|
I don't see any problem with electric PAS :) It's fuel efficient (no pump via belt) & maintenance free (no fluid to check)
|
>>maintenance free
I think you'll find a few people on technical who'll disagree with that.
|
I've driven 3 cars (that I know of) with electric, or perhaps electro-hydraulic, PAS - disliked every one.
As a direct comparison I test drove a 1.8 Avensis (electric PAS) and thought the steering was awful. I now own a 2.2 D4-D Avensis (hydraulic PAS). The latter is streets ahead of the former.
|
I've only driven one I think, a Punto hire car in Spain. The 'city' button changed the steering from numb and very light to numb and super-light.
It had no feel whatsoever but was accurate enough, so the lack of feel didn't matter really. It was a nice little car for getting about in cheaply but a bit like driving a washing-up machine.
|
Just for the record, SWMBO Getz has a conventional belt driven hydraulic PAS system. Yes, it feels disconnected from the road.
My Hyundai Coupe's hydraulic system is little better.
Never tried an electric system but if they are worse than the above......
|
Just for the record SWMBO Getz has a conventional belt driven hydraulic PAS system. Yes, it feels disconnected from the road.
My apologies, I was sure I had read somewhere that the Getz has electric PAS, but no it doesn't, I never properly checked to confirm it.
;o)
|
Cheers for the replies.
The Scenic has electric PAS, and although the weighting is actually OK, it has this horrible rubbery, springy feel to its self-centring which destroys any sense of feel of what the front wheels are doing. The Volvo has a conventional system which is just horribly over-assisted, but even that gives some degree of feel. These two cars illustrate that weight and feel are not necessarily the same thing.
Neither are a patch on my old mk2 Mondeo or particularly SWMBOs old mk4 Fiesta which had this constant "chatter" through the rim, with subtle shifting of weight and feedback over differing surfaces. It was irrelevant in most driving conditions, but it made the car feel good.
I'm still not sure why an electric motor on the steering column should rob feel when it is turned off and not doing anything, as it must be in most driving conditions.
Cheers
DP
|
|
|
|
>>I've only driven one I think, a Punto hire car ...
>>...a bit like driving a washing-up machine.
I haven't found the spin cycle on mine yet :)
Maybe it will happen one day with some vigorous cornering.
|
Why do we still have steering wheels anyway ?
Why not a Joystick or controller coupled to electric PS ?
|
Because one vital and highly sensible aspect of vehicle construction and use legislation makes a direct mechanical link between the steeering wheel (or tiller if you like) and the steering road wheels mandatory.
659.
|
Why not just have a computer keyboard? It'll be just like grand theft auto without the kit.
I mean please. Tiller steering was abandoned in the first years of the last century, more than a century ago in fact.
Does anyone imagine that a drive by wire update will be any better?
I ask you
|
|
|
Because one vital and highly sensible aspect of vehicle construction and use legislation makes a direct mechanical link between the steeering wheel (or tiller if you like) and the steering road wheels mandatory.
The antiquated, outdated, and luddite requirement for a direct mechanical connection really has outstayed its welcome.
There hasn't been a direct connection between pilot and control surface for quite some time!
It could now be replaced by a modified requirement to have either a direct mechanical connection or a fully redundant indirect connection, which would allow some meaningful technical advance.
In terms of vehicle controls, the history of passing control from human to computer has been extremely sucessful - is there any sensible reason to think that a computer controlled steering system would be unsafe. Consider a system like ABS - how often has ABS failure resulted in an unsafe vehicle?
Edited by Number_Cruncher on 22/05/2008 at 10:39
|
is there any sensible reason to think that a computer controlled steering system would be unsafe. Consider a system like ABS - how often has ABS failure resulted in an unsafe vehicle?
I agree.
When was the last time anyone heard of a drive by wire accelerator causing a crash either?
Many of us drive cars with no mechanical link between the throttle pedal and the engine, and don't think twice about it.
Cheers
DP
|
"When was the last time anyone heard of a drive by wire accelerator causing a crash either?"
Ford Focus Throttle position sensors causing cutting out at Junctions or roundabouts.
Must have been one or two incidents involving this, but just not enough to activate a recall.
To be fair many of these throttle position systems are still directly linked, the position sensor providing data to the ECU. I also suspect that the drive by wire is no more unrealiable than a traditional cable / flap arrangement which can break or stick.
|
I think we should not compare cars with aeroplanes. There are more numpties on road than on sky. In airlines, fly by wire is fine as there are back up devices in case of one control fails - and there is auto pilot (which can even land the plane safely).
I personally like to see more mechanical controls in cars than electronics. Modern electronics are highly reliable, but it can never be a substitue of mechanical "feedback". That's why computer gamers use expensive joysticks which give them physical shock during gameplay :)
|
fly by wire is fine as there are back up devices in case of one control fails
Yes, that's why I used ABS as the example. Within the controller, there is such a duplication or backup - there are 2 processors, each checking the output of the other. So, there are systems with back up on cars, and so, there's no reason why an indirect steering system shouldn't have two independant paths, independant sensors, indepenadant actuators, and processors.
|
|
Still sounds like a dumb carp idea though Mapmaker. What on earth is the POINT?
|
Lack of feeling - didn't realise the Octavia was electric until I tried to turn the wheel with the engine stopped.
As far as the link between the steering wheel and road wheels remember that these are the same regulatory bodies who require catalysts to be fitted rather than setting emissions performance levels to be met. Just imagine what lean burn would be like now if the regulations had not killed it off. Someone in the catalyst industry did a good job lobbying for that!
|
Just imagine what lean burn would be like now if the regulations had not killed it off.
When you look at the economy figures Ford were getting out of a lean burn optimised 1960's engine design running on a carburettor in a heavy family car back in the 80's, fairly impressive would be my guess.
Cheers
DP
|
|
Apologies Mapmaker. I meant Number Cruncher of course. Doh.
|
>>What on earth is the POINT?
Ah, so, should we still be rotating the entire dead axle about its centre using chains?
The point is that with more intelligent control, both vehicle manouvrability and vehicle handling could be improved. There would be no need to have a direct link between the left wheel and right wheel, so their relative positions could also be controlled.
The scrub, tyre wear, and inefficiency that results from the agricultural steering mechanisms we have now could be reduced.
Linking to the thread about could you design a better car, removing the direct mechanical link would free up lots of design options which are currently closed off owing to the need to provide lots of heavy metal work between the steering and road wheels.
|
No NC, we don't want to revert to wire-and-bobbin steering of the whole beam axle, and we don't want to return to tiller steering.
The fact is that even power-assisted steering, which retains a direct mechanical connection between steering column and wheels, is less than satisfactory when power assistance is lost. But it isn't as downright lethal as a fly-by-wire arrangement having conniptions might be.
As for all these sophisticated wheel-angling possibilities to prevent wear, tyre scrub etc., they don't sound as if theyt would work properly for long.
The suspension and steering of cars are heavy-duty parts doomed to a violent life. Their mechanical design has reached very high levels of sophistication, although of course you get what you pay for. The most perfect steering I have ever tried was in a fifties Lancia B20, unassisted of course. The very thought of a bunch of silicon chips and little actuators doing all this for me makes me sick with worry.
I think you are just trying to wind us up actually.
|
>>I think you are just trying to wind us up actually.
The pot is calling the kettle black!!
>>But it isn't as downright lethal as a fly-by-wire arrangement having conniptions might be.
If the controlling legislation were re-worded carefully, unsafe designs would still be excluded. It can be done - it might not be cheap though!
>>The very thought of a bunch of silicon chips and little actuators doing all this for me makes me sick with worry.
I'm the opposite. Once a system has been well developed, I'm much more likely to place my trust in digital logic than in the extremely variable response of a human being. Silicon chips don't get tired, they don't have hangovers or complicated personal lives!
To make a broader point, it's an odd observation that whenever something goes wrong with a car, the novice, inexperienced, and less than skilled always tend to blame the most expensive or complex part. How many ECUs have been replaced needlessly over the years when the true fault has been a corroded earth wire?
Are you equally unhappy about allowing silicon to control the ignition and injection of your engine, or would you rather carburettor and points?
ECUs in general are extremely reliable, and in the type of redundant system were talking about in this thread, reliable enough to be given full control authority over civil jet airliners, with the pilot there just to keep the seat warm!
In short, I think that this piece of legislation is holding back vehicle development. There could be a step change forward in what we think of as being a car if this law were updated.
Ideally, of course in the long term, the need for a driver would be removed, and the concept of steering feel itself would become obsolete. This removal of the one psychological element of subjective vehicle handling assessment would also be a good thing IMO.
|
OK NC, you're a techie writ large and I can only salute you for it.
But I think reading between the lines you've got it in for the automobile. What you really want is to get into an ownerless, sterile plastic egg, which of course will always be available when and where you want it, punch a few coordinates into a keypad, insert your credit card in a slot and swivel your seat round to face your companions and play backgammon, hold a business meeting or take drugs, while the machinery, wires under the road and so on, will quietly, comfortably and perhaps rather slowly take you to your destination.
I on the other hand have a motoring consciousness hovering somewhere between 1900 and 1960, moving back and forth quite a lot. I like tuning carburettors and getting contact breaker ignition spot on actually. It's why I liked Skodas when so many didn't and why my Skodas overtook Audis uphill when others seemed very slow.
Horses for courses innit? (bit scared of them actually, I know they're nice civilised animals but I don't understand their thought processes and they're so big and strong).
|
>>But I think reading between the lines you've got it in for the automobile.
That's a bit strong! - I suppose I don't think that it's sensible for things to continue as they are.
I do enjoy tuning an old tech engine, and transforming a rough coughing dog of a powerplant into a silky smooth one is one enjoyable aspect of a mechanic's work which has gone forever. However, I'm glad I don't need to do it to any of my family's cars anymore.
>>What you really want is to get into an ownerless, sterile plastic egg, ....
I've nothing against ownership, but, the bit about actually being able to use journey times for something useful is something I can't wait for - all time spent behind a wheel is lost, forever, and I resent every minute. If all of my driving were done over deserted moorland roads, then, driving might be a pleasure, but, in our crowded, scamera infested city streets, anyone who professes to enjoy rush hour urban driving can only be but one stop removed from the type who gains a certain kind of pleasure from the submission of control and the imposition of exquisite pain.
If the system were well controlled, there wouldn't be a need for progress to be rather slow - imagine an efficient road system, free of mimsers and carphounds!
|
imagine an efficient road system free of mimsers and carphounds!
There are moments when it's like that, but seldom for more than a few minutes. Of course fewer vehicles always make a road system feel better.
The pleasures of driving are many and various. Even nose-to-tail can have its moments in the right car if you're in the right mood. But I agree, most sorts of driving can pall when you aren't.
Of course the fully-automated plastic egg traffic would save us from mimsers and carphounds. But my guess is that for technical, financial and political reasons the system would be a mimsing system, in spades. Imagine the clamour when some fool gets run over by a failsafe 22mph road rocket running on a sip of hydrogen and controlled by some sort of government (or offshore pirate-owned) failsafe mainframe computer system. My heart sinks at the thought of it.
And would dinosaurs like me be allowed out in their heavy-metal, polluting, unregulated museum pieces? Brave new world and you know where you can stick it comrade (no offence though).
|
>>the system would be a mimsing system, in spades.
Not necessarily - there's the precedent of the railways where vehicles run to pre-determined paths.
>>Imagine the clamour when some fool gets run over by a failsafe 22mph road rocket
Again, if it's compared to railways, then I don't see the problem. Of course, plastic egg traffic would always obey pedestrian crossings, unlike normal traffic.
>>And would dinosaurs like me be allowed out in their heavy-metal, polluting, unregulated museum pieces?
Only if you're being towed by an egg!
>>Brave new world and you know where you can stick it comrade (no offence though).
Go on then Lud, paint your view of the future of motoring! How will the mimsers, the carphounds, the scameras, and the Brunstroms be kept at bay?
|
They won't of course. They are already an effective majority. We've had it.
You weren't comparing road traffic with many small vehicles swerving about all over the place with a much simpler railway system with few, large vehicles running, ahem, to a timetable were you?
No, surely not. A scientific element like you...
|
>>small vehicles swerving about all over the place
Not swerving about, I was thinking more of vehicles following controlled paths with controlled enforcement of when to stop, and when to go, without driver intervention, in other words a controlled infra-structure. I didn't imagine a timetable, but, I could imagine that for some paths at peak times your egg's computer might need to either book or queue.
|
Think of road systems in their entirety. Compare them with rail systems. I don't think 'swerving about all over the place' is putting it nearly strongly enough to be honest.
No doubt it could be made to work on a small scale given vast investment and enough crazed techies. But it would all work, one can be sure, very slowly in the name of 'safety'. And wallies would still get run over by these driverless intelligent machines and their relations would still scream the place down.
As you know perfectly well NC. You have succeeded in winding me up. Damn!
|
>>Damn!
Sorry Lud!
The thought of autonomous Xsara Picasso lookalikes whizzing about actually fills me with dread!, but, I still resent every wasted minute behind the wheel.
Since the birth of Number_Nipper, we've given in to the strong magnetic pull of the suburbs. Now, it's very difficult for me to use the train, and I must drive to work. Every day, I get about 1.5 hours less work done than before, and so, I need to use some (more!) time at the weekend. Having said that, the company in the car is much more congenial than that on the train!
|
My only piece of published fiction, a science fiction comedy I suppose you would call it, in the small, evanescent literary magazine Bananas, concerned a furious old geezer with a 1958 Vauxhall Cresta, just about able to run on the cylinders of gas available, in an early 21st century - about now actually - dominated by just such a nightmare automotive vision as we have been discussing, with of course the soft and plutocratic state dirigisme that would have to accompany it.
When I wrote it in the 70s (I think) I imagined the central character, Mr Murgatroyd, as an out-of-place angry little geezer with a bristling moustache, essentially reactionary and backward, one of nature's Telegraph readers as I then saw them. Ripping out the last bits of petroleum, in my fiction, had devastated much of the world including Wiltshire and Hampshire.
I realise not without a sort of horror that moustache apart, I have become a tiny bit like that myself in a way. But the world hasn't kept pace. No automated plastic eggs yet. And still a few billion barrels of the good stuff.
I wish that piece was available electronically actually, but I used typewriters in those days.
Edited by Lud on 23/05/2008 at 00:57
|
Lud, N_C, interesting exchange of opinions. I think that you are both right. The problem(joy?) of motoring is that it has many forms and as many practicioners of the art.
There is a tendency to treat driving as a means to an end, the actual controlling of the vehicle is only done to ensure arrival at the destination. This is the congestion nose to tail stuff where N_C's "automatic for the people" vehicle would be ideal. (I do wonder sometimes why someone hasn't tried the Laural and Hardy or was it Buster Keyton strong magnet principle, attach to front of car, and follow car in front).
Then there is the other reason for using the car, the driving is the end, the pleasure of controlling a mechanical device, the sound, feel and general sense of enjoyment of driving. This aspect of motor vehicle use is totally misunderstood by those who just see it as a chore. A few months ago I had the pleasure of driving a 1978 Porche 911. Right from my early days of reading D.S.J. in Motorsport, I had always wanted to have a go in something which would bite back. The car was everything I expected, fun exciting and an aural and sensual pleasure. I doubt that I took it anywhere near its bite back limit, it wasn't my car to risk. (A sticking/inoperative nearside front caliper was enough to deal with.)
|
For anyone that believes the egg scenario will happen anytime soon just go and look at the Docklands Light Railway.
Automatic trains but it took years to get the system to be able to work properly with just ONE junction.
How many junctions are within 1/2 mile of your home, then imagine how much computing power it will need to decide when to go and when to stop!
|
it took years to get the system to be able to work properly with just ONE junction.
Yes, it's a fair point that there's a lot of infra-structure changes required. But, in terms of logic and computing power, it's not that long ago that there was only ONE transistor in the world.
|
I've taken the DLR twice, there and back as it were.
I suppose they had to squeeze it in between existing and projected buildings and it is quite fun in a way, but lacks the solidity one always imagined would be present in the Dan Dare future, especially in the fifties when many products were badly made and designed. Indeed the track is exceptionally bumpy and wavy, and the wheels make awful noises on some of the very tight curves. The whole thing feels, and at close quarters looks, very flimsy.
|
|
The automatic train from railway to airport at Gatwick works much more suavely, but then it is a simple shuttle running in a straight line with a station at each end, hardly more complicated than an electric typewriter.
|
|
Been on that "Gatport Airwick" one a few times and the one at Stansted. Still feels like witchcraft if you are standing at the front!
|
|
|
|
|
|
