Road Relevance of 2014 F1 Engines

[Paul]

If largely the same engine produces more power for same fuel usage just by adding a turbocharger, exhaust gases cannot possibly be the same. The extra power has to come from somewhere, does it not?

[Tommy Cookers]

If you are disgreeing with my view, sorry to say I can't understand your point.

I would like to try.

[Scuderia Nuvolari]

Fellow enthusiasts !

Please be assured that I am sincere in my basic view, that a normally designed naturally aspirated engine does not have a high enough energy level in its exhaust gas stream to drive a normal turbocharger, (the designer has used the highest possible compression/expansion ratio, and made the expansion stroke (particularly in volume terms) as long as he reasonably can, to extract the maximum energy via the piston). The energy in the gases after the piston's power stroke is dumped as waste.




I still think that my earlier post demonstrates a broad understanding and appreciation of turbocharged engines !

'bye for now


R-1340 Cyclone (aka T.C.)

I have installed aftermarket compressors in my cars in the past and found out that it would typically double the bhp. These were all carbureted chev small blocks with stock cams with 3to 1 12 bolt dana rear ends. at the time we could only get 3 speed 400 trannies because the 700 horsepower tore up everything.
These were days when we had to use water injection to slo0w down predetonation.
Please don't come here and tell us that we can't put a turbo on a stock engine.

[Tommy Cookers]

I really don't think I said that !

I think your engine must have changed conditions at the piston due to your work !

Good fun though !

[Paul]

If I understand you correctly, you are saying that two similar engines, one with turbocharger, and one without, will have same exhaust gases on exit. Yet, the one with turbocharger produces more power. So my question is, where does this power come from?

[Tommy Cookers]

Increased induction pressure increases mass flow of air, then it burns correspondingly more fuel. imep is greater, bmep also greater as internal friction is not increased.

(basically the same as mechanically driven forced induction)

[WhiteBlue]

Please feel free to put forward evidence if you are trying to convince me otherwise !

The evidence is found in the first or second class text books of an automobile or mechanical engineering course. There are no corners to be cut. You better read up on the science. Your explanation doesn't hold water.

If you want it really simple you compare the energy or work required to pump up the inlet valve pressure to twice the atmospheric pressure. Then you inject fuel at 1.6 times the ratio of the normally aspired engine. You do get away with that low ratio because fuel evaporation and combustion is much improved in those new engines. After combustion has delivered work to the crankshaft you release the exhaust at a much higher pressure because you have burned more oxygen and more fuel in the same cylinder size. The higher exhaust pressure gets reduced by the turbine which is generating a work flow or energy that is used by the compressor wheel and - in the case of the F1 turbo engine - an electric MGU as well.

The main point here is that the turbine under peak conditions of a racing engine provides more power or torque than the compressor needs. The combustion is also more efficient with a higher air fuel ratio (AFR) expressed by the much lower rise in fuel consumption than the rise in air intake of the engine. If you want you can attribute the lower exhaust output temp to the lower relative use of fuel to air, but it is rather coincidental.

The combined power output of the crankshaft and the MGU in this case is more than twice the power of the naturally aspired engine. This is the explanation in laymen terms of the efficiency advantage. Perhaps this will help with the understanding.

[Tommy Cookers]

I shall give this my best shot tomorrow (very late here)

None of those books address my specific points

I have no problem understanding why the turbo is a good engine

I have followed your posts with particular appreciation (on the new engines)for months

Goodnight !

[machin]

a normally designed naturally aspirated engine does not have a high enough energy level in its exhaust gas stream to drive a normal turbocharger, (the designer has used the highest possible compression/expansion ratio, and made the expansion stroke (particularly in volume terms) as long as he reasonably can, to extract the maximum energy via the piston).

I think the point you are missing is that a normally aspirated engine's expansion ratio is limited by the maximum compression ratio that can be achieved without incurring preignition... this means the designer cannot actually achieve his/her desired expansion ratio, and as a result energy is lost as heat out of the exhaust... the turbocharged engine recovers some of this energy, and despite having a lower expansion ratio still manages to extract more useful work from each gallon of fuel as those VW figures show....

[Tommy Cookers]

a normally designed naturally aspirated engine does not have a high enough energy level in its exhaust gas stream to drive a normal turbocharger, (the designer has used the highest possible compression/expansion ratio, and made the expansion stroke (particularly in volume terms) as long as he reasonably can, to extract the maximum energy via the piston).

I think the point you are missing is that a normally aspirated engine's expansion ratio is limited by the maximum compression ratio that can be achieved without incurring preignition... this means the designer cannot actually achieve his/her desired expansion ratio, and as a result energy is lost as heat out of the exhaust... the turbocharged engine recovers some of this energy, and despite having a lower expansion ratio still manages to extract more useful work from each gallon of fuel as those VW figures show....

Trust me, I wasn't missing that point !

IMO the turbocharged engine doesn't need to do this (and doesn't), its good efficiency comes essentially from boosting the mass flow without significant increase in engine mechanical losses.
Engines with mechanically driven supercharger attain competitive efficiency in the same basic way (they use them today, don't they). This was also the position 80 years ago.
The centrifugal compressor (as in the turbo) has been used in road cars (mechanically driven) in the USA, but is inherently badly matched, and less suited to European engine sizes.
The turbo was to improve the matching (for road or track, starting about 40 years ago).
Certainly it was said that turbo engines necessarily opened the exhaust valve earlier (to feed the turbo more energetic gas than would naturally occur)).
The turbo must 'load' the gases upstream in order to work, so energy levels must be higher upstream than they would be in a normally aspired engine. IMO fitting a turbo to the normally aspired engine would inherently raise the energy levels upstream.

Certainly a modern low-boost everyday car application would need less energy in the exhaust than the intended 2014 F1 or win-or bust 1985 F1 etc.
My original post was related to range of cases, turbos for charging and recovery.

[WhiteBlue]

You are barking up the wrong tree. The efficiency advantage of the turbo engine and the even bigger advantage of the hybrid turbo compounded engine comes from the exploitation of the exhaust gas enthalpy which is mainly driven by the temperature.

You can check the numbers yourself if you read:

http://www.f1technical.net/forum/viewtopic.php?p=200560#p200560

Ringo developed a thermodynamic model with me and he made all the computations. At that time we over estimated the fuel flow at 32g/s. In reality it will only be 27g/s. But that isn't the point.

The main points here are the enthalpy differentials for the turbine and the compressor.

The compressor absorbs 147 kJ/kg at an air flow of 0.47 kg/s. The air temp increases by 140°.

The turbine is designed to extract the maximum enthalpy from the exhaust gas with 543 kJ/kg at the mass flow of 0.5 kg/s. The temperature difference is 739°C - 344°C=395°C

Please note that the turbine enthalpy is 3.7 times the compressor enthalpy. To formulate it in a different way we need only 27% of the turbine power to run our compressor. The rest can be used to drive the MGUH which produces electric power that will be directly fed to drive the car forward with the MGUK (used to be called KERS).

You will also note the different temperatures. The engine exit temp is 979°C. The exhaust gas looses another 240°C on it's way to the turbine entry where it enters with 739°C. After the turbine it exits with 344°C. We extract almost 400°C with the turbine compared to a naturally aspired engine that isn't equipped with a turbine.

Naturally you can also fit such a device to bigger engine without turbo charger. You simply have to make the engine big enough to suck the same amount of air. Then you can fit the same turbine without having to use 27% of it's energy flow to run the compressor. The total turbine enthalpy can be used to run the MGUH which would generate electricity to drive the car with the MGUK. One thing that will probably create a problem is the back pressure from the turbine. It will not be such a big problem for a charged engine, but it could be a significant problem for the NA engine.

[Tommy Cookers]

I shall be interested to consider this carefully. At a first glance, some of it seems (to me) to be compatible with some points in my earlier posts.

Can I again point out that I was complaining about the FIA and some others, not about the turbo, in part my complaint was about misrepresentation of how the turbo works.

In WW2 turbos were designed to run with upstream exhaust temperatures of 1725 F, presumably modern ones have a higher temperature capability. To me this still suggests that turbos run on exhaust gases at higher energy conditions than the unsupercharged car engine generates, whatever gases they run on, it's not the energy 'wasted' out of my Hyundai's tailpipe.
Turbos only got into cars (via the competition route with rules much kinder than F1 rules), after 40 years
of use in aircraft and diesels, so I'm thinking there was no compelling merit (for cars) then. They became commercially attractive for homologation of competition winning 'production' cars and as a cheap route to profitable premium cars (cheaper/quicker route to power than building the necessarily bigger/different non-turbo engines). Years earlier fuel injection came in for the same reasons (Merc,Peugeot,Triumph)

Regarding tailpipe emission temperatures of turbo and other engines, do these show up in Rolling Road tests, does anyone have results in this area ?

Regarding the fuel injection developments associated with the 2014 rules, prssumably they are ,in principle, also valuable to designers of naturally aspirated engines ?

They seem able to allow road car engines having the good characteristics of both diesel and petrol engines, I was assuming many would be n/a
The traditional way of having good efficiency in real world use is to choose the engine size that we need, not twice that size. This applies with any type of engine.
I wonder what FIAT says to the FIA, they have a conflict of interests I think.

[WhiteBlue]

Can I again point out that I was complaining about the FIA and some others, not about the turbo, in part my complaint was about misrepresentation of how the turbo works.

To those who understand the technology there was never a misrepresentation. The FiA objective is to save 35% of the fuel use of the V8 engines by introducing technologies like turbocharging, hybrid turbocompounding, direct injection, spray guided combustion and exhaust gas recirculation.

In WW2 turbos were designed to run with upstream exhaust temperatures of 1725 F, presumably modern ones have a higher temperature capability.

The WWII aero engines were predominantly supercharged. Later they used exhaust turbines for turbocompounding 12% of the engine power from the exhaust gas stream. The mechanical compressor and the exhaust turbine were not connected.

To me this still suggests that turbos run on exhaust gases at higher energy conditions than the unsupercharged car engine generates..

The only difference is not in temperature but in back pressure from the turbine. A charged engine can deal better with the back pressure.

..whatever gases they run on, it's not the energy 'wasted' out of my Hyundai's tailpipe.

And at this point you are wrong. The turbine extracts energy from the exhaust gas that would otherwise be released to atmosphere unused.

Turbos only got into cars (via the competition route with rules much kinder than F1 rules), after 40 years of use in aircraft and diesels, so I'm thinking there was no compelling merit (for cars) then.

Turbochargers first massive use in automotive occurred in small European turbo diesel road cars. Atm about half the cars newly sold in the EU have turbo diesel engines. The USA did not follow that technology because these cars need diesel without sulfur. The EU refineries have supplied this type of fuel for a long time. In the USA it was practically unavailable. The diesel turbocharger runs on lower temperatures than the petrol version. It took the industry longer to offer modern turbochargers with variable geometries at higher temperature. The sulfur and the temp problem conspired to prevent the massive use of turbochargers in the USA in the past.

They became commercially attractive for homologation of competition winning 'production' cars and as a cheap route to profitable premium cars (cheaper/quicker route to power than building the necessarily bigger/different non-turbo engines). Years earlier fuel injection came in for the same reasons (Merc,Peugeot,Triumph)

I believe you are once again unaware of the market mechanisms. Downsized turbocharged engines with the same power output as NA engines are lighter, smaller and less thirsty. This is why they are increasingly used now.

Regarding tailpipe emission temperatures of turbo and other engines, do these show up in Rolling Road tests, does anyone have results in this area ?

If you start at 1000°C at the exhaust valve and end up with 20°C ambient temperature it matters a great deal if you recover between 200-400°C with a turbine or let it all cool down in muffler pots and pipes. It isn't relevant how hot your exhaust temp is from the tail pipe but how the temps came down to the that point.

Regarding the fuel injection developments associated with the 2014 rules, prssumably they are ,in principle, also valuable to designers of naturally aspirated engines ?

Yes they are.

They seem able to allow road car engines having the good characteristics of both diesel and petrol engines, I was assuming many would be n/a

The market will sort this out. The trend is clearly towards turbo engines everywhere because turbo engines generally have higher efficiency and fit into smaller spaces.

The traditional way of having good efficiency in real world use is to choose the engine size that we need, not twice that size. This applies with any type of engine.

The traditional way would be a specification that defines the power, the mileage, the weight and size of the engine and then the engineers design the engine to fit that brief. As I said above the most competitive engines will be turbo diesel and turbo petrol. Perhaps in the future also turbo compounded hybrids.

I wonder what FIAT says to the FIA, they have a conflict of interests I think.

Fiat and Ferrari are happy with the new turbo engines except they wanted a high cylinder count for marketing reason. They eventually got the L4 exchanged to the V6 and now they seem to be reasonably happy. Their view is to get rid of the frozen V8s and gain competitive advantages from the new engines.

[pgfpro]

In WW2 turbos were designed to run with upstream exhaust temperatures of 1725 F, presumably modern ones have a higher temperature capability. To me this still suggests that turbos run on exhaust gases at higher energy conditions than the unsupercharged car engine generates, whatever gases they run on, it's not the energy 'wasted' out of my Hyundai's tailpipe.

I have personally installed turbochargers on these stock N/A engines with no engine mods other then head bolts.
1994 1.6L SOHC Honda
1993 1.6L DOHC Honda
2004 2.5L Nissan
1994 1.8L DOHC Honda
1988 351 CI Ford V8 Windsor

All the above have at least double their HP and some with an increase in fuel mileage. This was done with the same stock cams and cam timing.


The turbine side of the turbocharger creates a higher exhaust turbine expansion ratio. Not the engine. So all the above stock N/A engines after having a turbo installed generated enough exhaust energy needed to make the turbocharger work correctly. So yes even your Hyundai engine is capable of making a turbo work very well.

[Tommy Cookers]

Many thanks for this good and clear information !