1D Simulation of Automotive Transmission Valve System Behavior for Air-bubble-contained Transmission Oil

To improve the transmission performance at the design stage of model-based development (MBD), it is important to build a simulation model of the hydraulic control system of automotive transmission. This study constructed a measurement technology for linear solenoid valve behavior and a one-dimensional (1D) simulation model for the prediction of pressure control performance under air-bubble-containing oil conditions. In the pressure control valve of an automobile transmission, the load flow rate during pressure control is reduced and pressure is controlled with minimum power by balancing the annular gap flow in the overlap area of the spool, so it is necessary to build a simple flow characteristics model for the entire range from the underlap to the overlap state. In addition, it is also necessary to build a pipeline model that can freely set the retention of bubbles in the piping and load and the air mixing rate of the oil at each point. This paper presents the construction strategy of the 1D simulation model, including the modeling of the air-bubble-containing oil property and the modeling method of the spool position-valve opening area characteristics, which continuously expresses the lap condition of the valve port from underlap to overlap. The study findings contribute to the construction of automobile simulation infrastructure.