Engine Over-speed Shutdown

A diesel engine’s speed is generally controlled by varying the supply of fuel. In many environments having flammable or explosive vapors or dust, including: oil fields, mines, and chemical plants, diesel engine over-speed is a real concern.

In these environments, such a fuel source is drawn into the air intake of the diesel engine, resulting in uncontrollable engine speeds, also known as a runaway condition. In particular, the engine reaches a point where it can operate uncontrollably even though the engine's own fuel supply has been shut off (key turned off). The consequences of running an engine too fast are a catastrophic failure.

An over-speed shutdown is designed to completely block the engine’s air intake, cutting off the external fuel source and the air required to keep the engine running. The LH photo above is for a Cummins engine and is displayed next to a pen, for relative sizing. A sensor enables a guillotine which completely closes off the air supply to the engine, air being a key component of operation and the source for explosive vapors.

The RH photo shows how the shutdown is positioned within the system for diesel engines, as close to the intake manifold as possible. If a hose blows, then it defeats the purpose of the valve.

Once the event has ended the operator needs to manually reset the valve, retracting the device and opening the air way.

And now...

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