2025/2026 Hybrid Powerunit speculation

[saviour stivala]

''15000 Wright engines proved this wrong''. As have became your norm, you persists in interpreting your favorite, the Weight PRT in a totally wrong way in trying to compare its design function with that used in formula one. While the Wright PRT design made use of exhaust gas velocity and as such needed no waste-gate, A turbocharger turbine design makes use of exhaust gas pressure and as such needs the use of waste-gate. While the turbo-supercharger used in formula one in combination with the use of MGU-H technically needed no waste-gate per se, all design teams opted to make use of a waste-gate so as to gain a limited time power advantage running the ICE in electric supercharging mode. Runing the ICE in electric supercharging mode with waste-gate open eliminates any exhaust gas back pressure in collector pipe, and that is even before collector connection to turbine.

[saviour stivala]

''Many most aftermarket turbos do not have an internal waste-gate''. Which aftermarket turbo have an MGU-H mandatory couplet to the turbo shaft that functions like the one used in formula one. which eliminates the need of waste-gate controlling the boost. All exhaust gases out the exhaust valve are mandatory to pass through the exhaust tail pipe, and that now-a-day includes the waste-gate out exhaust pipe gas.

[henry]

5.10.1 With the exception of incidental leakage through joints (either into or out of the system) and power unit breather fluids, all and only the fluids entering the compressor inlet and fuel injectors must exit from the engine exhaust system.

Does this allow the use of a blow-off valve to send air from the compressor directly into the exhaust to help keep he turbo spinning?

I believe this is what Honda do, or at least did last season.

[mzso]

Out of curiosity: how was the H removed from the regulations? Do they ban anything running off the exhaust. Or just an electric motor on the turbo?
Is it possible to make use of the energy of the exhaust after 2026?

[saviour stivala]

Out of curiosity: how was the H removed from the regulations? Do they ban anything running off the exhaust. Or just an electric motor on the turbo?
Is it possible to make use of the energy of the exhaust after 2026?

Removing the MGU-H was regarded as one of the key gestures towards new manufacturers.
Looks like only the turbocharger is allowed to be run of the exhaust gases and nothing out of the energy of the rotating parts of the turbocharger may be transferred to any other component. All turbine exit and all waste-gate exhaust fluids must pass through the tail-pipe defined in article 3.8.2b.

[wuzak]

Out of curiosity: how was the H removed from the regulations? Do they ban anything running off the exhaust. Or just an electric motor on the turbo?
Is it possible to make use of the energy of the exhaust after 2026?

Only one MGU allowed.

No exhaust recovery, except for the turbo.

[Hoffman900]

the above is incorrect ......
unless the exhaust gas is entirely diverted away from the turbine and the main exhaust pipe

but .....
the turbine actually gets 1 atm exhaust so kinetic pulses/waves still (quite weakly) power the turbine and compressor
this power recovery-without-backpressure is the so-called blowdown recovery
here it somewhat reduces the amount of ES energy needed by the MGU-H in driving the compressor
so increasing the available duration of this ('electric supercharge') running mode

there is no evidence that the turbine responds only to mean exhaust pressure (is unresponsive to kinetic 'pulses')
clearly all 4 makes of ICE have exhaust manifolds designed to encourage these pulses
and the pulses are anyway relatively stronger in 1 atm exhaust than in the main ('backpressure') running mode

It is your accredits which are wrong. First. Any exhaust gas past the exhaust valve is 'blow-down' gas. Secondly. The turbine used in F1 is not a blow-down turbine like used by the Wright Cyclone, but a pressure turbine. A blow-down turbine will not have a waste-gate because it doesn't need pressure to produce useful work. The F1 turbine needs exhaust gas pressure to produce useful work, when waste-gate/s are opened the exhaust gas pressure is dropped to atmospheric pressure, and any gases inside the turbine at atmospheric pressure cannot make the turbine do any useful work because turbine can only do so under exhaust gas pressure.

With wastegate open, the pressure in the exhaust does not drop to atmospheric. Have you ever heard of wave tuning? The exhaust collector sees pulses of up to 2.5 atmospheres on a NA engine - higher on a supercharged engine. Are these pulses able to force their way into the rapidly spinning turbine and generate any power with the wastegate open? Who knows. Certainly there will be some partially-open settings for the wastegate where useful turbine power is generated while reducing average exhaust pressure sufficiently to increase crankshaft power.

One thing people are forgetting here is where the exhaust and wastegate dumps, is not at atmospheric pressure, as it will be less, and will vary with vehicle speed. Also, probably part of what Ferrari is doing is using the exhaust stream to help scavenge the waste gate stream. Running it in the exhaust will likely be easier to tune around as the pressure in it will likely vary less than the beam wing area. It’s almost like those exhaust breather systems… they can pull a small amount of vacuum when done right.

Everyone has to remember, underflow aero really works a lot better because of the pressure drop the rear wing causes. There is a big pressure drop in the vicinity of where these exhaust and waste gate systems dump.

[gruntguru]

F1 aero pressures are relatively insignificant compared to engine cycle pressures. An aero depression less than 4 kPa (0.6 psi) is not going to make a lot of difference to the exhaust.

[FW17]

Can the charge air be used to power a dual rotor MGU? One of the rotor will always be on generator mode (powered by charge air from the turbo) while the other is powered by the rear wheel.

[wuzak]

Can the charge air be used to power a dual rotor MGU? One of the rotor will always be on generator mode (powered by charge air from the turbo) while the other is powered by the rear wheel.

No.

Only one MGU is allowed.

5.20 MGU-K
5.20.1 The MGU-K must be mechanically fixed to either the survival cell or the ICE.
5.20.2 Under normal operating conditions all MGUK rotating parts must be permanently mechanically linked to the ICE with a fixed speed ratio to the crankshaft. The MGU-K and its drive axis must be parallel to the crankshaft axis.
5.20.3 All mechanical power to and from the MGU-K must pass through a single shaft to the MGU-K transmission. The connection to the ICE crankshaft must be ahead of XPU=100.

[FW17]

5.20.2 Under normal operating conditions all MGUK rotating parts must be permanently mechanically linked to the ICE with a fixed speed ratio to the crankshaft. The MGU-K and its drive axis must be parallel to the crankshaft axis.

Then if the fixed speed gear is selected for the MGU to spin at very high speed then the torque generated by the charge air turbine can directly be applied to the crank shaft.

Maybe there is some other section which says the MGU can be powered only by the ES

[wuzak]

5.20.2 Under normal operating conditions all MGUK rotating parts must be permanently mechanically linked to the ICE with a fixed speed ratio to the crankshaft. The MGU-K and its drive axis must be parallel to the crankshaft axis.

Then if the fixed speed gear is selected for the MGU to spin at very high speed then the torque generated by the charge air turbine can directly be applied to the crank shaft.

Maybe there is some other section which says the MGU can be powered only by the ES

5.2.11 ERS-K
The only part of the ERS allowed to propel the car. It is composed of the MGU-K, the CU-K and the phase cables.

[chrisc90]

Not sure how relevant or accurate this is, but it popped up on my Twitter.

[godlameroso]

Looking at the engine regs, they're making everything except the cylinder heads and pistons practically spec parts. They're going to have to conjure Joe Mondello's ghost and bust out the carbide grinder. Maybe give Dave "The Wizard" Vizard a call. Turbo seems pretty restrictive, although there's some leeway with regards to wheel geometry. Seems crazy to me that they're still not allowing variable valve timing, nor are they allowing variable geometry turbines. That stuff is already well developed by all OEM's looking to build engines.

People think that 2 valve heads are old obsolete tech, even if that's true, 2 valve guys work on hard mode. They're typically undervalved, and have to use much more lift than 4 valve engines to flow the same numbers. Which means the airflow has to flow across the valve and valve throat over a wider range than that of a 4 valve. Where a 4 valve engine may not see any more that 14-16mm of valve lift on the high end. The 2 valve guys need to open the single intake valve 22+mm. Those 2 valve guys know how the air flows into the engine because there's so much to gain from getting it right.

I say this because it looks like the development battle is going to be fought there in terms of ICE output.

[saviour stivala]

Year 2026 new Formula one ICE part of the power unit and still dreaming of a two-valve-head, totally confusing to say the least, but claiming that a two valve head can ever match a four valve head flow is balderdash.