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Old 22nd July 2015, 09:18   #46
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Re: 2015 British F1 GP Race Thread

Here is some interesting info on the F1 PU workings for those who are into it.
The paper is on an aspect of control engineering, for a current F1 engine. Professor Limebeer is supposed to be acting as consultant for Ferrari. Of course, there is an Indian connection in Professor Anil V. Rao, who has won numerous teaching awards throughout his career.
This paper comes from the IEEE Journal, which points to the critical need to assess these engines, as a complete system.
The bang-Bang type of controls states are as expected in a typical race car controls. However, the interplay between the PU components while on partial throttle on a medium speed corner is much more complex. If you see the graphs, it becomes obvious.

IEEE-CSM-14-0038.pdf

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Energy usage in the 2014 energy recovery systems under racing conditions.
The cyan line is the normalized vehicle speed; the red line is the normalized stored energy; the green line is the normalized fuel usage; the blue line is the normalized energy transfer from the motor-generator-unit-kinetic (MGU-K) to the energy store (ES); and the magenta line is the normalized energy transfer from the ES to the MGU-K.

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Power usage in the 2014 energy recovery systems under racing conditions.
The blue line is the normalized mechanical power delivered to the rear wheels; the green line is normalized fuel mass flow rate; the red line is the normalized motor-generator unit-kinetic (MGU-K) power.

Quote:
Figure 13 shows the optimal utilization of the vehicle’s energy resources. The normalized speed (speed/100) is shown (in cyan) as a convenient reference. The first point to note (shown in green) is that the car utilizes fully its fuel quota of 2.273 kg (Spa is a 44-lap race).
The MGU-K (shown in blue) generates its maximum quota of 2 MJ per lap, while the maximum quota of 4 MJ that can be transferred from the ES to the MGU-K (shown in magenta) is not fully exploited. This asymmetry in the MGU-K’s motoring and generating quotas was introduced to force the car to generate energy with the MGU-H.
The state of charge of the energy storage (shown in red) is constrained to be the same at the start and end of the lap so that the optimal lap can, in principle, be repeated if tire degradation and fuel usage are ignored. Interestingly, the energy storage capability of the ES is only partially utilized. If the plots are examined in detail, it is possible to see the MGU-K driving the car on the fast sections of the track, while it generates under braking on entry into most of the corners.
It is not possible to identify easily the contributions being made by the MGU-H, but they will be reflected in discrepancies between the ES’s state of charge and MGU-K usage. Figure 14 shows the power transfers occurring within the powertrain.
The green trace shows the fuel usage that operates in a bang-bang manner between its maximum and minimum values. Bang-bang type control behavior is to be expected because the optimal control problem’s performance index seeks to minimize the elapsed time and is not a function of the controls. In addition, the controls enter the system dynamics in a linear fashion. If the performance index and the system dynamics are linear in the controls, bang-bang control strategies are likely to result. The bang-bang principle follows immediately from the PMP [35, p. 246–247]. The red trace shows the bang-bang-type operation of the MGU-K, which operates as a generator on the entry to corners, and as a motor on the exit from corners and on fast sections of the track.
The car behaviour at individual corners can be identified by referring to the distance markers for the Spa circuit given in Table 1. The blue trace, which is the power delivered to the rear wheels, is also bang-bang in character, with a total power delivery of 560 kW possible.
Due to the energy efficiencies associated with its use, the waste gate is closed throughout an optimal lap and so is not shown. Under racing conditions, the waste gate is predominantly a safety device that can be used to prevent compressor over speeding under fault conditions.
During heavy braking, the mechanical power delivered to the rear wheels is negative, the MGU-K will be generating, and the fuel flow rate will be cut to zero. As shown in Figure 13, this strategy allows the ES to be recharged. During high-speed driving, such as the section between 400 and 2000 m, both the engine and the MGU-K are used at full capacity, which drains the ES. On the section between 2000 and 2200 m, the MGU-K is unused and the ES is recharged from the MGU-H.

Last edited by jfxavier : 22nd July 2015 at 09:20.
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Old 23rd July 2015, 05:41   #47
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Re: 2015 British F1 GP Race Thread

And for the lazy ones like me....
A video of a presentation by Prof. David Limebeer, University of Oxford.

In this presentation, the use of orthogonal collocation methods in the solution of optimal control problems relating to Formula One racing is analysed.

http://in.mathworks.com/videos/optim...ems-96763.html
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Old 25th July 2015, 19:58   #48
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Re: 2015 British F1 GP Race Thread

Less than a day for the Hungarian F1 GP with qualifying over and no sign of the race thread.
Did I miss it some where or its not going to be up for this GP?
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