## 2 Experiment Description
### 4-Equations for Calculation of the Unadjusted and Adjusted Fuel Consumption
\\  & **Fuel Efficiency = [EWF-10\(\times\)0.23\(\times\)CO+2.72\(\times\)SO]**:[0.66\(\times\)SC-NHV+12772] \\ \cline{2-3}  & Yvnn = (CO, CO\({}_{2}\)), NOK, HC, CHH, and NMTOy Weighted exhaust gas mass (gas/km, g/mile) \\  & Yct = mass of emission at the initial stage of cold start set (g/test phase) \\  & Ytht = mass of exhaust gas (g/test phase) at the initial stage of the hot start test \\  & Ys = mass of exhaust gas (g/test phase) at the stabilization stage of cold start test \\  & Dct = driving distances (km, mile) at the initial stage of the cold start test. \\  & HC, CO, and CO\({}_{2}\) (g/km) = exhaust gas concentration obtained from the above equation. \\  & CWF = the ratio of carbon content in the fuel. \\  & SG(g/mL) = the fuel density. \\  & NHV/g) = calorific power. \\ \hline \multirow{7}{*}{B} & (a) City mode EE = FTP\_75 EE \(\times\) 0.9 \\ \cline{2-3}  & FTP 75.5 EE: the fuel efficiency for FTP cycle \\ \hline \multirow{7}{*}{C} & (a) City mode EE = 0.905 \(\times\) (Statt FC-Running PC) \\  & Start FC-0.330 \(\times\)([0.23\(\times\)Statt FN-92\(\times\)0.24\(\times\)Statt FN-92\(\times\)0) \\  & Running FC \\ \cline{2-3}  & (0.48 \(\times\)0.41 \(\times\)0.11 \(\times\)0.5 \(\times\)0. As seen in Figure 5a, when the fuel efficiency value obtained from formula A is compared with that obtained from formula B, C, or D, the difference is approximately 10%, 22.4%, or 22.2%, respectively. It can be observed that the gap between fuel efficiency derived from the C and D equations when considering US06, SC03, and cold FTP fuel economy results, that helps to reflect various driving environments, and that obtained from Equation A when considering only one driving characteristic of the FTP-75 driving cycle, indicates a major difference. This observation suggests that fuel economy differs significantly, depending on how many driving situations are considered in producing fuel consumption. However, the fuel efficiency value calculated from Equation B differs somewhat from results from the Equation C and D, which calculate fuel efficiency value in consideration of various driving environments. So, it is thought to be inadequate to calculate corrected fuel efficiency value when considering the environment appearing on the actual driving road by simply multiplying by 0.9 constant value. Figure 5b shows the difference between highway fuel consumption values obtained from A, B, C, and D equations. This shows comparable trends to those shown in fuel consumption results of the urban way mode. Because same fuel consumption results obtained from SC 03, US 06, and cold FTP are also applied to adjusted highway fuel economy equations, C and D, this result is not unexpected. In the Equation B for highway mode, even the 0.75, a lower value than that of the city correction factor, 0.9, is multiplied by unadjusted fuel consumption for highway cycle, but the marked difference was represented in fuel consumption, when compared with results that were obtained from Equation C and D.  
Comparison between CO\({}_{2}\) Emissions in FTP75, HWFET, and US06 Drive Cycles According to 0, 6500, 15,000 and 30,000 km Mileage  
Figure 6 shows average CO\({}_{2}\) concentration that was obtained from the test vehicle according to each mileage during FTP-75 cycle tests. The experiment was repeated twice, and the arithmetic mean of CO\({}_{2}\) results calculated to reduce the effect on the change in CO\({}_{2}\) emissions caused by the driving behavior. CO\({}_{2}\) levels show differences by 3.24%, 3.77%, and 2.36% at 0 km, 15,000 km, and 30,000 km mileage, when compared with that at 6500 km mileage. In the case of the vehicle at 0 km mileage, CO\({}_{2}\) emission was emitted slightly higher than that at the 6500 km mileage. Since taming of the vehicle at the initial driving of the vehicle usually results in poor fuel economy, it is assumed that CO\({}_{2}\) concentrations at 0 km mileage were measured higher.