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+--- Thread: CO2 for runaway diesel. (/showthread.php?tid=1666)
CO2 for runaway diesel. - Actros617 - 08-23-2010
I was wanting to know how many pounds of Co2 does it required to stop a OM617.95, i am planning to build a emergency runaway shutdown system with tank of CO2 and a line to the intake manifold via EGR intake port or pre turbo.
RE: CO2 for runaway diesel. - willbhere4u - 08-23-2010
I don't think you will ever have that problem in a 4 stroke diesel
Evan if you pin the the throttle in neutral it governs out at 5k
RE: CO2 for runaway diesel. - ForcedInduction - 08-23-2010
These engines don't runaway except through incorrect replacement of the shutoff actuator or poor injection pump modification.
Oil hydrolock is far more a concern than runaway with a turbo failure.
RE: CO2 for runaway diesel. - tomnik - 08-24-2010
wrong.
runaway caused by oil leaking turbo is independent of the IP. The revs go up to mechanical limit (and beyond) of the engine.
To stop only by staying in gear and brakes (manual tranny).
It even can happen on a n/a engine with worn piston rings (via venting hose into the intake).
A flap in the intake might work also.
Tom
(08-23-2010, 05:43 PM)willbhere4u I don't think you will ever have that problem in a 4 stroke diesel
Evan if you pin the the throttle in neutral it governs out at 5k
RE: CO2 for runaway diesel. - ForcedInduction - 08-24-2010
(08-24-2010, 12:01 AM)tomnik It even can happen on a n/a engine with worn piston rings (via venting hose into the intake).An engine consuming such a large amount of oil will be smoking very badly long before it runs away.
And as said with a turbo, if the shaft seal fails it will be actively pumping oil into the intake and hydrolock will be more of a risk.
In either case, there will be ample warning to stop driving before a true runaway occurs.
And lets not forget that our engines have been consuming oil vapor for years through the CCV system without any issues.
Runaways are common in old 2-stroke engines (Detroit, pre-DDEC) because they used an external rack to each injector. A single one jamming meant the governor couldn't pull the rack back and it ran as high as it could at that fuel setting or until it grenaded.
Old MB's (pre-1976) had a shutoff flap in the intake because the pneumatically governed pump could allow the engine to runaway if the sensing tube broke, they could also start running backwards if it weren't for that flap.
Back to my point, you'll have ample warning of a problem before a runaway occurs, except through improper repair/modification procedures.
RE: CO2 for runaway diesel. - tomnik - 08-24-2010
so the flap might be an option instead of the CO2...
Two weeks ago I bought a Ford with 2.5 l turbodiesel DI engine. The turbo was leaking oil, this was the reason I got it cheap. It did smoke a bit until it warmed up and suddenly under load ran away several times (with lots of white/blue smoke). Driving it home was a horror.
Years ago I had a runaway with a Golf 1.6l n/a diesel on the motorway. This bastard did not announce it by excessive smoke. Same with my friend's Renault 1.8l n/a. Hydrolock slightly occurred when restarting the engine after cooling down and some of the oil accumulated in the intake hose.
Both Golf and Renault made it for some more years after new piston rings, the Ford also feels healthy again after turbo repair.
This is oil runaway not defective IP.
Tom
RE: CO2 for runaway diesel. - Deni - 08-24-2010
I don't know how much CO2 it would take to stop a run away diesel, but manual gears will help for sure.
I had my car run away twice on LPG (wrongly connected the solenoids
). Tried to stall the engine in first only to have a massive burnout, then 5th did the job 
.Car still working fine after 3 years.
RE: CO2 for runaway diesel. - Rudolf_Diesel - 08-24-2010
They is a guy that has 6.0L PSD called Stroked Lightning http://www.youtube.com/watch?v=pKTdcXsC9xY - He races drags and has a spring loaded gate type valve (like the ones on an RV dump tank, but steel) that he uses to shut down in case of emergency. It is located at the intake of the turbo, I think tractor pullers use a similar device as well.
RE: CO2 for runaway diesel. - meareweird - 08-24-2010
Would Co2 possibly cause stress from drastic thermal changes?
RE: CO2 for runaway diesel. - ForcedInduction - 08-24-2010
No. Diesel combustion can go from a few hundred degrees (deceleration) to thousands of degrees (full throttle) in a split second with no lasting effects.
RE: CO2 for runaway diesel. - meareweird - 08-24-2010
My thought was mainly for the intake manifold and intake valves.
RE: CO2 for runaway diesel. - ForcedInduction - 08-25-2010
I doubt it would be any different.
The question remains; why are you so worried about a runaway? The cost of a CO2 system would likely be higher than fixing whatever problem is causing the risk.
Several people have run the stock turbo far beyond its safe limits without failure. Injection pump runaway can be prevented by double checking your adjustments and knowing the safe adjustment limits. If the engine is consuming a lot of oil, replacements can be found for under $500.