public information about KERS impact on the lap time. Obviously it is impossible to know how accurate such statements are and how holistic they tend to be. I started in 2011 and finished with the last race.


Time unkown, seemingly in 2010, F1 homepage

Do the regulations place limitations on the use of KERS?

Currently the regulations permit the systems to convey a maximum of 60kw (approximately 80bhp), while the storage capacity is limited to 400 kilojoules. This means that the 80bhp is available for anything up to 6.67s per laps, which can be released either all in one go, or at different points around the circuit. Lap time benefits range from approximately 0.1 to 0.4s.

Mercedes KERS info, September 2011

Q: What is the lap time benefit of KERS at Monza?
A: The lap time gain from full use of KERS is over 0.4 seconds at Monza. This compares to a lowest value so far this season of approximately 0.3s per lap in Hungary.

Q: As well as high speeds, Monza features heavy braking. Does that make it a good circuit for harvesting energy?
A: The cars spend over 12 percent of the lap (more than 10 seconds) on the brakes in Monza, with the braking event for Turn One seeing them shed around 265 km/h. However, Monza is actually the most marginal circuit of the year for KERS harvesting, owing to the low number of braking events during the lap: just six in total (Turns One, Four, Six, Seven, Eight and 11).

Scarbs on the Merc KERS development, January 2012

When lapping alone KERS typically gains 0.45s per lap, although this varies slightly by track. Along with DRS is can boost top speed by 12kmh. As explained the driver uses a pre-agreed amount of boost, decided from simulation work done at the factory before the race.

Renault Sport F1 head of track operations Remi Taffin, September 2012

“It is very simple. In qualifying you gain four tenths of a second per lap with KERS. Sometimes it will be three tenths, sometimes five, depending on the track layout, but the average is four. In the race it is a bit different because you use it to overtake. We saw that in Spa very graphically when Kimi (Raikkonen) overtook Michael Schumacher: he actually used all of his KERS going down to Eau Rouge to try and be as close to him as possible. It can be very useful in the race to attack someone where they would not expect you to attack.”

Christian Horner, Japan, October 2013

Team principal Christian Horner said the KERS fault would have cost Vettel four to five tenths of a second per lap. “It was unlucky for Sebastian,” he said.

“The KERS we had an issue with this morning, we changed as much as we could. In the first session it failed, in Q1, it came back in Q2. And then in Q3 it failed immediately so both Sebastian’s laps in Q3 were without the KERS so a great performance from him to get the car onto the front row.”

Vettel said his car felt “phenomenal” during qualifying. “The first sector is… I think you realise afterwards the car was fantastic through there and you don’t get many days the car feels like that where the car feels great and you can really push it to the limit. So enjoyed qualifying and happy with second place.”

The last quotes all agree that now the advantage KERS gives is roughly from 0.3 to 0.5 tenths. Interestingly the Mercedes sources talks about 0.45 in 2012, while the Renault one puts it later this year more around 0.4. The lowest value is obtained in Hungary while in Suzuka it made a difference between 0.4 and 0.5 according to RBR.

I was surprised quite a bit that the value was so high, as I had three tenths as a rule in my mind. Obviously the big question if the value includes the impact on the EBD blowing, something which we of course can not know. Personally I hoped to get some information by comparing the later to better earlier information but I run out of time.

I will try to update that soon as possible.

[H2H]

I looked at some quotes from 2009-2010 about the KERS performance. Obviously we had at that time different circumstances, Scarbs put it, back in October 2010, far better then I can now:

Even within 2009 season KERS was not a huge success, the system had a FIA cap on the amount of energy that could be re-used, only 400kJ could be stored, which when used for 6.7s per lap, the car gained some 80hp. Thus although a 0.3s boost to laptimes, the system was ultimately limited in its potential to improve laptimes. Thus no team could create a competitive advantage from a more powerful system. Then the weight of the system created issues, At a time when the wider front slick tyres demanded an extreme weight distribution of up to 49% weight on the front axle, the 25+Kg of a KERS system mounted behind the CofG handicapped teams being able to push weight forwards. Most teams dropping or not racing their system cited weight as the main reason for its loss.

Pat Symonds of Renault F1 in September 2009 talking about bringing KERS back for Monza

"There are three aspects of KERS that need to be considered: laptime, the advantage it gives from the start, and the ability to assist overtaking," said Symonds.

"Firstly, the gain in lap time of running KERS in Monza is likely to be around a quarter of a second and it's worth even more in qualifying as you can do one release before you start a timed lap and another release during the timed lap.

In late April 2010, Sam Michael of Williams gave the most precise answer to it's absolute performance gain.

"The attraction from my point of view is it makes the car go faster. If someone's got KERS then you can't afford not to have it. You're talking three or four tenths [per lap].

"It was quicker [to have KERS] by the end of last year. If you look at McLaren, in Ahu Dhabi they were very competitive until they had the brake failure, and that was with the old front tyre as well. Now with the narrow front tyre it will be even easier to make KERS work."

Now there are some interesting observations to be made.

1. With the old regs and the wide front tyres forcing the teams to transfer ballest to the front KERS was obviously a two-edged sword. We all know which teams were most competitve during the season however Sam Micheal rightly points out that the KERS teams had greatly reduced the handicap and put it's advantage, seemingly in the new regs at 0.3 to 0.4.

2. Monza was and is still the place where the performance gain by KERS is the highest. For 2011 we have 'over' 0.4 sec (F1, Merc KERS) there while in 2012 we have over 0.5 according to Remi Taffin.

Sadly we have no way to tell what exactly is behind those numbers, but that is F1 for you. A big problem in this context is if they are talking about a quali lap or sustained race pace and if it is an absolute or relative gain. All too often too many close-guarded secrets to get a full understanding of all the details of a current technology.