common rail diesel....what is it?

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Mon 30 Nov 2009 23:12
common rail diesel....what is it? - barney100
Ihave a volvo v70 2003 2.5 diesel and I gather it has a common rail diesel but what is a common rail? and for that matter a dms.
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Tue 1 Dec 2009 01:01
common rail diesel....what is it? - Dynamic Dave
what is a common rail?


tinyurl.com/ykkjkxc
and for that matter a dms.


diesel management system?
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Tue 1 Dec 2009 16:08
common rail diesel....what is it? - Dave_TD
A quick Google suggests that DMS is the Dealer Management System, ie the computers used to pull servicing schedules together at the workshop. Are you sure you don't mean "DMF"? You should ask what one of those is on here and whether they're any good, I'm sure the responses will be enlightening... ;-)

Edited by Dave_TD {P} on 01/12/2009 at 16:08

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Tue 1 Dec 2009 16:21
common rail diesel....what is it? - Wurzel83
If you mean DMF then its Dual Mass Flywheel. Unlike a solid flywheel the dual mass varies the inertia about the crank shaft in order to reduce vibrations at certain rev renges. They can be troublesome if not treated gently and will cost over £1000 to replace.

Common rail is where a fuel pump sends diesel to a high pressure reservoir (rail) that is common to all 4/5/6 injectors. Upon a piston reaching a necessary point within its cycle the crank/cam position sensors tell the ECU to allow fuel into the cylinder via an electronic injector which is fed fuel from the Common Rail. Previous diesel engines had a crank belt/chain driven injector pump and were more proven reliable technology yet less precise and efficient.

ECU = Fuel Management System (onboard computer)

Edited by rtj70 on 01/12/2009 at 16:28

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Tue 1 Dec 2009 17:58
common rail diesel....what is it? - Armitage Shanks {p}
Modern aircraft hydraulic systems work at about 4000 psi (max) Common rail diesels are nearer 30,000 psi which I find more frightening than impressive.
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Tue 1 Dec 2009 18:02
common rail diesel....what is it? - FotheringtonThomas
If you mean DMF then its Dual Mass Flywheel (snip) can be troublesome if not
treated gently and will cost over £1000 to replace.


What the hell's the point of having a decent amount of oomph if you can't flippin' use it?
Mutter. Grumble. I've been reading about these things, and they seem most off-putting.
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Tue 1 Dec 2009 18:40
common rail diesel....what is it? - Old Navy
What the hell's the point of having a decent amount of oomph if you can't
flippin' use it?


Its not "you can't use it", its "how you use it".

Edited by Old Navy on 01/12/2009 at 18:41

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Fri 4 Dec 2009 21:09
common rail diesel....what is it? - Wurzel83
>>What the hell's the point of having a decent amount of oomph if you can't
flippin' use it? >>


Ask the manufacturers!

Fair enough Common Rail technology was necessary to an extent in order to comply with Euro Emissions standards and lower car tax however I presume the DMF was for performance reasons ie. to make the drive more refined? You do see threads where people have replaced these with solid flywheels and seen better results.
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