Nissan LMP1 Discussion

[Mt. Lynx]

Originally Posted by cokata

Wrong. It produces downforce the same way a wing does only much more efficiently. You create a pressure difference. The air is accelerated and therefore looses pressure beneath the car, and the diffuser acts as a expansion chamber, giving the air room to expand reducing it's speed and increasing it's pressure. And that pressure differential is what creates the downforce.

I was under the impression that if airspeed was the same above the diffuser, it would do nothing.

[wdave0]

Originally Posted by Mt. Lynx

I was under the impression that if airspeed was the same above the diffuser, it would do nothing.

Take a bunch of air and increase the space it is in you reduce the pressure, thus creating downforce.

[GasperG]

If the mechanical flywheel is true, there is a big question of measuring the energy that defines MJ class. Electrical system measure electicity to the el. traction motor, el. motor does not have 100% efficiency, at full power IMO figures quickly drop to 90%. Now if you have mechanical system and measure energy based on torque sensor (like ICE BSFC measure), where would you measure? At the flywheel before the CVT gearbox or after? If After then the mechanical system is in advantage.

[wolfhound]

Originally Posted by GasperG

If the mechanical flywheel is true, there is a big question of measuring the energy that defines MJ class. Electrical system measure electicity to the el. traction motor, el. motor does not have 100% efficiency, at full power IMO figures quickly drop to 90%. Now if you have mechanical system and measure energy based on torque sensor (like ICE BSFC measure), where would you measure? At the flywheel before the CVT gearbox or after? If After then the mechanical system is in advantage.

The amount of energy in a flywheel is easy to calculate. You just need its weight,diameter and speed (RPM)

[gustavobamba]

Flywheel Mechanical or Electrical!!!!!

Reporting to you guy´s who know about this stuff… is that possible to tell the differences?

If Nissan will use the mechanical and Audi use the electrical… Did petrol vs Diesel has anything about this choise???

Did Nissan spend this past year´s evaluating all the things to create a "Mighty LMP1" even aginst all ods!!!! Are they gathering the best things out there to create a winner??

Even if they could do it they will have to wait because PORSCHE will blast in 2015…WEC and Le Mans :-)

[MyNameIsNigel]

Question: Assuming that the Nissan will indeed use a Flybrid system derived from the solution formerly used by Hope Racing and Dyson Racing, i.e. a purely mechanical solution integrated into the ICE's gearbox, what will define the MGU as per the rules, bearing in mind that the rules mandate that the limited amount of energy released is measured/counted only from the MGU(s) ?

In the case of electrical equipments, as adopted by Audi, Porsche and Toyota, the rules do define where the measurements are to be taken, but there is no particular limitation as regards mechanical solutions, except that the means of measurement must be homologated.

Further question: How do you transfer the recovered energy to the rear drive train (assuming the speculations about a FWD concept are correct) ? Assuming that a prop shaft is provided to transfer (at least part of) the MGU's torque to the rear drive train, wouldn't that in effect amount to a 4WD system ?

[GasperG]

IMHO a MGU is directly a flywheel, what else could it be? So released energy must be measured at the flywheel, then you have CVT efficiency loss accounted in MJ calculation.

[MyNameIsNigel]

And the flywheel also inherently acts as Energy Store in such a case. Now, how do you exploit the energy accumulated in this flywheel to possibly release part of it (at least) to the rear drive train ?

Via a prop shaft driven intermittently and exlcusively by the flywheel-MGU ?

Via an electric motor on the rear drive train (provided an electric generator is coupled to the flywheel system) ?

[CyberMotor]

I agree with the thinking that it is mechanical mated with a CVT. Sounds perfect as the CVT can adjust to any RPM that the wheel is spinning.

I know that Honda went totally CVT with their Civic lineup in 2014 so it is becoming mainstream.

Jim Hall and the Chaparrals the last to use automatics in endurance racing?

[MyNameIsNigel]

Note that CVT systems are not permitted to transmit power of the Power Unit (including any MGU) under the current rules. Therefore, I am unsure that the CVT version would be allowed under the current LMP1 rules.

BTW, Hope Racing did use a Flybrid system fitted with a special clutched transmission system.

[chernaudi]

The CVT can only control the functioning of the flywheel, not transmit power directly to the drivetrain, as CVTs are considered fully automatic transmissions under FIA and ACO rules.

[MyNameIsNigel]

Just for the sake of completeness, Article 11.4.6 reads as follows:

Continuously variable transmission systems are not permitted to transmit the power of the power unit defined in Articles 1.16 and 5.

while Article 1.16 defines the Power Unit as:

The internal combustion engine, complete with its ancillaries, any energy recovery system and any MGU and all actuation systems necessary to make them function at all times.

A Flybrid system equipped with CVT would involve transmission via the CVT of power from the flywheel. IMHO that would be inconsistent with what the rules provide.

That would not prevent Nissan from using a derivative of Flybrid's CFT (Clutched Flywheel Transmission) system that was used by Hope Racing in 2011.

[GasperG]

transfer from el. generator to el. motor is actually a form of eCVT. For eg. Audi's flywheel drives the el. generator and this then drives the el. motor.

[MyNameIsNigel]

Originally Posted by GasperG

transfer from el. generator to el. motor is actually a form of eCVT. For eg. Audi's flywheel drives the el. generator and this then drives the el. motor.

As far as transfer of power via the MGU is concerned, it is my understanding that Audi's system uses fixed gear ratios between the MGU and the front drive shafts. These gear ratios are adapted depending upon the track characteristics, so I understand. In that respect, this would not qualify as a CVT system and I would expect that the ACO-FIA would have reacted otherwise. I also understand that Porsche and Toyota basically use similar solutions to transfer and deliver power to the front drive train.

Energy transfer to and from Audi's flywheel system involves conversion of energy through a separate motor-generator integrated in the flywheel unit. It may well be that the flywheel's control electronics are designed to ensure optimum energy transfer/conversion to and from the flywheel (I do not know actually ) but that does not really matter in this context since power is ultimately delivered to the relevant drive train via the associated MGU. And that is what the rules restrict when it comes to the use of CVT systems.

The situation is totally different in the case of Flybrid's CVT flywheel system as the MGU and flywheel-based Energy Store are basically combined in one integrated mechanical unit. In that case, the flywheel's CVT would be an integral part of the transmission used to transfer power to the drive train. That would not be compatible with the rules IMHO.

That's is why I am led to believe that Nissan might have opted for a derivative/evolution of Flybrid's CFT (Clutched Flywheel Transmission) system as used by Hope Racing back in 2011. In that context, it was reported back at the time that the roundtrip efficiency of such CFT system was of approximately 64%, which sounds pretty low compared to the expected efficiency of an electric motor used as MGU.

[TF110]

Maybe we'll find out in a few weeks.

[GasperG]

Roundtrip efficiency (almost) does not mater, what matters is the efficiency from where MJ is measured to the wheels.

Every generator-to-electricity-to-motor drive train acts like a CVT, Honda Accord hybrid uses this kind of transfer and it calls it CVT. Toyota uses it also with a little trickery of transferring half the power through mechanical path (efficiency), but gear ratio is defined only by generator to motor transfer, this is also called a CVT.

The rules were updated with all the ERS systems, but IMO they should be thoroughly rewritten because of consistency.

[CyberMotor]

Originally Posted by TF110

Maybe we'll find out in a few weeks.

And, there will probably be a lot of sports car fans watching a Super Bowl for the first time to see the Nissan introduction. Some people already watch just to see the commercials and this will probably add to that number.

[TME45]

Originally Posted by CyberMotor

And, there will probably be a lot of sports car fans watching a Super Bowl for the first time to see the Nissan introduction. Some people already watch just to see the commercials and this will probably add to that number.

So it is a great PR project?

[CyberMotor]

Originally Posted by TME45

So it is a great PR project?

And, a very expensive one. If they have multiple ads, it is going to be an extremely expensive PR project. Super Bowl ad time is some of the most expensive advertising in the world.

[MyNameIsNigel]

Originally Posted by GasperG

Every generator-to-electricity-to-motor drive train acts like a CVT, Honda Accord hybrid uses this kind of transfer and it calls it CVT. Toyota uses it also with a little trickery of transferring half the power through mechanical path (efficiency), but gear ratio is defined only by generator to motor transfer, this is also called a CVT.

The rules were updated with all the ERS systems, but IMO they should be thoroughly rewritten because of consistency.

I am not very familiar with the technology of the Honda Accord Hybrid, but it is apparent - after having done some search on the subject - that the "E-CVT", as Honda call it, isn't actually a CVT (based on this source at least).

I believe that "continuously variable transmission systems" as referred to under Article 11.4.6 of the Technical Regulations are to be specifically understood as referring to an type of "gearless" mechanical transmission used to transfer power to a drive train. In that respect, Flybrid's KERS with CVT would seem to be in obvious contradiction with this provision.

By contrast, Flybrid's "Clutched Flywheel Transmission" exhibits three defined gears and would be perfectly compliant with the rules.

So far, previous implementations of Flybrid's CFT KERS (as used by Hope Racing and Dyson Racing) all involved integration of the KERS within the ICE's gearbox. In that respect, I struggle to understand how such an implementation could be "compatible" with the speculation that the Nissan GT-R LM concept would involve hybrid energy release via the rear drive train. If the same "old" Flybrid concept is used by Nissan - and the FWD speculation is true - I struggle to understand how energy could be "sent" to and released via the rear drive train as the Flybrid system would necessarily operate - together with the ICE - on the front drive train only.

[cokata]

If they indeed go the flybrid route and it's proven successful, it could be the perfect solution for Toyota. It is pretty clear that they believe and in NA engines and they wouldn't put a ERS-H even on turbo engine for BSFC reasons. Which leaves them with a pure KERS car. The problem with that is the you need a storage device that can have a very high power density, and while Supercaps provide that they are extremely heavy and have very low energy density. The battery route would be very difficult for a KERS car especially if they go to 8MJ.

The flybrid will be by far the lightest solution, since you don't have electric motors, inverter, etc and they have the best power density available. Also we saw that on some circuits when they are not a lot of braking zones the toyota struggled to generate their energy allowance per lap, so the improved efficiency would be a big advantage too.The problem is that you will alienate the P1 car even more from the the prius and all the other hybrids toyota makes.

[blankfile]

From what i saw the toyota didn't have any troubles getting its energy recovery, the porsche on the other hand did

[TF110]

The storage is the biggest issue for Toyota. I think in the future they'll go battery and capacitor.

[TME45]

Originally Posted by CyberMotor

And, a very expensive one. If they have multiple ads, it is going to be an extremely expensive PR project. Super Bowl ad time is some of the most expensive advertising in the world.

but they make more ppl to watch Super Bow, it make their money more valuable.

[TME45]

Originally Posted by MyNameIsNigel

By contrast, Flybrid's "Clutched Flywheel Transmission" exhibits three defined gears and would be perfectly compliant with the rules.

I read but I can't understand how it work