# Analysis of Biodiesel Influence on Unregulated Gaseous Emissions of Diesel Motor Vehicles
## 4 Conclusions  
The article is focused on the influences of biodiesel, which is mixed with standard diesel fuel, and on gaseous emissions (both on regulated and unregulated) in the case of diesel engine, taking into consideration the infamous emission scandal, named \"dieselgate\". The results of the experiments performed with the fuel mixture biodiesel-diesel, concerning the controlled emissions, point out a relevant fact that during all the engine operational modes, CO emissions and also hydrocarbon emissions were reduced, and NOX emissions were increased in comparison with the combustion of pure diesel fuel.  
With regard to the unregulated emissions, it was noted that the emissions of acetaldehyde and formaldehyde increased together with the growing volume of biodiesel contained in the fuel mixture. An analogous situation is also characteristic for the emissions of propene, ethene and 1,3-butadiene. Biodiesel also increases benzene emissions, but at the same time it also reduces xylene and toluene emissions. However, no significant  
Figure 11: Experimental fuels and the ethene emissions.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Mode**} & \multirow{2}{*}{**Fuel**} & \multirow{2}{*}{\begin{tabular}{c} **Benzene** \\ **(mg/kWh)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Toluene** \\ **(mg/kWh)** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Xylene** \\ **(mg/kWh)** \\ \end{tabular} } \\ \hline \multirow{5}{*}{5} & ULSD-F & 79.0 & 9.5 & 34.1 \\ \cline{2-5}  & B-U (25.75) & 83.8 & 8.2 & 27.0 \\ \cline{2-5}  & B-U (50.50) & 88.2 & 6.7 & 22.7 \\ \cline{2-5}  & B-U (75.25) & 91.5 & 5.4 & 20.2 \\ \cline{2-5}  & Biodiesel & 95.1 & 4.3 & 8.5 \\ \hline \multirow{5}{*}{9} & ULSD-F & 43.2 & 3.6 & 12.8 \\ \cline{2-5}  & B-U (25.75) & 44.3 & 3.0 & 9.9 \\ \cline{2-5}  & B-U (50.50) & 45.9 & 2.5 & 8.0 \\ \cline{2-5}  & B-U (75.25) & 47.2 & 2.0 & 5.9 \\ \cline{2-5}  & Biodiesel & 49.8 & 1.7 & 3.5 \\ \hline \multirow{5}{*}{11} & ULSD-F & 21.0 & 1.7 & 5.3 \\ \cline{2-5}  & B-U (25.75) & 22.1 & 1.5 & 4.2 \\ \cline{2-5}  & B-U (50.50) & 22.5 & 1.4 & 3.1 \\ \cline{2-5}  & B-U (75.25) & 23.4 & 1.2 & 2.5 \\ \cline{2-5}  & Biodiesel & 25.2 & 1.0 & 1.8 \\ \hline \hline \end{tabular}
\end{table}
Table 5: The benzene, toluene and xylene emissions.  
changes relating to the BXT emissions were monitored, thanks to the fact that a higher volume of benzene emissions were simultaneously compensated by the lower xylene and toluene emissions. It is important to emphasize the reality that gaseous emissions, whether regulated or unregulated, are predominantly influenced by engine operational modes that are required according to the changing engine loading [17].  
Conceptualization, M.P. and M.K.; methodology, M.P. and J.Z.; investigation, S.K. and M.L.; data analysis, M.P. and M.L.; writing--original draft preparation, J.Z. and M.K.; writing--review and editing, M.L. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Slovak Research and Development Agency under the Contract no. APVV-19-0328. The article was written in the framework of Grant Projects: VEGA 1/0318/21 \"Research and development of innovations for more efficient utilization of renewable energy sources and for reduction of the carbon footprint of vehicles\", KEGA 006 TUKE-4/2020 \"Implementation of Knowledge from Research Focused on Reduction of Motor Vehicle Emissions into the Educational Process\" and this work was supported by the Slovak Research and Development Agency under the contract No. APVV-16-0259.  
Not applicable.  
The authors declare no conflict of interest.