Can anyone tell me why drivers of ANY diesel vehicle seem to have a penchant for leaving their engine idling for long periods ?
I am a diesel car driver myself and I've never been able to understand why people switch petrols off as soon as they stop for any reason whereas the diesel is left idling perhaps as some form of comfort blanket !
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Bus and coach drivers do it to keep the vehicle warm.
Also, somewhere on another thread, some bus company would only permit the mechanics to start the engines, so the drivers had to leave them running at their destination.
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If the diesel has a turbo it is highly recommended to leave it idling for a minute or so to let the oil cool the turbo bearings especially after a hard run.
Switching off straight away can cause oil starvation leading to premature turbo replacement due to fried bearings.
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None of this explains why the delivery van driving chav who lives in my street decided to leave his Transit engine running and sat in the van for 10 mins before he left for work at 5:30am today. Thanks for that.
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An idling diesel is running at the same frequency as a purring cat - 26 cycles per second.
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Drivers of freezer, chiller and ice-cream vans have a reason as the units are driven by the engine.
Can't think of any others though.
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An idling diesel is running at the same frequency as a purring cat - 26 cycles per second.
Surely that must depend on the engine? Are you saying that EVERY diesel engine in the world runs at exactly the same frequency?
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>Surely that must depend on the engine? Are you saying that EVERY diesel engine in the world runs at exactly the same frequency?
Just what I heard on one of those 'Factoid' thingies on the radio a week or so ago. Take it up with Steve Wright!!
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what EVERY CAT purrs at the same rate?
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I actually read that in the REDLINE magazine some years ago!
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Its not what you drive, its how you drive it! :-)
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>An idling diesel is running at the same frequency as a purring cat - 26 cycles per second< I'm dubious about both these 'facts': 26cps = 1560rpm, which is about twice the idle speed of my diesel, and 26cps is about the low limit of audibility, and I have no problem hearing my cat purr.
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But...the engine fires every half revolution of the crank (for a 4 cylinder engine). So if you are hearing the engine firing at 26 Hz, it will actually be going round at 780 rpm - which is pretty close to the idle speed of car engines. I suspect big lorry engine idle slower than this though (but then they have more cylinders, so might still get to firing at 26 Hz).
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RichardW
Is it illogical? It must be Citroen....
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Will a purring cat pass the MOT?
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None of this explains why the delivery van driving chav who lives in my street decided to leave his Transit engine running and sat in the van for 10 mins before he left for work at 5:30am today. Thanks for that.
Listen Mate, If I have to get up at 5:30 then so does everyone else.
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I noticed this idling engine sydrome particularly when I used to have ITV Digital. Every car that drove past sent the picture rolling and flickering but worse were the "boyfriends and girlfriends saying goodnight" in their cars which could mean 30 minutes with the engine running while I was trying to watch Star Trek. Get a Hotel.
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It's actually a secret plot by diesel drivers to get petrol owners to follow suit and wreck their engines - rich mixture, oil wash,etc.
Or
Could it be that they're just showing off that an idling diesel uses tiny amount fuel compared to a petrol.
No I won't be drawn into the waste / enviroment thing. I don't do it!
Steve.
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I usually switch off if i'm stuck in traffic for more than a minute and i have a diesel. No real need to leave it idling.
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My SIL tells me that when sleeping overnight in an HGV the spot to always avoid is next to a refrigerated unit which has to leave its motor running overnight.
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>>My SIL tells me that when sleeping overnight in an HGV the spot to always avoid is next to a refrigerated unit which has to leave its motor running overnight.
And I was thinking the drone would drive you to boredom/sleep..Ps dont they use a donkey engine not main engine??
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Steve
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Very efficient at idle - no throttle = no* pumping losses.
Can keep the engine on all night with the heater on and only use 0.1 litres an hour. Maybe it is the massaging vibration?
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I remember from years ago, with reference to boat engines, the accepted reasoning was that diesels had direct injection into the combustion chamber, with no wastage of fuel, so used a minutely metred amount simply to keep idling slowly.
Petrol engines of the period had carburettors, dependent on air intake flow to draw in a vapourised mixture, and in consequence idled very inefficiently.
Now that all engines are injection I wouldn't have thought there was a difference. But then as all fuel is much more expensive now it still seems a needless waste.
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Some of the most restful sleeps I have had in memory were in the sleeper bunk of an idling diesel HGV or van. The engines were kept going to maintain cab heat or airconditioning and on trucks that were equipped with idle control the tickover rpm was often increased to reduce engine vibration. Think of it as fine tuning the purr.
It could be argued that I was more tired as I was working, or exhaust fumes seeped into the cab making me more tired etc, but to this day I always like the sound of an idling diesel. Yes, I do like the sound of a purring cat and likened diesels to them even before I heard of this scientific explanation. I never could understand why people called diesels noisy.
That chirping bird that woke me up 2 hours ago, now *that* is noisy. Its a good thing guns aren't allowed in the UK. 8-)
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The reason diesel use less fuel idling compared to petrol is down to the fact that they don't need a roughly static fuel/air ratio (stoichiometric - about 14 parts air to 1 part petrol according to Chevron) as petrol engine does. In a diesel the engine speed/power is controlled by the amount of fuel injected.
www.diesel-central.com/News/cackle.htm
Steve
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When visiting teams' coaches waited outside the University sports centre on a Wednesday afternoon, the drivers would sit there with the engines idling for ages. Duration of warm-up and match, plus changing time and another hour for a good three or four pints afterwards. Often 3-4 hours.
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If one ended up in a really severe traffic jam, and was forced to spend the night in the car, a diesel engine would probably run all night, providing cab heat, light, and entertainment, and still have enough fuel left to get you to a service station in the morning.
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If the diesel has a turbo it is highly recommended to leave it idling for a minute or so to let the oil cool the turbo bearings especially after a hard run.
>>Switching off straight away can cause oil starvation leading to premature turbo replacement due to fried bearings.
True. All turbodiesel owners should take note.
Oz (as was)
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