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So for any given car, how should you drive to maximise fuel saving? Should you carry speed across to minimise the amount of energy spent re-accelerating, or should you drive straighter lines so that the energy is all being put down to bring the car forwards (and not being eaten up by cornering or tyre scrub)
You would want to carry speed through the corner and generally avoid scrubbing speed as much as possible. You will also want to drive as straight a line as possible, though mainly to maximize cornering radius;
Basically the things you already do to set a fast lap time. I don't think it makes too much difference, but a gentle touch on the throttle will probably help a bit with fuel economy, but if you're not doing things like lift and coast, other parameters will have a much greater effect on fuel economy.
We have to ask Bottas, Pat Symonds is quoted in AutoMotorundSport Magazine with something like that: "This guy drove so fuel efficient on his race sim, if he'd be my chauffeur I would save a lot of money."
Finishing races is important, but racing is more important.
raymondu999 wrote:So for any given car, how should you drive to maximise fuel saving?
All I read was still "lift and coast". So when there is no pitstop-window we will see not only tire conservation, but also "lift and cost" in nice 2sec gaps through the whole race.
raymondu999 wrote:
Should you carry speed across to minimise the amount of energy spent re-accelerating, or should you drive straighter lines so that the energy is all being put down to bring the car forwards (and not being eaten up by cornering or tyre scrub)
This should be still tire/grip dependent. Remember the "use your tires" radio in Singapur?
So they will not use "late apex" as long as they can afford it by the laptime just because of the tires.
Late apex/less power or geometric apex/more power should be the same regarding fuel economy and lap time.
raymondu999 wrote:So for any given car, how should you drive to maximise fuel saving?
All I read was still "lift and coast". So when there is no pitstop-window we will see not only tire conservation, but also "lift and cost" in nice 2sec gaps through the whole race.
Actually, Merc asserted that they only had to fuel save for a few laps, and that when they did have to, it only required a minor change in style.
I doubt much will change in a required driving style. In any non-refueling era there was a certain amount of fuel saving required, so nothing will change in that regards. Whatever it is that saves fuel might have to be done a little more this year, but I don't think a new style will be required.
As for slowing down less vs. straightening the car earlier, I read a while ago (though the details are a little fuzzy, so don't know if it's in general or to a specific vehicle/situation) that quick acceleration to then maintain a high speed is most fuel-efficient.
If someone has the time, I reckon comparing Vettel's and Bottas' onboards to other drivers to pick up distinct difference might be a way to find out.
Coasting the final second or two of the straight (while starting to brake a little later), not only saves quite a bit of fuel for minimal time-loss, it also saves the brakes and cools the engine.
The challenge is to do this while still attacking the turns as hard as ever - it's more difficult than you'd think. The driver will have to adapt his braking-point to account for how long the coasting period was. For example if he lifts off at the 300 meter mark, he might not need to start braking until 70 meters before the corner, but if on the next lap he lifts off at the 200 meter mark, he might have to start braking at the 100 mark in order to make the corner. And conversly: Braking at the 100 meter mark after having coasted from the 300 meter mark would cost lots of time, so the driver will have to be "on it" all the time - fuel saving does NOT mean that the driver can relax!
The big strategy decision will be to know when to push and when to save.
I believe that in the first few laps, most drivers will go flat-out while jockeying for position. Once things have settled in, those drivers who find themselves stuck behind a potentially slower car, will start to use this as an advantage by saving as much fuel (and tires) as possible while sitting in the DRS zone behind the slower car. Once they decide that they have saved enough to be able to go more or less flat-out for the rest of the race, they will turn it on and start to make progress through the field.
Others might find themselves at the end of a fast train of cars and will have to use a lot of fuel just to stay with the pack. They will build big gaps to the drivers behind who are in fuel-saving mode, but this may of course come back to hurt them in the end.
Safety-car periods will also throw a fork into the equation: On the one hand, a safety-car may be good for those who have spent more fuel, as they now get a chance to save fuel behind the safety car, but on the other hand the safety-car bunches up the field, so they will lose whatever time gap they have built up.
Also note that it's actually possible to save too much fuel. If you end the race with 10 kg fuel still left in the tank, it means your car has been 10 kg too heavy for most of the race, which has cost you 3-4 tenths a lap for no gain.
The way how i see it this year, with the flexibility of the engine, the driver doesn't have to do much to save fuel driving style wise. He probably can turn a few dials to limit the engines performance and he can continue to mash the gas and brake pedal.
The car has 8 gears, an electrical battery, direct injection, it's turbo charged and fully adjustable in their interaction.
I think adjusting those elements are enough to have fuel saving without driving style making a noticeable impact.
The cars are simply smart enough now. It's behavior and performance envelop will just be adapted and the driver wouldn't be asked to back off and coast or any of those things of the past V8. He'll be told to turn some dials.
You may be right, but I still think that's not the most effective way to do it. Tuning down the engine costs time in acceleration as well as top speed, while backing-off just before the braking-zone saves a measurable amount of fuel with a very minimal loss of time.
Instead of using fuel to accelerate from, say, 334 to 336 kph in the last 200 meters of the straight, you coast, and, as a result, drop from 334 to, say, 320 kph in the same 200 meters. So the average speed over these 200 meters will be 327 kph instead of 335 kph. So it will take 2.202 seconds to cover the distance, compared to 2.149 seconds while going flat out. That's a total of 0.053 seconds lost while spending 2.2 seconds on 0% throttle instead of 100% throttle. Do this four times a lap, and you lose in the region of two tenths a lap while spending 8-9 seconds less on full throttle. Instead of using full throttle for, say, 70 seconds during the lap, you will only use full throttle for, say, 61-62 seconds. That's a reduction of 12%, which should mean you spend 12% less fuel. 12% better fuel milage for just over two tenths a lap. I am sure that tuning down the engine to save the same 12% of fuel per lap will cost a lot more than two tenths a lap in performance.
Roland Ehnström wrote:The big strategy decision will be to know when to push and when to save.
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Safety-car periods will also throw a fork into the equation:...
Also note that it's actually possible to save too much fuel. If you end the race with 10 kg fuel still left in the tank, it means your car has been 10 kg too heavy for most of the race, which has cost you 3-4 tenths a lap for no gain.
This is why I can not see this big strategy decision. If you save fuel (we are talking about normal saving, not excessive saving when you are running into problems) before the last pit stop this is likely to cost you track position and ruin your race.
The same with the safety car: If you save fuel before a safety car period this is nonsense, because you run into the problem of having not enough tire left to burn your fuel. A safety car will solve all fuel problems.
So for me it is clear, that fuel saving will be only in the last stint, especially on tracks where it is not easy to overtake.
