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End of the MGUH


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#1 Wuzak

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Posted 17 September 2021 - 06:10

It is appearing more likely that the MGUH will be dropped from F1 power units in the 2026 rules.

 

The ERS power may be increased from the current 120kW to 350kW, with the possibility of recovery from the front wheels as well.

 

The problem I see is that cars don't brake for very long at most tracks. Which means limited amount of energy can be recovered from braking.

 

No doubt increasing the recovery rate will help this, as will a move to recovery from all 4 wheels.

 

But if the deployment power is the same the deployment time must be roughly the same as the recovery time.

 

At Monza the F1 cars brake for less than 11s of the time. Imola and Austria are even less. Spa is just over 13s. 

 

In current F1 much of the energy deployed through the MGUK is recovered by the MGUH. Going to a brake only recovery will reduce the amount of recovery and deployment per lap, making it more of a KERS type system.



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#2 Ben1445

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Posted 17 September 2021 - 07:59

But if the deployment power is the same the deployment time must be roughly the same as the recovery time.

Four wheel drive in F1 is basically a non-starter due to strong opposition to it, so a front axle motor would more than likely be recovery only and then deployment goes through the rear motors only. 

 

Same is true for Formula E's next ruleset for Gen3 (2023), for example, which will have up to 600 kW total braking recovery (250 front, 350 rear) and then deployment is capped at 300 kW in a race setting. I'd imagine that F1 would presumably follow the same type of arrangement.

 

Current F1 rules - if I'm not mistaken - are still that you can deploy up to 4MJ per lap whilst the MGU-K can recover up to 2MJ of that per lap. As a bit of a back of the envelope thing 2MJ is 0.55kWh, so with braking of 10 seconds you're talking about a ~200kW peak recovery, right? The system is then permitted to redeploy at 120 kW. 

 

Seems like the idea in future F1 is to have a 50:50 split in delivered power from the motors and the ICE. If you had a 400 kW sized rear MGU and a second, recovery-only MGU on the front (lets say 200kW for arguments sake) you would easily be taking a big leap forward in MGU-K recovery potential from today's cars up to something like FE's planned 600kW.

 

600kW for 10 seconds is (theoretically) ~6MJ which would be +50% on the permitted combined per lap deployment today from both MGU-K and MGU-H combined. Deployment could then still be capped to the proposed 350 kW to extend the deployment phase. 

 

In practice is a little more complicated, sure, but in theory that's how I'm seeing it. 

 

Additionally, I honestly think the way the way the world is going will mean that we will see ever tighter development restrictions on the ICE side whilst more of the competitive focus and development budgets will go towards the ERS, since that's the bit that's relevant no matter whether you're selling hybrids, EVs or fuel cell vehicles.

 

At the end of the day, the current ERS regulations were written in 2012/13 and have barely changed since. They need the update. 


Edited by Ben1445, 17 September 2021 - 09:00.


#3 Wuzak

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Posted 17 September 2021 - 08:20

Current F1 rules - if I'm not mistaken - are still that you can deploy up to 4MJ per lap (I mean just use kWh, F1, seriously) whilst the MGU-K can recover up to 2MJ per lap. As a bit of a back of the envelope thing 2MJ is 0.55kWh, so with braking of 10 seconds you're talking about a ~200kW peak recovery, right? Then permitted to redeploy at 120 kW. 

 

4MJ per lap from the ES to the MGUK. Energy transfer between the MGUH and MGUK is unlimited (also between the MGUH and ES).

 

The maximum MGUK recovery allowed at the moment is 120kW. And only one or two tracks come close to the allowable 2MJ of recovery - Singapore definitely.

 

Whilst braking takes 10-15s per lap on most tracks, not all braking events will allow for maximum recovery. Monaco has >20s per lap braking, but still does not get to 2MJ of braking recovery.

 

They may be using the ICE at higher power than requested by the driver in traction zones and then using the MGUK to ****** the ICE and recover more energy.



#4 Ben1445

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Posted 17 September 2021 - 08:43

4MJ per lap from the ES to the MGUK. Energy transfer between the MGUH and MGUK is unlimited (also between the MGUH and ES).

 

I did forget about this bit. Thanks.

 

Can you quantify how much energy the MGU-H provides over a typical lap? Presumably if it was pushing the full 120kW into the MGU-K for ~60 seconds that would be around 11MJ. And the ES is capped at 8MJ? How much of that potential does it reach? I'd honestly been assuming it doesn't really provide more than 10MJ per lap, but happy to be corrected. 

 

But still, I think F1's MGU-K recovery/deployment rules are woefully outdated now. Even in 2014 LMP1-H cars were recovering up to 8MJ, and Toyota competed in that category with front and rear recovery from two MGU-Ks instead of opting for the MGU-K and MGU-H route.  

 

Ultimately, I'd argue that F1 may well have been mistaken to allow the unlimited recovery and push technological boundaries on the turbo-specific MGU-H instead of the far more widely vehicle-relevant MGU-Ks.


Edited by Ben1445, 17 September 2021 - 12:18.


#5 Charlieman

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Posted 17 September 2021 - 09:51

I recall reading about patents from the 1920s about MGU-H style engines and it was certainly a discussion topic for high performance engines in military vehicles in the late 1970s. Does anyone have information about MGU-H costs in F1 -- cost of kW versus kW from other sources? How close to real world usefulness?



#6 desmo

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Posted 17 September 2021 - 14:19

Hybrid powertrains seem to me like a complicated kludge to bridge the transition between IC and full battery electric cars. Not sure why F1 embraced that tech dead-end, race cars should be simple and light.



#7 ARTGP

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Posted 17 September 2021 - 19:51

The problem I see is that cars don't brake for very long at most tracks. Which means limited amount of energy can be recovered from braking.

 

This is a deceptive statement. When an F1 car goes from 300km/h to 100km/h, energy is dissipated. The same amount is dissipated no matter how long or short the braking distance (that's approximately correct since there is some work done by the drag forces which could not be recovered).  The question is what proportion can you capture with the ERS-K vs the disc brakes. The limitation will always be how much energy can be recovered without blowing up the ERS-K and the battery :D . Front axle recovery reduces load on the rear MGU-K. Improving the power rating of the battery and ERS-K does the other part. I think F1 could go quite far here and this is the type of road relevant technology the manufacturers have been begging for. No electric vehicle should have a need for mechanical brakes except in an emergency. 


Edited by ARTGP, 17 September 2021 - 19:54.


#8 GreenMachine

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Posted 17 September 2021 - 21:53

I know (believe) that the ERS-H is expensive, and certainly was prone to failure.  But we now have four groups that can build a reliable H.

 

Cost?  I wonder where the cost comes from.  Turbo and compressor are well proven technologies, I doubt there is a (relatively) large cost there.  The high speed generator might be a challenge, I assume it is direct drive as I have seen no mention of gearing.

 

Complexity?  I think this is a major source of the cost, the interplay between the ICE output through the clutch, and the electrical output of the generator.  Put another way, using the ICE as a gas generator to produce electrical output.  I believe Merc were the first to see the potential for this, and to optimise the powerplant components around sustained high combined (total) outputs.  By comparison, Renault were late to the party, slow to grasp the possibilities the H provided.



#9 Wuzak

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Posted 18 September 2021 - 05:26

Cost?  I wonder where the cost comes from.  Turbo and compressor are well proven technologies, I doubt there is a (relatively) large cost there.  The high speed generator might be a challenge, I assume it is direct drive as I have seen no mention of gearing.

 

The turbo is restricted to 125,000rpm (IIRC), but the MGUH is not. The rules specifically allow for the MGUH to be geared and to have a clutch system to isolate it from the turbo.



#10 Wuzak

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Posted 18 September 2021 - 05:31

This is a deceptive statement. When an F1 car goes from 300km/h to 100km/h, energy is dissipated. The same amount is dissipated no matter how long or short the braking distance (that's approximately correct since there is some work done by the drag forces which could not be recovered).  The question is what proportion can you capture with the ERS-K vs the disc brakes. The limitation will always be how much energy can be recovered without blowing up the ERS-K and the battery :D . Front axle recovery reduces load on the rear MGU-K. Improving the power rating of the battery and ERS-K does the other part. I think F1 could go quite far here and this is the type of road relevant technology the manufacturers have been begging for. No electric vehicle should have a need for mechanical brakes except in an emergency. 

 

 I said that cars don't brake for very long, not that the braking distances are short.

 

Most tracks the braking is less than 15s per lap, and often it is not hard enough to recover energy at the maximum rate allowed by the MGUK. The result is that at most tracks the potential braking recovery is around 1/2 to 3/4 of the 2MJ allowed by the rules.

 

I agree that front energy recovery would be beneficial, and no doubt will make the electronic braking system easier to get right.



#11 Wuzak

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Posted 18 September 2021 - 05:37

Can you quantify how much energy the MGU-H provides over a typical lap? Presumably if it was pushing the full 120kW into the MGU-K for ~60 seconds that would be around 11MJ. And the ES is capped at 8MJ? How much of that potential does it reach? I'd honestly been assuming it doesn't really provide more than 10MJ per lap, but happy to be corrected.


That is hard to do, as it is a well guarded secret.

I would guess that the deployment per lap is 4MJ+, only 1MJ - 1.5MJ of which comes from the MGUK.

 

But still, I think F1's MGU-K recovery/deployment rules are woefully outdated now. Even in 2014 LMP1-H cars were recovering up to 8MJ, and Toyota competed in that category with front and rear recovery from two MGU-Ks instead of opting for the MGU-K and MGU-H route.


Up to 8MJ, which I am guessing only every occurred at Le Mans, a track with a lap time of ~3m20s. Compared to F1 where the lap times are all within 2 minutes, and some are barely over a minute.

The LMP-H rules also allowed for significantly larger MGUKs.

Porsche did well with one MGUH and one MGUK - which was on the front axle?



#12 Wuzak

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Posted 18 September 2021 - 05:39

It will be interesting when Indycar adopt hybrids. I can't see much brake energy recovery happening at the Indianapolis 500.



#13 Ben1445

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Posted 18 September 2021 - 07:55

That is hard to do, as it is a well guarded secret.

I would guess that the deployment per lap is 4MJ+, only 1MJ - 1.5MJ of which comes from the MGUK.

Well, I've found reference to the MGU-H accounting for 70-75% of the energy recovered per lap. Assuming that's accurate and you're right that the MGU-K is providing around 1-1.5 MJ on average, that would suggest 4-6 MJ of deployment, 3 - 4.5 MJ of which is coming from the MGU-H.

 

So that does sound pretty plausible to me, in fairness. 

 

Up to 8MJ, which I am guessing only every occurred at Le Mans, a track with a lap time of ~3m20s. Compared to F1 where the lap times are all within 2 minutes, and some are barely over a minute.

Porsche did well with one MGUH and one MGUK - which was on the front axle?

 Yes, the Porsche MGU-K system was a front axle, I think at 300kW deployment. They raced in the 6MJ class in 2014 and the 8MJ class from 2015. They reportedly got up to 60% of their recovered energy from the K system and 40% front he H system. 

 

Toyota raced in the 6MJ class in 2014-2015, with two MGU-Ks an 353 kW total deployment. They then moved into the 8MJ class from 2016, with 368 kW total deployment. 

 

The LMP-H rules also allowed for significantly larger MGUKs.

Well, quite. I was very much saying that the restrictions on the F1 MGU-Ks are at a comparatively low, arbitrary limit rather than anything majorly technological. 

 

The 120kW cap via a single, rear MGU-K was always small in comparison to LMP1-H.

 

Come 2023, we should see Formula E with kinetic recovery at 600kW, and the FIA's planned eGT series is slated to get up to 700kW in the same year. 

 

I still believe there is significant scope to increase the MGU-K contributions in F1. 


Edited by Ben1445, 18 September 2021 - 07:55.


#14 MatsNorway

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Posted 02 October 2021 - 18:57

Front axle recovery only as in without the drive on the front wheels is unlikely/should not be a thing. The extra dead mass you would be spinning up can give you some interesting handling characteristics. I am assuming a front KERS + shafts will weight 10-20kg+ 


Edited by MatsNorway, 02 October 2021 - 18:57.


#15 Ben1445

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Posted 02 October 2021 - 19:54

Well, that is exactly what Formula E are going to do in Gen3.

But in any case, the latest indications from the last few days seem to be that F1 is shifting towards not having any MGU on the front axle at all.

Edited by Ben1445, 02 October 2021 - 19:54.


#16 MatsNorway

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Posted 04 October 2021 - 20:43

Formula E has always been a shitshow so that does not surprise me. :rotfl:

 

Its probably fine if you want my serious opinion.



#17 Wuzak

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Posted 05 October 2021 - 13:49

Looks like they are going for 350kW recovered/deployed through the rear wheels only.

 

Will they recover enough energy to warrant the weight of the battery and MGUK?



#18 Ben1445

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Posted 05 October 2021 - 14:17

What would you quantify as being 'enough'? 



#19 desmo

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Posted 05 October 2021 - 18:36

Other than safety, I'm not seeing why the regulations should have any say at all on how, or even if, teams want to do heat recovery or regenerative braking. Give each car a set amount of energy to use (as either battery charge or fuel) and fully leave the technical decisions to the teams as they see fit.  The rules as they are are just unnecessary meddling for meddling's sake and because of their logical incoherence have to be constantly changed to great and pointless expense. A well-written set of regulations could last for many years with only slight, insignificant adjustments. If the rules are seen to need to substantially change on a regular basis, it only means that the people writing the rules either don't know what they are doing, what they want the regulations to achieve, or most likely both.



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#20 Wuzak

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Posted 05 October 2021 - 21:56

The new rules are aimed at getting Audi/Porsche into F1.