Williams Seamless Shift Transmission

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
luisandregg
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Joined: 01 Mar 2006, 20:53
Location: Campinas, Brazil

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DaveKillens wrote:If you could shave off .1 seconds each shift, and shifted ten times a lap, then in theory, you would be 1.0 seconds quicker a lap.
DaveKillens, are you sure of that? I mean, if you have great drag forces and friction loss your car will lose more time in shifting that a car with less drag and friction.

What I'm trying to figure out is why those two times (shifting times that you shave and lap times that you reduce) must be equal. Shouldn't we compare the power given by the engine and the power consumed at a given instant? The result must be the power left to accelerate or maintain a constant speed and that may provide us with the time reductions if we integrate (numerically) the speed in function of the time for a given distance.

I’m not sure of what I’m saying at all. So I would like to know you opinion about this.

walter
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Joined: 20 Oct 2002, 18:54

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Supposedly when the driver of an F1 car takes his foot off the accellerator the car experiences as much decelleration as what road cars experience when they brake. This is due to the immense downforce that is generatedby the wings. So if you think about that, every time that a gear shift is being made, the car is in in fact in decelleration. Yes its fractional, but from a theoretical point of view, it does add up after a few laps to something more considerable.

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Principessa
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Joined: 12 Aug 2005, 14:36
Location: Zottegem Belgium
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Yes it will save them time, but don't forget that both Rosberg and Webber had a lot of problems with it during testing and they ended up in the sandbox more than once! But if they'll keep the car on track, I think they will be really fast, not only thx to the seamless shift.

DaveKillens
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Joined: 20 Jan 2005, 04:02

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I was just picking a number out of the air to give an example. But my point is, any time not spent accelerating is wasted time. If one car takes .05 seconds to shift, and another .04 seconds, then after two shifts, the accumulated time difference is .02 seconds. Doesn't seem like much, but it may be the difference between getting a wheel under a car for a pass, and not.

RH1300S
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Joined: 06 Jun 2005, 15:29

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I must say I don't understand the fuss about seamless of CVT shifting, no need to define a shift time IMHO. As Dave says, in CVT, the ratio is fully variable, with a system of ratios there will always be a change in revs between a gear - to me that is a good enough definition of "not CVT".

As for whether it is worth shaving time off a gear-change - that's a bit like saying the qualifying just 1/100th off pole doesn't matter. Any tiny little time gain over a lap or race distance is worth having.

It was Ayrton Senna who bemoaned the introduction of semi-auto 'boxes as he felt that a fast gear change was one area a great driver stood out above the merely good.

zac510
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Joined: 24 Jan 2006, 12:58

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RH1300S, I agree. Seamless shift is the kind of thing I would like to have in my road car so for that selfish reason there is no reason why it shouldn't be in F1 :)

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Tom
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Joined: 13 Jan 2006, 00:24
Location: Bicester

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Mind you I wouldn't mind T/C (as long as I could turn it off for a bit of fun)
but I think its a shame that F1 drivers rely on it constantly.
On the other hand I would like to see active suspension reintroduced, but I suppose there is a big safety aspect if it all goes wrong.
Murphy's 9th Law of Technology:
Tell a man there are 300 million stars in the universe and he'll believe you. Tell him a bench has wet paint on it and he'll have to touch to be sure.

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Spencifer_Murphy
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Joined: 11 Apr 2004, 23:29
Location: London, England, UK

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Does anybody know how this "Seamless Shift" gearbox actually works. Even if its just a vague discription. I imagine its something to do with pre-loading the next gear ratio up and down from the currently selected ratio. But I could be wrong. Any ideas?
Silence is golden when you don't know a good answer.

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DarkSnape
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Joined: 01 Mar 2006, 15:07
Location: Bucharest
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Image

something like that..

"The computer controlled gearbox there are four shafts: two input shafts and two output shafts. The input shafts are concentric, with one shaft passing through the centre of the other hollow input shaft. There are two multi-plate clutch packs similar to those found in automatic transmissions. Each clutch pack connects one of the input shafts to the engine, so depending upon which is applied, either one of the two input shafts can transfer power. An oil pump at the rear of the gearbox supplies hydraulic pressure for the clutches.

The speed gears are divided between the two output shafts. First, third, fifth and reverse gear are on one output shaft while second, fourth and sixth gears are on the other shaft. Synchronisers are moved by the computer to lock each of the speed gears to their output shaft as required. Each output shaft has a pinion gear that drives the differential.

When the driver activate it , first gear is engaged inside the transmission, but the clutch doesn't engage until the driver steps on the gas. Because the clutch is running in oil, it can slip without burning up, allowing the car to creep along in first gear just as an automatic would. Step harder on the gas and the clutch is fully applied.

With the transmission engaged in first gear, the computer locks second gear to the other output shaft, but the input shaft clutch for that gear is not engaged. When it is time to shift, the computer releases the clutch for the first gear input and engages the clutch for the second gear input. In preparation for the next shift, the computer now shifts from first to third gear but leaves its clutch disengaged until the shift is requested. As the car's speed increases, the computer continues to pre-select the next gear so all it has to do is switch clutches. There is no grinding, no delays, and no shock"

Audi transmision

peroa
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Joined: 30 Jan 2006, 11:14
Location: Ljubljana, Slovenia

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DSG is not allowed in F1.
Easy on the Appletini!

zac510
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Joined: 24 Jan 2006, 12:58

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Spencifer_Murphy wrote:Does anybody know how this "Seamless Shift" gearbox actually works. Even if its just a vague discription. I imagine its something to do with pre-loading the next gear ratio up and down from the currently selected ratio. But I could be wrong. Any ideas?
It has been proposed that it is probably closely related to a Weismann or a Zeroshift gearbox as these two seem to be the market leaders at the moment.

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Spencifer_Murphy
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Joined: 11 Apr 2004, 23:29
Location: London, England, UK

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DSG is not allowed in F1.
Do you mean a Twin-Clutch gearbox? If so, I also thought that was banned in F1, ever since the MP4-18X (rumoured to have tested a Twin-Clutch system)
Silence is golden when you don't know a good answer.

Apex
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Joined: 08 Jul 2005, 00:54

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Firstly I'm a total VW nut!

Thats the best picture i have seen of the DSG box, and after finally understanding how it works I will be seriously consider this option when purchasing my next car! Previously i thought it was a bit expensive but seeing what all goes into it, its an engineering marvel! Ill take one!

Unfortunately for the F1 guys they cant check this option when deciding on their cars options. It is hard to say if this would make the world of difference. On first impressions if you had to ask me, having two clutches would increase the rotational mass of the box, so i guess. How much you gain by having seamless power vs the loss of an increased driveline mass is something that we would only be able to guess!

Besides, this was used in rally many many moons ago (by audi i think) - when last has an F1 derived system introduced into a road car?
Dont dream it, do it.