Hydraulic steering vs electric?

[Mr2Mike]

ging84 said:

a microchips are some of the simplest things in the world, this is why they are produced in the billions per year, they rival the simplicity of a screw or a paper clip.

Are you trolling or do you actually believe that?

[ging84]

Mr2Mike said:

ging84 said:

a microchips are some of the simplest things in the world, this is why they are produced in the billions per year, they rival the simplicity of a screw or a paper clip.

Are you trolling or do you actually believe that?

which bit do you not believe?
the bit about they are produced in the billions per year, that is fact
maybe paper clips were not the best comparison, they are a little bit too simple

How about they are as simple as a sheet of news paper, that's an analogy i am very happy with

[Kozy]

Can anyone explain why the EPS in the S2000 is routinely slated, yet the same Showa rack in the RX8 is praised?

IIRC, the RX8 has a slightly longer ratio, around 16:1 vs 13:1 in the S2000, but what else could make one a dog and the other superb?

[Terminator X]

Have the latter on the S5, feels very artificial to me certainly vs the 130i which is just power steering.

TX.

[gvij]

Tell all this to my mum who is on the 3rd rack in 8 years on her bought new 1.6fsi mk5 golf. Electric racks are ste.
Your looking at 1100 in parts+dropping subframe+4 hours labour+adapation+tracking=1500 per shot. 1 or 2 mpg is what 30 quid a year in fuel at most versus 1500 a time. They cant be reliably rebuilt as the ecus, sensors and mechanics aren't serviceable. Too much labour to be worthwhile buying used.
Basically new cars are ste

[JonnyVTEC]

Kozy said:

Can anyone explain why the EPS in the S2000 is routinely slated, yet the same Showa rack in the RX8 is praised?

IIRC, the RX8 has a slightly longer ratio, around 16:1 vs 13:1 in the S2000, but what else could make one a dog and the other superb?

The suspension?

[Mr2Mike]

ging84 said:

which bit do you not believe?
the bit about they are produced in the billions per year, that is fact

That is obvious, I have no argument with that.

ging84 said:

maybe paper clips were not the best comparison, they are a little bit too simple

How about they are as simple as a sheet of news paper, that's an analogy i am very happy with

Do you mean simple to produce as a piece of paper, or their operation is as simple as a piece of paper? Either way you are fundamentally, and hugely mistaken.

Just because something can be produced in high quantities for low prices certainly does not mean they are simple. Production of integrated circuits is fantastically complex, and involves a large number of operations that have to be performed under very tight control. Likewise the design of IC's is very complex, especially very large scale integration devices such as modern microprocessors and FPGAs. At the physical level, the operation of even a simple integrated circuit is also far from simple and beyond the understanding of most people.

You can make paper at home, could you make an IC in your kitchen?

[nickfrog]

To cost effectively produce a sheet of A4 that will reliably go through a laser printer, you need a lot of fairly sophisticated/complicated technology and chemistry.

And a huge investment (about £50 million £).

Visiting a decent size "paper mill" was one of the most amazing industrial experiences I have had.

Slightly OT, sorry !

[anonymous-user]

The point i guess is that the "cost" of something which isn't using a massive amount of raw materials (like a microchip, a sheet of paper, or whatever) is more about the volume it's produced in, and less about the complexity within!


A modern ARM processor has a around a billion transistors in it ( Transistor_Count ) yet can be purchased for less than £1 because they make 10s of millions of them a year....

Edited by anonymous-user on Tuesday 30th December 12:48

[buggalugs]

shoehorn said:

What is it with you lot?
You clearly do not seem to understand what the word complex means,or are missing the point!

Hydraulics are simple to implicate and simple to repair with little knowledge,we have built the world using hydraulics,farming uses it,the building industry,manufacturing,the next time some one digs a road,lifts something heavy,or comes to recover your broken down car they will be using hydraulics because it is not complex.

You've had a bad experience with a Corsa electric system, I've had a bad experience with the pump shaft shearing on my E46 while apexing a roundabout. My mate's Puma pissed all it's fluid out of a corroded cooler pipe. It's just whatever your comfort zone is I guess. Either way for better or worse we can all agree which way the wind is blowing!

[Mr2Mike]

Max_Torque said:

So, high frequency vibrations, typically those that are a result of road surface, tyre tread / carcase shuffling etc, get damped and do not make it up to the handwheel. This results in a "lack of feel" to a skilled driver.

Because these are damped by the motors inertia, the system cannot even measure this high frequency component, no matter what torque sensor or control bandwidth is available.

Out of interest, why could the heavy iron armature of motor not be decoupled from the rack at high frequencies using some kind of cush drive? Is this just a space problem?

[MagneticMeerkat]

Mr2Mike said:

Max_Torque said:

So, high frequency vibrations, typically those that are a result of road surface, tyre tread / carcase shuffling etc, get damped and do not make it up to the handwheel. This results in a "lack of feel" to a skilled driver.

Because these are damped by the motors inertia, the system cannot even measure this high frequency component, no matter what torque sensor or control bandwidth is available.

Out of interest, why could the heavy iron armature of motor not be decoupled from the rack at high frequencies using some kind of cush drive? Is this just a space problem?

I don't see why not, but you're kind of approaching this from the wrong angle. To the average driver, like me, the fact that shocks and vibrations get damped before they reach the steering wheel is a good thing! Unpowered steering offers this 'feel' everyone keeps droning on about; but in everyday situations it borders on the unpleasant. Thus the vibration damping effect of the electric motor is, more than likely, a happy side effect for the manufacturer who will wish to keep it there. Their market research people, the average drivers, will no doubt report back and state how nice it was to have a steady steering wheel!

So I don't see why it can't be done, but from a commercial perspective I doubt anyone would want to do it on the basis it would add complexity and make the product slightly worse. Also the only cush drive I've ever seen was designed to apply torque one way. I could be wrong, but as steering applies torque loads two ways, often in rapid succession, a rubber cushion is likely to break up? Perhaps things have come on since the eighties example I had to dismantle...

[anonymous-user]

Mr2Mike said:

Max_Torque said:

So, high frequency vibrations, typically those that are a result of road surface, tyre tread / carcase shuffling etc, get damped and do not make it up to the handwheel. This results in a "lack of feel" to a skilled driver.

Because these are damped by the motors inertia, the system cannot even measure this high frequency component, no matter what torque sensor or control bandwidth is available.

Out of interest, why could the heavy iron armature of motor not be decoupled from the rack at high frequencies using some kind of cush drive? Is this just a space problem?

You can, and in fact, it's been done. But adding some form of compliance or filter between the motor and the rack adds complexity, cost and another failure mode. None of those things are happy bedfellows with steering systems! Generally, the later EPAS systems use low mechanical inertia motors, with high speed brushless motor controllers that attempt to cancel the mechanical inertia completely. However, the control strategies and software development required has taken a while to perfect. Some prototype systems are demonstrating using an rotational accelerometer in the handwheel so this electronic filtering can be adapted in near real time.

[WinstonWolf]

Mr2Mike said:

ging84 said:

which bit do you not believe?
the bit about they are produced in the billions per year, that is fact

That is obvious, I have no argument with that.

ging84 said:

maybe paper clips were not the best comparison, they are a little bit too simple

How about they are as simple as a sheet of news paper, that's an analogy i am very happy with

Do you mean simple to produce as a piece of paper, or their operation is as simple as a piece of paper? Either way you are fundamentally, and hugely mistaken.

Just because something can be produced in high quantities for low prices certainly does not mean they are simple. Production of integrated circuits is fantastically complex, and involves a large number of operations that have to be performed under very tight control. Likewise the design of IC's is very complex, especially very large scale integration devices such as modern microprocessors and FPGAs. At the physical level, the operation of even a simple integrated circuit is also far from simple and beyond the understanding of most people.

You can make paper at home, could you make an IC in your kitchen?

I do NOT AND agree with you, once you get your head around them they're a doddle, there's just a lot of repetition

[AJB]

shoehorn said:

But How the hell can an electronic system that needs various data sources from various sensors,a computer or 2 to decipher and use that data,a motor,gearing,complicated software,relays,modules and decent controlled electrical supply be any simpler than something that boils down to basic physics.

You're saying the hydraulic system is a pump, a pipe, and a rack with a piston in it, but the electronic system has very many complex components. I could just as easily say that the electric system is a motor, a sensor and a few wires, whilst the hydraulic system has many fine tolerance seals, springs, valves, etc., as well as pump, pistons, belts, idler pulleys, cooling pipes, etc..

Hydraulic systems are probably still more reliable as they've had 50 years to work out how to make them. If electric systems had been around for decades, and then one manufacturer came up with a new mechanical/hydraulic system I'm pretty sure it'd be a disaster. It would get condensation in the fluid which would freeze on a cold morning and block some pipe. Or seals would fail. Or spinning the wheels from lock to lock in the air during an MOT would invert a seal. Or whatever.

shoehorn said:

a ball bearings trapped in a hole being pushed by a spring,hardly complex compared to even a simple microchip or an electric motor.
So how the hell is it less complex or less simple?

Thing is, making a ball bearing, a spring, and a seal to exactly the right tolerances out of exactly the right materials is something I couldn't do at home. If a seal failed, I'd need to get exactly the right one from the original manufacturer. If a capacitor failed in a control unit, I'd probably have a lot more chance of getting an off the shelf replacement from anywhere.

Although you might find electrics/electronics unfathomably complicated, mechanical systems attempting to do the same job are just as complex. The final iterations of carburettors were really complex as they had to meet ever tightening emissions laws. In comparison, early fuel injection was pretty simple.