Modeling the Magnetic Performance of a Fast Pneumatic Brake Actuator

Abstract

A novel pneumatic valve was constructed to improve the response of air-actuated brakes for heavy vehicles to demand pressures generated during electronically controlled braking by an order of magnitude. Investigations were made into the interactions between the magnetic, mechanical, and electrical subsystems of the valve with a view toward informing design optimization. The valve was modeled using a magnetic circuit approach. The quasi-static model included the influences of the permanent magnet, field-line fringing, saturation, and the coil. Mechanical forces outputted by the model matched physical measurements with an error smaller than 10%, and magnetic fluxes throughout the circuit were generally within 20% of those found from experiments based on Faraday's law of induction, Gaussmeter measurements, and FEA simulations. A magneto-mechanical simulation of the valve switching states was created using mechanical and electrical equations, and curve-fits to the outputs of the magnetic circuit model. The simulation produced time histories of the valve's armature position that matched experimental measurements and adequately predicted working pressures. The final model required an approximation to the influence of the coil based on experimental results. Consequently, further research is recommended into the influence of solenoid coils on fringing in magnetic circuits.

Investigation on Electromagnetic Models of High‐Speed Solenoid Valve for Common Rail Injector

“…It was discovered that solenoid valves with different soft magnetic materials have different characteristics of electromagnetic force. Miller et al [13], Shin et al [14], and Bianchi et al [15] carried out optimization research on the static electromagnetic force of an HSV to obtain the optimal structure parameters by FEM. However, because of the long solution time and high requirements for computer performance of FEM, the efficiency of research on the optimization and analysis of the structural parameters is low, especially when carrying out an iterative structural analysis for the detailed parameter design of HSV.…”

Design of a pressure modulator using fast-acting bistable valves

“…A simplified magnetic model was sought by the authors to be used as a design tool for future bistable valve designs, for cases where the overall valve shape would be similar. Figure 4 shows the FEA simulation presented by Miller et al 7 for the original bistable valve design. As can be seen, the pole-piece and flexure regions have considerably higher magnetic flux densities than the other parts of the valve.…”

“…This paper builds upon work presented in [6] and describes how the proof-of-concept fast acting bistable valve prototypes described in [4,6] have been further developed to enable implementation on a HGV. Simplified magnetic equations are presented to predict the magnetic forces within the bistable valve; key features are discussed that allow the bistable valve to operate at the supply pressures and battery voltages common to HGVs; pressure control equations and a brake chamber pressure observer are presented, allowing an aggressive, high-bandwidth pressure control regime to be implemented, even when pressure transducers cannot be mounted on the brake chamber.…”

“…when F coil shown in Figure 3 is zero) the flexure is attracted to either of the pole-pieces by a magnetic hold force (F mag ), hence being referred to as ''bistable''. As described in Miller et al, 7 in order for the flexure to ''stick'' against the pole-piece the following condition must hold…”

Development of Wheel Pressure Control Algorithm for Electronic Stability Control (ESC) System of Commercial Trucks

“…The proposed algorithm is intended for use in the ESC systems of trucks. The pressure control method proposed in the literature [ 12 , 13 ] was applied to the ABS system of a truck, which transmits the pressure provided by the air reservoir to a wheel cylinder. However, this method exhibited a delay problem.…”