Engine Speed Protection

34

Engine Speed Protection

Engine speed protection is designed to prevent the engine from starting at a high speed during a condition of low oil pressure. After the engine oil filter is replaced, a long time may be required before the ending oil pressure will reach the specified level. Engine damage may occur if the engine runs at the speed dial position of 10. The following information describes this function.

The engine oil pressure switch sends a signal to the Engine ECM. The Engine ECM controls the engine speed. The engine speed will be limited to the 5 position, if the engine oil pressure switch is open. The engine will start at speed dial position 5.

Engine speed protection prevents damage to the engine that is caused by overspeed during an overheating condition. Work that requires high pressure will be restricted during an overheating condition. The engine and other components are protected during this condition. The engine speed will be decreased to the second setting of the AEC (1300 rpm).

When it is cold and the temperature of the hydraulic oil is low, the machine may not operate smoothly. Pump output will decrease by a small amount. This allows the operations to be smoother until the temperature of the oil rises. When the hydraulic oil temperature sensor has detected an oil temperature below 15° C (59° F) the system limits hydraulic pump output pressure to 80% of maximum hydraulic horsepower. When the hydraulic oil temperature sensor detects an oil temperature that has risen above 20° C (68° F), normal control of the hydraulic oil will begin again.