汽車水溫感知系統之特性分析與故障檢測

在汽車修護實務上發現，當水箱或冷卻系統管路漏水，使得液面一直降到水溫感知器以下時，水溫表指針不升反降，導致駕駛者在不知不覺中車子就因缺水導致引擎過熱而拋錨停擺了。本研究採實驗方式進行，第一階段，自行設計一組冷卻水循環裝置，裝有兩顆水溫感知器，來模擬汽車引擎的冷卻系統，上述液面低於水溫感知器時水溫表無法正常指示的原因何在。第二階段，針對5年內國內生產組裝的各式小型車輛之水溫感知器所裝置的位置進行調查，統計出有多少比例的水溫感知器裝置位置不適當。第三階段針對水溫感知器裝置位置不適當的車型提出改善對策。本研究獲得如下之結論：水溫感知器的最佳裝置位置應該在測試點2的位置，也就是在汽門座上靠近燃燒室的附近。對於裝置位置不佳的改善對策如下： 1. 加裝冷卻水液面過低警告裝置。 2. 將水溫感知器裝置到汽門座本體靠近燃燒室附近的位置。 3. 加裝水溫開關於汽門座上的2號位置，線路並聯到水溫感知器線路上。

關鍵字

水溫感知器；液面感知器

並列摘要

Practice in automobile maintenance and repair found that any leakage through the radiator or cooling system pipeline can cause the level of coolant water to fall. And the leakage will further cause the engine to overheat when a driver is unaware of what had happened. This research is conducted in experimental methods (which involves 3 stages): The first stage concerns the design and development of a coolant cycling device. The device is equipped with two coolant temperature sensors for observing the dynamic behaviors of the cooling system in automotive engines. The goal is to find out the reasons of the malfunction of coolant temperature indicator. In stage two, we conduct an investigation in the positions of coolant temperature sensors in various types of engines for domestic light vehicles over the past 5 years. The approach provides a statistics about the percentage of the improper positioning of coolant temperature sensors. In stage three, we propose our counter-measurements to the mentioned positioning problems of the coolant temperature sensors. Base on the experimental results, we give the following conclusions: The best position of a coolant temperature sensor should be in the test point 2, a point closed to the combustion chamber. The counter-measurements to the sensor positioning are suggested below: 1.to add a coolant level sensor; 2.or to install the coolant temperature sensor closed to the combustion chamber; 3.or to add a water temperature switch on the position of the test point 2, and wires it to coolant temperature sensor in parallel.