idling diesels (loco/D(E)EMUs)

[dieselbashdave]

Hi All,

I'm wondering how long you can leave a diesel engine (loco/MU) running at idle at a terminus. At Inverness I notice the 158s shut down after about 30 mins automatically (no staff present).

I read a while ago somewhere that there is a chance that diesel locos have exhaust fires break out due to them idling for too long - apparently oil gathers in the system and then burns off when power is called for. I thin kit affected the Cl 66 and 67 family but I'd have to re-Google as it was a long time ago since I read it!

I'm wondering if the HSTs have a problem as I read that the MTU units have (had?) a spate of exhaust fires back when they were introduced and I'm wondering if it was due to them running at idle at a terminus for a while; if so does operational procedures take this into account and have diesel trains shut down after a while to prevent this?

Cheers in advance - I know it's a very unusual question!

 

[thewolf]

I think they shut down automatically after a while.

About 18 months ago, me and a few mates spent the night roughing it at Nottingham station after a gig, and the various multiple units parked up there shutdown of their own accord after about 30 minutes... Before someone came and started them up again. I assume there was a good reason for them restarting them fairly promptly even at 3am - probably to discourage people from trying to sleep at the station

 

[RPM]

Most DMUs shut down after 15 minutes unless the driver's key is left in, in which case they will idle indefinitely.

 

[NSEFAN]

The problem with diesels is that they don't always start up again, especially if they've been left out in the cold. Better to have them running so at least they will be warm and ready to go the next day.

Also, is there not a warranty clause in some modern locos that requires them to be left idling in some cases?

 

[BestWestern]

Idling can also cause problems though in diesel engines, certainly it doesn't help the lifespan if the units on most DMUs, though the newer stuff might be more sophisticated. On Sprinters and suchlike they always say that idling slowly damages the internals of the engine, something to do with unburnt fuel gathering in the cylinders thanks to the lesser levels of combustion going on apparently - I'm not overly expert on the subject!

The Rulebook states that engines should be switched off unless required to maintain aircon or heating, but more often than not your average DMU will be running pretty much all day.

 

[dieselbashdave]

@BestWestern - I think you're right on that one. My experience with engines is limited to the automotive variety but I'm sure if it's left at idle for a long time then you do get carbon deposits forming in the cylinders due to the low temperature of the idle combustion level.

I have had a small bit of experience with stationary diesel generators, and if you leave them at idle or on low output for too long they can get damaged - newer models incorporate computer gagetry in their control systems to reduce this whereupon they rev up every hour to raise the temperature. I think what happens is the engine's insides coke up like the inside of Kate Moss's nose!

But yeah the general consensus is that they may not start again if left to go cold! Some car manufacturers add Webasto heaters to their diesel cars (Rover, Volvo, VAG to name a few!) not only to warm up the interior of the car but to ensure starting in a cold climate, even with high prex injection and extreme compression ratios. Of course when the Webastos malfunction it's like the car's parked on top of a cloud of white smoke (atomised diesel) which can be a bit alarming to say the very least!

 

[BestWestern]

...But yeah the general consensus is that they may not start again if left to go cold! Some car manufacturers add Webasto heaters to their diesel cars (Rover, Volvo, VAG to name a few!) not only to warm up the interior of the car but to ensure starting in a cold climate, even with high prex injection and extreme compression ratios. Of course when the Webastos malfunction it's like the car's parked on top of a cloud of white smoke (atomised diesel) which can be a bit alarming to say the very least!

Oh yes, causes much worry at stations too when a Sprinter sits there with smoke pouring from below the solebar!!

 

[dieselbashdave]

Oh yes, causes much worry at stations too when a Sprinter sits there with smoke pouring from below the solebar!!

I've noticed quite a few of those - a few years ago a 158 even emitted flames from the aux heater at one point! My car has yet to do that - but the aux heater in my Volvo estate can sometimes pong the inside of the car out if I'm unlucky.

 

[moonrakerz]

Some car manufacturers add Webasto heaters to their diesel cars (Rover, .............

(My highlighting)

Who ????

 

[DesiroDom]

If the key is not in the desk then they will automatically shut down its a safety feature to avoid carbon deposits in the exhaust causing fires.

 

[dieselbashdave]

Thanks for clearing that up so to speak - so it's carbon deposits and not oil then it would seem. I'm wondering how long until diesel trains get fitted with diesel particulate filters (DPF/FAP) like most cars now - a complete nightmare and a half when they get blocked up and fail.

 

[driver9000]

If the key is not in the desk then they will automatically shut down its a safety feature to avoid carbon deposits in the exhaust causing fires.

What about when keys are left in for frost protection or to keep heating going in cold weather?

The auto shut down is to avoid wasting fuel. From an easily pleased mind I like the 'whumpf' sound from the burner when I press the pre heater button

 

[shedman]

We tend to leave power cars running in the winter because the lube oil becomes too thick and can't circulate and causes the pump to trip or something like that. MTU'd don't have that issue because they have to be kept warm on a shore supply and any 'cold start' adds extra hours onto the engine.