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Something is different with the McLaren transmission?


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#1 chipmcdonald

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Posted 26 July 2014 - 20:08

Listening to the in car, I am quite sure it is shifting at least twice as fast as the rest of the field...?



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#2 MatsNorway

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Posted 26 July 2014 - 21:06

Got video?



#3 chipmcdonald

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Posted 27 July 2014 - 04:06

Any of the in car footage of Jenson.  I don't want to post and ad to the FOM take down spree, but...

FOM coverage, Jenson, with about 6:00 remaining in Q3: when the McLaren shifts, there is zero "bobble" into the next gear.   Probably difficult to notice unless you're a musician or audio engineer, the time it's out of gear is nearly imperceptible, which for me is down in the 10-12ms range, much less than the 50ms or so the rest of the field is doing.



#4 Kelpiecross

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Posted 28 July 2014 - 11:23

F1 cars have "seamless" (allegedly) gearboxes which are never out of gear - even during gear changes. If all the cars are "seamless" then they all must have the same (zero) interval for the change. The engine cut out could vary amongst the cars though.
Ricciardo is a very good driver - possibly the best in the F1 field.

#5 chipmcdonald

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Posted 28 July 2014 - 17:10

Having a gear selected doesn't mean it's under power the whole time. 



#6 imaginesix

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Posted 28 July 2014 - 18:37

Could also be the energy harvesting strategy during gear changes messing with the sound.



#7 MatsNorway

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Posted 28 July 2014 - 19:09

hmm. Interesting idea actually. Could you instead of going off throttle, brake the engine with the kers to get the same effect?

 

But what kind of energy harvest do you get at say. 0.1 sec or less? if you can collect for 0.1 a sec and have a recover of 80kW you get 8kW?


Edited by MatsNorway, 28 July 2014 - 19:14.


#8 Wuzak

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Posted 28 July 2014 - 21:00

hmm. Interesting idea actually. Could you instead of going off throttle, brake the engine with the kers to get the same effect?

 

But what kind of energy harvest do you get at say. 0.1 sec or less? if you can collect for 0.1 a sec and have a recover of 80kW you get 8kW?

 

8kJ. Not very much in the context of the allowed harvest per lap (2MJ)



#9 MatsNorway

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Posted 28 July 2014 - 21:47

kan you get out 8kW for one sec then? But more importantly. I see no reason not to do it..


Edited by MatsNorway, 28 July 2014 - 21:52.


#10 gruntguru

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Posted 28 July 2014 - 23:28

You can. The reason not to do so is you are using fuel. It costs much less (fuel) to harvest from the MGUK under braking and from the MGUH. You would only burn fuel in order to send energy to the ES if you were unable to harvest sufficient energy by the other means.

 

You might do it if engine revs don't drop quickly enough with throttle off. Actually a better strategy would be fuel-cut, throttle open, use MGUK to slow engine revs for next gear. Harvests the (tiny bit of) engine inertia and gets the shift done a bit quicker.


Edited by gruntguru, 28 July 2014 - 23:38.


#11 Wuzak

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Posted 29 July 2014 - 01:34

The Ferrari engines, at least back in Albert Park, were remarkably quiet in the braking zones. You could not hear the engine at all. So maybe that is what they were doing, but also using the MGUK to match revs for the next gear.



#12 Kelpiecross

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Posted 29 July 2014 - 04:23

I am no expert on electrical matters - but I think switching motor/generators on and off is not an instant process like electronic switching. It takes some time for fields to build in coil windings etc. - more than 0.1 sec I would guess.

#13 gruntguru

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Posted 29 July 2014 - 05:11

You are right. There would need to be some anticipation/sequencing to the operation. The transmission would not respond instantly to a shift command from the driver for example.



#14 MatsNorway

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Posted 30 July 2014 - 10:28

I asked an electrical engineer here. He said none. No loss. A copper wire going through a magnetic field will generate electrisity in practically the speed of light.

 

So they would do it unless there is something we have not covered so far. They probably do it constantly and more aggressive in qualifiers.


Edited by MatsNorway, 30 July 2014 - 18:30.


#15 gruntguru

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Posted 30 July 2014 - 23:31

I would agree with Kelpie over your engineer. Ask him how quickly you can change the current through an inductor (coil).



#16 chipmcdonald

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Posted 31 July 2014 - 07:12

hmm. Interesting idea actually. Could you instead of going off throttle, brake the engine with the kers to get the same effect?

 

But what kind of energy harvest do you get at say. 0.1 sec or less? if you can collect for 0.1 a sec and have a recover of 80kW you get 8kW?

 

 

It's actually more like .05 of a second. 

 

 

 

 



#17 chipmcdonald

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Posted 31 July 2014 - 07:18

I would agree with Kelpie over your engineer. Ask him how quickly you can change the current through an inductor (coil).

 

They react instantly but have "slip" relative to the torque, they're not always going to be 1:1 linear with the input signal.  But then, that's how they can exploit that margin for traction control. Not that any teams would be doing that....



#18 Kelpiecross

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Posted 31 July 2014 - 10:32


According to this:
http://www.tonyfoale...on/Ignition.htm
The saturation time for an ignition coil is from 5ms to 20ms. In the graphs shown you can see the rise in current is certainly not instantaneous.
When a voltage is applied to a wire the beginning of the current flow is at the speed of light etc. - but it still takes time to reach a maximum value. Just what the delay would be in the F1 case I have no idea.
Switching 80kW would be a tricky too I would imagine.

#19 MatsNorway

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Posted 31 July 2014 - 10:44

5/1000 of a second? 0,005sec to 0,02sec Starting to get a very limited window to get energy. But ofc. One can offset that in the system so it does kick in fully once the engine cuts the fuel injection.