F1technical.net

Pierce89 wrote:

Pierce89 wrote:

WilliamsF1 wrote:The Merc engine has a log style exhaust, which in turn is a variable length exhaust

Does Merc have a variable length tuned intake system to compensate/compliment the exhaust system

a couple of systems come to mind

http://www.njstangers.org/members/norm- ... 3-vris.jpg

http://i181.photobucket.com/albums/x79/ ... MG1132.jpg

The log is a variable length exhaust? Care to elaborate?

Bump. Just wanted an answer. Did you simply mean it has unequal length primaries?

xpensive wrote:Which is xactly my point, an ICE-efficiency of 40% is pure fantasy, 35 would be impressive enough.

lio007 wrote:According to AMuS: http://www.auto-motor-und-sport.de/form ... 29184.html
...
- Ferrari and Renault are allowed to use the whole 32 Token (if they can’t finish til 28th Feb they are allowed to use the rest during the season)
...

lio007 wrote:

lio007 wrote:According to AMuS: http://www.auto-motor-und-sport.de/form ... 29184.html
...
- Ferrari and Renault are allowed to use the whole 32 Token (if they can’t finish til 28th Feb they are allowed to use the rest during the season)
...

So if Renault, Ferrari (and probably Mercedes) are allowed to use the rest of "unused" Token, what do you think about Honda?

Could it be that they are also allowed to make performance changes on their PU during the 2015 season?
(I would say no, because they're not limited to the 32 Token of changes, therefore they haven't any left to use during the season in 2015, like Renault and Ferrari)

Any opinion of a "regulation-expert" is appreciated!

The homologation regulations are pretty clear . They are controlled from year to year. Does that mean for Honda, that you must not change so much next year as Mercedes , Renault and Ferrari after their first season?

Yasuhisa Arai : Honda 2016 must freeze as much from the engine , like the others . The token system is exactly the same and also the schedule. We can not take the 32 tokens as the manufacturers this year , but only 28th

Mesteño wrote:

lio007 wrote:

lio007 wrote:According to AMuS: http://www.auto-motor-und-sport.de/form ... 29184.html
...
- Ferrari and Renault are allowed to use the whole 32 Token (if they can’t finish til 28th Feb they are allowed to use the rest during the season)
...

So if Renault, Ferrari (and probably Mercedes) are allowed to use the rest of "unused" Token, what do you think about Honda?

Could it be that they are also allowed to make performance changes on their PU during the 2015 season?
(I would say no, because they're not limited to the 32 Token of changes, therefore they haven't any left to use during the season in 2015, like Renault and Ferrari)

Any opinion of a "regulation-expert" is appreciated!

Im no expert, but found this:

The homologation regulations are pretty clear . They are controlled from year to year. Does that mean for Honda, that you must not change so much next year as Mercedes , Renault and Ferrari after their first season?

Yasuhisa Arai : Honda 2016 must freeze as much from the engine , like the others . The token system is exactly the same and also the schedule. We can not take the 32 tokens as the manufacturers this year , but only 28th

http://www.motorsport-magazin.com/forme ... iel-power/

For me it means Honda PU will freeze on February 28th. Then Honda will be able to develope 28 tokens for 2016, but not the rest of the teams -seems odd to me-.

Someone correct me if wrong.

gruntguru wrote:

xpensive wrote:Which is xactly my point, an ICE-efficiency of 40% is pure fantasy, 35 would be impressive enough.

Not at all. Anyone can walk into a Toyota dealer and buy a Prius with an NA SI ICE running at 38.5% TE. Many labs have NA SI engines operating above 40%. Turbo-compounding makes that number even higher.

Tommy Cookers wrote:

gruntguru wrote:

xpensive wrote:Which is xactly my point, an ICE-efficiency of 40% is pure fantasy, 35 would be impressive enough.

Not at all. Anyone can walk into a Toyota dealer and buy a Prius with an NA SI ICE running at 38.5% TE. Many labs have NA SI engines operating above 40%. Turbo-compounding makes that number even higher.

the Prius presumably has its best BTE of 38.5% at some partial power (ie close to max torque)
not at or very near maximum power as in F1
presumably the Prius BTE at max power is substantially less than 38.5%

J.A.W. wrote:Other than both seeking high fuel efficiency..
..the Prius plainly has a different set of power delivery parameters to F1..

& naturally - 'orders of magnitude' in level of tune/cost/quality/longevity of componentry..
.. so a direct comparison - other than for that thermal % of fuel utilization - is surely invidious,
..meaningful validity-wise?

"Indeed the power unit had been said to be the most efficent gasoline power train of all time"

- http://www.racecar-engineering.com/news ... a-1-guide/

gruntguru wrote:

J.A.W. wrote:Other than both seeking high fuel efficiency..
..the Prius plainly has a different set of power delivery parameters to F1..

& naturally - 'orders of magnitude' in level of tune/cost/quality/longevity of componentry..
.. so a direct comparison - other than for that thermal % of fuel utilization - is surely invidious,
..meaningful validity-wise?

Correct. My post made no reference to F1 - purely a response to Xpensive's claim that 40% (SI) ICE efficiency of 40% is fantasy.
(We all know CI ICE have climbed beyond 50%)

Tommy Cookers wrote:the NACA report 822 tells us what we need to know (as shown particularly in Fig 7 and Table III)
it's based on the R-2800 with 40deg valve overlap
because it has some sea level data it is much more useful than NACA 1602

the best bsfc at sea level is with a delta P of -20" Hg
and the best bsfc is consistent with best combined power

at 10000' power recovered is 263 hp and net ('crankshaft') power is 1043 hp with 85% turbine and 94% transmission efficiencies
this recovery figure is after the deduction of supercharging power
this is at -8" Hg delta P

a bit of mental extrapolation shows clearly that there would be more recovery at sea level
because of the best bsfc - delta P even with more overlap would be close to the above -20" Hg, say -15" Hg or -0.5 bar
and this gives more turbine power, as exhaust pressure is greater relative to ambient (than eg at 10,000')

I would say that efficient recovery of 30% of crankshaft power is available
(this is the crankshaft power at -0.5 bar)
because this 'backpressure running' gives the greatest efficiency

Tommy Cookers wrote: http://naca.central.cranfield.ac.uk/rep ... rt-822.pdf

the combined power is always best around best bsfc
best bsfc is with -20" Hg on the engine used (probably -15" Hg on an engine with more liberal valve timing)
ie the loss at the crank is the same or less than the gain via the MGUH as the delta P becomes more negative
so 120 kW recovered power might cost 100 kW crankshaft power without any fuel rate limit

but the bsfc as reported is 14% better at 10000' than the same engine with turbo
extrapolation suggests 10% better at sea level
so under a fuel rate limit there's 10% more combined power with this level of compounding

but the F1 engine 'boost' will be much higher, so the best bsfc delta P might be more, maybe close to -1 bar ?
so the bsfc gain over an equivalent turbo engine should be maybe 15%
(because recovered power is largely due to the pressure difference between exhaust pressure and ambient)
giving 15% more combined power with this 'best bsfc' level of recovery
of course a suitably big MGUH and related electrical system is needed

a lower level of recovery such as Wright actually used would according to this report give only maybe 7% bsfc gain
(at lower recovery levels the bsfc gain comes from recovery that costs very little crankshaft power)
and so only 7% more combined power under a fuel rate limit
but would use a much smaller capacity MGUH and related electrical system

with a turbine-electric recovery system as in new F1 .......
in a low recovery level system the electrical power can reasonably described as free
as the efficiency improves in proportion to the electrical power
at maximal recovery level as in NACA 822 only about half the electrical power can be regarded as free
because the efficiency gain is 'only' about half the recovery level
so we should resist the inevitable media and PR attempts to tell us that eg a 120 kW MGUH recovers that much 'free'

NACA 822 is based on running at pressure (loosely, 'boost') of 40" Hg Abs (about 1.35 bar Abs)
the supercharger power is rather low, around 3 % of output power