TERS : Thermal Energy Recovery System

[henry]

KERS recovery is from how much energy you can absorb by the rear axle. The tires in the back are going to be significantly wider, hence more KERS torque can be used to slow the rear wheels. More energy = more recovery, the thing that will be a challenge is designing batteries that can charge that faster than the ones they have now.

The wider tyres and higher downforce will not increase the peak torque. There is already more than enough grip at the start of a high speed stop to saturate the 120kw KERS. where it will come in to play is that the full torque will be available down to lower speeds, so increasing the length of time the full 120kw can be recovered, and more recovery at lower power points as well.

Some numbers to support that.

120 kW at 100m/s is 1200N Tractive effort. 3G on 760 kg needs 22,400N. I'm assuming a 4G peak deceleration with 1G coming from drag. So the KERS can only provide 5% of the Tractive effort.

At the other end with 400kg on the rear axle ( no aero) and an effective mu of 2.0 that's 8000 N of Tractive effort which would mean 120kw recovery at 15m/s (54kph) . That's a number that surprises me and I suspect that the gearing at low speeds will make a big difference reducing the torque, hence TE, and probably make that lower speed quite a bit higher. With 2016 tyre width 25% less that raises the equivalent low speed to 18.75m/s. (67 kph).

I'm pretty shaky on the MGU-K power/torque characteristics or what effect the 200Nm limit and gear ratios will have but I think the gist of my argument is still OK.

[henry]

Just to round this off. The maximum thickness permitted for the brake disks is increased from 28 to 32 mm for 2017.

So the issue of brake wear has been considered and acted on.

So back to square one. Expect less energy to the ES from the MGU-K during braking, even given the cars will be 4% heavier, or so.

[gruntguru]

KERS recovery is from how much energy you can absorb by the rear axle. The tires in the back are going to be significantly wider, hence more KERS torque can be used to slow the rear wheels. More energy = more recovery, the thing that will be a challenge is designing batteries that can charge that faster than the ones they have now.

I'm pretty shaky on the MGU-K power/torque characteristics or what effect the 200Nm limit and gear ratios will have but I think the gist of my argument is still OK.

I think it is safe to assume the MGUK has sufficient torque rating to allow the full 120 kW over the entire useable rpm range (say 8,000 to 15,000).

Regarding wider tires allowing extra power at the rear wheels - the difference will be negligible ( <<1% IMO)

[godlameroso]

How is the MGU-H cooled? Does it need cooling/heating to be efficient? If it's liquid cooled, there could be some interesting things you could do. Although it would probably be against the regulations because 5.2.4 The MGU-H must be solely mechanically linked to the pressure charging system. This mechanical link must be of fixed speed ratio to the exhaust turbine and may be clutched.

Just thinking out loud I guess.

[henry]

KERS recovery is from how much energy you can absorb by the rear axle. The tires in the back are going to be significantly wider, hence more KERS torque can be used to slow the rear wheels. More energy = more recovery, the thing that will be a challenge is designing batteries that can charge that faster than the ones they have now.

I'm pretty shaky on the MGU-K power/torque characteristics or what effect the 200Nm limit and gear ratios will have but I think the gist of my argument is still OK.

I think it is safe to assume the MGUK has sufficient torque rating to allow the full 120 kW over the entire useable rpm range (say 8,000 to 15,000).

Regarding wider tires allowing extra power at the rear wheels - the difference will be negligible ( <<1% IMO)

Thanks. I revisited my understanding and I think 200 Nm @ 5700 rpm is 120 kW

I think the wider tyres will actually reduce peak power exerted on the track, if only by a small. Higher inertia and increased hysteresis losses have an influence.

If, as I posited, the traction limited speed falls from say 160kph to 120 that will mean WOT will start about 25 m and 0.6 seconds earlier. And if braking starts later that places more emphasis on MGU-H output to reduce ES drain on the straights and replace the lost kinetic energy.

[Tommy Cookers]

@ godl
the MGU-H will be about 99% efficient
maybe at worst 98% (in qually or in the race when at highest torque accelerating the compressor)
so its heat loss/cooling capacity will be about 2 kW
no doubt liquid cooled

roughly similar will be the efficiency of the electronic drive for MGU-H motoring and generating

eg the rules (for the MGU-K) assume 95% efficiency or better from DC energy ex-ES to mechanical energy after delivery into the crankshaft

[godlameroso]

I've been thinking, there's more than one way to generate electricity. Spinning a set of windings around a magnetic field is only one way to do it, there are also thermoelectric devices https://www.youtube.com/watch?v=2b2wAB1uTLI

If you consider the possibility that some teams are maybe combining different electrical generating technologies into the mgu-h then the power levels I believe they're generating seem a bit more reasonable.

Again just thinking, I mean it's not like they're using a plutonium-238 TEG in conjunction with the field windings.

[Tommy Cookers]

TE can apparently be recovered by the catalytic dissociation of some fuels eg Methanol (into Carbon Monoxide and Hydrogen) using heat from coolant and exhaust.
The engine runs on a mix of these gases and (other) Methanol, on combustion the gases give more heat than their source Methanol contained.
The efficiency gain is about 10-15% at full power, and about 30% at low partial power (power reduction is possible without throttling, controlling the gas fuelling allowing super-lean running instead).

bumped from 2012 (was looking for posts on thermoelectrics)

[Tommy Cookers]

Heat recovery overview via a TurboSteamer, presentation from BMW in 2009.

A 15% increase in engine performance could be demonstrated with a Dual-Loop-Rankine and 10% increase in engine performance could result from a Single-Loop-Rankine.

http://www1.eere.energy.gov/vehiclesand ... bieglo.pdf
http://www.lolwtf.com.au/F1/ters_8.png

another bumped post

[godlameroso]

How about using resonant frequencies to boost the voltage output of the MGU-H ala Tesla coil? It's theoretically possible, would it be practically achievable is another matter entirely.

[gruntguru]

How about using resonant frequencies to boost the voltage output of the MGU-H ala Tesla coil? It's theoretically possible, would it be practically achievable is another matter entirely.

To achieve what? You could use a transformer if you wanted higher voltage. Or use a higher voltage MGU.

[godlameroso]

How about using resonant frequencies to boost the voltage output of the MGU-H ala Tesla coil? It's theoretically possible, would it be practically achievable is another matter entirely.

To achieve what? You could use a transformer if you wanted higher voltage. Or use a higher voltage MGU.

Increase efficiency, having thought about it you can boost voltage, but you're still limited to 1KV. Then the battery probably operates at 600v max, and you'll lose efficiency converting the voltage so this probably would not work.

[Juzh]

Someone school me on this topic please:

is it not true (or was) teams bypass the turbine entirely in qualifying by opening the wastegates and running turbo solely off of mgu-h, thus reducing pack pressure and gaining a bit of power? There was talk about this in past numerous times and we even had newey talking on the issue sometime before the season started about sound perhaps being louder in qualifying when people run open wastegates.

Or am I just not getting it

[Frank_]

thats my understanding too, electric supercharger and less pumping losses

[godlameroso]

Of course it's possible but then you severely reduce the amount of energy you can harvest from the H, if you have a substantial ES, you could do it for a few laps, or use it strategically more times per lap than your competition. Also I was told the inverter/control electronics is involved 100% in the energy transfer, meaning the MGU-H and MGU-K always recieve and send power via the CE/inverter first then the CE decides whether to send energy to the ES or to shuffle it between the two electric machines based on a variety of factors.