Impact of unlimited KERS on chassis design?

[timbo]

I completely agree within the projected new turbo regulations, it is another potential method for harvesting energy.
It does not compete with energy recovered from braking using a AWKERS system though.

The problem with recovering energy from braking is that for it to play any significant role in overall vehicle efficiency, you do need much more effective storage/transfer system.
Even wires between battery and M/G unit become a problem if we talk about power in order of hundred+ KW.

[WhiteBlue]

The big problem of HERS is the need to use a gas to gas or a gas to refrigerant recuperator to extract the heat from the exhaust.

http://en.wikipedia.org/wiki/Recuperator

Those units are heavy and bulky at the same time. They are often used for stationary processes where weight and space does not play a big role to create a secondary Rankine cycle.

http://www.proepowersystems.com/proe90.htm

Chrysler invented a unique recuperator that consisted of a rotary drum constructed from corrugated metal (similar in appearance to corrugated cardboard). This drum was continuously rotated by reduction gears driven by the turbine. The hot exhaust gasses were directed through a portion of the device, which would then rotate to a section that conducted the induction air, where this intake air was heated.

To shrink both weight and space requirements for a sensitive application like F1 will be difficult. The heat exchangers will be different to the radiators that F1 uses for rejected heat now. They will have to have much higher heat resistance.

[timbo]

The power consumption of the TC was covered earier, when I grossy underestimated the same. But even if the contraption steals as much as 100 kW, there's still plenty of thermal energy to recover, perhaps as much as 400 - 500 kW is lost.

Do you know any efficient/lightweight way to recover that energy?
I don't.
Actually, generator powered by turbo to feed all auxiliarities might be one of them.
AFAIK on later WWII aircrafts folks used turbos to add power to main engines, but that required heavy and lossy transmission.

[autogyro]

Radiator, now there is a term. Radiate heat to the outside atmosphere.
Not a very efficient concept for the new energy consciouse F1 is it.

[timbo]

Radiator, now there is a term. Radiate heat to the outside atmosphere.
Not a very efficient concept for the new energy consciouse F1 is it.

You would think of adiabatic engines.
Here's interesting pdf
http://www.sof.or.jp/en/activities/pdf/06_07.pdf

[xpensive]

The power consumption of the TC was covered earier, when I grossy underestimated the same. But even if the contraption steals as much as 100 kW, there's still plenty of thermal energy to recover, perhaps as much as 400 - 500 kW is lost.

Do you know any efficient/lightweight way to recover that energy?
I don't.
Actually, generator powered by turbo to feed all auxiliarities might be one of them.
AFAIK on later WWII aircrafts folks used turbos to add power to main engines, but that required heavy and lossy transmission.

In the process-related reality where I find my living, we would use those kind of flows and temperatures to boil water and feed a turbine, which in turn has only a 35% efficiency, but that's the goddamn Moliere's fault.

Whats BMW's solution WB?

[WhiteBlue]

Here's interesting pdf
http://www.sof.or.jp/en/activities/pdf/06_07.pdf

Its good for ships where weight and space is no issue.

[WhiteBlue]

Whats BMW's solution WB?

Their turbosteamer design used two secondary Rankine cycles with three recuperator stages.



Rankine cycle is a heat engine with vapor power cycle. The common working fluid is water. The cycle consists of four processes:
1 to 2: Isentropic expansion (Steam turbine)
2 to 3: Isobaric heat rejection (Condenser)
3 to 4: Isentropic compression (Pump)
4 to 1: Isobaric heat supply (Boiler/Recuperator)



They were planing to feed the recovered work from two steam turbines directly to the crankshaft of the engine.



This picture shows that they are actually using three stages of recuperation at 700 °C, 300 °C, and 70 °C with very high, high and low pressure.

Positions 3 and 4 are both condensers which shows that both circuits were using an evaporating fluid. The high pressure system may have used water and the low pressure system a refrigerant.



Here we see that the first recuperation unit had an exhaust temperature close 700 °C and the second unit 300 and 70 °C in separate circuits. The recuperation units are very bulky and probably very heavy.

So really the secret to HERS with an ICE would be a recuperator design that is highly efficient, low weight and low space. The turbo expander and the condenser would not be the problems. At the present state of the art you would probably need the weight and space of an entire engine for recuperation which makes it prohibitive.

[timbo]

Here's interesting pdf
http://www.sof.or.jp/en/activities/pdf/06_07.pdf

Its good for ships where weight and space is no issue.

Not really.
Increasing working temperature of engine is a viable way of increasing its efficiency.
You can already see this in F1, just look at shielding over Mercedes engines.
Coupling it with turbo-powered generator to operate engine auxes (getting rid of most hydraulics) should make very effective engines.

[xpensive]

Interesting indeed WB, any xplanation on how position 7 and 8 work, turbines or what?

[WhiteBlue]

Interesting indeed WB, any xplanation on how position 7 and 8 work, turbines or what?

They are most probably simple turbines like the exhaust side of a turbo charger. Nothing special really. Keep in mind that the temperature picture would look different for a turbo charged engine because the TC would take pressure and temp out of the exhaust gas.

BTW, I have finally verified from Racecar engineering the claims that average F1 tracks use above 50% full throttle.
Gilles Villeneuve : 57%
Silverstone: 70%
Monaco: 52%
Barcelona 58%
Shanghai 52%
Malaysia 65%
Australia 69%
Bahrain 65%
Average 61%

I also found a fuel consumption of 2.37 kg/5km and a time loss per 5kg of fuel of 0.07s/lap. I would accept a base fuel consumption of 150 kg for Bahrain in 2010 and for an average race.

[xpensive]

Intersting values you got there WB, but percentage spent between 16 and 18 krpm would be even more interesting?

However, I will take the liberty to simplify 2.37 kg/5 km to 0.6 liters/km, let me dwell on this and return later.

[timbo]

Intersting values you got there WB, but percentage spent between 16 and 18 krpm would be even more interesting?

I believe, you would get pretty close figures, +/-10%.
I have rpm traces from my laps in rFactor, which are reasonably good estimation, and there most of the time I'm on full throttle, and some times even at partial throttle, the revs are at 15-16k and higher.
They really go lower than that at slow speed 1st-2nd gear corners only.

[747heavy]

maybe some of you like to have a look here:

http://www.f1network.net/main/s107/st155787.htm

There is some interesting informations from Brembo/Williams in regards of the power absorbt by the brakes for the different tracks.
It may help with some KERS considerations on AWKERS.

example for Bahrain:
http://v4.sportnetwork.net/williamsf1/2 ... ahrain.pdf

[riff_raff]

A PM motor turbo/electric HERS operating at 100,000+ rpm would be very compact and lightweight compared to a similar power PM motor wheel driven KERS operating at a few thousand RPM. The amount of power transfer done by a modern high-speed turbocharger turbine/compressor system is actually quite impressive.