Turbocharger assisted Aerodynamics in 2014 and beyond

[ringo]

You can't do the same thing with a turbo charged engine what you have done with a naturally aspirated V8.
You cannot just leave throttle open against positive pressure. There will be a blow valve. There's no reason not to have one.

[Drewd11]

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.

Just a thought, 200 mm above the reference plane isn't that high. Can anyone think of a legal way to decrease pressure under the car using suctioned inlet air? I realise that it is pretty restrictive that they must be entirely visible from the front, never minding the floor regulations. Further, the power penalty might be quite high if they aren't taking untouched air.

I was thinking along the lines of using suction-powered vortices to create effective sealing on the rear tire cut-outs in much the same way as coanda exhausts used to do. The advantages to my mind are that you could easily control off and mid -throttle (corner entrance and exit) suction through MGU-h maps, potentially providing a much more consistent (and driver input independent) vortex than exhaust blowing, potentially making the system more manageable in terms of consistency.

Thoughts? Do the floor regulations make this sort of thing entirely impossible (I haven't read them in depth recently)?

[langwadt]

You can't do the same thing with a turbo charged engine what you have done with a naturally aspirated V8.
You cannot just leave throttle open against positive pressure. There will be a blow valve. There's no reason not to have one.

why can't you do that? keeping the throttle open accomplish the same as a blow off valve it just blows through the
engine instead of outside

[Holm86]

You can't do the same thing with a turbo charged engine what you have done with a naturally aspirated V8.
You cannot just leave throttle open against positive pressure. There will be a blow valve. There's no reason not to have one.

why can't you do that? keeping the throttle open accomplish the same as a blow off valve it just blows through the
engine instead of outside

I don't know either. And just remember that a blow off valve has to be directed into the exhaust. It cannot vent freely into the atmosphere.

[langwadt]

You can't do the same thing with a turbo charged engine what you have done with a naturally aspirated V8.
You cannot just leave throttle open against positive pressure. There will be a blow valve. There's no reason not to have one.

why can't you do that? keeping the throttle open accomplish the same as a blow off valve it just blows through the
engine instead of outside

I don't know either. And just remember that a blow off valve has to be directed into the exhaust. It cannot vent freely into the atmosphere.

The regulations says all air entering the compressor must exit through the exhaust, I'd say that allows a bypass around
the compressor

[wuzak]

I don't know either. And just remember that a blow off valve has to be directed into the exhaust. It cannot vent freely into the atmosphere.

The regulations says all air entering the compressor must exit through the exhaust, I'd say that allows a bypass around
the compressor

Yes, that's what Holms said.

[wuzak]

Re a blow-off valve - I'm not sure that it will be necessary.

Why? The blow off valve is to protect the engine when the throttles are shut and the turbo's momentum means it is still pumping air, against a much restricted air path - remember that even with closed throttles the engine will still have air passing through it.

The MGU-H will be able to stop the compressor completely if it needs to. It certainly will be able to rapidly slow the compressor down to an appropriate speed. And while it is doing that it will be generating power for the ES.

Recall that Renault mentioned the role of the MGU-H in braking energy recovery - this is what they mean. Use the turbo's momentum, which be larger than a normal turbo because of the oversize turbine, to generate power.

[langwadt]

I don't know either. And just remember that a blow off valve has to be directed into the exhaust. It cannot vent freely into the atmosphere.

The regulations says all air entering the compressor must exit through the exhaust, I'd say that allows a bypass around
the compressor

Yes, that's what Holms said.

I understood what he said is as a valve from compressor output to exhaust, that is different from a valve from compressor output to compressor input, sometimes called a recirculating blow off valve

[Holm86]

I understood what he said is as a valve from compressor output to exhaust, that is different from a valve from compressor output to compressor input, sometimes called a recirculating blow off valve

5.8.1 With the exception of incidental leakage through joints (either into or out of the system), all (and only) the fluids entering the compressor inlet must exit from the engine exhaust system.

All fluids entering the compressor inlet must exit from the engine exhaust. So when the air has been compressed it cant be redirected and exit before the compressor again.

[Holm86]

Re a blow-off valve - I'm not sure that it will be necessary.

Why? The blow off valve is to protect the engine when the throttles are shut and the turbo's momentum means it is still pumping air, against a much restricted air path - remember that even with closed throttles the engine will still have air passing through it.

The MGU-H will be able to stop the compressor completely if it needs to. It certainly will be able to rapidly slow the compressor down to an appropriate speed. And while it is doing that it will be generating power for the ES.

Recall that Renault mentioned the role of the MGU-H in braking energy recovery - this is what they mean. Use the turbo's momentum, which be larger than a normal turbo because of the oversize turbine, to generate power.

This is one of the reasons i want to keep the throttle bodies open.
1. When the throttle closes a large vacuum is created between the throttle body and the piston during the intake stroke. The engine has to work against this which is pure mechanical loss. If you open the throttle the piston dosnt have to work against this which means the MGU-K can be reponsible for the engine braking. Equals more energy to harvest.
2. There wont be as much air to brake the turbine meaning the MGU-H can be responsible for braking the turbine. More energy to harvest again.
3. No shock wave is created as it normally would when the throttle closes moving back toward the compressor helping turbine reliability.

[langwadt]

I understood what he said is as a valve from compressor output to exhaust, that is different from a valve from compressor output to compressor input, sometimes called a recirculating blow off valve

5.8.1 With the exception of incidental leakage through joints (either into or out of the system), all (and only) the fluids entering the compressor inlet must exit from the engine exhaust system.

All fluids entering the compressor inlet must exit from the engine exhaust. So when the air has been compressed it cant be redirected and exit before the compressor again.

depends on how you interpret that rule, I'd say a valve from output to input would be legal, the air entering will exit through exhaust it has just been through the compressor more than once

But as you also say, why have a blow off, just blow through the engine and/or harvest the energy with the mgu-h

[riff_raff]

I thought it was to drive the MGU-H as much as possible. Wasn't it?

If your intent is to recover braking energy using the engine, turbocharger and the MGU-H, then the situation becomes complicated. The fundamental problem is that F1 turbochargers are fairly simple devices due to regulations. They have a single compressor directly coupled to a single turbine, without much provision for adjusting the intake/exhaust gas flow balance between them. Since the turbocharger compressor and turbine are directly coupled by a shaft, the amount of energy input/extracted by the system must be in balance. If energy is being extracted by the MGU-H using the turbocharger turbine, then that energy must have been added to the gas flow downstream of the compressor, from engine compression braking or from combusting fuel.

[wuzak]

You're heading along a straight. Your ICE is making maximum power, this gives more energy to the turbine than it needs for the compressor, so you make power with the MGU-H, which feeds back into the MGU-K.

You come off the throtle and hit the brakes. The turbo is now going too fast and making too much boost for the engine. The MGU-H brakes the turbo, and generates power from the turbo's momentum. With the sizeable turbine, the compressor and a speed of ~100-125k rpm there will be a not insignificant amount of energy to be gathered. The turbine slowing also creates back pressure which helps the braking of the car.

[PlatinumZealot]

smikle, i have read other posts or articles including statements by someone who works in renault (cant find the link but its on this site somewhere) that throttles on a F1 car are left pretty open these days when the throttle is lifted, probably due to the fact In the EBD situation this was put to use to seal the diffuser but it could also be useful to blow now for the benefit of the turbo which is why were having this conversation. Its already been discussed here http://www.f1technical.net/forum/viewto ... 1&start=15 I guess what were describing is a form of antilag system or ALS for short but utilising cold blowing if thats possible. Id have thought its more useful/efficient to keep recirculating the energy than just dumping it in the exhaust pipe which is the only place excess boost is allowed to go seeing as according to the rules it cannot vent to atmosphere. If your blow off valve reinserts the air into the exhaust manifild between the exhaust ports and the turbine then maybe its acceptable. Im not saying they wont have a blow off for emergency sake, just that im not sure its needed. Potentially its getting slightly off thread as id consider it pneumatics

I already know that most street cars the throttle is left slightly cracked open/or idle control valve bypass as a Means of Idle control. I just didn't want to complicate the conversation. However even when they say the throttle is "open" the slight opening is very small,not much CFM can flow throug and a blow-off valve is still needed to protect the turbocharger.

You can clearly see this in an actual throttle body, or for those who don't want to get their hands dirty they can go on youtube and watch on of those Renault engine videos.

As far as I know, a blow-off valve is not required on a Diesel engine as typically those engines don't have throttles.

[PlatinumZealot]

Re a blow-off valve - I'm not sure that it will be necessary.

Why? The blow off valve is to protect the engine when the throttles are shut and the turbo's momentum means it is still pumping air, against a much restricted air path - remember that even with closed throttles the engine will still have air passing through it.

The MGU-H will be able to stop the compressor completely if it needs to. It certainly will be able to rapidly slow the compressor down to an appropriate speed. And while it is doing that it will be generating power for the ES.

Recall that Renault mentioned the role of the MGU-H in braking energy recovery - this is what they mean. Use the turbo's momentum, which be larger than a normal turbo because of the oversize turbine, to generate power.

Nope. Blow off is to protect the turbocharger not the engine. The engine wont see the pressure spike, but the turbo will!