Talking to a turbo expert

[ACRO]

well... split shaft gas turbines and turbo compounding in one housing is like i said a different story from a thermodynamic view.

in a gas turbine you have only RE-action turbine stages where the gas from the combustion chamber ALWAYS blows the gas in it and you have a homogenous gas flow.

in your construction you have one RE-action turbine which is driven by the combustion gas ( the turbine which charges the engine via boost) an the second compound turbine in some circumstages gets an AC-tion turbine. this happens when you like i said close the throttle and shift down and the engine screems up - closing throttles = no exhaust gas flow on the engine to one stage and simultany the socond, engine rpm dependent compound turbine, revs up like the engine. in this moment the turbine is not driven by the gases but by the engine itself and "sucks" air in the housing instead being driven by air ( exhaust gases) . in this moment you will get an immediate stall at the turbine blades, because the blades, like an airplane wing, cannot work in both airstream directions.

thats why everybody, when if all, build multiple turbochargers or compound systems downstream or parallel, but never in one housing- or, like our wright TC3350, use one system by super and the other by turbocharging.

it maybe complicated to describe it via a forum, but really, it will not work so.

it is right that in some turboprops and all turboshafts ( helicopter engines) one stage is the gas generator and the other connected to the gearbox for the prop/rotor, but here you have a very slim rpm margin in which the prop or rotor changes speed ( constant speed prop) and excluding the situation of a windmillimg prop when the engine failed ( autorotaion in helicopters) you never have a situation when the prop/rotor feeds the turine instead of being fed by it.

axial, centrifugal compressor stages... well, a story for itself. both sytsmems have advantages. it would be a story for itself. quickly said- an axial system has a better efficiency, a radial gives you more pressure from one stage.

so we build a turbocharger- axial gas driven turbine for good efficiency, centrifugal compressor for high boost pressure in one rotor stage...

[WhiteBlue]

i think you make here a mistake in thinking. the turbocharger is fed by the combustion gases . the more the charger pumps air in the engine the more fuel can be fed in the engine, the more exhaust gases are produced which drive the charger faster and faster giving more boost which allows to even more fuel be combusted. its a circle. at low rpm,s /low throttle instantly there are not enough combustion gases from the engine to fully drive the charger and a turbo lag occours.

when you set a benchmark to 650hp in our 2013 engine and it should be reached by turbo compunding it means that a part of power comes not from boosting but from mechanical assistance of the second charger.

this means that the first charger has too boost lower because the second charger also will do a job. this means that the lower boost give less exhaust gases for driving the second charger. its a circle again.

compunding would make fully sense when our 2013year 1.6 litre would not be able to accept a boost that is sufficient for reaching 650hp alone. then you could in compound systems look for additional power. but our 1.6 litre will accept 650 just from turbocharging and so it makes no sense to put a compound charger behind it only to boost lower or otherwise getting an engine that produces more than 650hp.

compounding is a way to rise overall power of the engine without rising the bmep - but when you can reach the wished power by boosting alone it makes no sense.

thats why all manufacturers go in charging and not charge-compounding with todays better materials of the engine core ( pistons, rods, crankshaft etc...)

You are contradicting yourself. As I have already explained turbo charging can never extract the full power potential of the exhaust gas. The more air you force into the engine by a turbo charger the bigger the losses become. So blowing an engine to 3 bar boost instead of 2 bar boost makes your efficiency worse.

When you start harvesting the energy potential above the turbo charger level you generate power from an energy stream that is otherwise dissipated to atmosphere. This is making an additional contribution to the energy balance of the engine. If we assume that it is 10% of the nominal engine power it opens the option to use that as a competitive advantage over other teams that do not have such power. Of course you also have to consider the weight penalty for the compounding equipment. We know that it was 20% of the engine weight in the case of the Writhe 3350TC engine. Applied to the 2013 F1 engine it could be 15 kg. I bet every team would give their arm and a leg for having 10% more power at a 15 kg weight penalty.

[ACRO]

[I bet every team would give their arm and a leg for having 10% more power at a 15 kg weight penalty.

right, but i do not think that FIA will define the rules in 2013 simply that the engine has a max boost of lets say 3 bars and a rev limiter but all other is "free" . of course the teams then might start search of rising power by e.g compound systems without exeeding max boost and use the rest energy of the gases (downstream compound syste or one housing, the problems ans solutions was my other thread)

i think that FIA will define the rules that NO engine will produce more than 650hp , whatever you reach that power level. and in this case just turbocharging is the better way. thats my way of thinking.

of course- when FIA is stupid enough to just limits the boost and rpms, go for compunding and use the last of exhaust heat and stream energy. but i dont think they will be so stupid. they will fully regulate the engine, no engine battle again.

[WhiteBlue]

The purpose of having a new engine formula is to find new ways of improving the efficiency of the whole race car. This also includes the engine.

A team like Red Bull derives their competitive advantage from the chassis. They will do all and everything to stop manufacturers to gain a competitive advantage from the engine. They will demand the cheapest possible engines and insist to use all the money for chassis developments. After all they are paying their chief aerodynamicist and technical director more than they are prepared to pay for engines.

I do not think this is the right way to look at it and I'm pretty sure the FiA isn't seeing it that way either. They definitely want to push for more drive train efficiency. They plan to limit an 800 bhp engine to 650 bhp by use of a fuel flow limiter. So improving engine performance can only be done by efficiency technologies like turbo compounding and direct injection.

I think it would be foolish not to allow such technologies because they will make road cars more efficient some years down the road.

Restrictions in exhaust gas turbine technology would be a massive failure by the FiA to promote the targets they have set. They should restrict the boost to 2 bars and that should be it. If they restrict HERS by banning turbo compounding or hybrid turbo charging they could as well keep the current engine format.

[ACRO]

lets wait and see how FIA will rule it. i also would prefer that they leave room for new technological solutions, no question.

but i think this engine will be more regulated than we think, including dimensions of the core engione block ( bore of the cyliders e.g)

in the past FIA seemed to be "pissed off" in their effort to limit power output by defining new rules and to see that engineers always found with immense development costs a way to compensate it with the new rules and even pushing the output higher.

some years ago they went radical and frooze the engines, also giving a rev limiter and so leaving not a chance for designing something new. in my eyes that was the end of what formula one was born for and of what it was decades after : an open class.

i think they want to keep full control over the output and lap times and they want not to leave room for costly searching for some extra horses out the powerplant.

somekind of hybrid systems will come i think, but that will be brake recovery and the power will be stored for somekind "push to pass" reasons.

well.. lets see

[djos]

I dont see why they cant just set financial limits on development costs, engine supply costs and engine manufacturing costs and leave the rules open for innovation?

[WhiteBlue]

The FiA will only rubber stamp the new regulations. The team majority will decide what will happen. This why I'm afraid that important parts of this new formula will be over regulated. Standardization of turbos was already mentioned. It would be a disaster if that happened.

I dont see why they cant just set financial limits on development costs, engine supply costs and engine manufacturing costs and leave the rules open for innovation?

That is obviously what Cosworth want but as I said the teams will decide this with the majority in the working group.

[autogyro]

I think Fota stand a very good chance of killing their golden egg which is F1 if they over regulate.
Ferrari will be the problem of course.
Making the fuel amount allowed for the race the cardinal rule will achieve all the regulation needed to achieve a limit on power and suitability for the cars to use F1 designed circuits.
It depends on if they have the b--ls to set a fuel limit low enough to force major aero change away from downforce and an open enough raft of regulations that can attract proper KERS, HERS and other efficiency development.
If they cannot achieve this F1 will fail IMO.

[MegaHurts]

A standard Turbo Charger doesn't have to be bad if it is only used as the name means. To deliver that 2 bar boost is easily done without having to open it up to development.

I think HERS is the bit you are really worried about WB. Surely as long as that is left open then development of turbines in the exhaust flow for electricity generation will happen as you want.

[WhiteBlue]

There is little chance that you will be allowed to use another turbine in the exhaust if they decide to put a common spec turbocharger in there. Such a decision would be made to stop people from exploiting power from the exhaust gases. Even if you are allowed to use an additional turbine certain options like a hybrid turbo charger would be excluded.

The only reason for a spec turbo is blocking the development to prevent costs. But this is exactly the area that needs development because F1 has not been active for a long time and much efficiency improvement can be found. You cannot optimize HERS if exhaust gas turbines are over regulated.

[ringo]

It is fine if you do that but please consider that the the 2013 engine will have a mass flow of 0.36 and not 0.48 kg/s. The target is reducing the fuel consumption by 25% which will directly impact the air mass flow.

Also the turbine design needs careful consideration. If radial turbines have only 70% efficiency and axial turbines had already 82% in 1950 F1 should not be using inefficient hardware. Please also consider the twin spool design which I proposed. I believe it is essential to a high efficiency of the total design by making the rpm of the compounder and the charger turbines independent of each other. Alternatively one could also avoid the concentric shafts of a twin spool design by exiting the compounder shaft as a free shaft to the other side.

I am doing a simple single turbine single compressor turbo charger. I'm using an existing turbo that should match the power requirements, a T61 turbonetics.
What's important is the compression ratio of the engine. This has to be matched to get the power, 650hp, that you want considering the boost pressure.
I'm thinking of an excell file so that the compression ratio and other variables can be adjusted to get the output power.

What is also important is the adiabatic flame temperature and pressure of the engine, equivalence ratio of fuel, and how much of the fuel that is left unburnt which affects the pressure and temp of combustion.

so far, with a 624 indicated power engine. yes too low, need to adjust the compression ratio later; i used 10:1.
Engine needs to speed up, 10,000rpm is too low as well!
I got exhaust temp of 951K, at 9.17bar going into the turbo. A turbine eff of 85% can produce 186kW exhausting to atmospheric pressure at 504K.
The compressor (76% efficiency) going to a pressure ratio of 2 requires 67.95 kW.

From this example the turbo has sufficient power left for another load. However the exhuast temperature of 504K is what happens when all the work is being used.
These calculations are steady state, so it is accepted that the turbo is only balancing the load, not accelerating. In steady state the turbo only produces power equal to the load.
If the turbo was loaded by the compressor alone;
the exhaust temperature would be 776K; higher than 504K because it throws away the rest of power as heat. Note also that 504K is the lowest exhaust temp possible, since this is controlled by the exhaust pressure. If it exhausts much lower the temperature will be lower and the potential work will be greater.

I'll show the calculation for 650 brake horse power later, I don't know where I'm going to get the friction power from, but we can ignore it for now. The above is just an idea of what to expect.

This is with a mass flow of 0.48kg/s, without consideration of volumetric efficiency. My intercooled air comes in at 40*C like the Honda RA18 Mclaren engine. 0.36Kg/s probably wont cut if for 2 bars of boost.

these numbers were done on a scrap of paper, so maybe there are a few mistakes. So until i put up the calculation, we can take these seriously.
edit: I have a correction for the flame temp, which affects the exhaust, but until i get everything together...

[ACRO]

well... on the one hand its a generall discussion what COULD be possible...

on the other hand, forget all the wishes.

a "simply" twin turbo inline4 with KERS, fully regulated with no option of introducing new ideas. all engines in the field will precisly produce 650hp and eat the same amount of fuel. who bets with me?

sad, but F1 will have so or so its spectators, will surely survive. when its not dead with an frozen engine and an rev limiter and its superb looking rear wing than the other stuff will also not kill it.

[WhiteBlue]

It is fine if you do that but please consider that the the 2013 engine will have a mass flow of 0.36 and not 0.48 kg/s. The target is reducing the fuel consumption by 25% which will directly impact the air mass flow.

Also the turbine design needs careful consideration. If radial turbines have only 70% efficiency and axial turbines had already 82% in 1950 F1 should not be using inefficient hardware. Please also consider the twin spool design which I proposed. I believe it is essential to a high efficiency of the total design by making the rpm of the compounder and the charger turbines independent of each other. Alternatively one could also avoid the concentric shafts of a twin spool design by exiting the compounder shaft as a free shaft to the other side.

I am doing a simple single turbine single compressor turbo charger. I'm using an existing turbo that should match the power requirements, a T61 turbonetics.
What's important is the compression ratio of the engine. This has to be matched to get the power, 650hp, that you want considering the boost pressure.
I'm thinking of an excell file so that the compression ratio and other variables can be adjusted to get the output power.

What is also important is the adiabatic flame temperature and pressure of the engine, equivalence ratio of fuel, and how much of the fuel that is left unburnt which affects the pressure and temp of combustion.

so far, with a 624 indicated power engine. yes too low, need to adjust the compression ratio later; i used 10:1.
Engine needs to speed up, 10,000rpm is too low as well!
I got exhaust temp of 951K, at 9.17bar going into the turbo. A turbine eff of 85% can produce 186kW exhausting to atmospheric pressure at 504K.
The compressor (76% efficiency) going to a pressure ratio of 2 requires 67.95 kW.

From this example the turbo has sufficient power left for another load. However the exhuast temperature of 504K is what happens when all the work is being used.
These calculations are steady state, so it is accepted that the turbo is only balancing the load, not accelerating. In steady state the turbo only produces power equal to the load.
If the turbo was loaded by the compressor alone;
the exhaust temperature would be 776K; higher than 504K because it throws away the rest of power as heat. Note also that 504K is the lowest exhaust temp possible, since this is controlled by the exhaust pressure. If it exhausts much lower the temperature will be lower and the potential work will be greater.

I'll show the calculation for 650 brake horse power later, I don't know where I'm going to get the friction power from, but we can ignore it for now. The above is just an idea of what to expect.

This is with a mass flow of 0.48kg/s, without consideration of volumetric efficiency. My intercooled air comes in at 40*C like the Honda RA18 Mclaren engine. 0.36Kg/s probably wont cut if for 2 bars of boost.

these numbers were done on a scrap of paper, so maybe there are a few mistakes. So until i put up the calculation, we can take these seriously.
edit: I have a correction for the flame temp, which affects the exhaust, but until i get everything together...

Exhaust temp is more likely 950°C or 1223°K.

To meet those standards, you must run at higher exhaust gas temperatures than modern engines. To comply with (projected) fuel economy and emissions standards, you must make your turbocharger very heat resistant. You need to run over 1,000 degrees Centigrade to be able to meet emissions standards at full load conditions. Modern turbochargers are very capable of doing that. There’s the possibility that turbochargers will be the first requirement of modern gasoline.

The engine rpm may go up to 10,500 according to some sources.

I would expect higher compression than 10:1 probably more like 10.5 or 11:1. Porsche's Panamera engine uses 10.5:1.
http://www.ultimatecarpage.com/car/3933 ... Turbo.html

The Panamera turbo uses variable valve timing and lift and is likely to run throttle less engine management. If F1 use high efficient spray guided direct injection compression should be higher. The injection comes much later in the compression stroke and the finely atomized spray will provide some evaporation energy which will work as anti knock and allow a bit higher compression than the Porsche type TFSI engine.

The compressor ratio is said to be up to 3:1 which means 2 bar boost pressure on top of 1 bar ambient. I don't expect that the engine will have full 3 bar intake pressure at 650 bhp. So the likely value is probably 2.6-2.8.

I can only speculate what kind of pressure drop the turbine will be able to run. The back pressure to the exhaust valves seems to be the limiting factor. If you generate too much back pressure you burn the valves. But an F1 engine has only very limited life time and can be designed for just 20 operating hours. So I would expect higher back pressures than in road cars, aero engines and commercial truck engines.

[ringo]

What they will do is have the compressor run higher than 3 bar, and make sure 3 bar reaches the manifold.
The reason for my low exhaust temp, is because of the flame temperatures and pressure.
There is a simple relation that can be used based on the fuel heating value and fuel to air ratio. This yeilds the higher temp and pressure.

Then there is the adiabatic flame temperature program that i used that has a lot of variable parameters. Somehow the temperature is way way less with this program.

So what i will do is stick to the simple theoretical relation; though i like the flame program.

[ringo]

The flame program is more accurate, i made some adjustments and upped the compression ratio to 10.5. The other equation, on the NASA website assumes the spefic heat at constant volume doesnt change; which only works at low temp.

the engine only gets 638hp at 10,000rpm.

However when i up the speed to 10,500 it pushes out 670hp. this is all at a volumetric efficiency of 1.
fuel flow rate is 0.5 kg/s at stoichometry.

looks like it was worth the wait building that excell file.

oh the whole reason i did this in the first place:
the turbine has 248hp or 185kW left over after it powers the compressor.
This is the useful work, heat is exhausted as well.
It throws away hot gases at 600K if all it's available power is used.
However by powering only the compressor, which takes about 98hp, more energy is wasted and gases exhaust at 964K.

So with a generator taking all the turbo has to give, 248hp, more energy escapes at 600k or 327 degrees. This could be used for heating.
248hp to the generator, sounds useful....