油電混合車輛動力系統之可靠度分析

Abstract

隨著近年來新能源車輛產業與市場的不斷擴大，其相關研究也成為熱門。本論文旨在探討油電混合車輛動力系統的可靠度，研究過程中，先參照市場上常見的油電混合車輛，提煉出三種具有代表性的動力系統配置，一一區分其子系統構成，並將其繪製成系統方塊圖；而後，分別參照NEDC (New European Driving Cycle)以及CLTC (China Light-duty Vehicle Test Cycle)兩種行車型態(Driving Cycle)，定義不同速度及加速度區間下動力系統的運作模式，確立不同模式下參與運作的子系統及其衰退情況；最後，依照電池容量衰減的半經驗模型，以及美國海軍可靠度手冊所載失效率資料，討論各子系統獨立運作時的可靠度，並結合不同子系統在不同運作模式下各自的衰退情況，探討油電混合車輛動力系統的可靠度。研究結果顯示，馬達及發電機等新能源車輛所採用的子系統可靠度較傳統車輛子系統可靠度低；本研究也發現，電池子系統可靠度會在一定區間內快速下降，其對整體動力系統可靠度的影響較為顯著。針對不同動力系統配置以及不同行車型態下的可靠度比較，本研究發現並聯式混合動力系統的可靠度相較於其他系統配置高，NEDC行車型態相對於CLTC下的可靠度也較高。

In recent years, the continuous expansion of the new energy vehicle industry and the market have made related research a popular topic. In this thesis, a method for evaluating the reliability of powertrain system of HEV is proposed. First, configurations of three typical powertrain systems are constructed based on HEVs commonly seen in nowady market, with their subsystem compositions identified and illustrated using system block diagrams. Subsequently, the reliability of individual subsystem is analyzed using a semi-empirical battery capacity degradation model and data from the U.S. Navy Reliability Handbook. Two driving modes are defined to reflect distinct driving characteristics across different regions by referencing the New European Driving Cycle (NEDC) and the China Light-duty Vehicle Test Cycle (CLTC). Based on these driving modes, the operational modes of the powertrain systems are defined, and the subsystems involved in each operational mode are identified. By assessing the impact of subsystem participation and degradation during each operation mode, the reliabilities of three powertrain systems are evaluated and compared under two driving modes that reflect cross-regional driving characteristics. The research results indicate that electric-involved subsystems, such as motors and generators, exhibit lower reliability than traditional mechanical subsystems. Furthermore, the battery subsystem’s reliability declines rapidly within a certain charge-and-discharge cycles, exerting a significant influence on the overall powertrain reliability. It is found that the powertrain arranged in parallel exhibited relatively higher reliability. Moreover, the driving mode of NEDC reflecting flat terrain driving characteristics resulted in higher reliability compared with that of CLTC.