Have a manual but don't like the clutch?

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MarkHawkins
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Have a manual but don't like the clutch?

Post by MarkHawkins » Sat Jan 06, 2018 8:12 pm

I saw an advert in a Land Rover (tmdtuning.com) magazine for a Semi auto clutch conversion for Defenders. Basically it's an electrically assisted clutch that is activated for gear changing by a push of a button on the gear lever. Taking off from rest is achieved by depressing the brake pedal which causes a controlled clutch release. I think Ford did something similar in the late 1950's a sort of Manumatic?


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Have a manual but don't like the clutch?

Post by scimjim » Sat Jan 06, 2018 9:11 pm

They’ve been around for years as a solution for disabled drivers but modern computers have seen them take off - and several super cars now use manual gearboxes with electro-hydraulic actuated clutches and paddle shifters because they can change gear quicker than an auto.


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Have a manual but don't like the clutch?

Post by Roger Pennington » Sat Jan 06, 2018 9:32 pm

One of the many advanced features of the Citroen DS19 in 1957 was that it had an automatic clutch, operated from the (column) gearchange lever, and actuated by the hydraulic system, which operated much of the car. :)


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Have a manual but don't like the clutch?

Post by halfpenny » Sun Jan 07, 2018 12:32 am

Manumatic was an AP Lockheed system which used a vacuum servo to operate the clutch. It also had a centrifugal engagement for drive away from rest. Newton had a similar system. Good reliable systems, but slow, and could be abused by setting off in top gear, with consequent massive clutch slip



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Have a manual but don't like the clutch?

Post by David Tew » Sun Jan 07, 2018 5:13 pm

Roger Pennington wrote:
Sat Jan 06, 2018 9:32 pm
One of the many advanced features of the Citroen DS19 in 1957 was that it had an automatic clutch, operated from the (column) gearchange lever, and actuated by the hydraulic system, which operated much of the car. :)
Similarly, the NSU Ro80 had a vacuum operated clutch controlled by an proximity sensor in the gearknob. Given the technology available at the time I can't imagine the change was that quick.

As ScimJim says, modern electronics now make this a much more sensible and easily achievable option.


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Have a manual but don't like the clutch?

Post by CNHSS1 » Sun Jan 07, 2018 6:58 pm

You can put a strain gauge sensor in the gear lever, when the lever loaded to shift it will engage the clutch. Race cars with dog engagement (not synchro) gearboxes use the strain gauge to fire a rev limiter to drop the revs allowing full throttle changes-- no need to lift throttle pedal


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Have a manual but don't like the clutch?

Post by Alan SS1 » Sun Jan 07, 2018 7:05 pm

two comments on servo clutch etc

I saw one about thirty years ago on a Regal, and as you gripped the bicycle lever attached to top of the gear lever it worked the servo!! dunno if there was any control or just on/off, I'd guess there must have been some control as a 701cc Regal didn't have stacks of torque :wink:

I think the NSU RO80 was so that the Wankel engine never actually stopped spinning at high revs as I'm sure there was also a fluid flywheel arrangement?

strain gauge sounds pretty fancy :shock: will it save your gear-box???


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Have a manual but don't like the clutch?

Post by halfpenny » Sun Jan 07, 2018 7:43 pm

The difficulty is not declutching to change gear - that bit is relatively easy. The big issue is modulating clutch engagement from rest, taking into account variables of gradient, load, throttle position etc. It is only the advent of microprocessors and multiple engagement maps that has made this reasonably effective for VW and others in DCTs (dual clutch transmissions). The centrifugal clutch in a manumatic works ok, but still removed a degree of driver control sufficient to make the system a commercial failure. Renault also tried quite hard with a similar system



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