氣壓式電磁閥之動態特性的數值研究

Transient CFD Analysis on Performance Characteristics of a Solenoid Valve

林顯群 ； 陳佑政 ； 林郁民 ； 黃昱菘

《機械工業雜誌》 435期 (2019/06) Pp. 24-32

摘要

汽車行駛中發生緊急情況必須踩煞車減緩車輛速度時，此時若裝載ABS系統便能以頻率式的踩放煞車限制其強度，如此即能避免車輪卡死導致駕駛無法操控方向，因而反使車輛煞車距離有增加之危險性。ABS系統中運用氣壓式電磁閥控制煞車強度，其靈敏度便極為重要，若能快速執行充、放氣的機制，便能以更高的頻率進行煞車控制；其中電磁閥之壓力上升時間(ts_(75%))與壓力下降時間最為關鍵，是否符合國際Tier1車廠規範的需求，即是電磁閥設計之成敗指標。本文利用CFD軟體計算出電磁閥作動時之壓力反應時間，採用真實可壓縮氣體方程式分析，並將鐵芯動態行為考量進來，此精準的分析模式將可提供做為電磁閥設計與改善之重要工具。

關鍵字

電磁閥 ； 壓力反應時間 ； 暫態特性 ； 可壓縮之真實氣體模擬

並列摘要

This research presents the unsteady CFD effort to realize the pressure-charging and releasing characteristics of a 3/2-way pneumatic solenoid valve, which is used in activating the ABS (anti-lock braking system). The actual pressure-rising action of solenoid valve is accomplished by executing the armature-moving process and the pressure-filling process. It follows that the course of armature movement is an extremely quick transient process and forms a time-consuming and problematic CFD challenge, which is thus ignored usually. However, the flow pattern at the end of armature movement is the initial condition for activating the actual pressure-charging process. Therefore, this work performs the transient simulation on the armature-moving process to understand the physical phenomenon in details and obtain the correct initial condition for the succeeding pressure-filling process. In addition, the real-gas relation is implemented in all calculations executed here to ensure the accurate and reliable numerical results.

並列關鍵字

Solenoid valve ； Pressure response time ； Transient characteristics ； Compressible real-gas simulation