What tool can be used to smother the intake of a runaway diesel engine?

A CO2 fire extinguisher is an effective tool to smother the intake of a runaway diesel engine because it works by displacing oxygen. Diesel engines operate on compression and require a mix of fuel and air to ignite and run. When CO2 is introduced into the engine's intake, it limits the availability of oxygen, which effectively helps to stop the combustion process. Since CO2 does not leave behind any residue, it remains a preferred choice in situations where preserving mechanical components is important, such as with engines.

In contrast, a fire blanket is primarily designed for smothering fires by blocking oxygen but is not suitable for an engine's intake system. A water hose is not effective because applying water to a diesel engine may not extinguish the flames and can create more hazards. A foam extinguisher, while good for flammable liquids, does not efficiently remove oxygen from the environment in the same manner as CO2. Thus, using CO2 is the appropriate and effective method for addressing a runaway diesel engine situation.