What will come after the 2.4 V8?

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
xpensive
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Re: Sensible ideas for what will happen after the 2.4 V8?

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ringo wrote:
xpensive wrote:A most interesting way to go about it smikle, where I have no problems following your thinking in enthalpy ways, though I would have used 0.45 kg, but thats just details which matters very little.

However, what I don't get is how air-temperature increases from 300K (27C) to 429K (156C), when compressed from 1 Bar to 2.5 Bar? When I'm a little rusty in thermodynamics, can you please elaborate on how you arrive at these numbers?

Also, I have difficulties with are the efficiency, I was thinking turbines in general being far more efficient than 70%?
The air is going to heat up when it is compressed, since it is being worked on. The efficiency of the compressor makes this heating worse. More work has to be put in than theoretical to get to the desired pressure.
But if you mean on a molecular level; when you force particles closer together, you are reducing their kinetic energy. In order for air to be more compressed the particles have to be forced to give up this energy in the form of heat, in order that they relax.
Compression is exothermic. Expansion is the opposite, the particles take on energy from outside to increase their internal energy. So there is a temp drop outside the gas itself.
Like rubbing alcohol on your skin, the particles take the heat from your skin then use it to vapourize.

Yes ringo, but not that rusty, how do you get those xact numbers that smikle got, enlighten me!
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ringo
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Oh sorry, :lol:

Gas turbines use the brayton cycle:

Image

The solid curved lines are isobars, or constant pressure line, anything along that line is the same pressure.
line 1-2 is compression from pressure 1 to pressure 2; notice the vertical axis is temperature and the horizontal is entropy.
So going from on pressure to the other vertically will be a temperature increase.

the top and bottom of the polygon is heat. The sides are work. Compressor and turbine are the sides, 1-2 and 3-4 respectively, they are the working parts. 2-3 is the combustor. 1-4 is heat rejection; these sides relate to heat energy.


Image

this equation represents going from P1 to P2 isentropically or constant entropy which is a vertical line, hence same x axis value. So it gives you the expected temperatures both for compression in compressor and expansion in the turbine at T3 and T4.

The gamma in the equation, (i used k) is a constant, it is Cp/Cv , specific heat capitiy of air at constant presure, and Cv is at constant volume.

Cp - Cv = R. R comes from PV= NRT. Cp/Cv for air is 1.4

This ratio is giving you your true temperature change after bumping the pressure.

The blue lines on the diagram are what happens in reality, This is how the efficiency comes in. The less vertical the isentropic line, the more inefficient the turbine or compressor. 2' 3' and 4' are when efficiencies are factored in.

notice 2' is hotter than 2. So less efficient compressor gives hotter air for the same pressur increase.
3' to 4' is shorter than 3 to 4 line, so turbine work is smaller as well since temp diff is smaller.

I hope that's what you were asking, and this gives a good feel of what's happening.

Oh yeah, you want a short a 1-2 work line as possible for the compressor and a long as possible work energy line for the turbine 3-4 since the compressor draws energy and the turbine gives.

more here: http://web.mit.edu/16.unified/www/FALL/ ... ode28.html
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PlatinumZealot
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Simply, when you compress air its temperature increases. (Hey! another topic too, Intercoolers...) You use this equation any time you compress air.

Image

And because the compressibilty of air changes with temperature you use an air Cp/Cv table. They are other air tables you can use too for enthalpy and "PR" ratio.

I don't think ringo has to bring the turbine into this though. The compressor side calculation should be enough to see what power is taken away from the the gas.
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Lord, it's coming back to me now, but slowly I admit...is it possible to simplify further with a "Lazy-dog" equation, T2 as a function of T1, P1, P2 and Gamma isentropically when passing through the compressor, or do you need tables?

As smikle says, I suspect that you shouldn't have to involve the turbine here?
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Use:

Temperature after compressor, T2 = T1 * Pressure ratio ^ 0.2875

The table is used to find the Cp of the air. You use T1 and T2 to find the Cp1 (before compressor) and Cp2(after compressor) from the Cp table. Find the difference in enthalpy (T2Cp2-T1Cp1) and then multiply by the mass flow rate.

Then Power used to compress the air = m dot * (T2Cp2-T1Cp1)

You divide by the isentropic efficiency of the compressor to find the power given to the compressor from the turbine. Then you divide that number by the isentropic efficiency of the turbine to find how much power is given by the exhaust gas to the turbine.
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xpensive
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Many thanks smikle, as well as ringo. Tthings are coming back enough now for me to realize why my attempt was not even nearly sufficient, I never took the compression phaze into consideration, only the resulting flowing power.
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Re: Sensible ideas for what will happen after the 2.4 V8?

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The main formulas you need are these 3; subscript 1 is atmosphere, 2 is compressor outlet :

T2 / T1 = (p2 / p1) ^(0.287)
[1]

after finding the theoretical compressed air temperature T2 use your compressor efficiency to find what it really is:

Eff = (T2 - T1) / (T2 real - T1)
[2]

put in it the work equation:

Work per kg = Cp * ( T2 real - T1) [3]

multiply Work/kg * Kg/s to get power. :mrgreen:

this is the simple way disregarding Cp changes due to temp.

but to get back on track about the sound, we basically arrive at ~ 100- 150hp taken by the turbine then?
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Let's stick with 100 kW for now guys, but the question is how much of this is for free from already wasted xhaust energy and how much will be stolen from the engine thru increased back-pressure?
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Perhaps one can shed some light by looking at the Porsche Cayenne S and Turbo engines. Both are 4.8L V8 DFI with 120 bar fuel injection pressure, so they obviously have the same injection system and basic engine except for the turbo charging. Bore ร— stroke: 96.00 mm ร— 83.00 mm

S-version:
Power: 294 kW @ 6,500 rpm
Torque: 500 Nm
Compression: 12.5:1
Fuel: 10.5L/100km

Turbo-version:
Power: 368 kW @ 6,000 rpm
Torque: 700 Nm
Compression: 10.5:1
Fuel: 11.5L/100km

Porsche have obviously not used the option to downsize the V8 to V6 and turbo charge it to the power of the V8. So it gives a good idea what is possible with the V8 in both NA and turbo version. While the fuel consumption goes up by 9.5% the power increases by 25% and the torque goes up by 40% when the turbo is added.
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Re: Sensible ideas for what will happen after the 2.4 V8?

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Interesting, do you know the boost-level on the turbo? Knowing that we should be able to estimate what the ideal power should be without xhaust losses and the difference towards the real numbers, though the rpm's are tlighty different?
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Re: Sensible ideas for what will happen after the 2.4 V8?

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The old Cayenne turbo S had one bar of boost pressure if I remember the data on a tuner site correctly. It should work as a ball park figure until we find confirmation.

http://www.edo-competition.de/de/cars/p ... turbo.html
This is a tuned version with + 1bar

http://autos.t-online.de/autotestberich ... urbo-S-SUV
and this is the original predecessor turbo-S with 4.5L engine and a total pressure of 1.9 bar

So 0.9 - 1.0 bar boost should be a pretty good ballpark figure.

Image

NA engine

Image

Turbo engine

Image

some info on variable valve drive
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Re: Sensible ideas for what will happen after the 2.4 V8?

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WhiteBlue wrote:
mx_tifosi wrote:
WhiteBlue wrote:...
The Ferraris which have recently hit the road with direct injection go to 7,700 rpm red line. I doubt the technology is there to do this 2.5 times faster. ...
The current DFI 4.5L V8 runs to 9,000rpm.
Interesting! Do you have a source for detail? It would be interesting to know what kind of direct injection system they use.

Not sure if this is true (Ferrari press release@IAA) but most likely BOSCH.

>>>>>
The Ferrari 458 was developed with the support of the following Supplier Partners:

* Alcoa Aluminum spaceframe
* Brembo Carbon-ceramic braking system
* Bridgestone Tyres
* Delphi HVAC, MagneRideโ„ข suspension & wiring loom
* Fontana Pietro Aluminum bodywork
* Getrag F1 Dual-Clutch gearbox
* Harman International Infotainment & High Power Hi-Fi system
* Magneti Marelli Instrument cluster, front lift & LED rear lights
* Michelin Tyres
* OMR Engine casting components
* Robert Bosch Engine management & ESP
* Shell Lubricants & fuel
* Valeo Bi-xenon head lamps & Human-Machine Interface

Engine

The engine is a dry-sump 90 degree V8 with a displacement of 4499 cc and is mid-rear mounted. It is an entirely new design engineered to reach a maximum of 9,000 rpm โ€“ a first on a road car โ€“ with a high 12.5:1 compression ratio and maximum power output of 570 CV. This equates to an outstanding power output of 127 CV/litre, a new benchmark for a naturally-aspirated production engine.

The generous torque available - 540 Nm at 6000 rpm, with over 80 per cent available from 3250 rpm โ€“ ensures rapid pick-up from all revs. The specific torque output of 120 Nm/l is another record.

The design of the engine components has been influenced by the carry-over of racing technology โ€“ F1 in particular โ€“ for maximum fluid-dynamic efficiency in order to achieve both performance and fuel consumption objectives, and meet the most stringent international emissions restrictions. The piston compression height was reduced as per racing engine practice. Similarly, thinner compression rings have been adopted to minimize friction between piston and liner. A graphite coating was applied to the piston skirt for the same reason.

To help further reduce internal friction, the cylinder block has four scavenge pumps. Two pick up oil from the cylinder heads and front and rear of the engine via dedicated oil recovery ducts outside the crankcase area, and two pick up oil from below the crank throws. The recovery ducts of the latter are interconnected in two groups of four cylinders to optimise the scavenge function and create a strong vacuum (800 mbar) around the crankshaft. This solution prevents excess oil splashing out of the sump and onto the rotating crankshaft and thus reduces power loss caused by friction. It also reduces losses due to windage caused by the pumping action of the pistons.

The engine oil pressure pump features variable displacement geometry which reduces the amount of power absorbed at high revs. Lowering the pumpโ€™s displacement actually increases the power available at the crankshaft for the same amount of fuel used.

As is traditional for Ferrari engines, the new V8 is equipped with continuously variable timing on both inlet and exhaust cams. The aluminum intake manifold has been lightened by reducing the wall thickness. It has short, almost straight inlet tracts to reduce losses and a system that varies the geometry of the manifold, optimising the volumetric efficiency throughout the rev range. This is achieved by incorporating three pneumatic throttle valves in the central section between the two plenums. The engine mapping provides four different configurations of the valves for optimum torque values at all revs.

The use of GDI with Split Injection improves engine performance by modulating the injection in two phases, increasing combustion efficiency and the torque at low revs (by up to 5 per cent). A high injection pressure (200 bar) guarantees adequate pulverisation of the petrol and an optimal air/fuel mix right up to 9000 rpm. This feature again results in better performance and lower fuel consumption.

The exhaust system was designed to provide the kind of thrilling soundtrack owners of Ferrariโ€™s V8s are used to whilst also guaranteeing high levels of acoustic comfort. One of the main objectives with the exhaust was to reduce weight. The catalytic converter is attached to the central section of the exhaust by a flexible element to reduce the amount of vibration transmitted and to thus allow thinner metal to be used. Similarly the pre-catalytic converter has been eliminated, lowering overall weight and reducing back pressure whilst still respecting strict Euro 5 and LEV2 emissions.

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Re: Sensible ideas for what will happen after the 2.4 V8?

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If Bosch is supplying the engine management, then it's about 99% certain they are supplying at least the injectors. Pretty common these days with Ferrari.
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WhiteBlue
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Re: Sensible ideas for what will happen after the 2.4 V8?

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As we find variable valve timing and lift for better power and fuel economy in leading road car engines I feel it will probably appear in the new formula as well. These engines are planned to closely feature and improve on all the top technology of road cars in that respect.

The injectors wil probably be outward opening with either piezo or single coil solenoid drivers. The fuel pump should have 200+ bar injection pressure. I would still be very surprised if the revs will exceed 12,000 rpm, considering that today's maximum is at 9,000.

If they want to add something spectacular dual fuel with LPG or ethanol would be great. If you add a small amount of such fuel by a second direct injector the compression can be increased and combustion efficiency significantly raised. It would be a nice option on the technical side. The road relevancy would not be so good which such a system as many countries probably do not have the infra structure.
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PlatinumZealot
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Re: Sensible ideas for what will happen after the 2.4 V8?

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From Wiki. I don't think high rpm is a real limitation for Direct injection.
Petrol/gasoline engines
Main article: gasoline direct injection

Modern petrol engines (gasoline engines) also utilise direct injection, which is referred to as gasoline direct injection. This is the next step in evolution from multi-point fuel injection, and offers another magnitude of emission control by eliminating the "wet" portion of the induction system along the inlet tract.

By virtue of better dispersion and homogeneity of the directly injected fuel, the cylinder and piston are cooled, thereby permitting higher compression ratios and more aggressive ignition timing, with resultant enhanced power output. More precise management of the fuel injection event also enables better control of emissions. Finally, the homogeneity of the fuel mixture allows for leaner air/fuel ratios, which together with more precise ignition timing can improve fuel efficiency. Along with this, the engine can operate with stratified (lean burn) mixtures, and hence avoid throttling losses at low and part engine load. Some direct-injection systems incorporate piezoelectronic fuel injectors. With their extremely fast response time, multiple injection events can occur during each cycle of each cylinder of the engine.
It is also possible to inject more than once during a single cycle. After the first fuel charge has been ignited, it is possible to add fuel as the piston descends. The benefits are more power and economy, but certain octane fuels have been seen to cause exhaust valve erosion. For this reason, most companies have ceased to use the Fuel Stratified Injection (FSI) operation during normal running
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