Alternative engine formula idea

[trinidefender]

Here is a simple solution that I have thought through and believe would have provided the optimal solution when it came to a combination of weight, power and efficiency.

Instead of doing all this fancy MGU-H generating electricity stuff they could keep the MGU-K and replace the MGU-H with gearing the turbocharger to the crankshaft. I.e. The original turbo compounding idea used in the Wright and a few other engines. The MGU-K can still be powered by a battery but that battery is recharged purely by regenerative braking as it was done previously.

Reasons:
1. You get rid of the inefficiencies associated with converting a mechanical force into electricity so immediately you have an efficiency bonus.
2. Because there is less energy to store as the MGU-K is only powered by electricity from the battery which gets electricity from braking, the battery itself can be made smaller and lighter....and cheaper (ya know, that whole thing that they've been blabbing on about for a while now).
3. It focuses much more on conventional car technology which is far more applicable to the current road car industry.
4. No MGU-H and a less complicated electrical deployment system means its cheaper and lighter (more stuff they've been blabbing on about). Sure you gain some of the weight back through the gearing of the turbocharger to the crankshaft but that is tried and tested technology so wouldn't be expensive to develop and manufacture and wouldn't weigh much.
5. The conditions that F1 cars mostly run (high load and high rpm) is perfect for turbo-compounding. When in the general high power rev range at high load I.e. most of the time, the turbine will recovering exhaust energy and will be putting it right back into the crankshaft.
6. 8 gears is enough that at any part on almost any circuit the car will be in its rev range therefore the compressor will be spinning at a sufficient rpm regardless of throttle load without having MGU-H assistance. This means that lag is pretty much a non-issue. Before somebody says "but that reduces efficiency just remember at present we have to take electricity from a battery (efficiency loss) and turn it back into mechanical energy (more efficiency loss) just to spin the turbocharger. I didn't work out the numbers but I wouldn't be surprised if in a total lap using electrics is less efficient to keep the turbocharger spinning for the low load sections when there isn't much exhaust flow.
7. These new engines have probably been a headache to develop as most of it hasn't been tried before. I'm sure quite a lot of the costs have been pure R&D which were then passed onto the teams (more money blabbing talk)

And lastly the best reason of all No. 8. If it ain't broke, don't fix it.

Thanks for reading and end rant.

Thoughts?

[Tommy Cookers]

the Wright was not compounded in the way that you (and some popular textbooks of Indian origin) suggest
it had an independent 2 ratio mechanical drive to the supercharger ie the supercharger was not coupled to the 3 turbines

and cars at F1 type circuits never successfully used a mechanically driven centrifugal supercharger
because the delivery is rather proportional to the square of the rpm, so is mismatched to the engine's needs
the V16 BRM was attempting to go for a VG inlet supercharger development to alleviate 'response' problems (matching really)
(F1 etc often used Roots type superchargers, potential matching problems alleviated by their poor efficiency with rpm rise)

the current F1 rules (fuel rate/rpm) are more demanding of matching than conventional rules were
some form of intake throttling seems necessary and possible

only when the turbocharger was made (eg the Porsche 917) to have a suitable match did it change the world

btw - all those (WW2 US) so-called turbocharged aircraft engines had single ratio mechanically driven centrifugal superchargers
the turbo was a second stage that had an effect only with altitude

[wuzak]

btw - all those (WW2 US) so-called turbocharged aircraft engines had single ratio mechanically driven centrifugal superchargers
the turbo was a second stage that had an effect only with altitude

In fact, the turbo only compensated for altitude.

In theory the engine would have thought it was always at sea level.

[trinidefender]

Ok a picture shall explain better. It is similar to how the Nomad 2 is set up in this picture however with a centrifugal compressor instead.


With 8 gears these engines have a very narrow operating range anyway. To add to that the regulation enforced fuel flow limits is a gradual scale increasing with rpm (up to 10,500). The increasing fuel flow with an increase in rpm goes some way to the increasing airflow as supercharger rpm increase. This should help match the fuel flow and airflow requirements that prohibited their use before.

[NL_Fer]

But won't the air pressure at low rpm, be mediocre? Making the engine useless at low/mid rpm?

[trinidefender]

But won't the air pressure at low rpm, be mediocre? Making the engine useless at low/mid rpm?

Define low rpm. Remember there are 8 gears this season, this reduces the required gear ratio change per gear helping to keep the rpm up. Please tell me how often you see the rpm drop one these current engines to anything you would consider low.

All they would have to do is modify the current regulations to make maximum fuel flow occur around 13000 rpm and we will have a similar rev range as we do now.

Lastly please tell me the last time before these engines had anything but top end power? The last time was the turbocharged era. All the naturally aspirated engines were gutless at low to medium rpm's. All my concept will do is give a more naturally aspirated looking power curve.

I am convinced that the current engines aren't particularly as powerful as people make them out to be, surely not above 900hp while in self sustaining mode, however where they make up for it is in their broad power curve. They essentially have more power under the curve.

[Tommy Cookers]

......With 8 gears these engines have a very narrow operating range anyway. To add to that the regulation enforced fuel flow limits is a gradual scale increasing with rpm (up to 10,500). The increasing fuel flow with an increase in rpm goes some way to the increasing airflow as supercharger rpm increase. This should help match the fuel flow and airflow requirements that prohibited their use before.

the gear ratios are wider than in the N/A 7 speed boxes (these ratios and the final drive ratio were varied for each event)
because the current scheme has 8 gearbox ratios fixed forever and 1 final drive ratio fixed forever (ie for all events)
the current ratios are no closer than would conventionally be in 6 speed box
the cars don't use all 8 over the weekend

as I see it (with the current fuel regime) .....
a season-typical running point might be 11250 rpm ie 7% over the 'fuel threshold' 10500 rpm
7% rpm rise in (turbine) rpm creates 15% more supercharger pressure, so about 10% absolute pressure, massflow and AFR/leaning)
alternatively, maintaining the optimal AFR requires lowering the supercharge pressure by 5% (at 11250 rpm)
in principle you must accept sub-optimal AFR most of the time or reduce this by regulating inlet pressure by throttling
actually as things get much worse (eg if needing to maintain eg 11700 or suffer upshift to 10400) throttling is unavoidable
throttling of course (used eg even at takeoff in millions of aircraft engines) reduces the power taken by the supercharger

so with regulation by throttle mapping (backed up by knock sensing) the current fuel regime forces a tolerable power curve
(if the 'flat' fuel regime was waived we would need no regulation, but without it driveability would as in the past be intolerable)

regardless of fuel regime ....
there will be some rpm (presently 10500) below which the engine needs full boost, but the supercharger simply won't give it
so the power curve will still be inferior (to that current)

and mgu-k motor action will be even more valuable
we should increase the mgu-k power limit, for more recovery from hard braking

[pgfpro]

IMO I would think they would have some turbo lag when coming out of a corner after off throttle even at a higher rpm? The higher rpm would help some but not give them what they have now. Anti-lag would help and give back some cool sound for the spectators. but wasting fuel is not the direction F1 is going.

[trinidefender]

IMO I would think they would have some turbo lag when coming out of a corner after off throttle even at a higher rpm? The higher rpm would help some but not give them what they have now. Anti-lag would help and give back some cool sound for the spectators. but wasting fuel is not the direction F1 is going.

How would fuel be wasted? Turbo compounding is taking the same energy that the MGU-H would usually recover and then turn into electricity and instead putting the force directly into the crankshaft. With the reduced conversion efficiency loss I think lower BSFC can be achieved than present.

Secondly why would there be any lag. It would respond like any centrifugally supercharged car.

[pgfpro]

IMO I would think they would have some turbo lag when coming out of a corner after off throttle even at a higher rpm? The higher rpm would help some but not give them what they have now. Anti-lag would help and give back some cool sound for the spectators. but wasting fuel is not the direction F1 is going.

How would fuel be wasted? Turbo compounding is taking the same energy that the MGU-H would usually recover and then turn into electricity and instead putting the force directly into the crankshaft. With the reduced conversion efficiency loss I think lower BSFC can be achieved than present.

IMO I think the fuel amount used during anti-lag would be more then what the MGUH motor electricity uses (that came from braking and some from MGUH generator mode from fuel) to spool up the turbo compressor wheel?

[trinidefender]

IMO I would think they would have some turbo lag when coming out of a corner after off throttle even at a higher rpm? The higher rpm would help some but not give them what they have now. Anti-lag would help and give back some cool sound for the spectators. but wasting fuel is not the direction F1 is going.

How would fuel be wasted? Turbo compounding is taking the same energy that the MGU-H would usually recover and then turn into electricity and instead putting the force directly into the crankshaft. With the reduced conversion efficiency loss I think lower BSFC can be achieved than present.

IMO I think the fuel amount used during anti-lag would be more then what the MGUH motor electricity uses (that came from braking and some from MGUH generator mode from fuel) to spool up the turbo compressor wheel?

What anti-lag? I think you are missing how this is set up. There is the turbocharger as normal with a compressor and turbine wheels. Then on the shaft there is gearing which means the turbocharger is always spinning at a fixed ratio compared to the crankshaft regardless of the throttle load.

There is no free wheeling unit here. Look at Nomad 2 in the picture I posted above. The hydraulic clutch may or may not be included depending on preference of the engineer but for simplicity sake on this model let us assume there is no clutch there and just purely is geared to the crank.

[NL_Fer]

http://youtu.be/enO9Uvhndfg

Dropping to 4500-7000 in every corner. And i remember the V8 going down to 7000-8000 in the hairpins, that was 40% of the rev limit at 18000 rpm.

Besides, it will again be a formula one, dedicated setup. Where a conventional twin turbo and kers will be closere to any road and electric car. We need simpler engines, but technicly attractive for car manuacturers to develop.

[pgfpro]

There is no free wheeling unit here. Look at Nomad 2 in the picture I posted above. The hydraulic clutch may or may not be included depending on preference of the engineer but for simplicity sake on this model let us assume there is no clutch there and just purely is geared to the crank.

So your saying that it will be a centrifugal super charger with a turbine attach to it? If so it will have parasitic drag that will use crankshaft energy to turn the compressor and turbine wheel, until the turbine has enough load to overcome this. Just before going into a corner say at 10500 rpm the engine at boost will be flowing around 54 lbs/min of air as soon as you lift (braking zone) the engine will go into vacuum and now be flowing around 5 lbs/min of air, the car comes out of the corner and goes WOT now the engine has to increase air flow to back to 54 lbs/min of air, since its a super charger it will happen faster then a turbo charger but there will still be a delay. At this point its using crankshaft power until the turbine can load up and and deliver through the compressor 54 lbs/min.

If there isn't any viscous coupling or some type of clutch the turbine wheel will always be spinning with the compressor wheel. Won't this make drag at low exhaust flow? Even though the turbine wheel is cup at the inducer for the direction of flow "turbine inlet to outlet" it still will create drag. Now in IMO I think todays F1 engine are opening the waste gate when under braking and having the MGUH in motor mode spinning the turbos compressor and turbine wheel for instant boost and power for coming out of the corner with the gate open it helps with the drag at the turbine wheel. In your case this could probably help with your design also??? But I don't know its all just mental masturbation on my part;)

[Brian Coat]

Of course we are just participating a thought experiment here. But why not, eh?

If concerned about low rpm torque you could allow teams to decouple the blower from the turbine and drive it by a small variable or stepped transmission (via a clutch if desired). I know this has all been done before but there's a reason for that.

The ability to harvest energy with this mechanically coupled turbine is constrained by the demand level of +ve torque from the driver. Unlike the MGU-H you cannot harvest by "exhaust blowing".

The ES could be smaller/lighter? EDIT: Oops, like wot OP already said!

[gruntguru]

Perhaps allow variable geometry for the turbine and compressor housings to help widen the useable rpm.