本文針對車載診斷系統二(OBDII)之通訊協定ISO 14230進行探討,並藉由ISO 14230的實體層、資料鏈結層與應用層規範,規劃本電腦診斷系統功能架構與電路設計。本研究採用符合ISO 14230之Varica車輛引擎作為電腦診斷系統製作之平台,其中,在系統連結上,由於系統間通訊協定與電腦通訊介面之規範不同,因此,設計符合診斷系統與電子控制單元之電路,並應用於收發器電路的製作。另外,在電腦診斷系統程式設計上,採用Visual C++6.0整合式發展環境程式軟體,作為系統之連線系統、人機介面、診斷系統開發平台,其中,依照ISO 14230資料鏈結層的快速初始化來建立診斷系統之連線功能;ISO 14230應用層之ReadDiagnostic- TroubleCodeByStatus、ClearDiagnosticInformation、ReadDataByLocal- Identifier診斷服務建立診斷系統之診斷功能,藉以對Varica車輛引擎作擷取與消除引擎故障代碼及引擎運轉參數,其中,Varica引擎運轉參數之回應(Response)數據為車廠規範所制定。最後,本研究將對Varica引擎運轉參數探討分析,並歸納出引擎各項參數之轉換公式,藉此建立符合Varica診斷系統之雛型,進而提供維修人員作為Varica車輛故障診斷之工具。
The purpose of this thesis is to study the ISO 14230 communication protocol for the On-Board Diagnostic System II (OBDII) and scheme the structure of the fault diagnostic system and circuit design. We adopt the Varica vehicle engine to be the fault diagnostic system object and we also develop a circuit to deal with the problem of switching protocol between vehicle electronic control unit (ECU) and our fault diagnostic system. Furthermore, we use Visual C++ 6.0 Integrated Development Environment to design the software of Human-computer interface (HCI), communication system and the fault diagnostic system. Based on the ISO 14230 data link layer and application layer protocols, we can use fast initialization to setup communication functions and gather Varica engine trouble code and parameter responses whose variables are defined by the vehicle manufacturer. Finally, we particularly analyze the engine parameters and generalize each exchange function to provide a diagnostic tool functions of Varica.