Re: [MV] runaways

From: DaveCole (davidcole@tk7.net)
Date: Mon Apr 02 2001 - 11:48:37 PDT


This may sound a bit extreme, but I can't imagine how less extreme a runaway
diesel might be, but what if someone was to dump some water (hopefully in a
controlled manner into a diesel engine that was running away. Has that ever been
done??

It is common (at least to me) to run a small amount of water into a running gas
engine to clean out carbon deposits. It actually works quite well. The trick is
to dump it in slowly so the engine can pass the water through it, however if you
dump it in too fast, the effect is that the engine will slow down substantially
until it stalls. The water cools off the charge sufficiently to shut down the
engine. Obviously sticking a running water hose into the air intake would
probably blow the engine, but I'm not talking about doing that. Having a can of
water near the engine upon startup might be a lot more available than a C02
extinguisher or something that can effectively be used to cut off the airflow.

Dave
>>>>>>>>>>>>>>>>>>>>>>>>>

DDoyle9570@aol.com wrote:

> While on the subject of runaways, there is something that has been
> missed....I am telling this from memory, not the manual, so, while the
> principle is correct, the numbers may not be exact.
> The military multifuel engine is governed to 2800 RPM (could be 2600, again
> this is from memory), ASSUMING the governor is working correctly, the
> injection pump will not pump enough fuel to blow the engine up, REGARDLESS of
> the throttle setting. In fact, either the injector or engine manual tell you
> top operate the engine at full throttle with no load for so many minutes as
> part of the break in procedure.
> Now, if the governor section of the injection pump has failed, you can blow
> the engine up, even if the throttle works properly, simply by mashing the gas
> too far.
> As some one else has already mentioned, the most likely way to blow the
> engine up is by introducing fuel from a source OTHER than the injection pump.
> Crankcase oil is the most likely source of this outside fuel. When faced
> with this situation there is NOTHING you can do to the fuel system to shut
> the engine down, as the fuel causing the runaway is not going through the
> injection pump or any other part of the fuel system. The only practical way
> to shut it down is shut off the air. (you MAY be able to choke the truck
> down by putting it in high gear, high range and releasing the clutch) One
> way to shut off the air is by slapping a board over the air intake(s),
> another way is to discharge a 15 pound CO2 fire extinguisher into the air
> intake. The key under either method is that the engine MUST completely stop
> revolving. If you run out of CO2 before it quits turning, or move the board
> it will start all over again.
> Hope this helps,
> David
>
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This archive was generated by hypermail 2b29 : Tue May 01 2001 - 07:42:38 PDT