Potential F1 engines beyond the 2013 1.6L turbo L4

[Formula None]

Sort of like a Prius transmission with a turboshaft in place of the ICE? Fixed gear ratio?



S=Sun gear
C=Planet gears
R=Ring gear

The two MGU's (sun and ring gears) vary their speed and direction of rotation relative to the engine's speed (planet gear carrier).

Simulator here (bottom of page): http://eahart.com/prius/psd/

[machin]

The electric motor would run at variable speed and variable load. The electric motor's input speed, and even direction of rotation, would determine the output speed of the combining gearset. It would be a form of CVT.

Heck, you wouldn't even need a clutch. If the electric motor input to the differential gearset was the same speed as the turboshaft input, but in the opposite direction, then the differential gearset output speed would be zero.

Is my idea stupid?

Riff_Raff, knowing that Autogyro can't post here, I thought it only fair to point out that this is essentially Autogyro's transmission idea... something you commented on here: viewtopic.php?p=224723&f=4

I agree, you've added the use of a turboshaft engine, but I guess Auto would be the first to say that he always intended his gearbox to be mated to variety of prime movers.

I would also point out that the arrangement in itself is nothing new -"Shunt transmissions" have been around in industry for some time, although traditionally the variable speed portion is provided using a hydraulic variable speed machine which absorbs some of the power of the prime mover, and re-transmits it at a different speed to input it back via the ring gear of an epicyclic gearbox, This provide the ability to change the speed as you have described.

The problem with a single stage epicylic used in this way is that a lot of the power has to be added/absorbed (depending on if you are increasing or decreasing the output speed) by the electric motor if you want to change the overall output speed by a large amount.

For example, if you want to decrease the output speed by 50% the electric motor attached to the epicyclic unit's ring gear needs to absorb half the power of the primemover. That could be a lot of power to find a "home" for. One solution could be to put the power "back in" further down the tranmission using a second motor. However, that means having two electric motors (and associated control system) which are sized for quite high power levels... that means extra weight. Also since a lot of the power is converted to electrical and back again you fall foul of the conversion efficiencies....

Autogyro's transmission gets around this by having multiple epicyclic stages so that you only use the electric motors to seamlessly shift between gears (although you need to reduce the output torque from the prime mover whilst doing it if you want to keep the "shift motors" small), the rest of the time the gearbox works in a purely mechanical way with various parts locked to provide different gears.

[Edis]

Sort of like a Prius transmission with a turboshaft in place of the ICE? Fixed gear ratio?



S=Sun gear
C=Planet gears
R=Ring gear

The two MGU's (sun and ring gears) vary their speed and direction of rotation relative to the engine's speed (planet gear carrier).

Simulator here (bottom of page): http://eahart.com/prius/psd/

Turbine cars of the past like the Howmet TX simply used a single speed reduction gearbox to transfer the power from the free turbine engine to the wheels. For a racing car I think that this is still the best solution. The solution for a practical gas turbine powered passenger car would however be different. Most of them I've seen so far have used the serial hybrid design. That also simplify the turbine engine design since a free power turbine isn't needed, you only need a high speed alternator connected to a single shaft.

[riff_raff]

machin,

The gearbox architecture I described is called "geared neutral", and yes, it has been around for many years.

The main idea behind my suggestion was a hybrid system that allows the turboshaft engine to run at constant speed but variable load. Turbine engines can tolerate fairly rapid changes in load without encountering combustion instability, but they don't like changes in speed.

edis,

the serial hybrid would require a turbine engine, electric motor and generator all sized for close to 100% of power requirements. The parallel system would only need the turbine engine to be sized for 100% power. That would be the best compromise for weight, since the turbine engine gives the best power-to-weight.

riff_raff

[machin]

The main idea behind my suggestion was a hybrid system that allows the turboshaft engine to run at constant speed but variable load.

The arrangement certainly works... Below is quick mock-up of the required arrangement if you want to use a generator and an electric motor to decrease the speed of the output:-



The generator attached to the epicyclic's ring gear absorbs some of the power of the engine whilst also allowing the ring gear to rotate. This rotation causes the output speed to reduce (i.e larger gear ratio). To put the power "back in" you need a motor further down the transmission system.....

The problem then is the extra weight of the the generator + motor and control system and the fact that the power they transmit is subject to the efficieny of the electrical system.

That's not to say it wouldn't work.....if you can gain enough efficiency back by optimising the prime mover to run at just one speed then overall the system may give an advantage....

The parallel system would only need the turbine engine to be sized for 100% power. That would be the best compromise for weight, since the turbine engine gives the best power-to-weight.

If you wanted to reduce the output speed of the arrangement above by 50% then 50% of the power needs to go through the generator-motor... I agree, that's better than the series arrangement, but obviosuly still a lot more weight than a purely mechanical arrangement.....

[ringo]

It's flexible and it addresses the issue with the turbine sensitivity to speed.

This may be a bit heavier and more crude than either the free power turbine or the gear neutral one, but i would have the hot wheel geared to the final drive as usual.
Then on the back or side of the turbine I'd have the generator geared. The generator only comes in when the relative speeds of power turbine to gas generator turbine are too great.
Generator then directly powers an MGU on the rear axle.

I like the flexibility of the epicyclic system though.

One thing though, as the planet carrier goes to zero, or the wheel speed, while the turbine is at rated speed.
Most of the power will be going to the generator ring gear.
Will the generator power the already slowing motor on the drive shaft or charge some batteries.
It looks like a conflicting concept if batteries aren't involved.
correct me if i am interpreting it wrongly.

[Edis]

the serial hybrid would require a turbine engine, electric motor and generator all sized for close to 100% of power requirements. The parallel system would only need the turbine engine to be sized for 100% power. That would be the best compromise for weight, since the turbine engine gives the best power-to-weight.

riff_raff

For a regular passenger car weight wouldn't be much of an issue since the turbine and alternator doesn't have to be sized for 100% power requirement, you only need to size them for the average power and the average power of a passenger car is rather low. 60 kWe would probably be enough for most typical passenger cars. The engine can be made as a simple single shaft engine with a high speed generator directly coupled to it. A turbine engine is inefficient at part load so a turbine engine sized for the average power need is a much better solution. A PM magnet 60 kWe alternator can probably have a weight as low as 10 kg + power electronics.

The traction motor doesn't have to be rated to handle maximum power for any longer duration since a passenger car is usually not driven that way. At the same time, this will make the slow response from the gas turbine a non issue.

If we look at gasturbine hybrids from Volvo, Toyota, Honda and others, the serial hybrid have been the solution used by all of them.

[machin]

One thing though, as the planet carrier goes to zero, or the wheel speed, while the turbine is at rated speed.
Most of the power will be going to the generator ring gear.
Will the generator power the already slowing motor on the drive shaft or charge some batteries.
It looks like a conflicting concept if batteries aren't involved.
correct me if i am interpreting it wrongly.

You have two options:-

Either charge a battery,

or

reduce the torque from the prime mover... the speed is still constant but since the torque is now negligable the power is just enough to keeping everything spinning (i.e. to overcome friction) so there's nothing "left" to dissipate.