The Air Shut Off Valve is utilized on a Diesel Engine Inlet Air Connection between the Air Intake Filter and the Turbocharger Inlet (or Intake Manifold if the diesel engine is not turbocharged) as an emergency device to shut down the air inlet flow into the combustion chamber to shut down the engine.

Also known as ASOV, AISV, ESD or emergency shutdown valves, air intake shut off valves are systems that allows for emergency over speed shutdown and protection for diesel engines. They are by far the most efficient systems are used to prevent engines getting into runway situations today.

Air intake shut off valves provide emergency overspeed shutdown protection for diesel engines and are the most effective way of preventing a runaway situation. The valves completely block the engine air intake system, cutting off an uncontrolled external fuel source and the air required to keep the engine running.

Positive air shutoff systems are used to protect people and equipment from diesel engine runaway. This occurs when a diesel engine ingests a hydrocarbon vapor and uses it as an uncontrolled fuel source. When this happens, the only way to effectively shut down the engine is by either removing the air or fuel supply.