Matching flexible fans and reducing power consumption is an important means to reduce fuel consumption for engines. Compared with traditional direct-connected fans and three-speed electromagnetic fans, electronically controlled silicone oil fans had a wider speed governor modulation range. To control fan speed more accurately and minimize power consumption, PID closed-loop control based on fan speed was increasingly applied to silicone oil fans.But certain speed ranges were difficult to stabilize because of the elastic properties of internal spring, the viscosity characteristics of silicone oil, solenoid valve duty cycle drive characteristics, and the disengagement characteristic. A method was hence put forward to suppress the speed fluctuation of silicone oil fans by combining traditional PID closed-loop control with dynamic integral freezing technology, achieving smooth fan control and greatly solving the problem of speed fluctuation in the control dead zone of fans. By carrying out fixed-point steady-state tests and transient variable-speed tests on a certain excavator, the technology could effectively eliminate the phenomenon of speed fluctuation at the fan dead zone operating point, and the percentage of speed fluctuation operating conditions reduced from 18.3% to 0%.