Posted By Stefan Daunt
I would imagine, the fuel cost saved, will be out weighed by the cost of a new starter motor and flat batteries with lights left on and the engine not running.

Posted By Chris Packham
Volkswagen actually produced and marketed a Golf that automatically switched off the engine whenever the car came to a stop. As soon as you pressed the accelerator the engine started again.

Doesn't appear in the current range, though, so presumably it didn't catch on.

Chris

Posted By John Allen
The new BMW 1 series cars have an engine management system that stops the engine when the vehicle is stationary in neutral. The engine starts again when the clutch pedal is depressed.

I've been running one for three months without problem. You can override the function eg when constantly stop/start in a slow moving traffic queue.

Tha car has other energy saving features including 6 speed box and the alternator only takes power from the engine at certain times. the result is reduction in emmissions from 180 to 130 and lower rate of VED.

Posted By Bob Shillabeer
Tried hard but can't see the implecations for H&S in this one.

Posted By Fornhelper
Word of advice...when I turn my car engine off the steering lock comes on...so to encourage people to shut down an engine when the car is still moving could, in some circumstances, result in a pretty nasty accident...particularly if quick, evasive action is necessary.

FH

Posted By Ian Mitchell
Just read my post and it sounded snooty, not my intention - I just didn't use smilies etc!

Posted By Michael S Ward
Morning all

While on the face of it, it seems to be sensible, however I haven't seen, or am aware of, any scientific evidence to show that what is being suggested actually works. I think it's a bit simplistic, and taking it to the extreme, wouldn't 'freewheeling' down hills save even more fuel etc? If the suggestion was viable wouldn't the government and the various bodies like the AA, RAC, Brake etc suggest it? I think you have to take a more holistic approach to a whole set of issues.

Environmental

As most people press the accelerator when starting, to ensure they don't stall, the amount of fuel used doing this has to be offset against what is purportedy saved. Have you seen the increased emissions from the exhaust of a 'started engine' as against to a 'running engine'?

What about the increase wear & tear on engine parts e.g. starter motor, batteries, if switched off for a longish period oil will run from piston chambers and hence increase wear & tear on piston rings and linings. If these parts need to be replaced earlier or more frequently what about the environmental effect caused by the manufacture of the extra parts, fitting and testing them and then the environmental issues with disposal of the worn parts, oils and lubricants!

Economic

What may be saved in fuel would have to be offset against the issues as above, plus whilst a vehicle is off the road being serviced we are running other vehicles more frequently (increasing their wear & tear) or renting one to replace it. What would the insurers think, could it be seen as a greater risk and increase the vehicle policy?

Safety & Legal

Most modern cars have power assisted steering so with the engine off you would lose this and the steering wheel would lock, which if you have to move in an emergency could be hazardous. If you continuously switch of the engine in HGV's, LGV's, Arctic's etc over a short period of time you may lose the pressure required to ensure brakes and other systems would be effective. I once was told that it takes approx. 5-10 mins for a battery to replace the charge used in starting, hence continually switching engines off and on is likely to increase the risk of stalling and battery failure, especially in winter.

What about lights in winter, switching engines off may in some case only only leave you with side lights, and lights on without engine running would probably drain the battery quicker.

Switching off the engine is a deliberate act, as opposed to stalling etc, and this may be seen as you 'not being in full control of your vehicle' due to loss of ability to quickly manoeuvre, and hence could lead to prosecutions under the 'Road Traffic Act'.


Better ways to reduce fuel & emissions

Better ways to reduce fuel consumption and hence emissions is to follow government and various professional bodies guidance:
Regular maintenance,
Drive steadily, no harsh braking or fast accelerations,
Keep tyre pressures correct for the vehicle and its load,
Reduce number of journeys, and share cars if possible,
Better planning of journeys and monitor traffic information so you don't end up in long queues,
Think, do I really need to use this size vehicle or would a smaller one suffice?
Regards

Posted By Ian Mitchell
My car has a gauge that constantly tells you what your economy is. It is accurate right down to every tiny blip of the accelerator. This is a great way to promote fuel-efficient driving and somewhat dulls the fun of a good boot on an open stretch of road!

I find myself trying to maximise economy by using the measures that the previous poster but one talks about at the end of his post.

Posted By Tony Priest
On most modern vehicles switching the ignition off will not activate the ignition lock. Normally it isn't until you remove the key from the ignition the lock will be activated. If you are stopped why would you require power steering?

Posted By David F Spencer
A bit late in the day to respond, but Auto Express mag are currently recommending switching off engines if idling for any length of time. Other posts mention BMW's having a cut-off & some 90's model VW's having the facility - some recently introduced Citroens have the same arrangement. If Citroen, with their reliability record can get it right, I have little doubt about other brands being OK.

One contributor writes about coasting to rest - not a good idea, as it uses more fuel than lifting off in gear in modern cars. Use the over-run to slow down, it's more economical, as it stops all fuel going to the engine with modern fuel supply systems.

However, planning the journey and reading the road ahead will probably save as much fuel as switching off every time you come to a halt. Now if you are heading north on the M1 around J23A on a Friday afternoon, then that's a classic case for switching off the engine...

Posted By Barry Cooper
Yawn
I'm off to bed