以真空衰退法檢測噴射機車油氣蒸發系統洩漏之診斷研究

Study on the Diagnostics of Evaporative System Leak by Using the Vacuum Decay Method for Fuel Injection Motorcycles

王顯斌(Hsien-Pin Wang)

指導教授 ： 鄒忠全

崑山科技大學/工程學院/機械工程研究所/碩士(2011年)

摘要

本文主要研究以真空衰退法檢測油氣蒸發系統之洩漏，利用引擎怠速時之進氣歧管真空將油氣蒸發系統抽真空，並測量其真空之衰退，以判斷此系統管是否發生破損與洩漏。若油氣蒸發系統發生破損與洩漏，將會導致油氣散發至大氣之中而造成空氣污染。
本研究在油氣蒸發系統管路中加裝真空感測器，並在活性碳罐進氣口端加裝常開電磁閥，以及在進氣岐管端加裝常閉電磁閥。當引擎在怠速時，利用進氣岐管的真空將油氣蒸發系統之管路、活性碳罐和油箱抽真空，並利用真空感測器測量此系統中之真空衰退之上升斜率，藉以檢測系統管路是否發生破損及其大小。將油氣蒸發系統抽真空時，因油氣太濃會使引擎運轉會不穩或熄火，所以須進行引擎怠速穩定控制。本研究利用MatlabSimulink軟體撰寫噴油控制與怠速穩定控制程式，利用空燃比感測器測量排氣之空燃比值，使用PI控制器做噴油時間修正，並同時控制怠速空氣旁通閥，以解決引擎怠速不穩的現象。本研究使用美商國家儀器(National Instruments , NI)之LabVIEW軟體撰寫真空衰退之檢測程式。
　　本文在系統管路中，設置直徑為0.5、0.7、1、1.5 mm的破損孔徑之銅管，以模擬實際管路中所發生的破損，利用真空衰退法可以正確判斷以上之破損孔徑。

關鍵字

真空衰退法 ； 油氣蒸發系統 ； 機車噴射引擎

並列摘要

The study of this thesis is how to use the vacuum decay method to diagnose the evaporative system leak of motorcycles with the fuel injection system. When the engine is at idle, the vapor in the evaporative system is sucked by the intake manifold vacuum. If the parts in the system is broken, the vapor will leak out and pollute the air. In order to test whether the pipe of the system was broken or not, we can check the rate of vacuum decay by using the vacuum decay method.
First, one vacuum sensor was installed in the pipe of the evaporative system near the fuel tank. One normally open solenoid valve was installed in canister inlet and another normally closed solenoid valve was installed in the feeder near the intake manifold. The vacuum in the intake manifold at idle was used to suck the vapor in the pipes, canister, and the fuel tank of the evaporation system. The rate of vacuum decay measured by the tank vacuum sensor can decide whether the evaporative system is broken or not. To avoid the engine instable or stall, the idle stability control must be equipped. The program of the fuel injection control and idle stability control was written by using the MatlabSimulink software. The PI feedback controller was to trim the injection period with the help of a wide-band O2 sensor. The opening of the idle air control valve was regulated to stabilize the idle at the same time.
To imitate the evaporative system leak, the bronze tubes with 0.5 mm, 0.7 mm, 1 mm, and 1.5 mm aperture were installed in the evaporative system in experiments. The results of experiments prove the vacuum decay method can diagnose the aperture size of the tubes.

並列關鍵字

Vacuum decay method ； Evaporative system ； Fuel injection motorcycles

參考文獻

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