How long do you have to have stopped for before it's more economical to turn off a diesel engine and start it up again than keep it running?
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Can't answer that, but I remember reading that in -50 northern Canada and Alaska it is regarded as cheaper to leave the big diesels in trucks, road graders, snowploughs and so on idling all the time, day and night, than keeping them from freezing solid until next spring by some other means.
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Given that a diesel engine selects excess fuel to start (hence the puff of black smoke on start-up) and idles at about 50:1 air fuel ratio the "payback" time for a diesel is a lot longer than that for a petrol engine.
Having said that, I would turn off if the anticipated idling time was likely to exceed 2 minutes.
Petrol engines should be stopped immediately!
659.
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An old farmer I knew always used to say it cost him a shilling to start the tractor - meaning it was cheaper to leave it running while unhooking or emptying something.
Obviously that will cease to be true after a time, which, er, brings us back to the original question.
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Blimey, i couldn't be bothered to turn the engine off for less than 5 minutes unless i'm somewhere that noise or possible smell from the exhaust would cause a nuisance to someone.
If we are getting into the fantastic realms of calculating the fuel used ticking over as against leaving the thing running for a few, then we'd better add in the extra fuel used to recharge the battery, and the shortening of the life of the starter and ring, the extra use of the stop solenoid and any other valves or like in that oh so fragile diesel system, not forgetting the flagrant overuse of the ignition key/stopstart button.
Might get the environment police breathing down your neck for contemplating leaving the horrid thing running anyway.
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Seem to think some of the newer BMWs stop and start their engines automatically when crawling in traffic or whatever. I think that would irritate me, but then perhaps I am just naturally technophobic.
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>>some of the newer BMWs stop and start their engines automatically when crawling in traffic>>
Volkswagen used to offer a special Golf model in the early 1990s with the 64bhp diesel unit that automatically switched off when stopped and restarted with a touch of the accelerator.
It used a heavy duty starter motor and battery; however it never really caught on possibly because most people, like me when I drove it in London traffic, used to worry that there would be a time when it might not start...:-)
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Blimey i couldn't be bothered to turn the engine off for less than 5 minutes
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GB - that old farmer I mentioned owned about 600 acres of Worcestershire, easily worth £3k an acre even then, not to mention sundry cottages, outbuildings, etc.
Look after the pennies and the pounds will look after themselves.
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GB - that old farmer I mentioned owned about 600 acres of Worcestershire
And i dare say like every farmer i've met and thats a lot, spent most of the time bemoaning how hard up he was, and then pedalled away on his old bike?
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Blimey i couldn't be bothered to turn the engine off for less than 5 minutes
Keep away from Oxford then.
archive.oxfordmail.net/2008/4/28/242129.html
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Keep away from Oxford then.
Thanks DD, i don't go into towns anyway, unless i'm working, and anywhere the size of Oxford..no way.
Good job that must be, beats the hell out of a days work.
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Even if you don't mind London Gb, the middle of Oxford these days is mini motoring hell.
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Even if you don't mind London Gb the middle of Oxford these days is mini motoring hell.
Lud, maybe its coming to a certain age, but i can't stand even large towns any more let alone cities, maybe trying to recover my childhood, living in the middle of nowhere.
Just adds to my loathing of the places, the ever increasing army of petty officials, each seemingly more obnoxious than the last lot, usually to be seen in a hi vis, with either a clip board or pocket computer, complete with massive ego, only missing the Freddie Starr wild stare and the pencil moustache of one of his characters. (maybe not missing those attributes at all)
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The extra fuel needed for a start on a diesel on a hot engine equates to about 3 seconds worth of running time
obviously this is a bit higher if starting a cold engine and having to power the battery back up to full charge etc and if you have a lot of battery power usage when you have the engine stopped
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about 3 seconds worth of running time
Brilliant. Thanks very much, Defender.
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