# The Indicator of GDI Engine Operating Mode and Its Influence on Eco-Driving
## 5 The Results and Discussion  
Thanks to the use of registration of signals from the vehicle speed sensor, the time of car motion (\(t_{m}\)), the covered distance (\(D\)), and the average speed (\(v_{a}\)) of each run can be calculated. Almost the same distance of 82.5 km +/\(-\) 0.1% was recorded for each of the 18 road tests. The car's average speed (\(v_{a}\)) varied slightly at around 60 km/h, excluding test nos. 1, 2, and 6. The registration and acquisition of the injector signals enabled the calculation of the sum of average active injection time per one kilometre (\(\Sigma t_{ia,av,k}\)), which is proportional to fuel consumption. The results are presented in Table 1.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Test** & \(D\) & \(t_{total}\) & \(v_{a}\) & \(t_{green}\) & \(S_{green}\) & \(t_{red}\) & \(S_{red}\) & \(t_{blue}\) & \(S_{blue}\) & \(t_{i,av}\) & \(\Sigma t_{i}\) & \(\Sigma t_{ia,av,k}\) \\
**[**–**]** & **[km]** & **[s]** & **[km/h]** & **[s]** & **[\%]** & **[s]** & **[\%]** & **[s]** & **[\%]** & **[ms]** & **[s]** & **[ms/km]** \\ \hline \hline \multicolumn{10}{c}{drives without the indicator} \\ \hline
1 & 82.384 & 5204 & 57.0 & 2508 & 48.2 & 2073 & 39.8 & 623 & 12.0 & 1.071 & 61.84 & 750.7 \\
2 & 82.359 & 4627 & 64.1 & 1042 & 22.5 & 2733 & 59.1 & 851 & 18.4 &  
Table 2 contains the output from the Excel \(t\)-Test two-sample, assuming unequal variances tool. For the significance level \(\alpha\) = 0.05, the hypothesis of the mean value difference for two series of the sum of average active injection time per one kilometre \(\Delta\Sigma t_{iu,avg,k}\) = 50 [ms/km] was verified. The hypothesis was accepted. The average speed of the car for each test and the sum of average active injection times per one kilometre (\(\Sigma t_{iu,avg,k}\)) are presented in the diagram (Figure 7). Figure 7 shows an apparent lack of dependence between the average vehicle speed and the sum of average active injection time per one kilometre (\(\Sigma t_{iu,avg,k}\)); the correlation coefficient is 0.26. This can be explained by minor differences in the average car speed \begin{table}
\begin{tabular}{r c c c c c c c c c c c c} \hline \hline
**Test** & \(D\) & \(t_{total}\) & \(v_{a}\) & \(t_{green}\) & \(S_{green}\) & \(t_{red}\) & \(S_{red}\) & \(t_{blue}\) & \(S_{blue}\) & \(t_{i,av}\) & \(\Sigma t_{i}\) & \(\Sigma t_{ia,an,k}\) \\
**[–]** & **[km]** & **[s]** & **[km/h]** & **[s]** & **[\%]** & **[s]** & **[\%]** & **[s]** & **[\%]** & **[s]** & **[ms]** & **[s]** & **[ms/km]** \\ \hline
14 & 82,467 & 4934 & 60.2 & 2722 & 55.2 & 1769 & 35.9 & 443 & 9.0 & 1.068 & 57.90 & 702.1 \\
15 & 82,512 & 4940 & 60.1 & 2779 & 56.3 & 1702 & 34.5 & 458 & 9.3 & 1.035 & 58.40 & 707.8 \\
16 & 82,464 & 4818 & 61.6 & 2868 & 59.5 & 1542 & 32.0 & 408 & 8.5 & 1.041 & 57.82 & 701.2 \\
17 & 82,395 & 4981 & 59.6 & 2899 & 58.2 & 1632 & 32.8 & 449 & 9.0 & 1.003 & 58.19 & 706.3 \\
18 & 82,406 & 4934 & 60.1 & 3005 & 60.9 & 1533 & 31.1 & 395 & 8.0 & 1.014 & 57.33 & 695.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: \(Cont.\) \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Drives without** & **Drives with** \\  & **the Indicator** & **the Indicator** \\ \hline First data & 750.7 & 690 \\ \hline Mean & 763.7875 & 710.075 \\ Variance & 2080.104107 & 330.2792857 \\ Observations & 8 & 8 \\ Hypothesised Mean & **50** & \\ Difference & df & 9 \\ t Stat & 0.213879122 \\ P(T \(<=\) t) one-tail & 0.4177041 \\ t Critical one-tail & 1.833112923 \\ P(T \(<=\) t) two-tail & **0.8354082** \\ t Critical two-tail & 2.262157158 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The output of the Excel \(t\)-Test: two-sample assuming unequal variances to series of the sum of average active injection time per one kilometre (\(\Sigma t_{iu,avg,k}\)) for drives without and with the indicator. Figure 7: The sum of average active injection time per one kilometre (\(\Sigma t_{iu,avg,k}\)) vs. the average vehicle speed (v\({}_{a}\)) in each test.