2026 Hybrid Powerunits

[johnnycesup]

470kw from ICE would be over 56%

Show your calculations please.

I'm not the person you're replying to, but there's a 3000MJ/h limit to the fuel energy flow in the regulations. Now MJ/h (unit of mechanical work per unit of time) is obviously a unit of power, so 3000 MJ/h = 833 kW.

So considering the internal combustion engine can burn the fuel perfectly and nothing else is burned (so no oil burning shenanigans), a 470kW output is equivalent to 56,4% thermal efficiency. A bit optimistic IMO


EDIT:
Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.

[saviour stivala]

The turbine used in F1 utilises both pressure and blowdown pulses. Have you heard of a company call GARRETT? They know a thing or two about turbochargers. Here is an article posted on their website. https://www.garrettmotion.com/wp-conten ... vanced.pdf

Yes. Agree that the 'twin-scroll' exhaust turbine housing design minimizes the effect of mixing all exhaust pulses into one collector, by dividing said pulses into two collectors. As the formula 1 ICE is a V-6 cylinder, using a twin-scroll exhaust turbine housing means that two sets of three selected cylinders will each blow their respective exhaust gas through a primary, with all three primary in the set pumping into a collector, with each of the two collectors pumping into the nozzle aimed at the turbine. The system of multi primaries (more than one) pumping into a collector with the collector pumping into the turbine nozzle aimed at the turbine, will still render the exhaust turbine a 'pressure turbine'. The fact that a variable opening waste-gate is used, provides the exhaust gases from cylinders to turbine with two paths, when the waste-gate is opened exhaust gas pressure is at atmospheric pressure, and no turbine recovery is possible, When it is closed, exhaust gas is above atmospheric pressure and turbine recovery is possible.

It uses some form of pulse effect because they would all stay with log manifolds if it were only a pressure turbine.
The exhaust lengths do indeed seem to be tuned, and notice each runner meets at nearly zero degrees to minimize pulse blow-back.

Agree that minimizing pulse blow-back is a must, If the turbocharger exhaust turbine type used in formula 1 wasn't a pressure turbine, there will not be pulse blow-back to minimize, because the usual pulse blow-back wouldn't be present to eliminate by the usual exhaust piping design, the design standard thing. A number (more than 'one') Individual cylinder-to-exhaust turbine exhaust stacks/pipes/primaries all individually/separately discharging into the exhaust recovery turbine, would render the exhaust turbine a 'blow-down' type of turbine, and would have eliminated pulse blow-back as well as exhaust gas back pressure.

[wuzak]

Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

But didn't the maximum power occur when the MGUH was being powered by the battery, and not recovering energy?

[johnnycesup]

Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

But didn't the maximum power occur when the MGUH was being powered by the battery, and not recovering energy?

Actually it makes a lot of sense that the MGUH couldn't power the MGUK with pure harvesting, haven't really thought of that before. So peak efficiency should be around 56 or so %, that seems more reasonable.

As for max power, what difference does driving the compressor with the MGUH makes? Genuine question, since the ICE will be providing plenty of air to spin the turbine. Is it a back pressure reduction, and if so, how significant is it?

[saviour stivala]

Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

But didn't the maximum power occur when the MGUH was being powered by the battery, and not recovering energy?

Maximum power possible was deployed when when at full throttle and at full fueling and with waste-gate fully opened with both MGU-K and MGU-H sharing battery power. Apart from when maximum power possible could be deployed, wasn't the MGU-H used to generate electricity that could be send directly to the MGU-K, effectively boosting its power output beyond what the brakes could capture and store in ES, which allowed for longer deployment of electric boost, which in turn effectively extended the duration the MG-K could provide its ~120 kw boost?.

[Abarth]

[...]will still render the exhaust turbine a 'pressure turbine'. The fact that a variable opening waste-gate is used, provides the exhaust gases from cylinders to turbine with two paths, when the waste-gate is opened exhaust gas pressure is at atmospheric pressure, and no turbine recovery is possible, When it is closed, exhaust gas is above atmospheric pressure and turbine recovery is possible.

This is circular reasoning.
For example, if the pulses are at 25% and the 'constant' pressure is 75% of the total energy that the turbine can convert into mechanical work, opening the waste gate will lead to
a) the engine experiencing almost zero backpressure (it was an important feature for engines with MGU-H).
b) reducing turbine speed and charge air pressure to manageable levels, but not necessarily to zero. This was also the goal of introducing twin-scroll turbos: maintaining a higher turbine speed at low loads and harvesting pulse energy without negative effects on scavenging.

Lower backpressure at equal compressor power increases MEP without a consumption penalty, which is an obvious goal of engineering in this field.

[saviour stivala]

[...]will still render the exhaust turbine a 'pressure turbine'. The fact that a variable opening waste-gate is used, provides the exhaust gases from cylinders to turbine with two paths, when the waste-gate is opened exhaust gas pressure is at atmospheric pressure, and no turbine recovery is possible, When it is closed, exhaust gas is above atmospheric pressure and turbine recovery is possible.

This is circular reasoning.
For example, if the pulses are at 25% and the 'constant' pressure is 75% of the total energy that the turbine can convert into mechanical work, opening the waste gate will lead to
a) the engine experiencing almost zero backpressure (it was an important feature for engines with MGU-H).
b) reducing turbine speed and charge air pressure to manageable levels, but not necessarily to zero. This was also the goal of introducing twin-scroll turbos: maintaining a higher turbine speed at low loads and harvesting pulse energy without negative effects on scavenging.

Lower backpressure at equal compressor power increases MEP without a consumption penalty, which is an obvious goal of engineering in this field.

As I explained, the pressure type of exhaust turbine as used in formula 1 incorporates a variable opening waste-gate set-up into the design, even when the exhaust turbine is of the 'twin-scroll' type, The presence of the waste-gate will in turn provide the exhaust gases pre-turbine with two possible paths, one is with waste-gate closed where the exhaust gases goes through the turbine at above atmospheric pressure, and the other is with the waste-gate fully open, where the exhaust gases (pre-turbine) are at atmospheric pressure, the exhaust gases will follow the easy way out like water does, end exit though the waste-gate and therefore bypass the exhaust turbine, the exhaust gases exiting through the waste-gate will be at atmospheric pressure, meaning zero back pressure in the exhaust system, A situation which was capitalized on by running the turbocharger compressor in electrical mode to produce the highest possible power output.

[mzso]

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

Depend on how you look at it. All energy comes from the burning of the fuel. So if you're talking about the TE of the power unit, it should very much be included. If you only think about the ICE than obviously not, and it will be less.

[Hoffman900]

Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

But didn't the maximum power occur when the MGUH was being powered by the battery, and not recovering energy?

Most of the quoted TE was never quantified in the sense that it was done in conditions actually used on track, or if the MGUH was involved, or it was a “hero” TE run in the test cell to maximize bragging rights.

[BassVirolla]

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

Depend on how you look at it. All energy comes from the burning of the fuel. So if you're talking about the TE of the power unit, it should very much be included. If you only think about the ICE than obviously not, and it will be less.

But while draining the battery is not a sustanaible mode.

Real efficiency can be measured without taking into account the energy storage, as in the MGUH motoring the MGUK.

While draining the battery you take a false higher efficiency, which would be offset by a necessary lower efficiency (lower Torque x rpm net output) when recharging the ES.

Edit: Charging batteries with the MGUK by braking, in a whole, could be measured as improving efficiency, but muds the picture a lot while talking exclusively about the PU. At last, the inertia of the car comes from the fuel.

Take it this way: What could be the maximum efficiency with the PU isolated in a dyno?

[PlatinumZealot]

470kw from ICE would be over 56%

Show your calculations please.

I'm not the person you're replying to, but there's a 3000MJ/h limit to the fuel energy flow in the regulations. Now MJ/h (unit of mechanical work per unit of time) is obviously a unit of power, so 3000 MJ/h = 833 kW.

So considering the internal combustion engine can burn the fuel perfectly and nothing else is burned (so no oil burning shenanigans), a 470kW output is equivalent to 56,4% thermal efficiency. A bit optimistic IMO


EDIT:
Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.

Ok thank you. I see why you guys are wrong. Please have a look at the 2014 engine threads.

Engines do not work like that. You can't just pluck some numbers from the regulations and work backworks ( or rumours for that matter!).

You take numbers from a known physical engine or known physical/lab derived phenomena.

The previous rules had a fuel flow limit of 100kg/hr. This is equivalent to 4350 MJ/hr or 1230kW (note 4350 is higher than the 3000 number). The ICE engines (not the power unit!) as was calculated before by many forumers here is around 630kW. This smacks you sqaure at 52% thermal efficiency.

We know the combustion behaviour of these engines and we have estimated the MGUH and addition to efficiency and MGUK addition to output over 12 years of observation. So you use that and extrapolate. We do know that they were at limiting returns.

What you do, you see, is listen out when the season starts if you hear Mercedes shouting from the mountain tops of any record in thermal efficiency. They used to do this each year as the hybrid V6 developed because it was good for marketing their brand and the sport. And indeed those efficiency increases were genuine. With this new engine i am almost 100% sure that you will NOT hear any announcement on breaking any efficiency records.

[wuzak]

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

Depend on how you look at it. All energy comes from the burning of the fuel. So if you're talking about the TE of the power unit, it should very much be included. If you only think about the ICE than obviously not, and it will be less.

Bt that's using fuel that is outside the current fuel flow.

[mzso]

The 1,000hp includes power (up to160hp) from the battery system, so should not be included in the TE calculation.

TE would be around 51%, assuming all power for the MGUK comes from the battery.

It would be ~56% if about half the energy comes from the MGUH to MGUK.

Depends on how you look at it. All energy comes from the burning of the fuel. So if you're talking about the TE of the power unit, it should very much be included. If you only think about the ICE than obviously not, and it will be less.

But that's using fuel that is outside the current fuel flow.

It's still utilized for drive. I guess that just means you can't assess the efficiency of a PU by taking an arbitrary point in time.

[Tommy Cookers]

... I guess that just means you can't assess the efficiency of a PU by taking an arbitrary point in time.

yes
and you can't assess the efficiency of a PU if it recovers KE .... because ....
you've already counted the energy given by the PU - so recovery is double counting ....
double counting (as if it's PU-dependent) of something that is PU-independent ...
because recovery is recovering something that is vehicle/task dependent not PU-dependent

[BassVirolla]

... I guess that just means you can't assess the efficiency of a PU by taking an arbitrary point in time.

yes
and you can't assess the efficiency of a PU if it recovers KE .... because ....
you've already counted the energy given by the PU - so recovery is double counting ....
double counting (as if it's PU-dependent) of something that is PU-independent ...
because recovery is recovering something that is vehicle/task dependent not PU-dependent

Should be constant dissipated power, as in a dyno, where you can't recover inertia of the car.