F1 will see a complete change in engine regulations in 2014, and we're having a closer look at what that means exactly
I still doubt it and fail to see why burning 27.8 g/sec should crave 3.5 bar, when 2.5 was enough for 40+ g/sec 25 years ago.gruntguru wrote:The number that really contrasts to the turbo years is AFR (lambda) and that's what's dictating the boost requirement.
Turbo Years - 0.75 - 0.98
F1 2014 . . . - 1.2 - 1.6
Because instead of running rich you are running lean, so with the same amount of fuel you need more air. More air = more boost.xpensive wrote:I still doubt it and fail to see why burning 27.8 g/sec should crave 3.5 bar, when 2.5 was enough for 40+ g/sec 25 years ago.gruntguru wrote:The number that really contrasts to the turbo years is AFR (lambda) and that's what's dictating the boost requirement.
Turbo Years - 0.75 - 0.98
F1 2014 . . . - 1.2 - 1.6
But time will tell I guess
Yeah, that’s obviously a first order estimate with some assumptions made (including that of AFR constant that, as you say, likely is varying), not dissimilar in method from what posted already by others, I just thought that using real rpm data would help seeing the effective application range; playing around with other input variables obviously causes change of comp. ratio but relatively small (+/- 0.1), at least as long as we stay in a range of what should be sensible assumptions.gruntguru wrote:Interesting analysis reca thanks! You seem to have assumed 100% VE and intercooling to ambient which is sensible if not accurate - but then we would only be guessing if we said 110% and 70* CAT.
The interesting think is how much the boost has to change and how quickly - if the AFR is to remain constant. I think we can safely say the AFR has to vary as the engine accelerates through the gears - at least a little.
I use a Matlab routine I wrote myself various years ago and improved every now and then, in particular to have a time resolution compatible with needs of rapidly varying rpm of a racing engine. There should be a thread where I posted the basics of the method long ago.Brian Coat wrote:Reca: you have a nice audio to rpm software (very little drop out at low rpm / noise points on the lap) what s/w is it?
The engines have more than 100% VE.gruntguru wrote:Interesting analysis reca thanks! You seem to have assumed 100% VE and intercooling to ambient which is sensible if not accurate - but then we would only be guessing if we said 110% and 70* CAT.
The interesting think is how much the boost has to change and how quickly - if the AFR is to remain constant. I think we can safely say the AFR has to vary as the engine accelerates through the gears - at least a little.
I couldn't agree more!gruntguru wrote:No big deal.
If the VE is 110% thats 10% extra air mass. If the MAT is 27 degrees above ambient thats 10% less air mass. Combine the two - no change.
(This is VE of the piston engine i.e. charge air not atmospheric)
How did you get 10% less, I got 17% less for 27 deg above ambient (22)?gruntguru wrote:No big deal.
If the VE is 110% thats 10% extra air mass. If the MAT is 27 degrees above ambient thats 10% less air mass. Combine the two - no change.
(This is VE of the piston engine i.e. charge air not atmospheric)
Did you use 22 as ambient?ambient air temp is considered 15 degrees Celsius and 29.92 in.Hg/1013 MPa by ISA conditions.irsq4 wrote:How did you get 10% less, I got 17% less for 27 deg above ambient (22)?gruntguru wrote:No big deal.
If the VE is 110% thats 10% extra air mass. If the MAT is 27 degrees above ambient thats 10% less air mass. Combine the two - no change.
(This is VE of the piston engine i.e. charge air not atmospheric)
