Handling Of Diesel Generator Set -runaway- (speed Loss Of Control) Faults

I. Emergency Handling of Overspeeding of the Unit (Engine Shutdown Priority)

Definition of Overspeed: Diesel engine speed uncontrollably surges, abnormal noise, dense smoke, power becomes uncontrollable, easily causing cylinder scoring, crankshaft fracture, total engine damage, and even injury.

1. Fastest Emergency Shutdown Procedures (Priority on Site)

1. Cut off air intake (most effective, no side effects) - Immediately block the air inlet of the air filter tightly with cardboard, cloth, or wooden board to isolate oxygen. The engine will instantly stop. Note: Do not block with your hands as high-speed airflow can injure hands.

2. Cut off fuel from high-pressure oil line (when air intake cannot be blocked) - Mechanical fuel pump: quickly loosen any high-pressure fuel line to cut off fuel supply; - Electronic injection unit: directly disconnect the diesel pump solenoid plug or close the manual fuel shut-off valve.

3. Load/brake assistance (for power generation units) - Engage high-power load (resistive load, water pump) to forcibly increase resistance, combined with fuel/air cutoff for shutdown.

4. Strictly prohibited operations (fatal mistakes)

❌ Repeatedly increase/decrease throttle or repeatedly turn the key on/off;

❌ Loosen belts or remove fans;

❌ Stay near flywheel, couplings, or high-temperature exhaust parts.

2. Inspection Steps After Shutdown

1. Wait for the engine to completely cool before disassembly;

2. Check if the governor, fuel injection pump, or throttle linkage is stuck;

3. Check for fuel leakage or engine oil entering the combustion chamber;

4. Inspect valves, pistons, and cylinder liners for scuffing or damage.