[btsave]

Since there are no mechanical connections from the Driver to the steering, throttle, etc., what happens in the event of a computer or power failure?

Will we still be able to steer?

Is there a backup system of sometime?

Thanks!

[Martin L]

Steering and brakes are still mechanical, so you will be able to steer and brake, but extra force will be need as no power assistance will be there.

I was reading about the Mercedes concept car that "tilts" it's wheels when cornering and this has brake by wire
This is too scary to even contemplate electrical failure

[MCS1]

Martin,

When did you last fly? If you were in any Airbus, a new Boeing 737 or 777 or I think 747-400, then you were flying by wire....and the consequences of electrical failure at 35 thousand feet are slightly worse than at mini height

Drive by wire will be fine - there will be lots of redundancy, and the software will help improve the stability if the car through corners, and in sidewinds and so on....in fact, cars'll get to the point in 10 years time, that the driver will be completely superfluous! Mmmmm, maybe that's not so good then

John

[Martin L]

Quote:

Originally posted by MCS1
Martin,

When did you last fly? If you were in any Airbus, a new Boeing 737 or 777 or I think 747-400, then you were flying by wire....and the consequences of electrical failure at 35 thousand feet are slightly worse than at mini height

I fly at least once a month, usually in a 757 or Airbus, and yes they are fly by wire.
Point taken but how many more millions are invested in aircraft develpoment/safety then cars??????
A new small airbus is around £50m and jumbo about £120m so I think what you are getting is a far more technically sound piece of kit when buying a plane.

When I'm in control of something I like to have the reassurance of mechanical back up

[btsave]

When In turn my steering wheel, i can hear the small electric motors turning the front wheels. Maybe I've missed something, but when I open the bonnet, I cannot see a steering column. Additionally, when i look at the brake line, i do not see any mechanical connection between the pedal and the master cylinder. Also, the accelerator is simply to a box with electrical wires going to the throttle control assembly.

I don't want to quibble, and I'm probably missing something here.

Where do I look to see the mechanicall linkages from steering wheel, brakes and accelerator to their complementary systems? Also, are you certain that it really is "power assisted" steering, rather than true "power steering"? Thank you!

confused.

BTW... when we can buy a jet for the price we paid for our mini's, I think I would begin to take the Tram.

[Paul]

Steering is power assisted, not just power.

The steering system on a MINI is electro-hydaulic. i.e. it does not use an engine driven pump, but an electrically driven that pumps hydraulic fluid to the steering rack.

The benefit of that system is that during normal straight driving, the pump is not required and not driven (unlike an engine driven pump) and gives the benefit of a small decrease in fuel consumption. More modern cars are/will use the same system. I think the new Vectra/Astra do?

Brakes are normal, ABS brakes I think, although they are of course wired to the ECU for cornering brake control etc. (which is, I think, part of the ABS system).

The only true 'drive by wire' component is the throttle.

[btsave]

Thank you for the clarification!

[chiph]

Quote:

Originally posted by Paul_Mullett
<snip>The benefit of that system is that during normal straight driving, the pump is not required and not driven (unlike an engine driven pump) and gives the benefit of a small decrease in fuel consumption. More modern cars are/will use the same system. I think the new Vectra/Astra do?<snip>

The new Saturn SUV, the VUE, also has electro-hydraulic steering. I don't think ya'll get it (or the Saturn brand) in Europe. http://www.saturnbp.com/vue/

Chip H.

[BruceK]

Quote:

Originally posted by btsave
..Where do I look to see the mechanicall linkages from steering wheel, brakes and accelerator to their complementary systems? Also, are you certain that it really is "power assisted" steering, rather than true "power steering"? ...

Just to add a little info more about the steering. It is completely mechanical with the steering rack (as in "rack and pinion") running horizontally across the width of the car physically connecting the two front wheels together - one wheel can't change angles unless the other does in (roughly) parallel. Complimenting this mechanical arrangement, as Paul mentioned is, an electro-hydaulic pump that helps reduce the effort of turning the steering wheel. Note: "power steering" and "power assisted steering" really mean the same basic thing: the manual effort needed for a driver to turn the steering wheel is lessened by some degree(s) by use of hydraulic or electronic means (in the MINI, it's a combination of both).

If you want to prove to yourself that the MINI steering is mechanical and works without any electrical power, it is possible (but takes a lot more effort) to turn the steering wheel when the car is powered off and have the angle of the front wheels affected.

[HarryHBMCC]

Quote:

Originally posted by chiph
The new Saturn SUV, the VUE, also has electro-hydraulic steering. I don't think ya'll get it (or the Saturn brand) in Europe. http://www.saturnbp.com/vue/

Chip H.

Several of the Saturns have fly-by-wire throttles too, as they are based on the same platform as the Opel Vectra.

Harry

[sjbartnik]

Quote:

Originally posted by btsave
[b]When In turn my steering wheel, i can hear the small electric motors turning the front wheels.

No you can't, because there are not small electric motors turning the front wheels. There is a mechanical steering rack (rack and pinion steering) connected to the wheels in the conventional way, i.e. tie rods.

The steering wheel moves the rack back and forth via the mechanical steering column. The MINI has an electrical power steering pump, which pressurizes the power steering fluid to provide steering assist when needed (as opposed to most other cars which have an engine-driven pump to do the same thing). That is probably the noise you are hearing.

Steering-by-wire technology does exist but not on any production car that I'm aware of and certainly not on a car that sells for $16,000.

Quote:

Maybe I've missed something, but when I open the bonnet, I cannot see a steering column.

You've missed something. I can assure you it's there.

Quote:

Additionally, when i look at the brake line, i do not see any mechanical connection between the pedal and the master cylinder.

Then you are not looking hard enough or not looking in the right place. Most of this linkage would be found under the dashboard. Brake-by-wire technology does exist and Mercedes-Benz currently uses it on some of their higher-end cars, but a mechanical backup system is included.

Quote:

Also, the accelerator is simply to a box with electrical wires going to the throttle control assembly.

Sure is. The only "by-wire" thing on the MINI is throttle-by-wire. There is no mechanical connection between the accelerator pedal and the throttle.

The pedal is connected to a spring-loaded sensor to approximate the feel of an accelerator cable and the signals generated are sent to the engine control unit and from there to an electric motor which operates the throttle.

Many manufacturers have been using this type of setup for years, including Volkswagen, Audi, BMW, and Mercedes-Benz. I haven't heard of any issues relating to the technology. It is a self-diagnostic thing and if it detects anything out of the ordinary it will go into a limp mode and illuminate a warning light on the dash. Worst case scenario for total failure would be no throttle response at all (like if your accelerator cable broke on a non throttle-by-wire car).

You would probably say that no throttle response could put you in a dangerous situation, and surely it could but no more dangerous than a broken accelerator cable, and it certainly doesn't seem to happen any more often than that.

I think the manufacturers have taken due steps to ensure redundancy and safety on the throttle by wire system, ever since the whole "unintended acceleration" thing that Audi went through back in the '80s. That wasn't even throttle-by-wire and furthermore that wasn't even a problem with the car, just driver error.

But no company wants a repeat of something like that as far as publicity and public perception is concerned.