2014-2020 Formula One 1.6l V6 turbo engine formula

[ringo]

Why are you so sure Merc's claim is "only ICE" and not the total PU.

Because:
1. What you are suggesting does not meet any definition of an efficiency that could be used to usefully compare power units. The number obtained would depend on a vast array of irrelevant variables including aerodynamic drag, friction, rule limitations on MGUK output, track layout etc
2. Mercedes Benz actually employ engineers - people who understand thermodynamics - and would never use such a nonsensical metric. Their reputation would be trashed.
3. 40% is way too low for the metric you describe. 40% is the thermal efficiency being currently achieved by auto makers - without compounding. With compounding 40+% is what you would expect from the current F1 PU's.

It makes more sense to efficency rate the whole PU as it was all designed to run in an integrated fashion.

No it doesn't. All you are doing is adding a number dictated by the rules - 120kW - to the crankshaft output of the ICE. Doesn't make any sense at all.

You have just displayed that you don't know what you are talking about.

[ringo]

The braking energy is to be included in the calculation. The car didn't get up to speed by some magical power.
The very same engine that was burning fuel accelerated the car to 200mph before the brakes were applied.

The efficiency of the POWER UNIT, the break thermal efficiency, is the power delivered to the output shaft from the unit as a whole compared to the energy content of the fuel being input. That's a fair and simple judgement.

If the cars are 33% more fuel efficient, then the power units are 1.33 x 32% (old V8) = 42.56% brake thermal efficient.
simple, and that includes all the electrical thingamajigs.

[trinidefender]

The braking energy is to be included in the calculation. The car didn't get up to speed by some magical power.
The very same engine that was burning fuel accelerated the car to 200mph before the brakes were applied.

The efficiency of the POWER UNIT, the break thermal efficiency, is the power delivered to the output shaft from the unit as a whole compared to the energy content of the fuel being input. That's a fair and simple judgement.

If the cars are 33% more fuel efficient, then the power units are 1.33 x 32% (old V8) = 42.56% brake thermal efficient.
simple, and that includes all the electrical thingamajigs.

That would be one method of working out the fuel efficiency of the car as a whole. The problem is it doesn't take into account weather changes, aerodynamics of the car (which is less drag this year than last), the road surface that they are driving on (rolling resistance as a result of the friction of the surface) and a big factor, tyre wear etc etc etc. There are simply to many changing variables in that equation.

When engineers quote the efficiency of engines whether it be gas turbines to power aircraft, automobile engines, ship engines, power stations or anything else they generally give you a peak efficiency running at max load at optimal rpm at, and this is very important, ISA conditions.

ISA conditions are international standard atmosphere conditions of 15 degrees Celsius and 1013.25 hPa (hectopascal) at sea level. Below about 10,000ft pressure altitude the standard lapse rate for temperature is 1.98 degrees Celsius per 1000 ft you increase in altitude.

Then they will give you graphs showing the energy efficiency at different loads and different rpm's and with different temperature/pressure combinations.

In almost every case the efficiency percentage given to the media (I.e. not proprietary information to companies using their engines) is indicative of best case efficiency of the engine at ISA conditions when the engine is almost brand new.

This is what leads me do believe the "more than 40%" efficiency is the amount of energy that the ICU + ERS-H (as it can be used to generate some power above a certain exhaust gas flow continuously) running at peak load at max efficiency rpm at ISA conditions.

[ringo]

The engine makers didn't target fuel efficiency based on the tracks and the aerodynamics.
The efficiency target was met with the engine initially. So it is not literally meant to say that the cars will finish a specific race with 2/3 of the fuel. They are simply saying they know their engines are 33% more efficient than the past v8.

[gruntguru]

If the cars are 33% more fuel efficient, then the power units are 1.33 x 32% (old V8) = 42.56% brake thermal efficient.

You have misused the term "thermal efficiency". It is a term used in thermodynamics to quantify the conversion of heat energy to mechanical energy. http://en.wikipedia.org/wiki/Thermal_efficiency Important quote from the link:
From the first law of thermodynamics, the energy output cannot exceed the input, so

When expressed as a percentage, the thermal efficiency must be between 0% and 100%.

If you evaluate a hybrid drivetrain and include recycled energy (energy that has been sent to the drive wheels more than once), it is possible to produce an "efficiency" number greater than 100% - this is NOT thermal efficiency. In fact it is not efficiency in any engineering sense because engineers prefer to avoid using the term "efficiency" for any ratio that can exceed 100% eg "Coefficient of Performance" is used for refrigerators and heat pumps since this number can be >1.

[gruntguru]

The engine makers didn't target fuel efficiency based on the tracks and the aerodynamics.
The efficiency target was met with the engine initially. So it is not literally meant to say that the cars will finish a specific race with 2/3 of the fuel. They are simply saying they know their engines are 33% more efficient than the past v8.

"The new F1 engines have a thermal efficiency of "40% and above" - better than that of a road-going diesel."
This is the quote from Professor Weber at Mercedes Benz. He is talking about the "engines" not the whole car, not the hybrid drivetrain, not the fuel usage over a race - he is talking about "Thermal Efficiency" which is a term you hopefully understand now that you have read the Wikipedia page I linked.

[ringo]

Nope he is not.

[chip engineer]

The engine makers didn't target fuel efficiency based on the tracks and the aerodynamics.
The efficiency target was met with the engine initially. So it is not literally meant to say that the cars will finish a specific race with 2/3 of the fuel. They are simply saying they know their engines are 33% more efficient than the past v8.

"The new F1 engines have a thermal efficiency of "40% and above" - better than that of a road-going diesel."
This is the quote from Professor Weber at Mercedes Benz. He is talking about the "engines" not the whole car, not the hybrid drivetrain, not the fuel usage over a race - he is talking about "Thermal Efficiency" which is a term you hopefully understand now that you have read the Wikipedia page I linked.

It seems clear to me that 'thermal efficiency' cannot include energy recovered from regen braking.
It could refer to just ICE efficiency or could include the MGU-H running in 'self-sustaining' mode as shown in the Cosworth simulations. Either of those 2 make engineering sense.

I suspect the getting numbers much above 40% would require the energy from the MGU-H.

[trinidefender]

Nope he is not.

Ok Ringo be so stubborn that it is impossible for you to be wrong. Gruntguru is actually correct in his definition of thermal efficiency. If you don't believe any of us go look it up or go ask a chemical/mechanical engineer. The efficiency targets are met by first setting targets. These targets are met when the engine builders say " ok we have this much fuel to play with and this maximum fuel flow rate." Then they say "this years cars will run about 20% (or whatever number they used) less drag then before" and run simulations as to what effect that will have on lap times and throttle time and load. Through that they get estimated fuel usage for various tracks in various conditions and obviously add in a safety margin.

Once they have these targets and the target thermal efficiency that they know they need to meet then they actually start work on producing the maximum hp while keeping their thermal efficiency at or above their target.

[wuzak]

It seems clear to me that 'thermal efficiency' cannot include energy recovered from regen braking.
It could refer to just ICE efficiency or could include the MGU-H running in 'self-sustaining' mode as shown in the Cosworth simulations. Either of those 2 make engineering sense.

I suspect the getting numbers much above 40% would require the energy from the MGU-H.

IMO energy from the battery is another input source, like the fuel.

Energy routed directly from the MGUH to the MGUK is not a separate source, as is contained within the unit, and is not stored for later use. It is equivalent to a direct mechanical link - a proper turbo-compound.

Stored electricity could be the equivalent of stored fuel. If the FIA allowed a small storage device for fuel after the fuel flow meter, which allowed an extra 20% fuel flow for a certain period per lap then it would be improper to calculate the efficiency of the PU based on the fuel flow regs (100kg/h) when you were actually using that 20% more (120kg/h).

[Tommy Cookers]

thermal efficiency refers to the indicated heat/work process (in-cylinder, ignoring friction etc) and is useful only to designers
brake thermal efficiency, being based on actual output (at the flywheel) is useful in the real world and is the convention
TE x mechanical efficiency = BTE
so true efficiency (BTE) is always lower than TE

we have to guess what some sources eg Mr Mercedes-scientist mean when they use the term TE
there's a tradition of European sources by mistranslation giving the term TE when they really mean BTE
and ......
it is conventional in engineering to use the (fossil) fuel's Lower Heating Value when considering the efficiency of engines
(significantly flattering and scientifically speaking surely incorrect, eg the flattery would very large with Hydrogen fuel)
inconveniently for our purposes the Upper Heating Value is the one usually given in reference material
LHV ignores the latent heat trapped in the combustion water vapour content of the exhaust, UHV does not
(so heating systems with recovery by this convention claim efficiencies over 100%)
engine conventions have also ignored the latent heat of vapourisation of the fuel, this may not be trivial eg with alcohol fuels

[ringo]

Nope he is not.

Ok Ringo be so stubborn that it is impossible for you to be wrong. Gruntguru is actually correct in his definition of thermal efficiency. If you don't believe any of us go look it up or go ask a chemical/mechanical engineer. The efficiency targets are met by first setting targets. These targets are met when the engine builders say " ok we have this much fuel to play with and this maximum fuel flow rate." Then they say "this years cars will run about 20% (or whatever number they used) less drag then before" and run simulations as to what effect that will have on lap times and throttle time and load. Through that they get estimated fuel usage for various tracks in various conditions and obviously add in a safety margin.

Once they have these targets and the target thermal efficiency that they know they need to meet then they actually start work on producing the maximum hp while keeping their thermal efficiency at or above their target.

I'm an engineer. it simply depends on what you consider the system. The power unit is the whole power unit not the IC alon

[Pierce89]

Nope he is not.

Ok Ringo be so stubborn that it is impossible for you to be wrong. Gruntguru is actually correct in his definition of thermal efficiency. If you don't believe any of us go look it up or go ask a chemical/mechanical engineer. The efficiency targets are met by first setting targets. These targets are met when the engine builders say " ok we have this much fuel to play with and this maximum fuel flow rate." Then they say "this years cars will run about 20% (or whatever number they used) less drag then before" and run simulations as to what effect that will have on lap times and throttle time and load. Through that they get estimated fuel usage for various tracks in various conditions and obviously add in a safety margin.

Once they have these targets and the target thermal efficiency that they know they need to meet then they actually start work on producing the maximum hp while keeping their thermal efficiency at or above their target.

I'm an engineer. it simply depends on what you consider the system. The power unit is the whole power unit not the IC alon

As am I , but just let them tell us how an "engineer" would do it. Its clear to me that if Merc were quoting only the ICE at "over 40%", then the PU as a whole has more power than I thought. If the ICE alone has over 40% efficiency they would be close 900hp once the mgu-k is added. That ain't right.

[Pierce89]

Did you really write that last question? Do you not understand the compression/temperature benefits of high pressure GDI with a very late injection? Surely, if you're talking stratified charges you should already understand these benefits.

Besides, you don't have to have "significant" stratification to run slightly richer around the plug tip. The "fully stratified" systems with no fuel at all close to the cylinder walls effectively reduce your volumetric efficiency in exchange for the increase in thermal efficiency. In other words, you've got a smaller less powerful but very efficient engine. That's why its not done in WOT situations. It reduces overall power and the extra boost requirement would reduce rcoverable power at the turbine too.

My understanding is the same, a Stratified Charge can only be used under light and moderate loading and not at high RPMs. A Homogeneous Charge (either stoichiometric or slightly rich) is needed at WOT for maximum power generation.

You can run lean (or even super lean), but you will not generate the same level of power as a homogeneous charge. There are no free lunches!

I keep being surprised by the number of posters who do not "get" how the curent F1 formula works.

What you are saying about a homogeneous charge being required for max power applies to an "airflow restricted engine" - where you are given an engine with a given size and breathing ability. (This is the traditional performance engine challenge.) When max power is required, you must add the quantity of fuel that makes the most power from the airflow you have been given to work with. This usually turns out to be a lambda ratio of about 0.9. If you attempt to do this with a stratified charge, the rich section of the charge will be richer than 0.9, the lean section will be leaner than 0.9 and combustion will not be ideal for max power. The answer is a homogeneous charge when running rich for max power on this category of engine.

The current F1 engines are "fuel flow limited". When max power is required the engine is operated somewhere above 10,500 rpm and 100 kg/hr of fuel is injected. Since the engines are capable of flowing far mor than the stoichiometric quantity of air, the engine developer now has a wide choice of how much air to add to this 100 kg/hr of fuel to extract the maximum power. With a traditional fuelling system capable of producing a homogeneous charge only, the best efficiency and therefore the best power will be obtained when about 10% - 15% excess air (lambda = 1.1 - 1.15) is added.

For a "fuel flow restricted engine with the possibility of a stratified charge", it will probably be more efficient to produce a mixture of 1.1 - 1.15 in the central burn zone and encapsulate that in some extra "fresh air" to eliminate wall quench and heat loss effects. This would result in a mixture which is still leaner.

You don't "get" f1. Its the same engineers as road cars but with less resources. They are not likely running fully sratified charges at 12000 rpm WOT. They're just not quite there yet.

[chip engineer]

...
For a "fuel flow restricted engine with the possibility of a stratified charge", it will probably be more efficient to produce a mixture of 1.1 - 1.15 in the central burn zone and encapsulate that in some extra "fresh air" to eliminate wall quench and heat loss effects. This would result in a mixture which is still leaner.

You don't "get" f1. Its the same engineers as road cars but with less resources. They are not likely running fully sratified charges at 12000 rpm WOT. They're just not quite there yet.

At least Renault and Ferrari are not quite there yet...