車輛系油壓煞車系統含水量預警裝置之研發

Development of an Alarm Device for the Moisture Content in of the Hydraulic Fluid of the Automobile Brake System

煞車油是一種油狀液體，由乙二醇基化合物所組成，主要作為傳動力的介質，供各種車輛之油壓煞車系統傳導煞車力量。但是煞車油的性能卻會被水份所限制，當煞車油含有水份時，煞車油之沸點溫度會因此而降低，因為當煞車時，煞車蹄片會將煞車所產生的熱傳導至煞車分泵，使得含有水份的煞車油，因為沸點降低而沸騰。這種現象會使原本是不可壓縮的煞車油變成可壓縮性，導致煞車失效。在本研究具體成果為建構了一個以煞車油電阻值，偵測煞車油含水量之預警系統。本系統是藉由量測在不同含水量煞車油中的電壓訊號，並經由訊號放大及統計分析，決定出煞車油含水量之警界值。同時提供了參數調整方法，藉此使本系統可適用於所有品牌之煞車油。當煞車油含水量百分比超過安全範圍時，則預警系統將會傳遞警告訊號至儀表板，以警示駕駛人。而這一項預警系統具有價格低廉、容易安裝以及提高車輛之安全性的特性。

Hydraulic fluid is a glycol organic compound which exhibits high boiling temperature characteristics. Moisture content will lower boiling temperature of the hydraulic fluid. Because the heat from the brake friction can be conducted to hydraulic cylinders to raise the temperature of the hydraulic fluid, high percentage of moisture content in the hydraulic fluid may result in the boiling of the fluid. The hydraulic fluid will become compressible which will cause the failure of the brake system. In this research, an alarm system is developed which can detect moisture content in the hydraulic fluid by using the resistance measurement. The moisture content signal was statistically analyzed to define a thresh-hold value to and send the an alarm signal. A calibration method was provided based on the data controlled collected to adjust for various brands names of brake fluid. When the moisture content exceed the safety margin, the system will transmit a warning signal to the instrumental panel for the driver. The system is inexpensive, easy to install and will greatly increase driving safety.