j.yank wrote: ↑06 Aug 2017, 18:38
henry wrote: ↑05 Aug 2017, 17:47
godlameroso wrote: ↑05 Aug 2017, 16:08
Don't forget that the MGU-H is still capable of harvesting even with the wastegates open, with "blowdown" exhaust, like in the Wright TC plane did all those years ago. I remember the Renault engine does it, or did at the beginning of the season.
I'm not sure that's the case. I think it takes around 80 kw to drive the compressor and I think, although I can't remember why, that blowdown is only about 40 kw. Hence my suggestion of 40 kw drain on the ES. Maybe blowdown is more than 40 kw. Maybe a key difference between the power units is the ratio of blowdown to heat recovery. I don't know and I don't know how an external observer would find out.
Edit: I remember where the 40kw to drive the turbo comes from. It's in prof Limebeer's paper on optimal control from 2014. Can't find the paper on line but here's a presentation.
http://www.matlabexpo.com/uk/2014/proce ... ystems.pdf Some grains of salt needed since he puts ICE output at 440 kw and MGU-H at 20.
The paper can be found here:
http://vdol.mae.ufl.edu/JournalPublicat ... covery.pdf
Look at pages 28-30, especially fig. 14 and 16 - they explain the differences between qualification and race lap. The main difference is that the waste gate is almost all the time closed (harvesting mode) in race lap but fully open (engine boosting mode) in qualification lap. In both cases it is clear that the main deficiencies of Honda are coming from the ICE - lack of pre-chamber ignition and worst torque curve - both of them lead to either lack of power in qualification lap or to more fuel in race distance.
Thanks. I have a copy so I'm familiar with the difference it suggests for Barcelona. I think the key thing about the paper is the methodology, the numbers are, I think, disguised, and certainly a long way off current.
My point was that, at Spa particularly, if you can reduce the drain on the ES by driving the compressor with blowdown you can deploy the wastegate for longer. It appears that Mercedes have a deployment advantage over the field in qualifying. I'm suggesting that difference in turbine implantation is an area that would offer an explanation for being better in qualifying but not so in the race.
It's a theory, that if you can make the same power with the turbo overall the higher the blowdown proportion the better.
Given Honda's overall deficiency it's an inevitable conclusion that they don't extract enough energy from the fuel. I think they are closer in qualifying where they can burn more fuel per lap. It will be interesting to see what their new turbo does for them.
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus