how much fuel used in idle mode

Ultrasonic

harleq1962 wrote: »

starting the engine is where most of the wear and tear is done to the engine,
http://www.caranddriver.com/features/gas-pains-mileage-myths-and-misconceptions-turning-off-the-cars-engine-saves-fuel-when-the-stops-are-long-but-its-not-a-good-idea-for-short-stops-page-7

That article is advising people without automatic stop-start systems not to switch their engines off for short stops. It isn't really relevent to mutley's car.

Ultrasonic

mutley74 wrote: »

If I am waiting in a heave traffic queues (unless its very dark) I usually turn my headlights from full beam to dipped level to reduce engine demand.

Do you possibly mean dipped to sidelights? If not, you shouldn't have full beam on in a queue of traffic anyway, not just to save fuel.

bigjl

harleq1962 wrote: »

starting the engine is where most of the wear and tear is done to the engine,
http://www.caranddriver.com/features/gas-pains-mileage-myths-and-misconceptions-turning-off-the-cars-engine-saves-fuel-when-the-stops-are-long-but-its-not-a-good-idea-for-short-stops-page-7

Don't really agree with that statement.

Most of the wear and tear is caused by cold starts.

There is thousands of Prius in the UK alone that sre used for private hire or taxi work doing anywhere from 30k to 60k a year, as far as i have read there are no special oils used, a specific one perhaps but nothing with special additives.

And i have not read about any mods to the engine that you might not find on any other modern car.

Will have a read of your link but hage read some innacurate stuff written by journalists over the years.

bigjl

Had a read and lost interest when they started talking about starter motor wear and the need to build oil pressure when starting a hot engine after a few seconds, an engine that a few seconds ago had oil being pumped to the top end and ehich the oil pressure light goes out after milliseconds.

I find it best to ignore anything on the internet posted up by American journalists.

That is a country where they think you can put mineral oil like GTX in an AMG Mercedes as long as you change it every 3k.

iolanthe07

That is a country where they think you can put mineral oil like GTX in an AMG Mercedes as long as you change it every 3k.

Their custom of frequent oil changes is a good thing, though. Maybe part of the reason why their engines last such a long time - A quarter to half a million miles is not that unusual in California.

Richard53

In answer to your question: a modern engine uses next to no fuel when idling, and unless your driving is all town and city start/stop, I doubt if there would be any benefit that you could measure without laboratory instruments.

We occasionally get loaned a car for security work when our proper vehicle is in the workshop, and a couple of these have been stop/start. To be honest, they drive me mad and I wouldn't have it my own car at any price.

It also gave me probably the biggest scare I can remember in my adult life

I was checking out a deserted building as part of a middle-of-the-night patrol, which is located off a very small B-road in the middle of thick woodland. I pulled the car up to the gate, and the engine switched itself off, although I had the headlights on. After I had done the checks (about 1 minute) I got back to the car and needed a pee. I was standing with my back to the car, about halfway through relieving myself, when the engine started all by itself, and when I turned round the interior lights were coming on and there was no-one in the car. For about two seconds I was absolutely !!!!ping myself, until I realised the system had detected a low voltage and had switched it back on to save the battery. Cue a very red face, good thing no-one was around.

I reckon start/stop is a good idea for a city runabout, but for everyone else it's an answer to a question no-one was asking.

daveyjp

Sounds like a useless stop start system. If mine activates and I take my seatbelt off to get out the engine starts.

Ultrasonic

Richard53 wrote: »

In answer to your question: a modern engine uses next to no fuel when idling, and unless your driving is all town and city start/stop, I doubt if there would be any benefit that you could measure without laboratory instruments.

Nonsense. Fuel use is low but certainly not negligible. Just do some city driving and watch trip mpg drop while you are stationary. If it was as miniscule as you suggest there is no way car manufacturers would have gone to the huge expense and trouble to create complicated start-stop systems.

Ultrasonic

daveyjp wrote: »

Sounds like a useless stop start system. If mine activates and I take my seatbelt off to get out the engine starts.

Did you mean engine stops?

daveyjp

No, if the engine stops because stop start is working the engine will be off. To prevent me getting out and leaving a car which could start up on its own the engine restarts as soon as the seatbelt is removed from the buckle, alerting the driver that the engine needs switching off properly.