Rally1 hybrid cars (2022-)

[AnttiL]

https://www.mtvuutiset.fi/artikkeli/...1496#gs.mnr39v

Suninen says here that the wheels should not lock in order to regenerate energy. So likely handbrake will not help either.

[WRCStan]

Will the driver notice a big difference in feeling when braking the Rally1's with the regen slowing the car more than the brakes ? Also how does the handbrake act on on the new cars in terms of brakes or regen ?

It only works under the foot brake so you'll get it alongside the friction brakes which are still doing the overwhelming portion of the work. There is also 3 regen maps to set where they want it to fit around the brakes through the brake pedal, I'm not sure what scenarios they have in mind. My instinct is they won't notice any difference. Braking is braking, it's only whether that tiny portion is there one time and not the next that could throw them.

Handbrake doesn't change unless you are somehow using it to slow the car instead of using the footbrake and denying the regen process. The wheels need to be turning so locking up and slowing with tyre/road friction is no good either as Teemu says in Antti's link.

[kubiczech]

After some discussions on this topic I realized that the total capacity of the battery is what limits the recuperation power to a relativerly low value like this.

Maybe the safety is also factor in this. When similar system in F1 car fails (it still happens, after 7 years of development), result is driver cannot stop the car where he anticipated, sometimes resulting in crash even on supersafe circuit. I guess i would not want to suddenly loose all my rear brakes, because of software glitch, on downhill braking from 150kmh somewhere on Col de Turini. When regen system fails and you loose only 30kw of braking power, you should be able to stop the car.

(i think F1 is regenerating max 120kw when braking, but i might be wrong)

[Mirek]

Maybe the safety is also factor in this. When similar system in F1 car fails (it still happens, after 7 years of development), result is driver cannot stop the car where he anticipated, sometimes resulting in crash even on supersafe circuit. I guess i would not want to suddenly loose all my rear brakes, because of software glitch, on downhill braking from 150kmh somewhere on Col de Turini. When regen system fails and you loose only 30kw of braking power, you should be able to stop the car.

(i think F1 is regenerating max 120kw when braking, but i might be wrong)

I understood that the main issue was overcharging of the battery. It can be charged and drained only up to certain current values depending on its capacity. Some circuit cars use supercaps instead of batteries to remove this limitation but those are useless for cruising on the road section.

You might have a point with the safety factor too.

[traxx]

It seems that hybrid boost allowed by stage for Monte is between 100 and 150 kj, so less than 1,5s for each boost after a regen ? (and if enough energy is available)

[becher]

https://www.youtube.com/watch?v=-mbCJecCDr8

Apparently, removing the active centre diff and paddle shifter allows to remove the hydraulic system which saves money.

That would save some development costs for sure.

[becher]

That's true but it also removes the possibility to control the shifting by the ECU. Honestly I have no idea how the WRC gearshift system was designed but I would expect that indirect shifting by the hydraulics can be set that it prevents shifting which would set the revolution speed outside of the safe range. With direct mechanical lever it is not possible. In the end the effect on the reliability may be worse than saving created by not using the hydraulics.

Damage from improper shifting used to be quite common with the S2000 cars where improper downshifting was really an easy mistake. I recall situations when RPM in the range of 10-11 thousand was achieved by mistake and it often lead to catastrophic damage.

Hmm yes, that makes sense. They won't be able to play with the ECU to improve shifting any more either i would guess.

[Tom K]

After making some "research" and puting together a bit scattered info, I would say that the strategic side of hybrid era and drivers' part of job is not where to deploy the energy, but where not to regenerate it...

In other words. After initial boost at the start, the regen counter will be zero. On the first braking driver can regenerate and if the regen is valid some portion of this energy is available (and used) after corner when car accelerates (because driver does not have any boost button, and hybrid is "on" during whole stage). And situation repeats until the energy limit of boost is reached - for example stage no 2 - 100 kJ.

So, the strategic side: If team decides, that the best option is to have 100 kJ available in one long straight in the middle of the stage, then the will would be not use it earlier (for example in slow twisty section when acceleration from ECU is enough). As driver cannot turn on/turn off this boost, he should try not to regenerate energy up to chosen section before long straight mentioned before.

Am I (at least a bit) right?

[WRCStan]

After making some "research" and puting together a bit scattered info, I would say that the strategic side of hybrid era and drivers' part of job is not where to deploy the energy, but where not to regenerate it...

In other words. After initial boost at the start, the regen counter will be zero. On the first breaking driver can regenerate and if the regen is valid some portion of this energy is available (and used) after corner when car accelerates (because driver does not have any boost button, and hybrid is "on" during whole stage). And situation repeats until the energy limit of boost is reached - for example stage no 2 - 100 kJ.

So, the strategic side: If team decides, that the best option is to have 100 kJ available in one long straight in the middle of the stage, then the will would be not use it earlier (for example in slow twisty section when acceleration from ECU is enough). As driver cannot turn on/turn off this boost, he should try not to regenerate energy up to chosen section before long straight mentioned before.

Am I (at least a bit) right?

Hybrid deployment is in the boost or not at all. I've heard several people saying it is on all the time, but I've taken it to be their way of saying there are no buttons to press to activate anything. After each valid regen you get the boost immediately which you can lose by braking, this may happen on twisty bits. Although then you'd get another boost from 1 second of reasonable braking.

They don't have to regenerate 100kj to get 100kj boost, in Monte SS2 they will use maximum 100kj under acceleration boost, then regenerate minimum 30kj by braking, then repeat this to the end of the stage. In general the battery should deplete across the stage. Realistically I don't think you could plan or would want to have it available in a particular place.

[Tom K]

As I expected, one "question-answer" pair will induce another one. This 100 kJ is the maximum of the each boost available after each valid regen (min 30 kJ) or it is sum of energy which can be used during whole stage, so all boosts on SS2 should give sum of energy equal 100 kJ? I thought the later is true, but now the former sounds reasonable...
Thank you