Hand clutches, but not in single seaters?
Discussion
There are various systems that operate the clutch via electro/hydraulic with ecu control.
Havent heard of one where it moves clutch to hand control though.
I guess whether you wanted mechanical operation or some sort of electronic, transferring hand movement to clutch movement shouldnt be that big a challenge ?
Havent heard of one where it moves clutch to hand control though.
I guess whether you wanted mechanical operation or some sort of electronic, transferring hand movement to clutch movement shouldnt be that big a challenge ?
I've used the Shiftec clutch system in various applications including road cars. Very clever, very easy to implement and if you have air on the car already for gearbox or active aero it's a very small amount of weight to add. Can also be driven directly from the engine/gearbox ECU to automate the clutch or for LCS etc.
http://www.shiftec.com/clutch_control.html
http://www.shiftec.com/clutch_control.html
It's more of a "how difficult would it be to drive" thing rather than a "how would i do it" (at this stage)
On my car, because it has "expanded" wheelhouses, and i'm a lanky git, the pedal box is necessarily offset towards the centre of the car. If i could get rid of the clutch pedal, could move it more in line with the driver, which would be nicer, and also swap to a floor mounted pull type pedal box (lighter, lower CofG etc). Adding in the capability for an autoclutch gives access to other clever stuff like antistall and disconnection during ABS operation etc.
My concern, is that most of the systems i've seen are only used in either disabled driver cars (heavy, slow to actuate) or single seaters (likely to be difficult to modulate, as single seats don't really generally have clutches that can be slipped to any great degree (you certainly never going to have to do a hill start at a tight T junction in a formula car, for example!))
I looked at that air powered system, and a quick first order model suggests it will be pretty awful for fine positional control (spring mass system with low friction and a non linear (and possibly regressive) load = difficult to control).
My car already has air pressure in it (for the transmission shifting) but i think i'd go for a spring augmented electromechanical system to gain higher positional accuracy. There is no need to use the clutch for gearshifts (as i have a dogbox) so that means really the clutch is just used for pulling away or stopping, and i wondered how hard that would be to do with a small finger paddle behind the hand wheel (maybe with some small detentes to give a degree of positional feedback to ones fingers etc?)
On my car, because it has "expanded" wheelhouses, and i'm a lanky git, the pedal box is necessarily offset towards the centre of the car. If i could get rid of the clutch pedal, could move it more in line with the driver, which would be nicer, and also swap to a floor mounted pull type pedal box (lighter, lower CofG etc). Adding in the capability for an autoclutch gives access to other clever stuff like antistall and disconnection during ABS operation etc.
My concern, is that most of the systems i've seen are only used in either disabled driver cars (heavy, slow to actuate) or single seaters (likely to be difficult to modulate, as single seats don't really generally have clutches that can be slipped to any great degree (you certainly never going to have to do a hill start at a tight T junction in a formula car, for example!))
I looked at that air powered system, and a quick first order model suggests it will be pretty awful for fine positional control (spring mass system with low friction and a non linear (and possibly regressive) load = difficult to control).
My car already has air pressure in it (for the transmission shifting) but i think i'd go for a spring augmented electromechanical system to gain higher positional accuracy. There is no need to use the clutch for gearshifts (as i have a dogbox) so that means really the clutch is just used for pulling away or stopping, and i wondered how hard that would be to do with a small finger paddle behind the hand wheel (maybe with some small detentes to give a degree of positional feedback to ones fingers etc?)
I'm sure with either mechanical or servo style assistance, a setup with feel operated via hand is very possible ?
But then wouldnt full ecu control of the clutch then be the easier option ?
DSG manage it, disabled car setups manage it ( and are programmable for each car ). Yes they have smoother clutches, but it has been done
But then wouldnt full ecu control of the clutch then be the easier option ?
DSG manage it, disabled car setups manage it ( and are programmable for each car ). Yes they have smoother clutches, but it has been done
Max_Torque said:
It's more of a "how difficult would it be to drive" thing rather than a "how would i do it" (at this stage)
I've done well over 10K KMs on the road with one with no issue at all. It becomes second nature just like the clutch on a bike does. Max_Torque said:
I looked at that air powered system, and a quick first order model suggests it will be pretty awful for fine positional control (spring mass system with low friction and a non linear (and possibly regressive) load = difficult to control).
Worth looking at it a little bit more closely as it works extremely well. Same system as employed on F2, FRWS, various LMP + similar and our road car project to name but a few. It's very developed by this stage and you'll be surprised at quite how well it works and the level of control that can be achieved with it - I was quite skeptical at first too!Ok, it doesn't sound to bad then!
I wonder how the air actuated systems cope with the gain reversal that occurs when the diaphram spring in the clutch goes "over centre" towards the end of it's travel? I suspect they simply use physical stops to prevent the actuator ever getting that far?
A quick simulation suggests that such a system will need accurate calibration and possibly even some additional damping to be added to perform really well:
I wonder how the air actuated systems cope with the gain reversal that occurs when the diaphram spring in the clutch goes "over centre" towards the end of it's travel? I suspect they simply use physical stops to prevent the actuator ever getting that far?
A quick simulation suggests that such a system will need accurate calibration and possibly even some additional damping to be added to perform really well:
Max_Torque said:
Ok, it doesn't sound to bad then!
I wonder how the air actuated systems cope with the gain reversal that occurs when the diaphram spring in the clutch goes "over centre" towards the end of it's travel? I suspect they simply use physical stops to prevent the actuator ever getting that far?
A quick simulation suggests that such a system will need accurate calibration and possibly even some additional damping to be added to perform really well:
Initial calibration is done on the bench, essentially with a test rig that will carry your existing flywheel, clutch pack, release bearing and slave cylinder. This deals with the linerisation of the clutch pack as far as the controller is concerned. Easiest way to do this for a single application is to farm it out to Shiftec who are very reasonably priced for this work. The actuator limits are set in software.I wonder how the air actuated systems cope with the gain reversal that occurs when the diaphram spring in the clutch goes "over centre" towards the end of it's travel? I suspect they simply use physical stops to prevent the actuator ever getting that far?
A quick simulation suggests that such a system will need accurate calibration and possibly even some additional damping to be added to perform really well:
The only thing we have ever found is that the hydraulics side of things needs to be perfectly bled and kept air free as the system relies on the movement of the master being reflected accurately in the slave. In practice this is no effort and with modern components it's not like things need bleeding on a regular basis. It's certainly much less labour intensive then our LVDT on the clutch pack setup we run on the F1s.
With aggresive clutches it's also possible to change the relationship between paddle and cluthc posistion in much the same way as it is possible to change the relationship between PPS and TPS on a DBW throttle system which can be very useful when working with clutches with aggresive bite and small slave cylinder travel between initial bite and engagement.
poppopbangbang said:
Initial calibration is done on the bench, essentially with a test rig that will carry your existing flywheel, clutch pack, release bearing and slave cylinder. This deals with the linerisation of the clutch pack as far as the controller is concerned. Easiest way to do this for a single application is to farm it out to Shiftec who are very reasonably priced for this work. The actuator limits are set in software.
The only thing we have ever found is that the hydraulics side of things needs to be perfectly bled and kept air free as the system relies on the movement of the master being reflected accurately in the slave. In practice this is no effort and with modern components it's not like things need bleeding on a regular basis. It's certainly much less labour intensive then our LVDT on the clutch pack setup we run on the F1s.
With aggresive clutches it's also possible to change the relationship between paddle and cluthc posistion in much the same way as it is possible to change the relationship between PPS and TPS on a DBW throttle system which can be very useful when working with clutches with aggresive bite and small slave cylinder travel between initial bite and engagement.
Interesting info thanks, any idea if it has wear/temperature compensation?The only thing we have ever found is that the hydraulics side of things needs to be perfectly bled and kept air free as the system relies on the movement of the master being reflected accurately in the slave. In practice this is no effort and with modern components it's not like things need bleeding on a regular basis. It's certainly much less labour intensive then our LVDT on the clutch pack setup we run on the F1s.
With aggresive clutches it's also possible to change the relationship between paddle and cluthc posistion in much the same way as it is possible to change the relationship between PPS and TPS on a DBW throttle system which can be very useful when working with clutches with aggresive bite and small slave cylinder travel between initial bite and engagement.
Max_Torque said:
Interesting info thanks, any idea if it has wear/temperature compensation?
Wear yes, temp no but it would be entirely possible to implement it. There is plenty of spare IO on the controller. The initial design was to allow paddle or ECU clutch control on a standard hydraulic clutch setup so it could be used with existing conventional race car boxes hence the slave position infered from master position for example. I have plenty of spare Parker hydraulic pumps, Moog valves and valve blocks if you want to home brew something hydraulic up by the way but if you have air on the car already then it makes sense to limit the number of systems.
poppopbangbang said:
I have plenty of spare Parker hydraulic pumps, Moog valves and valve blocks if you want to home brew something hydraulic up by the way but if you have air on the car already then it makes sense to limit the number of systems.
I must admit, i had considered moving the car over to full hydraulic power, as i could then "activate" the diff as well........ ;-)Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff