Analysis of flow field characteristics in a proportional solenoid valve for cotton picker power shift transmission considering temperature effects

The proportional solenoid valve (PSV) of the power shift transmission (PST) of the cotton picker is taken as the research object, and the influence of temperature on its flow field characteristics is analyzed. The finite element model of the flow field is used to study the changes in the pressure and velocity fields with various valve opening degrees at 40 °C, and the accuracy of the model is verified by experiments. Comparing the flow field distribution of the valve in a wide temperature range of −20 °C, 40 °C, and 85 °C, the evolution mechanism of the flow field under the influence of temperature is revealed, and the flow resistance characteristics at high and low temperatures are analyzed. The results show that when energized, the temperature affects the flow field through the viscosity of oil, the low temperature shows the characteristics of high pressure difference and high velocity, and the maximum velocity reaches 7.93 m/s, while the high temperature shows the characteristics of low pressure difference and uniform flow, and the maximum velocity is about 3.37 m/s; when de-energized, the flow rate and velocity at the same valve opening increase significantly with the increase of temperature. When the temperature rises from −20 to 85 °C, the peak velocity increases from 40.41 to 55.46 m/s. Additionally, the flow resistance coefficient at low temperature is obviously higher than that at medium and high temperatures, and it is significantly affected by the valve opening. This study provides a theoretical basis for the design of a proportional solenoid valve in a wide temperature range.