Turbocharger assisted Aerodynamics in 2014 and beyond

[Tommy Cookers]

I'll quote something I wrote in another thread.

Im not quite sure about the blow-off.
But I suggested something earlier this year which would also remove much of the need of running a blow-off valve.
I suggested that they should run cold blowing of the engine if that is allowed in 2014. This means when the driver lifts off the throttle pedal the throttle plates should open 100% instead of closing as normal. This would keep a higher flow through the turbo so you can harvest more energy with the MGU-H. It would decrease pumping losses which would decrease natural engine braking effect which allows the MGU-K to harvest a larger procentage during braking. And last it would prevent the shockwave moving backward from the throttleplate to the compressor when the throttleplate closes. The fuel and ignition would off course be cut.
IMO it should be legal as there is no aerodynamic advantage from cold blowing next year with the new exhaust exit regulations.
And when it comes to the turbo assisted aero I think the regulations are pretty clear. Just like wuzak pointed out.

Any cold blowing will be as a part of an engine map. When your not cold blowing, ie, different map, without cold blowing, then the engine will need a DV. The advantage of this setup is that the escaping air is 'before' the compressor and should be exempt from the rules regrading exiting via the exhaust. This air could then be channeled into/onto certain area's of the bodywork for a gain in aero.

apologies for any quote misattribution above ......
IMO .....
cold blowing only means blowing by engine running at normal ignition timings (ie not specially retarded timing)
CB means passing more air than would otherwise be passed, by any means other than that special ignition timing
so CB means less engine braking/aka 'over-run push', and complete cancellation of engine braking is allowed ('zero torque' rule)
and the MGU-K is slaved to the crankshaft, so generation torque will come from engine running not braking, via this rule
and the generator power is now 120 kW, not the 60 kW of KERS

at races other than the most fuel-hungry there is free fuel for this engine running
free except for the weight penalty, which is insignificant relative to the benefits

and modulated displacement is here to stay, complementing, and an integral part of, the CB/non-brake KE recovery running mode ?
MD is of course unaffected by the reduction in map count

from flag to flag the engine's throttle plates will be almost continuously open, or substantially so
there will be plenty of air or gas passed when the driver is off the accelerator etc, more than in 2013
about as much in massflow terms as hot blowing had

[ringo]

And then there are the intake rules.

5.14 Engine intake air :
5.14.1 With the exception of incidental leakage through joints or cooling ducts in the inlet system
(either into or out of the system), all air entering the engine must enter the bodywork through
a maximum of two inlets which are located :
a) Between the front of the cockpit entry template and a point 500mm forward of the rear
wheel centre line longitudinally.
b) No less than 200mm above the reference plane vertically.
c) On vertical cross-sections normal to the car centre line.
Furthermore, any such inlets must be visible in their entirety when viewed from the front of
the car and without the driver seated in the car.

I would question whether the solution would provide enough aerodynamic benefit to justify foregoing the ram effect that the roll hoop intake provides. Recalling that any air pressure increase in the intake due to ram effect reduces the pressure ratio the compressor needs for a given MAP that the engine requires, and thus potentially allows more energy to be recovered from the exhaust.

That in red is the only think that would stop a team from putting an inlet in a advantageous area. the other regs are quite non restrictive.

[Pierce89]

If the air is dumped before the compressor then it hasn't entered the compressor and isn't compressed - it is just ambient air. And thus it would work just as the current systems do - independently of the engine.

.

But the air came from the compressor to get to the engine in the first place

[wesley123]

5.14 Engine intake air :
5.14.1 With the exception of incidental leakage through joints or cooling ducts in the inlet system
(either into or out of the system), all air entering the engine must enter the bodywork through
a maximum of two inlets which are located :
c) On vertical cross-sections normal to the car centre line.

I'm having a bit of a rough time understanding this part of the rule. Does this mean that the Engine air intake must be on the car centreline? Or 90 degrees(straight position) to the car centreline?

[wuzak]

If the air is dumped before the compressor then it hasn't entered the compressor and isn't compressed - it is just ambient air. And thus it would work just as the current systems do - independently of the engine.

.

But the air came from the compressor to get to the engine in the first place

First it comes in through the intake. You could use that air, as is done now. Actually, they have separate intakes for that.

Once it enters the compressor (turbo) it has to exit the exhaust. You could run a blow off valve, but that would have to feed into the exhaust.

Since the air-flow modification systems (F-duct, double DRS) expel air to achieve the desired result, you cannot use the air from the blow-off valve to do this job and then return it to the exhaust. It is impossible.

[ringo]

5.14 Engine intake air :
5.14.1 With the exception of incidental leakage through joints or cooling ducts in the inlet system
(either into or out of the system), all air entering the engine must enter the bodywork through
a maximum of two inlets which are located :
c) On vertical cross-sections normal to the car centre line.

I'm having a bit of a rough time understanding this part of the rule. Does this mean that the Engine air intake must be on the car centreline? Or 90 degrees(straight position) to the car centreline?

No it's just saying that the inlets must be forward facing. So you cannot have them angled or rotated.

[wuzak]

5.14 Engine intake air :
5.14.1 With the exception of incidental leakage through joints or cooling ducts in the inlet system
(either into or out of the system), all air entering the engine must enter the bodywork through
a maximum of two inlets which are located :
c) On vertical cross-sections normal to the car centre line.

I'm having a bit of a rough time understanding this part of the rule. Does this mean that the Engine air intake must be on the car centreline? Or 90 degrees(straight position) to the car centreline?

No, it does not require the engine intake to be on the centreline.

It requires that the opening is vertical and the plane on which it sits is perpendicular to the longitudinal centreline of the car.

As was pointed out earlier, the old Benetton solution would conform to that regulation. However, the rules for the sidepods and driver side head protection may make them impractical. In any case, the air from above the driver's head is a better solution.

[wuzak]

And then there are the intake rules.

5.14 Engine intake air :
5.14.1 With the exception of incidental leakage through joints or cooling ducts in the inlet system
(either into or out of the system), all air entering the engine must enter the bodywork through
a maximum of two inlets which are located :
a) Between the front of the cockpit entry template and a point 500mm forward of the rear
wheel centre line longitudinally.
b) No less than 200mm above the reference plane vertically.
c) On vertical cross-sections normal to the car centre line.
Furthermore, any such inlets must be visible in their entirety when viewed from the front of
the car and without the driver seated in the car.

I would question whether the solution would provide enough aerodynamic benefit to justify foregoing the ram effect that the roll hoop intake provides. Recalling that any air pressure increase in the intake due to ram effect reduces the pressure ratio the compressor needs for a given MAP that the engine requires, and thus potentially allows more energy to be recovered from the exhaust.

That in red is the only think that would stop a team from putting an inlet in a advantageous area. the other regs are quite non restrictive.

The rules preclude openings over a large area of the sidepods. This would also restrict where you could place such intakes, and the benfits that could be achieved.

[wesley123]

Thanks guys for the explanation!

[shelly]

5.14 Engine intake air :
5.14.1 With the exception of incidental leakage through joints or cooling ducts in the inlet system
(either into or out of the system), all air entering the engine must enter the bodywork through
a maximum of two inlets which are located :
c) On vertical cross-sections normal to the car centre line.

I'm having a bit of a rough time understanding this part of the rule. Does this mean that the Engine air intake must be on the car centreline? Or 90 degrees(straight position) to the car centreline?

No, it does not require the engine intake to be on the centreline.

It requires that the opening is vertical and the plane on which it sits is perpendicular to the longitudinal centreline of the car.

As was pointed out earlier, the old Benetton solution would conform to that regulation. However, the rules for the sidepods and driver side head protection may make them impractical. In any case, the air from above the driver's head is a better solution.

Yes hoping to see the benetton inlet on a car next year requires a bit of wishful thinking.
IIRC last time we saw a not conventional airbox was with merc and force india a couple of years ago, with the blade roll hoop. I do not know what exactly was the design aim for them, bar the usual "cleaner flow to the rear wing".

With next year reg limiting rw except for the central y+/-75mm, maybe it is worth pursuing something different in the airscope zone:
-interaction with central exhaust outlet
-developed monkey seat
-vortex generation along the 75mm lines in order to have very different aoa for central and side parts of the rw

then I do not see how big the difference in dynamic pressure can be between a conventional airbox and a well placed (thanks to cfd) benetton inlet.
The turbo would smooth the lhs/rhs difference in yaw; also placing the inlet close to the radiator inlets could create some interesting coupling for the two flows (full throttle =>less air through rads => less drag, then full flow through rads on partial throttle)

wuzak, can you point out why the conventional roll hoop position is superior?

[wuzak]

wuzak, can you point out why the conventional roll hoop position is superior?

It is free from the influence of the tyre wake. The driver's helmet has some impact, but it has less issues with airflow off the car's body.

[neilbah]

drivers helmet position in corners might also affect split/benetton design detrimentally aswell. What about last years lotus drd inletss and an open central part of the roll hoop? I had also wondered about a monkey seat behind the roll hoop but i guess the fact its so narrow means it will be of little use and just creating drag and messing up airflow to the rear of the car, maybe just a monaco special .

[riff_raff]

I still do not fully understand what "cold blowing" implies. The only way I can see that it provides an advantage is by taking advantage of a loophole in the rules to direct additional airflow to the diffuser exit via the engine exhaust pipes. However, the amount of airflow from the engine exhaust will be quite modest when the engine is operating with closed throttles during braking. And the airflow thru the turbo compressor will also be limited, since the work done by the turbocharger compressor must be in equilibrium with the work output of the turbine.

[Tommy Cookers]

....... However, the amount of airflow from the engine exhaust will be quite modest when the engine is operating with closed throttles during braking. .......

IMO
even in recent years the throttles have been far from closed during braking
and in 2014 the amount of airflow from the exhaust can continue to be rather large during braking (maybe larger than before)
enough airflow to run the engine at or near max rpm unloaded ie equivalent to a 10500-13000 rpm idle
(because it is allowed to produce 'over-run push' (zero torque rather than engine braking) when the driver is 'off accelerator')
and added to this enough airflow to run the engine to generate 120 kW from the MGU-K (still counting as zero torque)
and FWIW here it can run on eg 3 cylinders

so rather a lot of gas can pass through and emerge from the engine in the braking phase if this is desired
also in any low-torque activity after braking
given that at many (less fuel-hungry) tracks a 100 kg fuel fill will leave scope for this running via the fuel rate limits
surely this available fuel will be used, as in 2013, 2012 etc, not left in the pits ?

[henra]

The turbo intake has to be the roll structure as in current rules.

Not necessarily.
But the question is whether slightly improving airflow to the Rear Wing is worth creating disturbances elsewhere plus having a little bit less ram effect.
The other issue is that there is a minimum width of the engine cover (IIRC defined at 850mm above Reference plane) which limits the amount of structure you could shave off the the area behind the roll hoop (you would probably be able at best to make the upper 100 mm a flat plate) and thus the gain of clean air flow to the Rear Wing.