Kiril Varbanov wrote:I have been very curious about the total torques available from the new PUs. The unofficial response I've got from Mercedes was "lot more than 450 Nm at low revs, but close to your ballpark guestimate of 500 Nm at high RPMs."
Today I see numbers cited: 610Nm @ 5,000rpm and around 530Nm @ 10,500rpm (ICE + MGU-K).
Thanks Kiril, however I feel the need for putting these numbers into context. Numbers come from the latest issue of Racecar Engineering mag, which cites Tom Kempynck's MSc thesis from Cranfield University...
Thesis:
"The design and simulation of a F1 engine as defined by 2014 regulations"
Professor Adrian Reynard award for best individual thesis project
Supervised by Mr. Stuart Grove (Chief Engine Designer F1 1994-2005 Ilmor Engineering)
They designed and simulated an engine model that conforms with the 2014 F1 regulations and correlates with the Renault power values by using the software AVL Boost.
As I said, part of this work was published in RCE Vol24 No5, p54-59; and I highly recommend you guys to check it out!
However, for the sake of this discussion, below are some figures from the article.
Figure 8 shows the obtained performance values of the engine without the recovered energy of the MGU-H, but it incorporates the assistance of the MGU-H to reach the fuel mass flow rate limit. The maximum power is 454.82kW @10,500rpm, while the maximum torque is 415.48Nm @7000rpm. It can be seen that the torque remains nearly constant from 5000 until 10,500rpm due to the MGU-H assistance.
The MGU-H power curve is illustrated in Figure 9. Before 9200rpm the MGU-H is acting as a motor while hereafter it is operating as a generator and recovering energy.
Figure 10 displays the obtained performance with the addition of the MGU-K. The maximum power is 574.82kW @10,500rpm and maximum torque is 611.83Nm @5000rpm. It should be noted that the torque of the MGU-K @5000rpm had to be limited from 229.35 to 200Nm, because this is the maximum allowed torque according to the regulations. The power curve with MGU-K is a parallel line above the curve without MGU-K because it adds a fixed amount of 120kW.
Figure 5 shows the calculated operating points on the compressor map of the GTX3076R. It can be seen that the compressor is operating close to the surge line at low engine speed. This surge line is the dashed line closest to the left of the compressor map. When the compressor is operating at this line, flow reversals will start to occur and the flow will become unstable. A solution for this is to use a smaller compressor or to use an inlet guide vane system to move the surge line. Finally, the GTX3076R turbocharger has been chosen because the smaller compressor was not going into surge at low engine speed while the smaller turbine made it possible to recover more energy.
When looking at the turbine map (Figure 6), it can be seen that it is less accurate compared to the compressor map as only the pressure ratio, turbine flow and maximum efficiency are given. So, for example, if you take a random point on the turbine curve, you do not know at which efficiency the turbine is operating at nor the rotation speed. Therefore, in order to perform a correct comparison between turbochargers, more accurate turbine maps are required.