Created on:2021-10-19 10:25

Locomotive equipment_ Fault analysis of locomotive hydrostatic system

Locomotive equipment_ Brief introduction to faults of locomotive hydrostatic system

On de4b locomotive, the cooling fan is driven by hydrostatic transmission technology. This technology can meet the requirements of large power regulation range and frequent heat load change of locomotive diesel engine. Through the constant temperature element in the static temperature control valve, the change of cooling fan speed is organically combined with the change of diesel oil and water temperature, so as to realize the automatic constant temperature control of diesel oil and water temperature.

DF4B locomotive adopts two cooling fans, each with an independent hydrostatic transmission device. Figure a is the working principle diagram of the hydrostatic system of DF4B locomotive. The working principle of the system is as follows.


When the diesel engine is running, the hydrostatic pump is driven to suck hydraulic oil from the hydrostatic oil tank, and then the high-pressure oil is sent to the hydrostatic motor through the pipeline. The motor rotates and drives the cooling fan under the action of pressure oil. The high-pressure oil returns to the oil tank after the work is completed. At the same time, the high-pressure oil also flows through the temperature control valve and the safety valve installed between the high-pressure pipeline and the return pipe. When the oil and cooling water temperatures of the diesel engine are lower than the specified 55 ℃ and 74 ℃ respectively, the temperature control valve in parallel in the hydrostatic motor pipeline is open, and the pressure oil directly returns to the oil tank without passing through the hydrostatic motor. With the increasing temperature of diesel oil and water, the mixture of paraffin and copper powder in the thermostatic element is heated and the volume expands, so as to push the slide valve in the temperature control valve, gradually close the bypass port, and the pressure oil gradually enters the hydrostatic motor, so that the hydrostatic motor gradually reaches full speed from low speed. The cooling fan then runs from low speed to full speed. When the load of the diesel engine changes, the oil and water temperature will change accordingly, which will promote the action of the thermostatic element in the temperature control valve and change the speed of the hydrostatic motor, so as to control the diesel oil and water temperature within the required range.

Because the hydrostatic system is more complex and there are many pipelines and components, the reasons for the non rotation or abnormal speed of the fan are also more complex.

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