Cutting all the power based on only the key must be the most stupid thing I've heard today, especially power steering?! Really, I've worked in automotive and all designs I've seen keep important components alive as long as the vehicle is moving, regardless of key position. THAT is the design flaw here, not that the key is too easy to twist.
This can be quite a hot topic, I frequently see people wanting the key as a "last line of defense against electronics and programming error switch" and i can understand that concern and sometimes think that way myself but really, if they are not confident enough in their system and think they require a human controllable "main switch" they might as well put a big red emergency shutdown button in the middle of the dashboard, i wonder how many people would buy such a car.
If you cut engine power hydraulic steering is basically dead, as are the brakes. The power assist on brakes usually uses engine vacuum and power steering is mostly driven by a hydraulic pump running off the motor. I'm not sure about the newer electric steering models.
But for most cars, simply having a stalled engine makes them nearly undriveable due to the weight of the controls.
I think that driver training should start with unassisted cars - no abs, power steering, power brakes and no stability control. And that early training should include skid control.
Once competency in those areas is gained, then move to bugger cars with power systems and electronics.
I'll always be grateful for learning to drive in a completely manual car with no power assist on anything. It means I can always tell when the car is doing something for me. I still drive an older car for fun which is completely 'analog'. It's mic more rewarding to make good progress by using skill rather than silicon.
The point is key switches as cut offs work fine when the component doesn't have major faults.
Any other electrical control system could cause just as many issues if designed poorly. Imagine if GM was just as sloppy with a push-to-start electronically controlled system that could shutdown due to EMF.
And there have actually been issues with push-to-start systems. One model I can remember required the user to hold down the button to shut off power in an emergency, when the most common user reaction was to rapidly jab the button.
>The point is key switches as cut offs work fine when the component doesn't have major faults.
GP is correct. Cutting the electrical power to the power steering assist while the car is in motion is a design flaw. Can you think of any reason why the car should not have operational power steering when it is in motion[1]?
[1] If you thought "for towing", that situation can be handled by the tow truck operator manually disabling the steering.
>Can you think of any reason why the car should not have operational power steering when it is in motion[1]?
You can't have an electrical cut-out that doesn't cut-out certain components. The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay). If the ignition switch is not used for that purpose they would need to put a big red button on the dash like GP said.
The ignition switch cutting all power has worked without incident in every other brand for many decades. The issue here is GM's incompetence, and I'm not inclined to the idea that they would have competently implemented another system.
If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary).
1. You get a fuel leak in the engine bay while driving.
2. There is not already another safety system detecting this.
3. The driver actually notices this while driving.
4. The driver decides to take action by turning off the key, without stopping the car first?!
5. For the scenario to be dangerous we are also assuming this leak is severe enough to eventually cause ignition and catch fire.
This is like taken from a b-grade action movie and doesn't happen. Any scenario i can think of where you would require an emergency shutdown you would also want to get the hell out of the car asap. You could also imagine that things like cruise control "get jammed" but i find that extremely unlikely since software doesn't have the same wear and tear as mechanical components and sensors. Worst worse case you can always stop the car use the mechanical brakes or gearbox since those have more power than the engine. Unless we are talking about brake by wire or similar but those have _completetely_ different safety standards, there is also a reason those are not on the market yet.
>You can't have an electrical cut-out that doesn't cut-out certain components.
Nonsense. Even the old mechanical ignition switch simply engages a number of relays and other electrical/electronic controls.
>The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay).
Fuel cutoff relays exist and have been in use since, not long after electric fuel pumps were put into use.
>The ignition switch cutting all power has worked without incident in every other brand for many decades.
In no way is that statement predictive of the efficacy of such a simple scheme going forward with more advanced electronic controls.
>The issue here is GM's incompetence,
No arguments there.
>If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary).
It is limited. It's more properly called power assist. It shouldn't be scary. Power steering is most useful only at low speeds.
GM failed to perform an adequate hazard analysis. Faultiness is inherent in any vehicle driven for a number of years, and as we've seen a single fault can disable many safety-critical features like ABS or Power Steering.
The potential impacts of the failure modes of the key switch are quite severe, although in normal use the likelihood of any one is low. Because of the severity, some risk mitigation should have been in order regardless of whether the component "works fine" or not.
I'm fine with that. I just think people are throwing out the baby with the bathwater by declaring mechanical ignition switches to be the problem (when they have worked fine for decades in every other brand).
This can be quite a hot topic, I frequently see people wanting the key as a "last line of defense against electronics and programming error switch" and i can understand that concern and sometimes think that way myself but really, if they are not confident enough in their system and think they require a human controllable "main switch" they might as well put a big red emergency shutdown button in the middle of the dashboard, i wonder how many people would buy such a car.