change time to change gear smart

[Robys]

Allow me to speak on this subject because in the past I've been involved in systems "robotization" of gear, I have studied several (both the implementation system: hydraulic, electromechanical, or mixed, both the application and on the gearbox itself).
Someone has said that the Smart exchange usa a selection system desmodromic as the one used in the bike...correct, but the transmission of the bike is the front couplings on the gears, not the synchronizers as used by all the cars in the series for reasons of comfort, silent operation? in the graft, and more.
The synchronizers require time infinitely more? long a currency grafts on the front to make the gear change, and these times also depend on the characteristics, costs and dimensions of the synchronizer. In all cases, the times changed with the synchronizer will never be comparable to those of an exchange couplings on the front...which is why the car is running you can use the command-sequential(manually operated or actuated) with desmodromic and grafts in the front and on the cars of the series, if you want to speed? shifting fast, even with a mechanical gear and synchronizers, all are now gone on systems, dual clutch transmission, which pre engage with the ratio higher or lower (in a manner transparent to the driver). The Smart system ? sly why? using a desmodromic, you ? used only one actuator (electric in this case) for the change, instead of the two for the selection and engagement, as is usually the case, and then you ? managed to reduce costs (a desmo costs less than an electric motor), to simplify the HW and the SW command (not c'? to manage the selection and engagement separately), and in part to reduce the overall dimensions.
But from the point of view of speed, maintaining the internal structure of the exchange rate unchanged...can you? do a little bit...unless you want to force the hand...and drastically reduce the duration of the same. Also shortening the implementation time of the clutch, this is feasible, changing, for example the actuator, the gear change is seen, however, the big limit in the internal structure of the exchange itself is not worth much worth of work ****l actuator gear...
For the record, I ? happened to realize some projects of "robotics" mechanical gear motorcycle...them, for the type of gearbox plug-in in the front, no ? difficult to get to the gear changes around 4-5 hundredths of a second...
In the field of car with a conventional gearbox arrive in time changed 10 times more? long, ? gi? a nice result...
For time shifting, I mean by torque transmitted off a transmitted torque on.

[Robys]

You! I agree with you that 0.4-0.5 seconds to the time shift in the case of the Smart would be gi? a very good thing! In this moment I'm under the hand of the acquisitions made at the time, but the times in the case of the Smart were superior to those of the first magneti marelli selespeed (that already? they were not very exciting...). I can confirm that one of the major problems in the "push" to try to get a shorter time shifting ? the synchronizer...which in summary is to dissipate the energy due to the different speed? of rotation between the primary and secondary side of the exchange (and its inertia) at the time of the transition from one relationship to another.
What I can add, and which perhaps can? be considered as a council to try to reduce the shift times on the Smart...but ? something very "delicate"...? what was done by some manufacturers to reduce the shift times on the first systems selespeed...in practice, with the clutch still engaged and torque is transmitted, is going to "preload" the actuator (? a bit as if in a mechanical gearbox manual car started to pull the shift lever is in the third when we still have all the torque available and with the clutch fully engaged...), and only later took the couple and opened the clutch to enter the next relationship (in the example I made, to enter the fourth)
I repeat, was used in this system and allowed you to earn something in the times changed, but she is in a hurry to do the damage...
In the case of the Smart then it would be to try to fly (with a reduced current!) the electric motor that controls the desmo, before removing the pair and open the clutch and then insert the next report.

[Robys]

Hello, yes, you explained it perfectly;
with regard to the management of the driving of the electric actuator, in fact, you should (I think, although I don't know in detail what maps are on this unit control the actuator) to adjust the strategies driving the most? the maps...what's that ? very simple if you had the source of the SW, of the controller...but if not...very complicated...(you have to forgive me, but for my past experiences, I will, in a sense, easy to think of changes to ****llo strategies, but ? obvious that not knowing everything ****th e SW in the ECU, this ? very complicated) .
As regards, instead, the discourse "mechanical", the shape of the teeth engagement of the synchro ? as they say in the jargon, "coffin" (...even if not so beautiful): when the gear ? inserted is retained finch? c'? transmission of positive or negative torque (in range or release). And this is the reason why if you try to pull the gear lever to put it in neutral without pressing the clutch, and without removing the foot from the accelerator, the thing is not ? simple unless you apply high loads, but ? better not to do it...what more? simple if you lever your foot from the gas and pull the lever before the pair reverses...what? we go to the phase of the engine brake.
To simplify, this type of control system as a strategy (in closed loop) it works cos?:
the electric motor is driven by the control system, and rotates the drum at the stage where you ? choked the couple (via the motorised butterfly), and of course ? open the clutch. The potentiometer mounted on the drum of the desmo, informs the control system of the actuator if the drum ? rotated tot degrees, and then if the gear ? surely inserted, at that point they are reset to the couple and closed the clutch to complete the phase shifting.
During the rotation of the drum (or during the engagement, when the drum is not c'?), the actuator pu? be driven with the values of the current variables in function of the angle (it seems to me the Smart was cos? but they are not sure...? the past few years... but ? enough to see the PWM driving the motor during the rotation, if it changes or not as a duty cycle); this in order to be fast, where can you? (typically not during the insertion of the cord) and pull forces (or pairs if you are talking about the rotary drum) pi? reduced during the synchronization.
If there were maps "accessible" that control the steering with a duty cycle variable of the engine, maybe some experiment you could do, but there would remain the problem of "anticipate" with respect to the standard, the phase of the driving engine to preload the disengagement...this is not, I believe, is controllable by the map...
I hope I was clear too...if not, please ask!