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Old 19th January 2015, 15:33   #1
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Default What's the point of a Hydraulic clutch, why not go the "EPS" way

Many cars made the shift from a hydraulic power steering to an electronic power steering.
Now, that move has an impact on handling, so there are pro's and cons.

However, there is one system on the vehicle which is still hydraulic(diesels) or cable driven(petrol vehicles and low power vehicles).

That system is the clutch of a vehicle.
As per my understanding, most "trip tronic" systems use this electronic clutch thing, but can't we move to electronic clutch or semi-electronic(you still press it, but signal transfer is electronic).

The advantage would be that the problems of hard clutch etc., would be a thing of the past.
An electronic system with sensors etc., can also give accurate clutch wear indication.

Overall, the benefits are similar or even better than EPS vs HPS thing with no obvious drawbacks(other than extra electronics, but that is happening everywhere).
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Old 19th January 2015, 16:18   #2
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

Nice thinking Tanveer. Should these systems make way to consumer vehicles, hard clutch would surely be a thing of past. However, if the system, like the EPS sources its power when the engine is running, then it might be tricky if the driver stalls his car in a gear. With no engine running, he cannot use the clutch and also, he cannot crank the engine because the clutch is disengaged. However, if the power can be sourced from the battery straightaway, then may be it should work fine. Just a thought.

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Old 19th January 2015, 16:29   #3
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

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Originally Posted by saket77 View Post
Nice thinking Tanveer. Should these systems make way to consumer vehicles, hard clutch would surely be a thing of past. However, if the system, like the EPS sources its power when the engine is running, then it might be tricky if the driver stalls his car in a gear. With no engine running, he cannot use the clutch and also, he cannot crank the engine because the clutch is disengaged. However, if the power can be sourced from the battery straightaway, then may be it should work fine. Just a thought.

Regards.
Yes, that is a good line of thought. I think this is a deal breaker if car stalls in gear, what to do?
What if battery runs down and you need to tow the car?
But then this problem would also be there in triptronic vehicles. I guess that is why you cannot tow them, you have to flatbed them.
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Old 19th January 2015, 16:37   #4
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

http://www.team-bhp.com/forum/techni...ic-clutch.html (Bosch develops new electronic clutch)
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Old 19th January 2015, 17:06   #5
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

How is it too different from AMT? At least in part. I had read one post on this forum where a guy had installed a box that replicated the clutch action but using a button on the gear stick. He still had to shift the gears manually. So I think if an FNG can do it then the manufacturers definitely can, but whether they should just do this part automation or go complete hog and fit an AMT would depend on a business case.
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Old 19th January 2015, 17:34   #6
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

My view may not be popular but it has to be shared. When components are fully mechanically connected, as in with real mechanical parts like master-cylinder, slave-cylinder, hydraulic chamber, hydraulic oil, belts, sprockets, spindle etc etc, one gets an actual feel of the working of the components when the vehicle is in motion.

The reality is fully mechanical cars are very, very reliable & gives an indication of wear-tear in most cases. I personally dislike motor driven steering due to its overly light, numb feel - dislike being the softest term I can use. Let me be clear though, just because I like hydraulics and mechanical bits & pieces and hate electronics it doesn't make me a 'better' enthusiast, its just a point of view. I even dislike drive-by-wire even though there is no disadvantage to having it - its even quicker to respond than conventional accelerator but I just like knowing there's that mechanical connection to everything, its very reassuring.

The hydraulic clutch, much like steering gives a kind-of organic motion due to its assembly. The resistance it gives, the way it moves in are all a result of real components working during the process. With each car its an exciting learning process - at which point the clutch holds the vehicle, where exactly the motion begins (if its half-clutch or a bit more),etc. Making the pedal input electronic means any resistance has to be artificially tweaked & other input functions have to be programmed which really doesn't sound like a car to me personally. Its very easy for electronic components to fail (fully battery dependent). For eg., electronic hand brakes fail if a sensor or solenoid goes kaput. That being said this is only my personal view, I'm sure those who want modern electrical-linked inputs can come up with their own views to justify the same.

Last edited by dark.knight : 19th January 2015 at 17:38.
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Old 19th January 2015, 18:01   #7
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

Apart from the ^ Well AMT is almost an electric clutch only, why not? Well it makes it more complicated and feel would totally dependent on the spring load of the pedal. KISS - Keep It Simple Stupid - Maybe?
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Old 19th January 2015, 21:30   #8
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

I'm no expert but from my experience with electrical drives and actuators, I think the main reason that clutches are still hydraulically actuated (when automated) is because of technical limitations with electric drives. Clutch actuation requires fine control and a fast response. This is particularly hard to achieve with electric actuators in a practical and economical manner and easiest to do with hydraulic actuators. The retrofit kits currently available are crude implementations of electric drives and lack the refinement of a well designed system.

Hydraulics might evoke big earth movers, excavators and other brute force machines but in reality, the degree of control that is possible with hydraulics is extraordinary. A quick Google for excavator and egg pick up with show amazing demonstrations of what is possible.
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Old 19th January 2015, 21:45   #9
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

^Good point. Imagine scenarios of quick shifts, clutch press, gear shift and clutch release are done so fast and is synchronized. If there is even a small delay in clutch activity, gear shift won't happen properly. We need a super quick response from the electronic clutch or a double clutch in that case and it only adds to the cost.
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Old 19th January 2015, 22:02   #10
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Default Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

I'm with Dark.Knight here. I'm no puritan but we're fast getting to a point where cars (and bikes) are getting overly complex, and electronics-dependent. One unexpected failure can result in a 50-lac rupee statue of metal, rubber and plastic.

We had an old Fiat, the Premier Padmini. It was almost entirely mechanical, but like the Bullet, replacing CB distributor with an electronic ignition made it more reliable, as also the Bullet with it's CDI/TCI ignition over CB points. Electronics were limited to stereo and ignition then. EFI was welcome too, in next generation of cars, but it was proven reliable before it was accepted en masse. Enthusiasts no longer can easily fiddle with the machine , apply jugaad to temporarily get going until proper garage is found - we're sitting ducks should one of our modern machines fail us in late in the night, or in a far our area due to an electronics failure that we aren't prepared for, not like simple fuse replacements or duct-taping frayed wires.

Now if your battery goes flat in the middle of nowhere, you're up the creek without a paddle, as they say. Are batteries more reliable now than in 1970s/80s ? Yes. But if your battery died then, you only lost stereo and lights. Now, you lose the door locks and even starting. And we still get cases of batteries dieing on us with minimal or no warning of impending failure.

The electronic-controlled and networked cars get, the more they get susceptible to points of failure, and hacking. If there is any sort of receiver on your car, it could be a target for malicious attacks, and already smartphones have become means of tracking, and cracking, into identity and banking information. With cars, a proverbial ghost-in-the-machine scenario waiting to happen, unless engineers think of blocking or reliably protecting every possible external input.

Take aircraft for example. Aeronautical designer go the extra mile to make the plane weigh as little as possible, yet they provide a manual jack to the pilot to open the cockpit canopy in emergency. I hear 5th generation US fighters skipped this backup. Then one day, a pilot was trapped in the cockpit for 5 hours and the canopy perspex had to be cut open with chainsaws.

I don't mind the electronics. I certainly don't want to go back to days where engine ignition timing advance was done by hand. But beyond a point, electronic aids become bottlenecks and the cost of incorporating them and the risk of failure leaving you stranded and helpless is raised. But like with IT and aviation , stress the importance of back up, back up, backup and manual override. Electronic aids should remain just that - aids.

Last edited by Ricci : 19th January 2015 at 22:12.
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Old 20th January 2015, 14:14   #11
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Post Re: What's the point of a Hydraulic clutch, why not go the "EPS" way

Quote:
Originally Posted by tsk1979 View Post

As per my understanding, most "trip tronic" systems use this electronic clutch thing, but can't we move to electronic clutch or semi-electronic(you still press it, but signal transfer is electronic).

The advantage would be that the problems of hard clutch etc., would be a thing of the past.
An electronic system with sensors etc., can also give accurate clutch wear indication.
well using a tiptronic system make you use manual shift even if your cars an automatic. if you prefer manual and you know you can shift better than the car's inbuilt program, why get the system anyway. Cost is also a concern here in the cars we use and by this system we will be investing more money on the electronics stuffs which I think removes the fun. I believe there is no clutch for this , and that makes this transmission into a work of simply moving up and down the paddle or gear lever.
That would take the fun out of shifting gears.
Taking it to a higher rpm, pausing it while holding the clutch and shifting up.
That's driving. I hope Trip tronic is same as Tiptronic.
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