Fly-by-wire manual control for DCT?

[Eunos_Cosmo]

Does anyone know enough about dual clutch transmissions to whether or not you could create 'true' manual mode for a dual clutch gearbox?

When placed in manual mode, the automatic gear selector (is it a fork in a DCT?) is simply programmed to respond to input from the h-pattern (which is only sending a signal, rather than a mechanical connection) to select gears.

Similarly, the 'clutch pedal' would send a digital signal to the transmission to operate the actual clutch.

You'd obviously be arbitrarily assigning any feedback (mechanical or with other methods) to the pedalbox and gear selector similar to video game wheel setups, but it doesn't seem entirely inconceivable. Maybe it would be too gimmicky to sell, but some people might be interested in it. You could even have levels of automation. Don't feel like messing with the clutch, set it to automatic so that it is activated by motion of the gear selector.

Random thought.

 

[TexRex]

I don't see any reason it wouldn't be possible. I'm given to understand a DCT operates much like a standard manual but its layout is complicated enough to warrant computer control. Manual mode would be a matter of telling the computer when to shift.

My old neighbor was an electrical engineer and converted a gas car to an EV, and one of the extra tricks he was confident he could employ was a simulated gear shift by limiting motor speed corresponding to pickups in the shifter assembly.

Similarly, pickups would likely be used to signal a shift to the computer.

 

[tps_b86_]

Hard to do on a DCT as they work so fast due to having two sets of gears (1,3,5,7 on one shaft, 2,4,6,8 on the other) each with its own clutch. The reason DCT boxes are so quick is because the Dual Clutch arrangement allows the ‘box to pre select the next gear and just engage the clutch when the shift is commanded.

A better way of doing this would be on some of the older “Sequential Manual Transmission” type ‘boxes such as the BMW SMG, Lambo Egear, Ferrari F1 etc which are in essence regular manual transmissions just with hydraulics handling clutch and gear selection.

HTH

 

[GDII]

It probably could be done but might still have the DCT problem when you suddenly decide you want to downshift when the car has selected the next gear up on the second clutch making it slow. IDK if the problem is reduced or gone now with the modern DCT but I know it is a thing with the older ones.

 

[kikie]

Look, also my idea, sort of.

Isn't it possible to make an H-pattern manual gearbox with a clutch which can be an automatic as well? Sim Racing hardware has it?

I mean an H-pattern manual with a fly by wire clutch pedal which can be operated by a motor (robot or whatever you call it) mounted on the gearbox when you choose automatic mode.

My Fiat 500 has a standard 5-speed manual gearbox (no clutch pedal) and the clutch is operated by a small robot mounted somewhere nearby or on the gearbox.

 

[TexRex]

Look, also my idea, sort of.

Isn't it possible to make an H-pattern manual gearbox with a clutch which can be an automatic as well? Sim Racing hardware has it?

I mean an H-pattern manual with a fly by wire clutch pedal which can be operated by a motor (robot or whatever you call it) mounted on the gearbox when you choose automatic mode.

My Fiat 500 has a standard 5-speed manual gearbox (no clutch pedal) and the clutch is operated by a small robot mounted somewhere nearby or on the gearbox.

Provided the shifter is outside the box, all you really need is a linear actuator to move a shift rod forward and back, and another connected to an appendage on the shaft to allow for torsional movement. It's even less complicated with cable operated gearboxes, in theory.

Mind you it's easy as can be on a bike because of the sequential gear selection, but here's a setup for shift-by-wire on a bike:

And I'm given to understand that system can be manually overridden at any point.

The topic at hand, however, is simulating a manual shift in a gearbox that is controlled by computer. In theory it should be even easier because of the absence of mechanical intervention, just a device through which the manual shift is simulated, which then sends a signal to whatever controls the shifts.

 

[homeforsummer]

I suppose logically you could do it by having two clutch pedals, but as a driver you'd need to have one engaged and one disengaged at any one time (so one pedal pressed down ready for the next gear). Come gearshift time you move the lever simultaneously to stepping off one clutch pedal and onto the other.

I'm already forseeing the problem with this being that a DCT can engage one clutch just as the other disengages and vice-versa in one smooth and swift movement. Unless you used both feet during a gearchange - ready to engage the clutch with one foot as you disengage with the other - you'd have a period where two gear shafts are trying to send power to the output shaft at the same time, and that sounds like a recipe for cogs where there shouldn't be cogs.

Ultimately you'd still have to have electronics actuating the clutch, and at that point you're just moving a stick about for the sake of it, a bit like the old Saab Sensonic, Renault Easy or early 1960s Beetle automatics. All of those had a conventional transmission pattern but moving (or even just touching) the lever actuated the clutch, with drive continuing when the car was in the next gear and your hand left the lever.

 

[kikie]

A standard manual (no dual clutch) with a fly-by-wire clutch pedal and a robot clutch operated by software (like in a Fiat 500 automatic) could be do-able. In manual mode, you have a standard clutch pedal and an H-pattern shifter. In automatic mode, the clutch robot does all the shifting.

It is absolutely not as fast as a dual clutch.