Actually very simple. Why would you only use one foot when there are two pedals?
Of course if you do have a problem reverting when driving a manual, best not to. But you're just as likely to stall etc if you can't adapt to driving both.
Yes, it is important to get the car to a standstill as safely as possible. Why would you increase your workload to do something unusual in a moment of stress instead of doing something routine?
'cause a diesel, burning it's own oil, will just carry on switched off or not... B-)
So just use the foot brake a bit harder than normal to bring both car and engine to a safe and controlled standstill.
The orginal start of this thread was based in the US. They mostly drive automatics over there so the pigging thing will change down to counter act the braking. Selecting N still doesn't strike me as "right" though, selecting the highest fixed drive and braking ought to work. Assuming the auto box and/or computers will allow that change to happen with the engine under full throttle.
Yep, my single cylinder diesel genset has a decompression lever so (if your feeling fit) can pull start it. Try and pull it without releasing the compression and it's like trying to pull the QE2. For normal use It has electric start and battery kept topped up with small solar panel. B-)
Any diesel that is/was intended to be hand startable will have one.
It'd have to operate on all cylinders to enable hand starting...
Yes, the whole concept of removing the mechanical load from an engine that is running out of control seems counter-intuitive, when the object would seem to be to remove the problem at source by cutting off the fuel which is best achieved by turning off the ignition. That hinges critically on not accidentally locking the steering wheel: the thing that the video said was highly likely but people on this thread have said doesn't happen until the keys are removed - unless anyone knows of exceptions to that for certain vehicles.
Braking the engine when it is transmitting power to the wheels will lead to a "fight" between brakes and engine, with the risk that the energy that the engine is generating will heat up brakes too much. If you have an engine generating maybe 100 hp, you've got to dissipate that sort of energy in the brakes. What is the effect of the discs heating up dramatically: can it cause loss of braking force? They did mention something about "burning out the brakes" which was the reason for contemplating using the "emergency brake" instead, as if that magically used different pads and wouldn't be affected in exactly the same way by brake heating.
Working out that turning off the engine if the throttle has suck open increases your work load?
And it's certainly not natural to apply the brakes while the engine is pulling hard. Unless a rally driver, etc.
But that's not a stuck throttle. ;-) And I'd say pretty rare?
As I said with my auto which as drive by wire throttle, if you brake with the throttle pedal still pressed, it cuts the engine.
However, selecting neutral with any gearbox while the throttle is wide open might well result in engine damage. So why risk that when you can switch off the engine?
Basically we're talking older cars. Many modern ones are drive by wire, so far less likely the throttle can stick open.
I'm always amazed that my car starts on a very cold morning when the oil will presumably be more viscous. It sometimes takes longer to fire, but apart from one time when the battery was on it last legs (wouldn't hold as much charge) it turns over as fast as normal. I suppose once you get past the first cylinder compression and over top dead centre, that stored pressure will act in your favour and counteract the compression stroke that is beginning on the next cylinder etc. But you have to overcome the first compression stroke.
I'd say any vehicle which locked the steering when you simply turned off the ignition faulty. As well as positively dangerous.
I suppose any fault with the pedal position sensor that feeds info to the ECU could cause the engine to race uncontrollably. However if you press the brake, the ECU *may* be designed to cut the power on the basis that you shouldn't be braking and accelerating at the same time - the ECU doesn't know whether it's a stuck sensor or your foot hard on the throttle pedal.
A lot depends on where the sensor is. If it's in the footwell, right by the pedal, it's less likely to stick. If it's at the far end of a bowden cable, under the bonnet, as was the case on my first diesel car, then a frayed cable *could* be a problem.
But, yes, I was talking about an older car with no ECU and a carburettor which will carry on pumping fuel and air mixture as long as the cylinders suck it in, and an engine that will carry on igniting the mixture until the HT (or LT) is cut off.
My dad made a Heath Robinson immobiliser on one of his cars - I think it was one of his Citroens. Since none of us smoke, he modified the cigarette lighter with a steel disc that my grandpa turned on his lathe instead of the normal heating element, and altered the wiring to put this "switch" in series with the LT. Unless you pressed the cigarette lighter in, the car would never fire. OK, so a savvy thief might hot-wire the coil directly to the battery, but it would deter opportunistic thieves. He had to remember to change the wiring back for when he sold the car :-)
That would have been a great kill switch in this situation: pull the cigarette lighter out and the spark goes away, even though the key is still in its original position and so there is power to everything except the ignition. Not that he anticipated that need...
Yes so would I. In the heat of the moment I wasn't going to risk it and so I turned the switch off carefully to the accessory position - just in case. But I would say that the steering should only lock if the key is removed, not just turned off. There are various reasons why you may need to kill the engine in a hurry - a passenger might need to do it if the driver becomes incapacitated and keeps pressure on the accelerator. I've always thought that cars should be designed with the ignition key on the side of the steering column that is nearer the passenger, as was the case on first few cars I owned. So LHD cars still have the ignition on the RHS, which is the passenger's side for LHD? Or is that part of the steering column housing mirrored for LHD? I know that indicator and wiper stalks are still the same way round, which fooled me for a few seconds when I first drove an LHD because I expected the stalks to be mirrored.
I now have a stop-start car. For normal starts it uses the pinion-based starter, once warmed up sufficiently that stop-start comes into operation, it uses the alternator to re-start through the belt.
The stop-start takes a little getting used to (many factors that influence whether it will or won't operate, such as aircon, steering angle, gearbox mode, etc).
Annoyingly it's not fully predictable, e.g. you brake to a stop, the engine stops, the hold-assist on the brakes kicks in (saving you from having to apply the parking brake while preventing brake lights from annoying the car behind) when you take your foot off the brake
*sometimes* the engine will restart immediately, surely it could have worked out before stopping that it would need to restart, and not bothered stopping?
Correct. Also found on soem motorcycles (mainly big single cylinder jobbies) to make kick starting easier.
I remember a friend of mine had a 500cc 'single' that seemed to do about
5 rpm!
Our Honda has stop-start which can be turned off if you want. I hadn't realised it doesn't always use the starter motor to restart - maybe that's model-dependant, because it sounds exactly the same noise as when the car is started on the key.
I was apprehensive at first that the car wouldn't start quickly enough when I was ready to set off, but I've never beaten it yet: by the time I've pressed the clutch pedal (the trigger to restart), put the car into first gear and lifted the clutch, the engine is running and the car sets off as if the engine has been on al the time.
The car supposedly has hill start assist, which may also work when the car is on a gradient when it is stopped due to auto-start, but I've never tried it. I was taught to always apply the handbrake and go into neutral when I stop; the only time I don't is if I anticipate that I'll be starting off again in a few seconds.
What I have noticed with this car is that there is a horrendous about of slack in the handbrake mechanism. If I brake to a halt on a gradient, apply the handbrake and then release the footbrake, the car lurches forwards or backwards (depending on gradient) before coming to a very sudden stop. It feels like a lot of play, but it may only be an inch or so of rotation. It makes it very difficult to stop smoothly on a gradient: I find that I have to deliberately release the footbrake slowly so the car still rolls but at least doesn't come up hard against the end-stop. The Honda garage couldn't understand what I was complaining about and said that this was standard with cars that have hill-start assist. I asked what was involved in disabling hill-start assist so the car stays where it is when you brake to a halt, apply the handbrake and then release the footbrake, but they said the design doesn't allow for that. They seem to have done something that has reduced the amount of play and/or reduced the ferocity of the sudden stop at the end of the play, but it's still nowhere near as good as my old Peugeot with no hill-start assist.
Sometimes you can have too much automation and assistance. Automation is fine as long as you don't have to work around it and make allowances for it not doing what a competent manual driver would do.
They are rather more than a simple pot or position sensor. Designed to fail safe.
Interesting. One design I saw used an alternator built into the flywheel or whatever. So no drive mechanism needed.
I'm rather surprised the drive belt is up to starting an engine.
If the alternator is capable of starting the car why don't they just remove the starter motor and save the cost and weight?
This can be disabled temporarily, and I gather VCDS can reverse the switch so it defaults to off and you can enable it when required.
Because the oil viscosity when cold means the alternator couldn't (always) manage it. The alternator does start it very quickly when it's warm.
It does "light hybrid" jiggery-pokery, which I assume amounts to not recharging the battery immediately after a start, but recuperating the energy later when coasting or braking. I don't think it ever uses the alternator to provide drive to the wheels.
Some people talk or behave as though the foot brake is some incredibly delicate system that will break if the pedal is pressed down hard.
Given that the accelerator pedal now only operates a potentiometer and autos don't bring mechanical connections to the driver, there is no easy way of knowing what a "stuck throttle" fault is and how things are going to respond to the driver's random fiddling. The foot brake is a known quantity and the only system with sufficient independence.
Which is what our Auris hybrid does.
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