Page 908 of 1332
Re: Honda Power Unit
Posted: 03 Apr 2018, 16:28
by CLKGTR
I found in 2018 FIA Technical regulations that F1 engine must have cylinder diameter of 80 mm, but I didn't find anything about stroke.
Renault and Ferrari state that their stroke is 53 mm while I didn't found data for Mercedes and Honda. Is this 53 mm stroke also regulated or is it just a coincidence that Ferrari and Renault engines have same stroke?
Re: Honda Power Unit
Posted: 03 Apr 2018, 16:32
by DiogoBrand
CLKGTR wrote: ↑03 Apr 2018, 16:28
I found in 2018 FIA Technical regulations that F1 engine must have cylinder diameter of
80 mm, but I didn't find anything about stroke.
Renault and Ferrari state that their stroke is 53 mm while I didn't found data for Mercedes and Honda. Is this 53 mm stroke also regulated or is it just a coincidence that Ferrari and Renault engines have same stroke?
It's no coincidence. To achieve 1600cm3 with 6 cylinders of 80mm bore you need 53 mm stroke.
Pi*4,0^2*5,3*6~1600
Re: Honda Power Unit
Posted: 03 Apr 2018, 16:35
by CLKGTR
Thanks, now it sounds logical
Re: Honda Power Unit
Posted: 03 Apr 2018, 16:56
by Sieper
It almost gave me a stroke.
Re: Honda Power Unit
Posted: 03 Apr 2018, 19:38
by godlameroso
DiogoBrand wrote: ↑03 Apr 2018, 16:32
CLKGTR wrote: ↑03 Apr 2018, 16:28
I found in 2018 FIA Technical regulations that F1 engine must have cylinder diameter of
80 mm, but I didn't find anything about stroke.
Renault and Ferrari state that their stroke is 53 mm while I didn't found data for Mercedes and Honda. Is this 53 mm stroke also regulated or is it just a coincidence that Ferrari and Renault engines have same stroke?
It's no coincidence. To achieve 1600cm3 with 6 cylinders of 80mm bore you need 53 mm stroke.
Pi*4,0^2*5,3*6~1600
How you achieve that stroke is where the fun starts, as the rod ratio has a huge influence in a lot of the mechanical properties of the stroke. Increasing the crank throws shortens the rods, reducing the throws lengthens the rods, longer rods have longer dwell times at TDC and BDC, and lower acceleration from TDC and BDC. However with the rapid combustion these engines use maybe super long rod ratios aren't beneficial.
Re: Honda Power Unit
Posted: 03 Apr 2018, 21:22
by Big Tea
godlameroso wrote: ↑03 Apr 2018, 19:38
DiogoBrand wrote: ↑03 Apr 2018, 16:32
CLKGTR wrote: ↑03 Apr 2018, 16:28
I found in 2018 FIA Technical regulations that F1 engine must have cylinder diameter of
80 mm, but I didn't find anything about stroke.
Renault and Ferrari state that their stroke is 53 mm while I didn't found data for Mercedes and Honda. Is this 53 mm stroke also regulated or is it just a coincidence that Ferrari and Renault engines have same stroke?
It's no coincidence. To achieve 1600cm3 with 6 cylinders of 80mm bore you need 53 mm stroke.
Pi*4,0^2*5,3*6~1600
How you achieve that stroke is where the fun starts, as the rod ratio has a huge influence in a lot of the mechanical properties of the stroke. Increasing the crank throws shortens the rods, reducing the throws lengthens the rods, longer rods have longer dwell times at TDC and BDC, and lower acceleration from TDC and BDC. However with the rapid combustion these engines use maybe super long rod ratios aren't beneficial.
Can't get my head around this. If the throw of the crank is set, is the stroke not also set independently of the length?
Does length not just decide the start point of travel (TDC?)
I am usually wrong mind
Re: Honda Power Unit
Posted: 03 Apr 2018, 21:28
by 63l8qrrfy6
godlameroso wrote: ↑03 Apr 2018, 19:38
DiogoBrand wrote: ↑03 Apr 2018, 16:32
CLKGTR wrote: ↑03 Apr 2018, 16:28
I found in 2018 FIA Technical regulations that F1 engine must have cylinder diameter of
80 mm, but I didn't find anything about stroke.
Renault and Ferrari state that their stroke is 53 mm while I didn't found data for Mercedes and Honda. Is this 53 mm stroke also regulated or is it just a coincidence that Ferrari and Renault engines have same stroke?
It's no coincidence. To achieve 1600cm3 with 6 cylinders of 80mm bore you need 53 mm stroke.
Pi*4,0^2*5,3*6~1600
How you achieve that stroke is where the fun starts, as the rod ratio has a huge influence in a lot of the mechanical properties of the stroke. Increasing the crank throws shortens the rods, reducing the throws lengthens the rods, longer rods have longer dwell times at TDC and BDC, and lower acceleration from TDC and BDC. However with the rapid combustion these engines use maybe super long rod ratios aren't beneficial.
Stroke is independent of rod length. It is 2 times the distance from the main journal centreline to the pin journal centreline. You can put in 10 meter long rods, the stroke is the same.
Re: Honda Power Unit
Posted: 03 Apr 2018, 21:41
by PhillipM
And you can't change the throw lengths because your stroke is fixed.
Re: Honda Power Unit
Posted: 03 Apr 2018, 21:57
by etusch
I think this was shared here. There was an article talks about rod lengt but I couldn't find it.
http://rehermorrison.com/tech-talk-93-a ... ting-rods/
Re: Honda Power Unit
Posted: 04 Apr 2018, 02:45
by godlameroso
Mudflap wrote: ↑03 Apr 2018, 21:28
godlameroso wrote: ↑03 Apr 2018, 19:38
DiogoBrand wrote: ↑03 Apr 2018, 16:32
It's no coincidence. To achieve 1600cm3 with 6 cylinders of 80mm bore you need 53 mm stroke.
Pi*4,0^2*5,3*6~1600
How you achieve that stroke is where the fun starts, as the rod ratio has a huge influence in a lot of the mechanical properties of the stroke. Increasing the crank throws shortens the rods, reducing the throws lengthens the rods, longer rods have longer dwell times at TDC and BDC, and lower acceleration from TDC and BDC. However with the rapid combustion these engines use maybe super long rod ratios aren't beneficial.
Stroke is independent of rod length. It is 2 times the distance from the main journal centreline to the pin journal centreline. You can put in 10 meter long rods, the stroke is the same.
You're right, I feel silly.
Would it be worth using short rods to shorten the deck height? Would it be worth using longer rods to reduce thrust loads, but a taller engine? Somewhere in the middle? Would combustion process influence this? Shorter rods are also less prone to detonation, but longer rods favor mid and high speed operation. I guess playing around with this wouldn't be worth it cost wise as the gains would be marginal if any one way or the other.
Re: Honda Power Unit
Posted: 04 Apr 2018, 03:31
by PlatinumZealot
Gonna take a swing: long rods means more rod and more engine block and more weight. Shorter rods means slower velocity as the piston rises up and down. Slower piston motion can mean more power if combustion is relatively slow, but with TJI it is very fast.. So shorter rods are a disadvantage for this. So overall it is an optimization between rod
weight, engine weight, reliability and response (side loads), and the cylinder pressure characteristics.
Re: Honda Power Unit
Posted: 04 Apr 2018, 06:27
by gruntguru
PlatinumZealot wrote: ↑04 Apr 2018, 03:31
Gonna take a swing: long rods means more rod and more engine block and more weight. Shorter rods means slower velocity as the piston rises up and down.
Shorter rods mean shorter dwell (higher acceleration) around TDC and longer dwell near BDC. Infinite rod length yields simple harmonic motion (same dwell and acc' at TDC as BDC).
Average piston velocity doesn't change with rod length.
Re: Honda Power Unit
Posted: 04 Apr 2018, 06:49
by rscsr
godlameroso wrote: ↑04 Apr 2018, 02:45
Mudflap wrote: ↑03 Apr 2018, 21:28
godlameroso wrote: ↑03 Apr 2018, 19:38
How you achieve that stroke is where the fun starts, as the rod ratio has a huge influence in a lot of the mechanical properties of the stroke. Increasing the crank throws shortens the rods, reducing the throws lengthens the rods, longer rods have longer dwell times at TDC and BDC, and lower acceleration from TDC and BDC. However with the rapid combustion these engines use maybe super long rod ratios aren't beneficial.
Stroke is independent of rod length. It is 2 times the distance from the main journal centreline to the pin journal centreline. You can put in 10 meter long rods, the stroke is the same.
You're right, I feel silly.
Would it be worth using short rods to shorten the deck height? Would it be worth using longer rods to reduce thrust loads, but a taller engine? Somewhere in the middle? Would combustion process influence this? Shorter rods are also less prone to detonation, but longer rods favor mid and high speed operation. I guess playing around with this wouldn't be worth it cost wise as the gains would be marginal if any one way or the other.
Cosworth stated once in a RET that they used the shortest rod possible, since they found that it had no measurable power penalty to them (back in the V10/V8 days).
Re: Honda Power Unit
Posted: 04 Apr 2018, 08:00
by sosic2121
DiogoBrand wrote: ↑03 Apr 2018, 16:32
CLKGTR wrote: ↑03 Apr 2018, 16:28
I found in 2018 FIA Technical regulations that F1 engine must have cylinder diameter of
80 mm, but I didn't find anything about stroke.
Renault and Ferrari state that their stroke is 53 mm while I didn't found data for Mercedes and Honda. Is this 53 mm stroke also regulated or is it just a coincidence that Ferrari and Renault engines have same stroke?
It's no coincidence. To achieve 1600cm3 with 6 cylinders of 80mm bore you need 53 mm stroke.
Pi*4,0^2*5,3*6~1600
Maybe Mercedes downsized their engine and that's why it is so efficient
Re: Honda Power Unit
Posted: 04 Apr 2018, 11:34
by Big Tea
sosic2121 wrote: ↑04 Apr 2018, 08:00
DiogoBrand wrote: ↑03 Apr 2018, 16:32
CLKGTR wrote: ↑03 Apr 2018, 16:28
I found in 2018 FIA Technical regulations that F1 engine must have cylinder diameter of
80 mm, but I didn't find anything about stroke.
Renault and Ferrari state that their stroke is 53 mm while I didn't found data for Mercedes and Honda. Is this 53 mm stroke also regulated or is it just a coincidence that Ferrari and Renault engines have same stroke?
It's no coincidence. To achieve 1600cm3 with 6 cylinders of 80mm bore you need 53 mm stroke.
Pi*4,0^2*5,3*6~1600
Maybe Mercedes downsized their engine and that's why it is so efficient
5.1.2 Engine cubic capacity must be 1600cc (+0/-10cc). Someone must have tried it before