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Emergency diesel shutdown
A paragraph in a book I've been sent to review seems to be in error.
Either that, or I'm not properly intuitice about this situation. The paragraph poses a mulitple choice question. "What is the best way to shut down a runaway diesel engine?" One choice is a throw-away. "Cut off the electrical supply." Bzzzt! "Thanks for playing, and we do have some lovely parting gifts for you........" The other two choices: 1. Cut off the fuel supply 2. Cut off the air supply I immediately thought, "the fuel supply. You shut down a diesel by cutting off the fuel." According to the author, the correct answer is supposed to be "Cut off the air supply." The author recommends "discharging a fire extinguisher into the air intake." Well, first off it would need to be the correct type of fire extinguisher. Some extinguishers are charged with halon (which is no longer legal to mfg in the US but is imported or recycled from other extinguishers) and a diesel will run like crazy on halon. And, I'm aware of emergency shut downs that have been accomplished with CO2 extinguishers, etc. I just thought those were cases where it was impractical to cut off the fuel supply. Wouldn't putting a postive stop to the fuel supply from the injector pump be a more certain solution? "Some" air might get sucked into the air intake along with the fire suppressant, maybe enough to allow the engine to cough past the extinguisher discharge and keep running. But, the engine absolutely will not run without fuel. Shutting off the fuel very far upstream wouldn't be a good choice, as an engine can run quite a while on the fuel in lines, filters, etc. Somebody care to agree, disagree, or show me why my preference for fuel shut down would be wrong? I've been told that in certain circumstances diesel engines can run on the oil in the crankcase being sucked into the cylinders, particularly Detroit Diesels. If this is true, that would make the air shutoff the only correct answer. Barry |
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Emergency diesel shutdown
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Emergency diesel shutdown
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#4
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Emergency diesel shutdown
James Johnson wrote:
Happened to me in the Navy on a GM 278CD (Large 2 stroke V-8 emergency diesel generator). The only way to shut it down was to close the ventilation for the compartment and shut the induction valve - this was on a submarine. An 8-278 as an aux? Must have been a heck of a squeeze down there. Rick |
#5
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Emergency diesel shutdown
On Sun, 14 Dec 2003 21:48:23 GMT, Rick wrote:
The compartments on a submarine are designed to be isolated for flooding including the ventilation system. As I had posted it wasn't running away just not shutting down. We evacuated the compartment, isolated it, and then shut the induction valve. As soon as the diesel stopped we equalized pressures and remanned watchstations. It powered an AC emergency generator for a 7,000 ton missile sub (a small one as these things go). JJ James Johnson wrote: Happened to me in the Navy on a GM 278CD (Large 2 stroke V-8 emergency diesel generator). The only way to shut it down was to close the ventilation for the compartment and shut the induction valve - this was on a submarine. An 8-278 as an aux? Must have been a heck of a squeeze down there. Rick James Johnson remove the "dot" from after sail in email address to reply |
#6
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Emergency diesel shutdown
James Johnson wrote:
It powered an AC emergency generator for a 7,000 ton missile sub Oh, a nuke. I wasn't aware that they used Clevelands on the nuke boats. All I ever saw on them was the little FM's. Real subs 8-)like I sailed on used 268's or short FM's as there wasn't enough width for the 278's in the engine room lower level. Rick |
#7
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Emergency diesel shutdown
On Thu, 18 Dec 2003 19:29:00 GMT, Rick wrote: James Johnson wrote: It powered an AC emergency generator for a 7,000 ton missile sub Oh, a nuke. I wasn't aware that they used Clevelands on the nuke boats. All I ever saw on them was the little FM's. Real subs 8-)like I sailed on used 268's or short FM's as there wasn't enough width for the 278's in the engine room lower level. The SSN-585's (Skipjack class) and the SSBN-598's (George Washington class) had the diesels in the lower level machinery space on the centerline aft of the reactor, pretty much filled the whole level. Lighting them off while snorkeling was a contortionists nightmare - simultaneously operating controls and monitoring gages that were in front and in back of you. The human engineering of pretty much everything on those old boats was non-existant. They were rush through designs from the height of the cold war. The 598's were 585's with a missile compartment added. The George Washington was originally going to be the Scorpion (which sank in 68), they cut it apart on the ways and added the missile compartment. JJ Rick James Johnson remove the "dot" from after sail in email address to reply |
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