Mercedes won, Redbull was
second And McLaren was third. Many cars dropped out with engine
trouble as the new turbo V6's are very complicated indeed. They don't
call it turbo compound but "energy recovery". That is because a large
percentage of time a road racing car is under braking and one want's
to recover that energy as well as waste exhaust energy.
That braking energy recovery does not help at all on the freeway or
autobahn. It just adds a lot of unnecessary weight.
The exhaust energy is recovered by a shaft coming out the turbo
charger compressor driving a generator. This charges a battery.
Similar to the attached 3D.
This is not an efficient way of doing it in a passenger car. Say the
generator is 90% efficient and the motor is 90% efficient over all
energy recovery is then only 81%.
Again the battery is just more dead weight. Typically the electronc
controller could also be 90% efficient so over all recovery
efficiency could drop to 73%. All this waste heat heats up the engine
compartment.
There is no beating a gear box between the exhaust turbine and the
crankshaft. That would be 95% efficient or higher.
The battery is also charged from the retarding force on the rear
wheels under braking in a road racing car. These generators also
serve as motors that provide extra torque under acceleration and in
the case the turbo charger generator it is also used in electric
motor mode to accelerate the compressor. This reduces the notorious
turbo charger throttle lag.
One can imagine this is a programmers worse nightmare. Not only is
the competition among the drivers and engineers but now programmers
are competing to see who can write the best control program. I
wonder what chip they are using? I would not be a bit surprised if it
was an ARM variation of some sort.
That is like using your cell phone to control 800 HP :)
The generator connected to the compressor shaft is interesting as it
must be geared down as the turbo is turning at 125,000 RPM. An
electric motor would probably blow up due to centrifugal loads on the
copper windings if it were to run at 125,000 RPM.
Or they good be using switched reluctance motor with no windings on
the rotor.
http://www.rotaryeng.net/Oxford-640-4802.wmv
Paul Lamar
Nice writeup, Paul. Do you think they have made it complex (and
expensive) enough? I am not enamored by the V6 exhaust note.
Gary Knutson
Thanks Gary.
I am about to blast them on that silly narrow rear wing. The vast
majority wing drag is induced drag. They would get along with a lot
less fuel if they doubled the width of the rear wing.
"In aerodynamics, lift-induced drag, induced drag, vortex drag, or
sometimes drag due to lift, is a drag force that occurs whenever a
moving object redirects the airflow coming at it. This drag force
occurs in airplanes due to wings redirecting air to cause lift and
also in cars with airfoil wings that redirect air to cause a
down-force."
The wing induced drag factor is equal to the lift coefficient squared
divided by pi times to aspect ratio. Aspect ratio is width divide by
cord. In Formula 1 cars aspect ratio is about 2.
So the current induced drag factor is about 0.16. If they doubled the
width and kept the down-force the same it would be one divided by
four times pii or 0.08. In other words, half the wing drag.
That is why they get those enormous vortex's off the wing tips in the
rain.
Assume the current wing area is 4 square feet and C sub l is one. The
down-force at 150 MPH is 52 time 4 or about 200 pounds. Drag is then
32 pounds. 150 MPH is 220 FPS. HP consumed by the wing is then 7040
foot pound second or 12.8 HP. That is roughly 8.3 pounds of fuel
burned, per hour, by the wing alone.
The slotted wing down-force is probably double that so that number
could be as high as 33 pounds of fuel per hour. Rough calcualtions
all. Two hour race 66 pounds less fuel. The current F1 fuel limit is
220 pounds.
The high end plates help but they have their own drag associated with
them.
Here is my resume :)
http://www.rotaryeng.net/AIAA-Paper.pdf
http://www.rotaryeng.net/Oxford-640-4802.wmv
Paul Lamar
Gary Knutson,
A agree re the Fi engines. The exhaust is not noteworthy.
jd
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