Do modern seamless F1 transmission still give a violent push upon gear engagement?

[gold333]

I’m setting up tactile feedback for a simulator. I know that early semi automatic F1 gearboxes made quite a jolt when changing gears.

I’ve been told that modern seamless F1 gearboxes change gear in approximately 3 milliseconds because the next gear is engaged before he shifts. Is that true?

And does anyone know what the level of feedback is upon gear engagement? Is it 0 (i.e. does the driver feel absolutely nothing) when a gear is changed, or is there a thud / kick in the back.

[Tommy Cookers]

.... And does anyone know what the level of feedback is upon gear engagement? ....

Honda does - they covered this in their SAE papers
another (watered-down summary) Honda paper is publicly available

it seems to show the variation of clutch-transmitted torque through time
(said torque being actively controlled in a way that we usually associate with Moog hardware)

usually at this point the poster replying asks if the OP has searched this part of the forum

[Jolle]

Not a car but a first hand insight from a bike rider might give you an idea.

He calls it “like butter”

[hollus]

Maybe it would be easier to ask the drivers, current and past, directly. Lots of them are in twitter?
And share the results here!

[saviour stivala]

The development of the seamless gearbox if anything, made it possible for drivers to change gear even when cornering. Two of my old jotted down notes are as regards the first semi-automatic sequential gearboxes (servovalve – operated gear change/sequential barrel selector) introduced and are about drivers of the time personal feelings/reaction to the new way of changing gear. It was all about like and dislike. And so not about gear change with seamless-shift gearboxes and jolts or whatever the driver feels when changing gear. The following might be of interest to some.
About 10-11 years before John Bernard refined and implemented for racing what FERRARI already had in their cupboards gathering dust. The first FERRARI prototype semi-auto sequential gearbox was designed/build by M Forghieri and first tested on the 312-T3/312-EVO in January 1979 by driver Giogio Enrico. In March 1980 in the presence of Enzo FERRARI Villeneove tested again at Fiorano and ASKED to continue with the manual gear-stick change gearbox. And the project was ordered to be put on hold. Velleneove told Enzo FERRARI:- ‘I am sorry, the project is good, really good, but if you take away the pleasure of changing gear manually engaging the clutch, you kill me’.
According to Petrik head in 1993 there was discussions about banning the semi-auto sequential boxes because people like Alain Prost viewed changing gear with a lever as part of driver’s skill-set. But the semi auto boxes were kept, because apart from reducing the gear change by gear lever time from 200-250 milliseconds to 30-50 milliseconds when changing gear with the semi auto sequential 95% of engine failures due to driver over-revving when changing down to early was eliminated. (the moment you have gear-shifting under electronic control, over-revved engines are out of the driver and life is much cheaper).

[saviour stivala]

Sharing information is what a forum is supposed to be about. When information is years old it is either from memorised or had been noted down. The information in my last post comes from notes that had been noted down. There is nothing wrong in asking for a source/citation for information shared. But to the doubter that that was shy of asking for a source/citation and his from behind the screen thanks for me sharing said notes. Be assured that my notes have their source/citation at the very top.
At around 2004-5 when the development of seamless shift was about to be introduced in F1. The regulator had already banned the twin (friction clutch) each one on two separate input shaft system which was the first version of seamless gear shifting. Also banned was CVT (constant variable transmission). But these bans did nothing to stop the speculations and miss-information and so the usual polemics surrounding the introduction of seamless shift gearbox. The interpretations doing the rounds at the time - were :- seamless gear shifting constituted a CVT. The regulator mandated a minimum shift-time and so some had to modify their boxes to meet that minimum shift-time. But what the regulator actually mandated was that ‘there must actually be a gear-shift’ between gears/’there has to be a break in power’.

[NL_Fer]

The big difference between a traditional (dog)box and a seamless shift, is that a traditional box always has short moment, where there is no gear engaged between shifts. For a few milliseconds there no power to the wheels, and the car is actually slowing down during that period (because of the drag).

With a seamless shift the wheels are always driven, no interruption of power. Only the rotational speed difference of the engine is converted into torque. Ofcourse they can use the clutch, mgu-k or ignition timing to reduce the torque-spike. But not to much reduction, because it is also power/acceleration in a situation where every millisecond counts.

[Tommy Cookers]

there is no such thing as perfect non-interrupted power throughout the gearshift

people need to read ....
Honda Power Unit Hardware & Software thread P 1035 etc

and both these Honda Technical Review 2009 papers ....
Development of gearbox control during Honda Formula 1 Third era
Development of seamless shift for Formula one car

[strad]

I would think that since they cut the engine between the shifts there would be minimal jolt.

[gruntguru]

There will be some jolt because the engine has inertia and has to be slowed down to match the higher gear. The only way to eliminate the jolt AND have seamless power delivery is to dissipate that surplus energy somehow - eg slipping a clutch. The MGUK could be used to absorb some the energy but the spike would be very high - a clutch slip would be required in tandem. Depends on the duration of the shift.

[Tommy Cookers]

I would think that since they cut the engine between the shifts there would be minimal jolt.

12000 rpm is 5 millisec per rev
at these rpm the load path interruption with shifting will be about 1 millisec
yes we can regard this as non-interrupting

12000 rpm gives about 17 millisec between power strokes
so 'instantly' cutting the engine won't eliminate the jolting input
(for that it would need to drop the PU rpm by about 13% in 1 millisec)
cutting early may be better - trading-off between one kind of non-ideal behaviour and another

even controlling the torque transmitting capability of the clutch can't be 'instant enough' to eliminate the jolting input
but it can also act 'early' - and in combination with 'engine cutting'
it's not ideal but it allows the best job overall (and may be useful in other ways ??)

now I should read what I said others should read ...

[saviour stivala]

‘There will be some jolt’. Yes. There will always be as long as a gear ration change takes place. No matter how near to zero jolt development progress will get the jolt. Zero jolt in gear ration change can only be achieved with a CVT gearbox.
Seamless gearbox provides instant gear ratio change. But a gear ratio change there is/a gear shift between gears/no matter how small the time, there is a break in power. Because although it is said that 2 gears are engaged at the same time, in realty it is only possible to engage one gear ratio at any one time (technically speaking, an engaged gear ratio is the one that is transmitting the drive.
(HONDA) ‘Instant gear shifting causes instant change in torque equivalent to the change in inertia based on the gear ratio – spike torque increase’. This spike in torque can be minimised by optimizing torque by means of controlling the engine which is producing the torque.

[saviour stivala]

there is no such thing as perfect non-interrupted power throughout the gearshift

people need to read ....
Honda Power Unit Hardware & Software thread P 1035 etc

and both these Honda Technical Review 2009 papers ....
Development of gearbox control during Honda Formula 1 Third era
Development of seamless shift for Formula one car

Fully agree. Using a seamless gearbox a gearshift still takes place, and as long as a gearshift takes place there is a break in power no matter how small the time of the break is.

[strad]

if all that is so then why bother cutting the engine at all?

[saviour stivala]

Ignition cut on present day seamless shift is used mainly on down-shifts and that is more intended for helping engaging ratchet pawls of gear being disengaged disengaging.