F1 Energy store density for 2026 and hot swap batteries

[Hoffman900]

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

I would be interested to see more detail on an exhaust port that doesn't choke. Cylinder pressure at EVO is several times port pressure and a big valve still has a small curtain area when it is just off the seat.

At very small valve lifts as the valve lifts off the seat, then annulus between the two, sure, but I can tell you they didn’t have the technology to measure that when that graph you shared was made.

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf

What’s the SOS of exhaust gasses when first cracked open on a current Formula One engine?

[Tommy Cookers]

.... I can tell you they didn’t have the technology to measure that when that graph you shared was made.

as J.C.Morrison openly published details in 1951 (of his high-speed scanning valves and manometry)
presumably the NACA Lewis Propulsion Laboratory was using scanning in WW2 in compounding and exhaust work

[gruntguru]

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

I would be interested to see more detail on an exhaust port that doesn't choke. Cylinder pressure at EVO is several times port pressure and a big valve still has a small curtain area when it is just off the seat.

What’s the SOS of exhaust gasses when first cracked open on a current Formula One engine?

What's important is not the SOS but the critical pressure ratio which remains close to 0.5 for the range of temperatures typical for exhaust gas. So flow across the valve will be critical from EVO until cylinder pressure drops to less than double the port pressure.

[gruntguru]

.... I can tell you they didn’t have the technology to measure that when that graph you shared was made.

as J.C.Morrison openly published details in 1951 (of his high-speed scanning valves and manometry)
presumably the NACA Lewis Propulsion Laboratory was using scanning in WW2 in compounding and exhaust work

Brilliant stuff that.

[gruntguru]

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf

That paper speaks of choking in the port throat - not across the valve seat.

[Hoffman900]

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf

That paper speaks of choking in the port throat - not across the valve seat.

Depends on curtain area. You have no idea what that is in the current engines or what a P-V diagram looks like. So yeah, it likely occurs, but citing an old chart isn't applicable.

It's the same when you tried to use 30 year old graphs to argue with a then AVL combustion engineer now Ilmor.

[gruntguru]

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf

That paper speaks of choking in the port throat - not across the valve seat.

It's the same when you tried to use 30 year old graphs to argue with a then AVL combustion engineer now Ilmor.

. . . and with that comment your level of understanding neatly slips several rungs in my estimation.

A combustion engineer who argued that increasing turbo boost would dramatically increase pumping losses.
Also that best TE occurs at stoich????
Clearly you can get a job at AVL or Ilmor as a "combustion engineer" without knowing much beyond how stuff burns.

Perhaps you would like to re-open that old thread and argue his case? Personally I think he has reconsidered. Perhaps he eventually raised the points with some knowledgeable colleagues?

[gruntguru]

http://www.f1-forecast.com/pdf/F1-Files ... P2_10e.pdf

That paper speaks of choking in the port throat - not across the valve seat.

Depends on curtain area. You have no idea what that is in the current engines or what a P-V diagram looks like. So yeah, it likely occurs, but citing an old chart isn't applicable.

Pat Symonds video tells us a lot about what is in the current engines.

The "old chart" illustrates the point just fine.

. . . and the point(s) made in my post remain valid - advancing technology has not invalidated any of them, despite your (mis)interpretation of the Honda paper.

[Zynerji]

That paper speaks of choking in the port throat - not across the valve seat.

Depends on curtain area. You have no idea what that is in the current engines or what a P-V diagram looks like. So yeah, it likely occurs, but citing an old chart isn't applicable.

Pat Symonds video tells us a lot about what is in the current engines.

The "old chart" illustrates the point just fine.

. . . and the point(s) made in my post remain valid - advancing technology has not invalidated any of them, despite your (mis)interpretation of the Honda paper.

For this type of TJI turbo engine layout, would it be worth to just increase the stroke by 5mm? Would that significantly change the output hysteresis? I mean. Same flow limits, but more time acting on the pistons?

[saviour stivala]

Depends on curtain area. You have no idea what that is in the current engines or what a P-V diagram looks like. So yeah, it likely occurs, but citing an old chart isn't applicable.

Pat Symonds video tells us a lot about what is in the current engines.

The "old chart" illustrates the point just fine.

. . . and the point(s) made in my post remain valid - advancing technology has not invalidated any of them, despite your (mis)interpretation of the Honda paper.

For this type of TJI turbo engine layout, would it be worth to just increase the stroke by 5mm? Would that significantly change the output hysteresis? I mean. Same flow limits, but more time acting on the pistons?

Increasing the stroke by 5mm? Means a considerably smaller bore which forces the use of also considerably smaller valves which in turn pushes for smaller ports and!!!

[Zynerji]

Pat Symonds video tells us a lot about what is in the current engines.

The "old chart" illustrates the point just fine.

. . . and the point(s) made in my post remain valid - advancing technology has not invalidated any of them, despite your (mis)interpretation of the Honda paper.

For this type of TJI turbo engine layout, would it be worth to just increase the stroke by 5mm? Would that significantly change the output hysteresis? I mean. Same flow limits, but more time acting on the pistons?

Increasing the stroke by 5mm? Means a considerably smaller bore which forces the use of also considerably smaller valves which in turn pushes for smaller ports and!!!

No. Not reducing bore. Just increasing stroke. Make them 2.0l or whatever.

I'm just thinking more action time on piston extracts more energy. With flow limits in place already, they would not really gain from the displacement increase in the traditional sense...

Since they lean burn already, it would just start in that condition instead of artificially controlling everything to create a virtual one.

[saviour stivala]

''No. Not reducing the bore, just increase the stroke. Make them 2.0l."A racing engine is not made like that. Increasing the stroke by 5mm to up capacity to 2.0l, the bore will be way too small, bore stroke ratio will not be of racing pedigree. that is apart from everything else that matter, 'valves/ports' included being out of sync with a 2.0l formula one engine, And doing that on a racing engine, the only thing gained will be a higher fuel consumption for a race distance than at present.

[Zynerji]

''No. Not reducing the bore, just increase the stroke. Make them 2.0l."A racing engine is not made like that. Increasing the stroke by 5mm to up capacity to 2.0l, the bore will be way too small, bore stroke ratio will not be of racing pedigree. that is apart from everything else that matter, 'valves/ports' included being out of sync with a 2.0l formula one engine, And doing that on a racing engine, the only thing gained will be a higher fuel consumption for a race distance than at present.

I think this may be the most "Trust me, bro." subjective answer ever seen on F1Technical...

[saviour stivala]

''No. Not reducing the bore, just increase the stroke. Make them 2.0l."A racing engine is not made like that. Increasing the stroke by 5mm to up capacity to 2.0l, the bore will be way too small, bore stroke ratio will not be of racing pedigree. that is apart from everything else that matter, 'valves/ports' included being out of sync with a 2.0l formula one engine, And doing that on a racing engine, the only thing gained will be a higher fuel consumption for a race distance than at present.

I think this may be the most "Trust me, bro." subjective answer ever seen on F1Technical...

What better way to answer a question (opinion) based on personal feelings and opinion.

[Tommy Cookers]

For this type of TJI turbo engine layout, would it be worth to just increase the stroke by 5mm? Would that significantly change the output hysteresis? I mean. Same flow limits, but more time acting on the pistons?

... Not reducing bore. Just increasing stroke. Make them 2.0l or whatever.
I'm just thinking more action time on piston extracts more energy. With flow limits in place already, they would not really gain from the displacement increase in the traditional sense...

there isn't 'more action time on the piston'
with the same rpm the 'action time' is the same fraction of the time of the whole cycle (regardless of stroke)
unless they change the relationship of upward stroke time to downward stroke time - as the true Atkinson engine did
also ....
if the rpm is lower (seeking more 'action time') .... either .....
the charge per cycle is bigger for the same massflow so the mep is excessive ie unsurviveable ...or ....
the charge per cycle is not bigger so the mep isn't excessive - but the massflow is less and so the power is less