本文以TOYOTA生產之Prius油電混合車（簡稱HEV），進行實車FTP-75耗能測試，分析HEV電量變化對於平均油耗值的影響，分別在市區耗能測試前，以高、中、低之初始電量，進行耗能測試，結果發現Prius平均油耗值與初始電量成正向趨勢。進一步估算市區耗能值差異(%)與市區（充電能/燃料能）比值關係，則可發現若規範（充電能/燃料能）比值在2%內，則市區耗能值差異可在3%內。

This study is focused on the FTP-75 fuel economy (F.E.) test through Prius HEV (Hybrid Electric Vehicle) produced by Toyota Motors. In order to analyze the influence of F.E. testing on different SOC (State of Charge) of HEV, the initial SOC values are set at high, medium and low conditions. From the experimental results, it can be found that the average fuel consumption of Prius HEV is in proportion to the initial SOC value. In addition to calculate the difference of fuel consumption and the ratio of net charge stored electrical energy and fuel energy approximately, it can be found that if the ratio of net charge stored electrical energy and fuel energy is limited in 2 percentage, then the difference of fuel consumption is also limited in the period of three percentage.