At Purbeck we run a fleet of 6 MAN 7.5 Mt “stillage” type recycling collection vehicles.
At variouse times during their work they will be stationary with the engine idling, can any body suggest the maximum leangth of time the vehicles should idle for before it becomes more economic to switch the engine off and then restart it again?
(This may resolve a difference of opinion that I am having with the fleet supervisor!).
Thank you for your help.
Neptune.
neptune62:
At Purbeck we run a fleet of 6 MAN 7.5 Mt “stillage” type recycling collection vehicles.At variouse times during their work they will be stationary with the engine idling, can any body suggest the maximum leangth of time the vehicles should idle for before it becomes more economic to switch the engine off and then restart it again?
(This may resolve a difference of opinion that I am having with the fleet supervisor!).
Thank you for your help.
Neptune.
Hi neptune62, WELCOME.
One source of info might be the vehicle manufacturer.
Not very long at all…
TC
when i did a run for british bakeries they said if you are going to be sat for longer than 2 minutes turn the engine off, it will save fuel.
i have no idea if it is true or not but you never know!
quite a few engine/vehicle manufacturers are working on various stop/start systems incl. starter, alternator and flywheel merged into one piece, so that the engine can be switched off instead of being let idling, i.e. at traffic lights.
IMHO, in cold weather idling is perhaps preferable to short-term switch off.
Otherwise, switching the engine off any time you are not using it will save a lot of fuel. I, for example, switch the engine off even at railway crossings. Battery has somewhat harder life but I reckon the battery is cheaper than fuel.
I always let the engine idle for a couple of minutes prior to switching off to allow the turbo to run down - turning off the engine too soon starves the turbo bearings of oil as the oil pump isnt running.
I seem to remember either ■■■■■■■ or Cat (think it was Cat but open to correction) do, or did, switch themselves off after about two minutes’ of idling. Maybe that’s around the right figure?
Hombre:
I always let the engine idle for a couple of minutes prior to switching off to allow the turbo to run down - turning off the engine too soon starves the turbo bearings of oil as the oil pump isnt running.
I try to do this too, sometimes it isnt always possible, but I am amazed that manufacturers havent come up with an electric pump or thermostatically controlled pump for this. After all they have for the radiator fans.
My FM used to turn itself off which could be a pain in the arse as I only had to use tickover to drive my pto driven electric generator.
at my lads at min to switch off after 1 min to save fuel on ten trucks working 24 7 think should save me 5 grand in fuel a year. daf cf 480 uses 1.4 litres an hour on tick over.