Power unit power speculation

[pgfpro]

Mercedes said they could both run the MGU-K at 120 kW and also charge the battery with WOT and at Vmax.
Is it wise to do so? I think that depends on the track.

Do you have a link???

[hurril]

Mercedes said they could both run the MGU-K at 120 kW and also charge the battery with WOT and at Vmax.
Is it wise to do so? I think that depends on the track.

Do you have a source for this because I would like to read this. Very cool if true!

[pgfpro]

People think that the max the MGU-H can deliver to the K in self sustaining mode is ~100hp/70kw, I think it's almost double that. There's potentially ~400kw of heat energy in the exhaust that can be harvested when you account for the power that's absorbed by the crank, and is lost through inertia and friction, and the power lost running the turbine off exhaust gases. So, 150kw while extremely difficult is not impossible.

I'm at work right now but I think this thread is a very great read that gg has some excellent information.
http://www.f1technical.net/forum/viewto ... EP#p550966" target="_blank

As to compressor and turbine work, I have done some rough calculations for two scenarios.

1. MAP = 3.5, EBP = 3.0 Power(compressor) = 80 kW. Pt = 125 kW. Psurplus = 45 kW
2. MAP = 4.5, EBP = 4.0 Pc = 130 kW. Pt = 177 kW. Ps = 47 kW

The upshot is clearly line ball. Not much change in pumping losses, BMEP of the recip' machine nor surplus power from the turbo machinery. OTOH reducing the DP (by increasing EBP) to the following scenario might be useful.

3. MAP = 3.5, EBP = 3.5 Pc = 80 kW. Pt = 140 kW. Psurplus = 60 kW That's a 15 kW improvement. The PMEP will increase by 0.5 Bar so BMEP reduces to 37.5 and crankshaft work suffers by about 7.5 kW

All the above calculations are based on steady state flow, any harvesting of blowdown energy will obviously improve the numbers.

[hurril]

Where would we wind up if we took a stab at some blowdown numbers?

[Tommy Cookers]

Where would we wind up if we took a stab at some blowdown numbers?

25 KW is my stab, assuming that the expansion in-cylinder isn't sacrificed to benefit turbine power

the NACA showed around 1943 the benefits of exhaust pressure raised above induction pressure

[Tommy Cookers]

....... There's potentially ~400kw of heat energy in the exhaust that can be harvested ......

if there's 400 kW worth of energy in the exhaust about 140 kW of that is sensible heat
sensible heat is the part of the energy that cannot be accessed by an expander ie the turbine
(sensible heat from exhaust and coolant was the basis of the BMW Turbosteamer - coolant heat is all sensible heat)

EDITED - as above was WRONG - Wright said that most of the exhaust energy is NONUSEABLE SENSIBLE ENERGY

imo that's why the world makes widespread use of combined cycle power generation
this exhausts much energy from (gas) turbines as nonuseable, then uses it to raise steam, this then is useable by a (steam) turbine

[wuzak]

Mercedes said they could both run the MGU-K at 120 kW and also charge the battery with WOT and at Vmax.
Is it wise to do so? I think that depends on the track.

That doesn't necessarily mean they are putting 120kW from the MGUH to the MGUK and storing excess power. It could simply mean that the battery is powering the MGUK exclusively and the MGUH is topping up the battery as it goes.

Not sure it is the optimum strategy.

[gruntguru]

....... There's potentially ~400kw of heat energy in the exhaust that can be harvested ......

if there's 400 kW worth of energy in the exhaust about 140 kW of that is sensible heat
sensible heat is the part of the energy that cannot be accessed by an expander ie the turbine
(sensible heat from exhaust and coolant was the basis of the BMW Turbosteamer - coolant heat is all sensible heat)

Actually sensible heat is where the turbine work does come from. If you look at the Wright Turbo Cyclone exhaust energy balance (bottom image) you can see the turbine is recovering 160 hp (about 6%) of the total sensible heat in the exhaust (about 2.8% of the total fuel energy). "NONUSABLE SENSIBLE ENERGY" (65.5%) represents heat energy that could not be recovered in the WTC due to such things as:
1. Heat loss
2. 2nd law limitations. (A turbine with 100% isentropic efficiency still converts only a fraction of the heat to work)
3. Limitations of using a "blowdown only" turbine. More work could be extracted with a mixed (blowdown + pressure) turbine arrangement.





The overall thermal efficiencies of the WTC are interesting. 29.7% basic (uncompounded) plus 2.8% from compounding for a total of 32.7%. (extra 0.2% comes from rounding)

[Tommy Cookers]

the WTC seems to gain from exhaust recovery 18% free power at takeoff
if designed for slow (endurance) cruise without any need to takeoff it could have had 11:1 CR and 35% efficiency without turbines

regarding the point I was trying to make about the turbine recovery in F1 .... simply ....
the existence of combined cycle (gas turbine+steam turbine) plant proves that much or most of our exhaust energy is unuseable by our turbine

[dren]

Just a thought, I wonder how much power could be had at the turbine if the exhaust was reheated and recirculated? The regulations don't really allow for it; just a thought.

Here at work, after a good sum of the pressure is taken out of the steam from our turbines, it is reheated and reintroduced to several stages.

[gruntguru]

regarding the point I was trying to make about the turbine recovery in F1 .... simply ....
the existence of combined cycle (gas turbine+steam turbine) plant proves that much or most of our exhaust energy is unuseable by our turbine

Agreed.
At 3.5 bar BP and 1000 *C egt the turbine will reduce the gas temperature by 307 *C to 693 *C and generate 175 kW.
At 5.0 bar BP and 1000 *C egt the turbine will reduce the gas temperature by 375 *C to 625 *C and generate 215 kW.
(assumes ideal gas and 80% turbine efficiency)

Clearly there is a lot of sensible heat remaining. A Rankine cycle engine using the 693* C exhaust after the turbine to generate steam and cooling that exhaust to 100*C will extract nearly twice as much sensible heat as the turbine. Unfortunately the efficiency of this Rankine engine would be quite low and the useful power would be less than the turbine but still a useful addition. In very round figures the turbine would produce 175 kW and the Rankine plant 75 kW (assumes 25% Rankine efficiency)

[honda_fun]

NHK（Japan Broadcasting Corporation） broadcasted on March 24 about Honda F1-PU


On the dyno test, at HRD Sukura,
Ｗhen the number of the revs of their engine was 11552rpm, the revs of the MGU-H was 90168rpm.
and the boost pressure was 3.06bar. The exhaust gas temperature was 935degC.

At the upper left meter indicate the engine rev. the upper right meter indicate the engine torque.
Look at the torque of the engine, it was 451Nm(45.98kgf・m) when the engine rev was 11295rpm.
From calculation formula, Honda's ICE power is 46(kgf・m)×11295/716＝726ps
I think that the ICE+MGU-K peakpower become 886HP when I assume the MGU-K 160ps.

[godlameroso]

That's actually not too far off, they probably gained in the area of 35 hp since then.

[dren]

Until recently, I don't think they were harvesting enough to see full MGUK output during the race.

[Juzh]

Until recently, I don't think they were harvesting enough to see full MGUK output during the race.

Until now still no one does.