Control system for cooling fan, work machine, and method of controlling cooling fan

A work machine comprising:

• an engine;
• a work implement driven by the engine;
• a cooling fan configured such that the number of rotations is controllable independently of the number of rotations of the engine;
• and
• a controller that controls the cooling fan, wherein
• the controller obtains a frequency of the engine and a frequency of the cooling fan, and
• the controller controls the cooling fan to make a difference in frequency between the cooling fan and the engine larger than the difference at a time point when the controller obtains the frequency of the cooling fan, by changing the frequency of the cooling fan when the number of rotations of the engine is larger than a threshold value and the frequency of the cooling fan is within a prescribed range from the frequency of the engine while the work implement is in a standstill.

A method of controlling a cooling fan in a work machine, the work machine including an engine, a work implement driven by the engine, and a cooling fan configured such that the number of rotations is controllable independently of the number of rotations of the engine, the method comprising:

• determining whether the work implement is operating;
• obtaining a frequency of the engine;
• obtaining a frequency of the cooling fan;
• and
• controlling the cooling fan to make a difference in frequency between the cooling fan and the engine larger than the difference at a time point when the frequency of the cooling fan is obtained, by changing the frequency of the cooling fan when the number of rotations of the engine is larger than a threshold value and the frequency of the cooling fan is within a prescribed range from the frequency of the engine while the work implement is in a standstill.