汽車引擎溫度監測系統

Abstract

中文摘要 本研究的動機源於日常生活中汽車已成為人們重要的交通工具，而引擎則扮演如同心臟般的關鍵角色。當汽車在長時間行駛或高溫環境下運作時，引擎溫度容易升高，若未能即時監控與控制，將可能造成動力下降、零件損壞，甚至危及行車安全。因此，本研究的目的在於設計一套可靠且具實用性的汽車引擎溫度監測系統，藉由感測器與電路設計的整合，實現即時監測、準確判讀與警示功能，以提升引擎運行的穩定性與車輛安全性。

在方法設計上，本研究選用 PT100 鉑電阻溫度感測器作為核心元件。PT100 具備高精度、良好線性、低漂移與抗雜訊特性，特別適合應用於汽車引擎艙這類高溫且干擾頻繁的環境。為了將感測器的阻值變化轉換為可供處理的電壓訊號，本研究採用電阻分壓法並結合非反相運算放大器架構，使輸出電壓範圍符合微控制器（Arduino 或 ESP32）之 ADC 模組的輸入需求。系統電源則以單電源架構搭配穩壓模組（如 7805）設計，並透過虛擬接地與濾波電容來提升供電品質，確保整體系統的穩定性與相容性。

此外，針對汽車環境中的高雜訊問題，本研究同時加入多層次的抗干擾設計。硬體部分採用屏蔽線、RC 濾波器及退耦電容來抑制電磁干擾與電源紋波；軟體部分則透過移動平均與中值濾波演算法進行數據平滑化處理，避免溫度讀值受到突發雜訊影響。最後，系統輸出部分設計了簡單直觀的指示電路與顯示方式，當溫度超過設定閾值時，可透過 LCD、LED 燈號或蜂鳴器進行即時警示，使駕駛能快速判斷並採取應對措施。

這個系統能成功將 PT100 的微小電阻變化準確轉換為線性電壓，並在經過放大與數位化處理後，提供穩定且可靠的溫度監測效果。此設計不僅能有效提升行車安全與引擎維護效率，亦具備良好的擴充性，可延伸應用於電動車電池熱管理、智慧車載模組，甚至結合物聯網技術進行遠端監控與資料分析。綜合而言，本研究所提出的汽車引擎溫度監測系統展現了理論與實務結合的價值，並具備廣泛的應用前景與實際意義。

Abstract The motivation of this study originates from the fact that automobiles have become an essential means of transportation in daily life, with the engine serving as the core component comparable to the human heart. During long-term driving or under high-temperature environments, the engine temperature can easily rise. Without timely monitoring and control, this may lead to power loss, component damage, or even driving safety hazards. Therefore, the purpose of this study is to design a reliable and practical automotive engine temperature monitoring system. By integrating sensors with circuit design, the system aims to achieve real-time monitoring, accurate measurement, and effective warning functions to enhance both engine stability and vehicle safety.

In terms of methodology, the PT100 platinum resistance temperature sensor was selected as the core element. The PT100 features high precision, good linearity, low drift, and strong anti-noise capability, making it well-suited for the high-temperature and interference-prone environment of an engine compartment. To convert the resistance variation of the sensor into a processable voltage signal, a resistor voltage divider combined with a non-inverting operational amplifier configuration was adopted. This ensured that the output voltage matched the input range of the microcontroller’s ADC module (Arduino or ESP32). For the power supply, a single-supply architecture with a voltage regulator (e.g., 7805) was employed, along with a virtual ground and decoupling capacitors to improve power quality and ensure stability and compatibility of the system.

Furthermore, considering the high-noise automotive environment, multi-level anti-interference measures were incorporated. On the hardware side, shielded wires, RC filters, and bypass capacitors were implemented to suppress electromagnetic interference and voltage ripple. On the software side, moving average and median filtering algorithms were used to smooth data and reduce the influence of sudden noise spikes. The output design also included intuitive indicator circuits and display devices. When the engine temperature exceeded the preset threshold, the system could trigger immediate alerts through an LCD, LED indicators, or a buzzer, allowing the driver to respond quickly and appropriately.

The system successfully converted the PT100’s subtle resistance variations into linear voltage signals. After amplification and digitization, the system provided stable and reliable temperature monitoring. The proposed design not only improves driving safety and engine maintenance efficiency but also offers strong expandability. It can be extended to applications such as battery thermal management in electric vehicles, intelligent in-vehicle modules, and even integration with IoT for remote monitoring and data analysis. Overall, the proposed automotive engine temperature monitoring system highlights the value of combining theoretical concepts with practical design and presents significant potential and practical applications for future development.