2014-2020 Formula One 1.6l V6 turbo engine formula

[aleks_ader]

Its difficult to get a sense of scale from the image but as turbos go, that doesn't look particularly big.

How not? Look removable cover infront of it. To disassembly im pretty sure the compressor dia it not bigger than that. Even more, beacuse the attaching point are madanted (rules) we could use it as reference point and calculate approx dia of the cover (izometric view).

[Facts Only]

Its difficult to get a sense of scale from the image but as turbos go, that doesn't look particularly big.

Believe me, it's fooking huge. And the turbine wheel beggars belief.

It actually looks a bit smaller than it should because the main outlet tract is attached to the chassis and not the compressor housing (due to the limit of the FIA box that the PU has to fit inside.

[gruntguru]

The compressor and turbine are both selected on the basis of what the engine package needs. The way some people are talking around here you would think its a matter of "he who can get the biggest compresor to work will make the most power".

Essentially it is all defined by the engine operating point - Engine displacement, speed, volumetric efficiency, boost pressure, manifold air temperature - once those variables are known for each engine speed, the best compressor for the job can be selected. For a 1.6 litre @11,000 rpm, 110% VE, 3.5 bar abs, 70*C the air mass flow is about 0.5 kg/s. This is the peak power operating point so one essential requirement for the compressor would be highest possible efficiency at 3.5 bar PR, 0.5 kg/s flow.

Similar process for the turbine.

[wuzak]

GG, would you say that it is a bit different to a normal turbocharger setup in that the turbine isn't actually matched to the compressor, but instead matched to the needs of the MGUH and PU as a whole?

[gruntguru]

Definitely. The basic decision is what level of back pressure is appropriate. Increasing BP increases power available to the turbine but reduces crankshaft power in the recip'. There is also a tipping point somewhere near BP = MAP where reduced scavenge impacts combustion efficiency and thermal loading of the chamber.

Once the BP is decided (again this must be determined for a whole range of operationg points but focusing on the WOT points) the turbine selection is straightforward based primarily on efficincy at the known massflow, BP and inlet temperature. Maximising efficiency will maximise surplus power from the turbine unlike the turbocharger where turbine power is always equal to compressor power, so better turbine efficiency produces lower BP only.

[wuzak]

The complication being that the turbine and compressor have to turn at the same speed.

[gruntguru]

Yes that is a constraint on the selection process but not a big problem. Probably means that the ratio of MAP to BP can't be varied at will across the rpm range. Certainly not at full load anyway (WOT and WG closed).

[Facts Only]

I've talked about this before but I think its worth mentioning again. You have to try and adjust your pre-conceptions of a turbocharger with this system.
Unlike a normal road/race car turbo it doesn't spool up and slow down during a lap (or the race really), it runs at a constant RPM with the MGU-H working as a control unit 100% of the time, either harvesting energy to keep the speed down or powering the turbo when there is not enough exhaust gas to keep the speed up. Thus the compressor and turbine are sized to work with the optimum map in a very narrow RPM range. A pre-compressor throttle will be used to control boost pressure by cutting off the air-flow into the compressor with a small air bleed channel to avoid stalling/pulsing the compressor.

I'm working on some analysis to show some of these parts as they are visible in some of the pictures that have emerged.

It always makes me chuckle when people rant on about VGT and twin scrolls and how F1 is behind the times. Even if they weren't banned we wouldn't have used them anyway as they are of no-use in such an optimised peak operating environment. All VGT veins do is put a blockage in the system which reduces efficiency at peak operating conditions, on a truck or road car or non-MGU controlled turbo they are useful to improve the operating window of the map but that's not needed in F1.

[Tommy Cookers]

the question of what goes with the turbo loads 'off-throttle' is active at the moment

Porsche changed our world by making a turbo 917 be the first turbo race car that worked on a road circuit (ie not just at Indy)
iirc they did this by paying unprecedented attention to minimising the decay of turbo rpm when off-throttle
to this end, maybe they even did something on the exhaust side ?

we don't want to waste our stored electrical energy in any unnecessary motoring of the turbo off-throttle to maintain turbo rpm
so what would be the right things (including the exhaust side) to do ? (to serve this end)
eg would the turbine load be less with a near-vacuum in the exhaust manifold or with atmospheric air entering ?

btw one thinks of the billions of flying hours with crank-driven superchargers auto or manually throttled for boost regulation
presumably this gave reduced power consumption by the superchargers

[gruntguru]

Certainly on the compressor side there is a massive difference in power consumption if the intake is throttled - low pressure to the compressor inlet. The same would apply to the turbine though I'm not sure how that could be achieved. Opening the WG will at least reduce the upstream pressure to atmospheric.

[hurril]

Certainly on the compressor side there is a massive difference in power consumption if the intake is throttled - low pressure to the compressor inlet. The same would apply to the turbine though I'm not sure how that could be achieved. Opening the WG will at least reduce the upstream pressure to atmospheric.

What happens to the pumping losses/ engine braking magnitude at this point? Surely this also enters into an optimum strategy.

[gruntguru]

Good point. Assuming the MGUK is not harvesting at the max 120 kW, it would be advantageous to minimise engine braking and hand that energy to the MGUK. At the same time you need to minimise energy going to the MGUH to keep the turbo at speed. Would it be legal to hold the valves open to minimise pumping loss? I imagine not, as that would qualify as a form of VVT.

[hurril]

Good point. Assuming the MGUK is not harvesting at the max 120 kW, it would be advantageous to minimise engine braking and hand that energy to the MGUK. At the same time you need to minimise energy going to the MGUH to keep the turbo at speed. Would it be legal to hold the valves open to minimise pumping loss? I imagine not, as that would qualify as a form of VVT.

So in a way, engine braking with the throttle open but with no fuel going in ought to turn the ICE into a "heat engine" whereby the inherent heat of the cylinders causes an expansion that provides some little push on the turbine. I'm sure the valve overlap could indicate an optimum RPM-span where the compression isn't too great (doesn't break too much.)

[redoctober89]

All VGT veins do is put a blockage in the system which reduces efficiency at peak operating conditions, on a truck or road car or non-MGU controlled turbo they are useful to improve the operating window of the map but that's not needed in F1.

Fixed vanes would be allowed tho, they will also increase blockage and thus reduce the operating range but peak efficiency will be improved. Given that the turbo is designed specifically for one engine, the throat area could be optimized for the required operating range.

[mrluke]

Its difficult to get a sense of scale from the image but as turbos go, that doesn't look particularly big.

Believe me, it's fooking huge. And the turbine wheel beggars belief.

It actually looks a bit smaller than it should because the main outlet tract is attached to the chassis and not the compressor housing (due to the limit of the FIA box that the PU has to fit inside.

Bigger or smaller?