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?




http://www.tomorrowsbestseller.com/w...State/book.asp

Gould 0738 wrote:

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?



Shut off the fuel supply, block the air intake and keep a load on the
engine. You sure as hell don't want to pump CO2 down the airpipe.




--
Email sent to is never read.

On Sun, 07 Dec 2003 10:12:43 -0500, Harry Krause
wrote:
Shut off the fuel supply, block the air intake and keep a load on the
engine. You sure as hell don't want to pump CO2 down the airpipe.

=========================

Sounds about right to me. I'd start with shutting off the fuel. That
will work about 99.9% of the time. There's a rare condition however
where the engine will continue to run on it's own crankcase oil, which
gets quickly consumed with disasterous consequences. For that, you
need a way to cut off the air intake.

I once had a dangerous and freak condition where a small sailboat
diesel continued to run at high revs after I had shut it down. As
soon as the engine compartment was opened it stopped running but not
before the smell of gasoline fumes hit me. It turned out that a small
amount of dinghy gas had spilled into the bilge and the diesel was
running on the fumes!

Lucky we weren't blown up.

"Harry Krause" wrote in message
...
Shut off the fuel supply, block the air intake and keep a load on the
engine. You sure as hell don't want to pump CO2 down the airpipe.

Harry, I'm curious why you wouldn't want the engine to breathe CO2.

On the tugs of a company I worked for, we had the large bulkhead-mounted
tanks that could be used to flood the engine room with CO2. We were told to
use them in the case of a runaway engine after closing the engine room air
intakes.

Another thing we were told about a runaway engine is to never position
yourself beside it; always stand in front or behind the engine. That way
when a piston rod comes through the block, you won't get hit. It's obvious
when someone tells you, but it might not be something you think about when
trying to stop a runaway.

Snafu wrote:

"Harry Krause" wrote in message
...
Shut off the fuel supply, block the air intake and keep a load on the
engine. You sure as hell don't want to pump CO2 down the airpipe.

Harry, I'm curious why you wouldn't want the engine to breathe CO2.


Because the CO2 is very, very cold and spraying it down into that hot
engine will likely turn the engine into scrap in short order.




--
Email sent to is never read.

Harry Krause wrote:

Because the CO2 is very, very cold and spraying it down into that hot
engine will likely turn the engine into scrap in short order.

"Thanks for playing, and we do have some lovely
parting gifts for you........"

Sorry Harry, the CO2 will be a gas by the time you get it to the engine.
A CO2 extinguisher might work quite well. Or it might not, depending on
the reason for the engine running away.

Rick

LOL what do you do Harry, make this stuff up?

"Harry Krause" wrote in message
...
Snafu wrote:

"Harry Krause" wrote in message
...
Shut off the fuel supply, block the air intake and keep a load on the
engine. You sure as hell don't want to pump CO2 down the airpipe.

Harry, I'm curious why you wouldn't want the engine to breathe CO2.


Because the CO2 is very, very cold and spraying it down into that hot
engine will likely turn the engine into scrap in short order.




--
Email sent to is never read.

Lawrence James wrote:

LOL what do you do Harry, make this stuff up?

"Harry Krause" wrote in message
...
Snafu wrote:

"Harry Krause" wrote in message
...
Shut off the fuel supply, block the air intake and keep a load on the
engine. You sure as hell don't want to pump CO2 down the airpipe.

Harry, I'm curious why you wouldn't want the engine to breathe CO2.


Because the CO2 is very, very cold and spraying it down into that hot
engine will likely turn the engine into scrap in short order.




--
Email sent to is never read.



Oh? You wouldn't stop a runaway diesel by cutting off the air supply and
shutting off the fuel? What would you do? Stuff rolls of TP in it?

As for the CO2, more than one diesel guru has indicated that the temp
differential would seriously harm the engine.

--
Email sent to is never read.

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

ospam (F330 GT) wrote in message ...
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.

All of the Detroits I have had experience with (on trucks and
generators, not boats) cut off the air for emergency shut down. I
spring loaded plate dropped over the intake when you pulled the
emergency shut down lever. They are the only ones I recall having a
dedicated emergency shut down mechanism.