The Cosworth data indicates that they will rev between 11000 and 13000rpm for max acceleration. (At least for the gearing and Drag which I used)Phil wrote:I hadn't thought about the ICE actually. I was more thinking about the simple fact that with every higher gear, the torque at the wheels is significantly less, which is why even after the drop-off point, the engine might still be producing more power/torque at the wheel in that gear than shifting up. The main question is: how much torque at the wheel is the engine producing past its bhp-peak and how does it compare to the next higher gear at its lower RPM number.
Take this graph for example (posted in the what's wrong with the renault engine thread):
http://i59.photobucket.com/albums/g288/ ... ph_134.png
The difference between torque at the wheel between gears is so high that even after the BHP drop-off (which we don't see here since it only shows torque, but we can guess), you still have way more grunt than if you were to shift to the next higher gear. In F1 and thanks to 8 gears (closer gearing) this is of course minimized since all the gears would be closer to each other, but without knowing the exact drop-off, it's hard to say for sure.
If we assume that these engines produce max BHP at 85% of the rev range, we still don't know how much they produce say at the rev-limit. My guess is you would still have a gain to rev until 90-95% before upshifting (assuming engine reliability and strain is not an issue). How much this would yield over an entire lap is anyones guess though... My main point was more that it does make sense to rev higher than the peak BHP rpm point if you take gearing and the drop off into account. It's not as if the engine peak power suddenly drops to zero after it's max point.
unless there is something seriously wrong with the software the electric motor should/could be silky smoothLycoming wrote:I guess it's a possibility, but while the cornering loads haven't changed significantly, thermal load has increased significantly. Besides, cornering loads are just inertial loads. Even at 5G, that won't put much stress on most of the components. The big loads are things like dumping the clutch at redline, or apparently, sudden torque application from an electric motor.
For those interested. Here are some of the changes Renault have made since Jerez.
Change of battery cell provider. The individual cells that make up the Energy Store have individual over-charge and over-discharge protection. These were proving unreliable due to thermal/vibration issues. Whilst the energy store is sealed in our fitment, I am informed the cells are now supplied by Panasonic.
Change to MGU-K to Crank drive gearing. The original torque multiplication factor was calculated to give a wider spread of torque on acceleration. Track testing found that this was causing traction dificulties and overloading the gearset and causing failure of the crank casing.
Change to turbocharger wastegate function. Renault had originally intended for the H to regulate Turbine speed in 95%+ of normal running. They facilitated this by allowing the H to pull charge (when the energy store was at capacity) to an air cooled heat sink. This strategy proved ineffective in certain environments and a more coventional wastegate is now being used to supplement the H.
Due to both the change in K gear ratio, boost control strategy and the energy store, most of the software relating to the charge and discharge cycling has been modified daily and continues to be refined. There are still issues relating to turbine speed control via H but these are mostly to do with fine tuning of the control software and the syncronisation between H control and wastegate control.
There has been swift progress and software related driveability now appears to be the main issue.
Re the H to K transfer.
There are times when you can't (or wouldn't want to) transfer power from the H to the K but still need to limit turbo speed.
Think along the lines of a short burst of accel then slight decel then accel (such as feathering throttle for traction or in a switch back). The last thing the driver would want is for the K to feed power into driveline.
During those transitional situations Renault wanted to control the speed of the turbo by using the H to maintain shaft speed at or close to max rpm. It turned out (partly because of the driveability issues) that H was dumping to the heatsink far more than had been predicted or modeled. This was causing severe heat related issues in some cars at Jerez and the Renault 'patch' was to disable the H entirely and rely on the mechanical wastegate for the remainder of the test.
Obviously this resulted in dramatically increased lag and reduced performance but allowed some mileage to be put on the ICE.
In the interests of transparency it should be disclsclosed that we have had no first hand experience with the original spec PU used in Jerez.
Our running experience started with a version that had basic H functioning and limited K output.
They're used as a fail-safe device in case of mgu-h malfunction which could cause catastrophic ICE failure.beelsebob wrote:I'm puzzled by the "waste gate gets used some of the time" assertion. I was under the impression that that was banned in the regs.
Sure – I know they exist, and they're used as a fail safe, but the assertion above is that they use it in normal running.Juzh wrote:They're used as a fail-safe device in case of mgu-h malfunction which could cause catastrophic ICE failure.beelsebob wrote:I'm puzzled by the "waste gate gets used some of the time" assertion. I was under the impression that that was banned in the regs.