6 Speed automated shifting system idea
#21
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Rev matching without DBW is hard. And getting it perfect is even harder. This is the closest ive seen.
Nvm cant find it. It was on a yellow car. Something mid engined.
Nvm cant find it. It was on a yellow car. Something mid engined.
#22
Boost Pope
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In a modern F1 car, the driver is there simply to act as ballast and talk on the radio. And yet even with drivetrains controlled by Skynet and costing more than the GDP of Bolivia, they still have clutches.
#23
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Because I don't think the advantages of directly controlling each gear individually as suggested are worth the work. I don't think it would shift much faster (only tiny gains IMO), and it would increase the amount of work/engineering a lot. Now everything designed has to package inside of a transmission, for example vs controlling the already available/reliable shifter that's external. Yes it moves in two axis not one, but that's about the only downside. There are several upsides.
As I mentioned in post 1, if this happens, I'm not spending thousands to get it done. Might as well buy a sequential, or different transmission. So that also rules out 100's of hours of R&D too, just not worth it at all.
It would have to be affordable, and buildable withing a reasonable amount of time. Otherwise it's not worth messing with.
Mathew, the car already has a hydraulically actuated clutch, no need for a different version of the same thing. If I want to control the clutch hydraulically, that's as easy as installing a tee fitting and electric solenoid upstream of the tee to lock out the existing master cylinder. That's the easy part, hard part is how do you do the rest while remembering affordable/buildable.
So far nobody has any suggestion on how to improve upon the two electric solenoids/two linear pots method of controlling the existing shifter. What about the clutch? I know a pnuematic cylinder/tank/pump will make that work with great speed, but that's a heavy system. Is there any way to make that lighter and still as fast or at least comparably fast?
As I mentioned in post 1, if this happens, I'm not spending thousands to get it done. Might as well buy a sequential, or different transmission. So that also rules out 100's of hours of R&D too, just not worth it at all.
It would have to be affordable, and buildable withing a reasonable amount of time. Otherwise it's not worth messing with.
Mathew, the car already has a hydraulically actuated clutch, no need for a different version of the same thing. If I want to control the clutch hydraulically, that's as easy as installing a tee fitting and electric solenoid upstream of the tee to lock out the existing master cylinder. That's the easy part, hard part is how do you do the rest while remembering affordable/buildable.
So far nobody has any suggestion on how to improve upon the two electric solenoids/two linear pots method of controlling the existing shifter. What about the clutch? I know a pnuematic cylinder/tank/pump will make that work with great speed, but that's a heavy system. Is there any way to make that lighter and still as fast or at least comparably fast?
#24
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VW also built something very similar to this idea for their VW Lupo 3L/100km hypercar (I am not sure that thing was ever sold in the USA).
They also automated their manual tranny with a complex system.
You will find the technical description of the whole system here (it is in German though, but I can read that if you really want to know some details):
http://www.daffieproductions.nl/pdf/3.pdf
Mercedes also had some automated manual boxes back in the early 2000's.
I remember Smart cars having them and my father owned a Mercedes Sprinter van with an automated manual box. If there is one thing these boxes have in common, it is going to be the terrible slow shift speed. As increasing shift speed is your main goal: it may not be so easy..
Automating the current box will most likely not yield any improvements, I think the mechanical design needs to be suitable for easy/quick/stable electro mechanical control. The efforts I have seen from OEMs were not worth the trouble.
In the end I think it will not be worth the effort. I think a better start would be to look for a different transmission.
They also automated their manual tranny with a complex system.
You will find the technical description of the whole system here (it is in German though, but I can read that if you really want to know some details):
http://www.daffieproductions.nl/pdf/3.pdf
Mercedes also had some automated manual boxes back in the early 2000's.
I remember Smart cars having them and my father owned a Mercedes Sprinter van with an automated manual box. If there is one thing these boxes have in common, it is going to be the terrible slow shift speed. As increasing shift speed is your main goal: it may not be so easy..
Automating the current box will most likely not yield any improvements, I think the mechanical design needs to be suitable for easy/quick/stable electro mechanical control. The efforts I have seen from OEMs were not worth the trouble.
In the end I think it will not be worth the effort. I think a better start would be to look for a different transmission.
I know automating the clutch would make the shifts faster. I know a pnuematic cylinder can push in the ACT Extreme faster than I can. That is the most time consuming part of the shift is pushing the clutch in. I can change the gear relatively fast once the clutch is in.
I suppose I need to focus on how to control the clutch at this point, since that is the low hanging fruit regarding faster shift times. I think my original idea would shift the gears, though it wouldn't be as fast as directly controlling the individual gears as suggested. I think that difference would be like 20 ms though, not 100.
#25
Maybe try searching the formula SAE forums? A lot of them use pneumatic shifters on their bike transmissions. I know it's a completely different style of transmission and they don't need clutch control, but you can probably find some good discussion on pneumatic vs. electric.
There has to be some reason Xtrac and Mclaren chose pneumatic over electric.
Sneek Peek, KPAX Flying Lizard McLaren 650S GT3
There has to be some reason Xtrac and Mclaren chose pneumatic over electric.
Sneek Peek, KPAX Flying Lizard McLaren 650S GT3
#26
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Maybe try searching the formula SAE forums? A lot of them use pneumatic shifters on their bike transmissions. I know it's a completely different style of transmission and they don't need clutch control, but you can probably find some good discussion on pneumatic vs. electric.
There has to be some reason Xtrac and Mclaren chose pneumatic over electric.
Sneek Peek, KPAX Flying Lizard McLaren 650S GT3
There has to be some reason Xtrac and Mclaren chose pneumatic over electric.
Sneek Peek, KPAX Flying Lizard McLaren 650S GT3
The reason for using pneumatic over electric is it's faster. Looking at the link you posted, that car looks awesome.
#27
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While continuing to maintain that this whole idea is Bad and Wrong™, I offer the following insight:
Most Miatas already have a belt-driven hydraulic pump installed as standard equipment from the factory. And it's an easy retrofit for those which didn't come so equipped, using all stock parts. Just add a balloon-type pressure accumulator and you've got a system capable of driving a hydraulic TOB.
Of course, you'll never manage to get the car moving from a standstill without some fairly exotic electronics.
No good can come from any of this. And that's not Luddite thinking...
Of course, you'll never manage to get the car moving from a standstill without some fairly exotic electronics.
No good can come from any of this. And that's not Luddite thinking...
#29
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Also, I don't need it to take off from a stop, or rev match. Nothing fancy, all I want it to do is shift faster and more consistently than I can. That's it.
The whole point of this thread is to see if this can be accomplished cheaply and simply enough to be worth attempting.
The whole point of this thread is to see if this can be accomplished cheaply and simply enough to be worth attempting.
#30
Aren't both of those gearboxes of a staggered-gear twin clutch design?
While I know nothing about how the software on those transmissions is configured, with such a design you could have the synchros engage very gradually. It wouldn't matter if it took a full second for the engagement to occur, since synchro engagement time is not a limiting factor in how quickly such a transmission can shift.
The exact opposite is true here. With a single clutch design, you need to slam the synchros together as fast and as hard as possible if you want to speed up the shifting process, regardless of whether a human or an electronic device is moving the forks.
While I know nothing about how the software on those transmissions is configured, with such a design you could have the synchros engage very gradually. It wouldn't matter if it took a full second for the engagement to occur, since synchro engagement time is not a limiting factor in how quickly such a transmission can shift.
The exact opposite is true here. With a single clutch design, you need to slam the synchros together as fast and as hard as possible if you want to speed up the shifting process, regardless of whether a human or an electronic device is moving the forks.
Once a clutch is disengaged and the gearset unloaded in a traditional manual, with respect to synchro load it is pretty much behaving in the same way as the unloaded side of a twin clutch trans.
#32
By a strange coincidence I may have info on exactly what you're looking for. A mechanical engineer friend sent me this link the other day.
Very last photo of the article, Ikeya Formula sequential shifter, converts forward and back movement into a h pattern shift.
Look Closer... Do You See It? - Speedhunters
Very last photo of the article, Ikeya Formula sequential shifter, converts forward and back movement into a h pattern shift.
Look Closer... Do You See It? - Speedhunters
#33
By a strange coincidence I may have info on exactly what you're looking for. A mechanical engineer friend sent me this link the other day.
Very last photo of the article, Ikeya Formula sequential shifter, converts forward and back movement into a h pattern shift.
Look Closer... Do You See It? - Speedhunters
Very last photo of the article, Ikeya Formula sequential shifter, converts forward and back movement into a h pattern shift.
Look Closer... Do You See It? - Speedhunters
#34
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Rotational inertia and synchros are the limiting factor, not the human. Since you're keeping the stock flywheel, you'll never solve one of those. The other one might be solved if you replace every gear and selector in the transmission ($$$$$$$$$$$$$$), but if you do that, it's easy enough to buy a trans with external shift rods and a Z-gate shifter.
#35
Why not swap in a DCT trans from a generation agos m3, or isf or something? Some guys got them to work on supras and they hold alot more then the six speed from a miata. The trans them selves are like a grand the rest is just getting your standalone to control it (if yours is good enough) and making an adapter plate/driveshaft. The problem with automating the miata six speed is setting it up to actually shift properly will take along time and most likely nuke a couple transmissions before its correct so your already invest alot of money into it. Another and less automated option would be to move onto a twin disk clutch most multiple disk clutches are alot more user friendly/lighter unless it is a mini disk setup.
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