TERS : Thermal Energy Recovery System

[gruntguru]

That is just a convoluted way of transferring electrical energy from the MGUK to the ES and I am sure the authorities would rule as such.

[godlameroso]

Following up on the discussion in the Honda PU topic on MGU-H harvesting energy that is provided directly to the MGU-K, an energy flow which is unlimited.

Would it be technically possible and legal to do it the other way around as well, by any significant amount? The MGU-K is allowed to harvest 2MJ per lap straight into the ES. But there is no limit for energy going from MGU-K to MGU-H. So if you have filled up the 2MJ for that lap, you could use the MGU-K to boost the MGU-H during braking.

Of course this would only make sense if the MGU-H can do something useful with that energy. I don't know a lot about electric motors so my question is: would it be possible to have an MGU-H with two windings with separate control, one 'connected' to the ES and the other to the MGU-K? If so, would it be possible to have one winding on generator mode (using energy coming from MGU-K) and the other on harvesting mode to store this energy into the ES?

If this would work and it is legal, you could potentially recover more kinetic energy than 2 MJ per lap.

I'm sorry if this idea sounds ridiculous, I just don't have enough knowledge about electric motors to know any better.

More interesting is to ponder what kind of materials are used in the windings, surely there are better conductors of electricity than copper, and seeing as how it's essentially a spending free-for-all, I don't know why any top team would settle for mere copper windings.

[gruntguru]

Silver is about 5% better as a conductor. Sounds great but that only means the resistive losses can be reduced by up to 5%. Considering that those losses are probably only 2% (2.4 kW) the potential saving is perhaps 0.12 kW?

[hollus]

Following up on the discussion in the Honda PU topic on MGU-H harvesting energy that is provided directly to the MGU-K, an energy flow which is unlimited.

Would it be technically possible and legal to do it the other way around as well, by any significant amount? The MGU-K is allowed to harvest 2MJ per lap straight into the ES. But there is no limit for energy going from MGU-K to MGU-H. So if you have filled up the 2MJ for that lap, you could use the MGU-K to boost the MGU-H during braking.

Of course this would only make sense if the MGU-H can do something useful with that energy. I don't know a lot about electric motors so my question is: would it be possible to have an MGU-H with two windings with separate control, one 'connected' to the ES and the other to the MGU-K? If so, would it be possible to have one winding on generator mode (using energy coming from MGU-K) and the other on harvesting mode to store this energy into the ES?

If this would work and it is legal, you could potentially recover more kinetic energy than 2 MJ per lap.

I'm sorry if this idea sounds ridiculous, I just don't have enough knowledge about electric motors to know any better.

I don't know it it would be worth it, but I like the idea of having the KERS store extra energy via the MGUH.
Whether one can send energy down that route or not, you might have opened an interesting can of worms:

if the MGU-H can do something useful with that energy

There is unlimited energy flow, both ways, between MGUH and MGUK and between MGUH and ES, but, interestingly, also both ways between MGUH and the "Pressure charging system" and then between that and the engine (via the compressor, really, isn't it?).
It is always mentioned how quali modes might bypass the MGUH and use the wastegate to avoid backpressure if recovery is not being used, but in principle, couldn't the MGUH overspeed from its ideal recovery speed (on purpose) and actually pull gases from the exhaust? This would reduce the backpressure even further, possibly to negative values and even directly drive the engine to a limited extent by pure blowing. Probably a bitch to tune when it is linked to the compressor, but it might come handy in limited situations. And remember, "it may be clutched".

Is there anything conceptually preventing using the exhaust recovery to help the gases along their way instead of to hinder them? Or maybe this is common knowledge?

[godlameroso]

Silver is about 5% better as a conductor. Sounds great but that only means the resistive losses can be reduced by up to 5%. Considering that those losses are probably only 2% (2.4 kW) the potential saving is perhaps 0.12 kW?

What about areas like bearings, or better lighter insulation to the windings, or the armature(does an MGU-H even use an armature?).

Using silver you could make the unit lighter by making the windings thinner. If you can make each wire 1% thinner with the same conductivity and you have thousands of wires, it could make a difference.

[Juzh]

Is there anything conceptually preventing using the exhaust recovery to help the gases along their way instead of to hinder them? Or maybe this is common knowledge?

125.000 rpm limit? Not sure.

[gruntguru]

It is always mentioned how quali modes might bypass the MGUH and use the wastegate to avoid backpressure if recovery is not being used, but in principle, couldn't the MGUH overspeed from its ideal recovery speed (on purpose) and actually pull gases from the exhaust? This would reduce the backpressure even further, possibly to negative values and even directly drive the engine to a limited extent by pure blowing. Probably a bitch to tune when it is linked to the compressor, but it might come handy in limited situations. And remember, "it may be clutched".

Is there anything conceptually preventing using the exhaust recovery to help the gases along their way instead of to hinder them? Or maybe this is common knowledge?

Radial inflow turbine doesn't work that way. If you increase its speed by driving the shaft, the backpressure on the engine increases.

It is just as effective to drive the compressor speed up (with the WG wide open) increasing the boost. This will create extra crankshaft work by pushing the pistons down during the intake stroke. This must remain within compressor max speed and AFR limits.

[NL_Fer]

To exceed the 2MJ limit, a car would need to brake for over 16s a lap, never gonna happen in F1.

Just a thinking, would the backpressure be measured with a sensor and would it be a control value for the ERS/Wastegate strategy?

[henry]

To exceed the 2MJ limit, a car would need to brake for over 16s a lap, never gonna happen in F1.

I have 11 of the circuits in a spreadsheet with braking percentages from Brembo.

Based on a typical race lap, braking times:
The average is 17 seconds.
The longest, Singapore, 27 seconds.
The shortest, Silverstone , 10 seconds.
6 are longer than 16 seconds

However, the efficiency of recovery is around 45-50% so you really need around 32 seconds of braking to exceed 2 MJ.

They can, of course, top up to 2 MJ by driving the MGU-K with the ICE when traction limited.

Next year braking times will go down.

[R_Redding]

Next year braking times will go down.

Hamilton was interviewed in Baku ... and said that braking will be a significant issue in 2017.
The cars will be heavier ,with much larger tires ...but the carbon discs will be the same as this year as no supplier is building larger one currently..and they have a long tooling/lead time.
So braking times will most likely go up.

[henry]

Next year braking times will go down.

Hamilton was interviewed in Baku ... and said that braking will be a significant issue in 2017.
The cars will be heavier ,with much larger tires ...but the carbon discs will be the same as this year as no supplier is building larger one currently..and they have a long tooling/lead time.
So braking times will most likely go up.

Thanks. An interesting perspective. I hadn't heard it but since there are some circuits that are brake wear critical now it is not surprising.

Starting weight will be around 830kg versus 800 now and about 770 in the v10 era. With similar speeds, if not higher, we will probably see highest ever braking energies.

So we get an additional resource to manage. More lift and coast, this time to protect brakes as well as fuel ( which even at 105kg will be tighter than now IMHO) More emphasis to using as much electrical energy at the beginning of straights and lower top speeds due to increased drag might help, as will increased cornering speeds and hence higher speeds at the end of the braking events.

I'm guessing it will vary from circuit to circuit. And we will see even bigger differences between q3 times and race fastest laps than we have now.

Watching the brake issue evolve will be interesting at first but I doubt it will be beneficial to the spectacle in the long run.

[NL_Fer]

No, when braking full at high speed, when the car is slowing down, brake pressure has to be reduced by e driver to prevent lockup. With wider tyres, a driver can keep maximum brake pressure for a longer period, because of more tyre grip.

This will give 1: more brake wear 2: more brake heat 3: shorter stopping distance 4: shorter brake times.

[godlameroso]

More energy to harvest as well.

[henry]

No, when braking full at high speed, when the car is slowing down, brake pressure has to be reduced by e driver to prevent lockup. With wider tyres, a driver can keep maximum brake pressure for a longer period, because of more tyre grip.

This will give 1: more brake wear 2: more brake heat 3: shorter stopping distance 4: shorter brake times.

In qualifying yes. Nice new disks no worries about wear. But in the race the higher total energy going into the disks will wear them more and so drivers will have to forego some of the potential stopping power in the interests of getting to the end of the race. One way to do that is lift and coast. In 2017 I expect more drag and so more speed loss in the coast phase. Another technique will be not to brake as hard. Since teams use brake heat to manage tyre temperatures there may be merit in not using all the braking force available so as to keep the brake, and hence tyre temperatures in the right window.

As with so much of modern formula 1 this will be a subtle balancing act. Teams will measure and simulate over and over again and will then advise the drivers how best to use the brake performance, stopping power and wear, to get the best race performance. With the radio coaching restrictions drivers will need a good understanding of the trade offs to be made.

But I don't think this is new. I would expect that this year at Canada during the race drivers were not barrelling into every braking zone and braking flat out. And it may well be that this will be a more pronounced issue next year. And maybe it won't. It's something we can watch out for.

If the braking times are shorter and so KERS recovery less It will put a little more emphasis on the TERS.

[godlameroso]

KERS recovery is from how much energy you can absorb by the rear axle. The tires in the back are going to be significantly wider, hence more KERS torque can be used to slow the rear wheels. More energy = more recovery, the thing that will be a challenge is designing batteries that can charge that faster than the ones they have now.