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Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 02:23
by Just_a_fan
Big Tea wrote: ↑07 Mar 2021, 12:45
A L3 cyl is also 'half' a current engine size, and less cooling requirement. Would it be ridiculously inefficient to make it aircooled?
Thinking of all the saved radiator space
Isn't the issue with air cooling that it's not good enough in high performance car engines? The beauty of a radiator is that it can easily have massively greater surface area for heat transfer than any air cooled engine could achieve, also adding a larger radiator is easy compared to making the air cooled fins larger/more numerous.
Obviously Porsche have done quite well over the years with air cooled engines, but not in a compact installation like in F1 and not without a fan.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 11:54
by Holm86
V4 is better as a stressed member than L4 or L3.
And how are they supposed to increase the BTE from 50% to 60%?? 50% is pretty impressive as is.
And if they go with some sort of bio fuel, they need to up the fuel flow, as many biofuels doesn't have the same calorific value.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 12:12
by Just_a_fan
Holm86 wrote: ↑08 Mar 2021, 11:54
V4 is better as a stressed member than L4 or L3.
Could one run a three cylinder engine in a T shape? Inverted so the cross bar part was at the bottom, you'd have a good shape to use as a stressed member and a low crank height. I assume the vibration / harmonics (whatever the term is) would be horrible, but it would be very short and could be made very stiff. If one wanted to air cool it (as suggested by someone in the thread), that would also be easy as no cylinders get in the way of air flow of other cylinders.
But I know very little about engines and their design/implementation.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 12:43
by Holm86
Just_a_fan wrote: ↑08 Mar 2021, 12:12
Holm86 wrote: ↑08 Mar 2021, 11:54
V4 is better as a stressed member than L4 or L3.
Could one run a three cylinder engine in a T shape? Inverted so the cross bar part was at the bottom, you'd have a good shape to use as a stressed member and a low crank height. I assume the vibration / harmonics (whatever the term is) would be horrible, but it would be very short and could be made very stiff. If one wanted to air cool it (as suggested by someone in the thread), that would also be easy as no cylinders get in the way of air flow of other cylinders.
But I know very little about engines and their design/implementation.
You mean something like this??
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 13:19
by Just_a_fan
Holm86 wrote: ↑08 Mar 2021, 12:43
Just_a_fan wrote: ↑08 Mar 2021, 12:12
Holm86 wrote: ↑08 Mar 2021, 11:54
V4 is better as a stressed member than L4 or L3.
Could one run a three cylinder engine in a T shape? Inverted so the cross bar part was at the bottom, you'd have a good shape to use as a stressed member and a low crank height. I assume the vibration / harmonics (whatever the term is) would be horrible, but it would be very short and could be made very stiff. If one wanted to air cool it (as suggested by someone in the thread), that would also be easy as no cylinders get in the way of air flow of other cylinders.
But I know very little about engines and their design/implementation.
You mean something like this??
https://upload.wikimedia.org/wikipedia/ ... _angle.gif
Yes, something like that.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 16:44
by senja
That's more like W shape.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 18:22
by Big Tea
Holm86 wrote: ↑08 Mar 2021, 12:43
Just_a_fan wrote: ↑08 Mar 2021, 12:12
Holm86 wrote: ↑08 Mar 2021, 11:54
V4 is better as a stressed member than L4 or L3.
Could one run a three cylinder engine in a T shape? Inverted so the cross bar part was at the bottom, you'd have a good shape to use as a stressed member and a low crank height. I assume the vibration / harmonics (whatever the term is) would be horrible, but it would be very short and could be made very stiff. If one wanted to air cool it (as suggested by someone in the thread), that would also be easy as no cylinders get in the way of air flow of other cylinders.
But I know very little about engines and their design/implementation.
You mean something like this??
https://upload.wikimedia.org/wikipedia/ ... _angle.gif
mount it like this?
https://www.motortrend.com/uploads/site ... -view2.jpg
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 20:00
by mzso
Just_a_fan wrote: ↑08 Mar 2021, 12:12
Holm86 wrote: ↑08 Mar 2021, 11:54
V4 is better as a stressed member than L4 or L3.
Could one run a three cylinder engine in a T shape? Inverted so the cross bar part was at the bottom, you'd have a good shape to use as a stressed member and a low crank height. I assume the vibration / harmonics (whatever the term is) would be horrible, but it would be very short and could be made very stiff. If one wanted to air cool it (as suggested by someone in the thread), that would also be easy as no cylinders get in the way of air flow of other cylinders.
But I know very little about engines and their design/implementation.
Why not boxer 2 then?
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 20:47
by Stu
Why the resistance to using an inline engine (either 3 or 4 cylinder), if it was a part of the rules they would have to come up with something to tackle the installation stiffness. The rules are full of restrictions that force the designers to come up with solutions to non-ideal regulations.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 08 Mar 2021, 23:37
by mzso
gruntguru wrote: ↑07 Mar 2021, 02:09
Under current rules there is 100 kg of fuel and we can assume the heating value is about 45 MJ/kg so there is a maximum of about 4500 MJ of energy available. If we assume a conversion efficiency of 50% and a race duration of 2 hours, the average engine output is 312 kW.
That's not too bad. Though the races are more typically 1.5 hours long.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 09 Mar 2021, 00:47
by Holm86
Stu wrote: ↑08 Mar 2021, 20:47
Why the resistance to using an inline engine (either 3 or 4 cylinder), if it was a part of the rules they would have to come up with something to tackle the installation stiffness. The rules are full of restrictions that force the designers to come up with solutions to non-ideal regulations.
Of course they can come up with solutions to make it work, but why insist on an inline engine, when you can have the same number of cylinders in a V and keep the structural integrity??
If they have to find solutions to make the inline engine strong enough, it'll be heavier, and if there's something we don't want, it's heavier cars. They're already way too fat ...
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 09 Mar 2021, 03:18
by Rodak
Stu wrote: ↑08 Mar 2021, 20:47
Why the resistance to using an inline engine (either 3 or 4 cylinder), if it was a part of the rules they would have to come up with something to tackle the installation stiffness. The rules are full of restrictions that force the designers to come up with solutions to non-ideal regulations.
The BMW turbo engine needed a supporting structure to carry the suspension loads as the inline four block couldn't do it; of course, they were using a production block. Still, an inline four would be way less stiff than a V6. Maybe F1 should go really retro and require a 9 cylinder air cooled radial....
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 09 Mar 2021, 09:23
by Stu
...or a two cylinder rotary....
They already seem to be using external bracing on the V6 engines.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 09 Mar 2021, 12:52
by mzso
Stu wrote: ↑09 Mar 2021, 09:23
...or a two cylinder rotary....
They already seem to be using external bracing on the V6 engines.
Did anyone ever build an efficient rotary engine?
Edit: We might not have been thinking of the same thing.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 09 Mar 2021, 14:42
by Stu
No, we are thinking of the same thing!
Until they started designing for the 2014 engine regs there was no heed paid to the efficiency (TE) of F1 engines, therefore to build an efficient rotary would be a challenge for the builders!!
What needs to be borne in mind with any upcoming engine regs is that if they want it to be road-relevant they need to push the regs in a direction that leads to the ICE being a part of an electrical generator unit.