F1 Energy store density for 2026 and hot swap batteries

[wuzak]

Why would you coast?

Lots of braking with rear bias, no?

No, I think they will start recovery part way along the straight, at up to 100kW, while the driver is at full throttle.

I believe that's what they used to do in the LMP1 days - get up to speed in first part of straight, reduce power to save energy then start recovering before the braking zone.

Under LMh and LMDh rules it is a bit different.

For these the power curve is defined, and your engine can produce more power than the total allowed, which means that when the ICE is producing maximum power the ERS can be recovering, to be used when the ICE is below the power curve.

That's what I'm hoping but alot of people in this forum are suggesting that you cannot use the ICE to drive the MGU-K to charge the battery.

Well, one in particular.

[Zynerji]

No, I think they will start recovery part way along the straight, at up to 100kW, while the driver is at full throttle.

I believe that's what they used to do in the LMP1 days - get up to speed in first part of straight, reduce power to save energy then start recovering before the braking zone.

Under LMh and LMDh rules it is a bit different.

For these the power curve is defined, and your engine can produce more power than the total allowed, which means that when the ICE is producing maximum power the ERS can be recovering, to be used when the ICE is below the power curve.

That's what I'm hoping but alot of people in this forum are suggesting that you cannot use the ICE to drive the MGU-K to charge the battery.

Well, one in particular.

It's still abusable as traction control, imho.

[saviour stivala]

One in particular says;- Formula one MGU-K is used the recover kinetic energy under braking and convert it into electricity. Recovering energy by being driven the MGU-K by ICE when ICE is under power is recovering by the use of burning fuel.

[Tommy Cookers]

the rules say that traction control is only traction control if it detects and stops wheelspin
at present the PU torque map rules limit the PU's contribution to aiding the driver
the much bigger 2026-sized K won't make any difference unless eg the present rules are waived


another matter ....

The paper I linked earlier and co-authored by Ferrari explained it this way:

.....for the considered high-performance power unit the waste-gate is used to increase the engine power by diminishing the exhaust manifold pressure. The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero (when no upshift is taking place). The intake manifold pressure is not affected, the engine pumping power increases and so does the overall engine power....

I feel vindicated - eg that WGO the turbine makes power as (I said) Wright said 70 years ago
I should try harder to read the paper

[saviour stivala]

"The waste-gate is used to increase the engine power (when waste-gate is open exhaust gasses are bypassing the turbine = free load mode) by diminishing the exhaust manifold pressure (as it is a pressure turbine) and the turbine extraction is reduced to zero".

[Tommy Cookers]

"The waste-gate is used to increase the engine power (when waste-gate is open exhaust gasses are bypassing the turbine = free load mode) by diminishing the exhaust manifold pressure (as it is a pressure turbine) and the turbine extraction is reduced to zero".

the above could be seen as vindication for me

perhaps you could tell us from which page of the paper sourced by Hoffman900 you have taken it ?

[saviour stivala]

"The waste-gate is used to increase the engine power (when waste-gate is open exhaust gasses are bypassing the turbine = free load mode) by diminishing the exhaust manifold pressure (as it is a pressure turbine) and the turbine extraction is reduced to zero".

the above could be seen as vindication for me

perhaps you could tell us from which page of the paper sourced by Hoffman900 you have taken it ?

Read the Hoffman sourced and quoted paper carefully again maybe than you will not feel so vindicated and me feeling totally confused about your feelings.

[diffuser]

"The waste-gate is used to increase the engine power (when waste-gate is open exhaust gasses are bypassing the turbine = free load mode) by diminishing the exhaust manifold pressure (as it is a pressure turbine) and the turbine extraction is reduced to zero".

the above could be seen as vindication for me

perhaps you could tell us from which page of the paper sourced by Hoffman900 you have taken it ?

Read the Hoffman sourced and quoted paper carefully again maybe than you will not feel so vindicated and me feeling totally confused about your feelings.

Feeling are a complete 180 to facts.....anyways ...

I doudt anyone does that anymore. Since the move to a single map per track for the race and quali. All they can do is vary when and how much they deploy.

[saviour stivala]

the above could be seen as vindication for me

perhaps you could tell us from which page of the paper sourced by Hoffman900 you have taken it ?

Read the Hoffman sourced and quoted paper carefully again maybe than you will not feel so vindicated and me feeling totally confused about your feelings.

Feeling are a complete 180 to facts.....anyways ...

I doudt anyone does that anymore. Since the move to a single map per track for the race and quali. All they can do is vary when and how much they deploy.

By saying that you 'doubt anyone does that (use free-load-mode) anymore you are telling us that they used to make use of it. What changed by the mandated use of a single map for both qualifying and race was they could not use it (free-load-mode) anymore during a lap then they can during a race, they cannot use it more for qualifying than in the race, as they used to use it more during qualifying as both fuel and battery charge consumed is no problem for a qualifying lap. Apart from the deployment of electrical power, they do use free load mode, all one have to do to know when it's being used is listen to change in engine sound, when that happens, waste-gate is open and exhaust is bypassing the turbine.

[gruntguru]

The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero

I think if the MGUH went to 100 kW motoring (full electric supercharger mode) they would have said so. Fact is the turbine is still making some power - enough to drive the compressor in fact.

It is a fact that the wastegate can control turbine output from zero to maximum by varying wastegate opening. It is also well documented that considerable exhaust energy is available to the turbine without significant pumping penalty during the exhaust stroke. There are two main factors involved.

1. There is significant exhaust energy available to the turbine during "blowdown" while the piston is still descending on power stroke (480* - 540* in the diagram below). Flow is "choked" so there is no increase in flow if the pressure in the port is reduced eg by opening the wastegate fully. Choked flow persists through the early part of the exhaust stroke (540* - 650* in the diagram) so again, there is no reduction in pumping loss if the wastegate opening is increased. So the remainder of the exhaust stroke (650* - 720*) is the only period where pumping loss can be reduced by additional wastegate opening.

2. With appropriate wave tuning, the port pressure during the late stages of the exhaust stroke can be reduced to significantly less than the average exhaust manifold pressure ("manometer reading" dashed line in the diagram). It is likely that the wastegate only needs to be opened far enough to lower the average exhaust pressure to some value - say 1 Bar - to reduce exhaust pumping loss almost to the same level as would be achieved by opening the wastegate fully and bypassing the turbine completely.

We know that the exhaust header is designed to preserve blowdown pulses up to the turbine - use of a divided turbine housing and plumbing individual runners all the way to the turbine housing, with three even-firing cylinders sharing a turbine volute. It is not a "blowdown only" turbine but like any serious racing (or even street) turbo application these days, it makes use of blowdown energy to allow a lower average exhaust back pressure for the same turbine power output.

[saviour stivala]

The paper:-''In conventional gasoline turbocharged engines, the waste-gate is operated to diminsh the turbine power and thereby control the intake manifold pressure'' (This because in such engine's turbochargers the the waste-gate is build into the turbine housing, and as the exhaust gasess that are actually passing through the turbine housing are the ones being controlled, the waste-gate is in fact acting as a pressure control valve,controlling the pressuretype of turbine). ''By contrast for the considered high-performance powerunit the waste-gate is used to increase the engine power by diminishing the exhaust manifold pressure''. (Diminishing the exhaust manifold pressure, is diminishing the turbine power, because the turbine used is a pressure turbine, the formula one waste-gate not being build into the turbine housing, when fully open it bypasess exhaust gasess away from the turbine. And the engine power increases because when waste-gate is open and exhaust gaesess are bypassing the turbine, the compressor is in electric supercharging mode).

[Hoffman900]

the rules say that traction control is only traction control if it detects and stops wheelspin
at present the PU torque map rules limit the PU's contribution to aiding the driver
the much bigger 2026-sized K won't make any difference unless eg the present rules are waived


another matter ....

The paper I linked earlier and co-authored by Ferrari explained it this way:

.....for the considered high-performance power unit the waste-gate is used to increase the engine power by diminishing the exhaust manifold pressure. The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero (when no upshift is taking place). The intake manifold pressure is not affected, the engine pumping power increases and so does the overall engine power....

I feel vindicated - eg that WGO the turbine makes power as (I said) Wright said 70 years ago
I should try harder to read the paper

Read this one next:

'Low-level Online Control of the Formula 1 Power Unit with Feedforward Cylinder Deactivation'

Co-authored with Ferrari.

[https://arxiv.org/abs/2303.00372](https://arxiv.org/abs/2303.00372)

​

Abstract:

" Since 2014, the Fédération Internationale de l'Automobile has prescribed a parallel hybrid powertrain for the Formula 1 race cars. The complex low-level interactions between the thermal and the electrical part represent a non-trivial and challenging system to be controlled online. We present a novel controller architecture composed of a supervisory controller for the energy management, a feedforward cylinder deactivation controller, and a track region-dependent low-level nonlinear model predictive controller to optimize the engine actuators. Except for the nonlinear model predictive controller, the proposed controller subsystems are computationally inexpensive and are real time capable. The framework is tested and validated in a simulation environment for several realistic scenarios disturbed by driver actions or grip conditions on the track. In particular, we analyze how the control architecture deals with an unexpected gearshift trajectory during an acceleration phase. Further, we demonstrate how an increased maximum velocity trajectory impacts the online low-level controller. Our results show a suboptimality over an entire lap with respect to the benchmark solution of 49 ms and 64 ms, respectively, which we deem acceptable. Compared to the same control architecture with full knowledge of the disturbances, the suboptimality amounted to only 2 ms and 17 ms. For all case studies we show that the cylinder deactivation capability decreases the suboptimality by 7 to 8 ms. "

[Hoffman900]

1. There is significant exhaust energy available to the turbine during "blowdown" while the piston is still descending on power stroke (480* - 540* in the diagram below). Flow is "choked" so there is no increase in flow if the pressure in the port is reduced eg by opening the wastegate fully. Choked flow persists through the early part of the exhaust stroke (540* - 650* in the diagram) so again, there is no reduction in pumping loss if the wastegate opening is increased. So the remainder of the exhaust stroke (650* - 720*) is the only period where pumping loss can be reduced by additional wastegate opening.

Port pressure is going to vary depending on manifold pressure and cylinder pressure.

Furthermore, Honda showed even with Naturally Aspirated engines that the port may or may not choke, depending.

Point being, an 80 year old graph and speaking confidently without actually knowing isn’t always indicative of what is actually happening. You don’t know the mass, exhaust valve sizes, port throat and geometry, valve timing, and pressure prior to the turbo to really say.

I actually just did some port tests recently. A much larger exhaust valve, throat worked well on a single cylinder but did not translate to more power on a multi-cylinder, where the larger port actually lost power. Same as Honda found and it all relates to manifold pressure.

[diffuser]

Read the Hoffman sourced and quoted paper carefully again maybe than you will not feel so vindicated and me feeling totally confused about your feelings.

Feeling are a complete 180 to facts.....anyways ...

I doudt anyone does that anymore. Since the move to a single map per track for the race and quali. All they can do is vary when and how much they deploy.

By saying that you 'doubt anyone does that (use free-load-mode) anymore you are telling us that they used to make use of it. What changed by the mandated use of a single map for both qualifying and race was they could not use it (free-load-mode) anymore during a lap then they can during a race, they cannot use it more for qualifying than in the race, as they used to use it more during qualifying as both fuel and battery charge consumed is no problem for a qualifying lap. Apart from the deployment of electrical power, they do use free load mode, all one have to do to know when it's being used is listen to change in engine sound, when that happens, waste-gate is open and exhaust is bypassing the turbine.

Would the waste gate be controlled automatically and tied to boost? In other words if you cut the MGU-H load, the boost starts to climb, and as part of the MAP, the controller would automatically start to open the waste gate to regulate boost? No change in Map required ? Push-to-Pass?

[Zynerji]

I wonder what the F1 teams could get out of a current-battery sized unit like this?

https://hackaday.com/2023/06/07/the-int ... n-reactor/