# Pollutant Emissions and Combustion Efficiency Assessment of Engines Using Biodiesel
## 3 Results and Discussion
### Results of Experimental Thermography Tests  
Experimental thermography tests were performed using the Mpower(r) motor. The aim is to validate combustion efficiency with biodiesel blends and to analyze the thermal behavior of the combustion chambers.  
The results obtained are presented below.  
Figure 12 shows the results of the B5 mixture, with maximum combustion temperatures in the chamber of 174.12 and 174.37 \({}^{\circ}\)C, respectively. Block temperature reached 73.04 \({}^{\circ}\)C, and in accessories, it reached 45 \({}^{\circ}\)C.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & & & & & & & & & & \\ \hline  & **B0** & **B10** & **B20** & **B30** & **B40** & **B50** & **B60** & **B70** & **B80** & **B90** & **B100** \\ \hline VO & 11.18 & 11.03 & 10.88 & 10.72 & 10.57 & 10.42 & 10.27 & 10.12 & 9.96 & 9.81 & 9.66 \\ \hline VO\({}_{2}\) & 2.34 & 2.31 & 2.28 & 2.25 & 2.22 & 2.19 & 2.15 & 2.12 & 2.09 & 2.06 & 2.03 \\ \hline VCO\({}_{2}\) & 1.62 & 1.60 & 1.58 & 1.56 & 1.54 & 1.53 & 1.51 & 1.49 & 1.47 & 1.45 & 1.43 \\ \hline VSO\({}_{2}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 \\ \hline VN\({}_{2}\) & 8.83 & 8.71 & 8.59 & 8.47 & 8.35 & 8.23 & 8.11 & 7.99 & 7.87 & 7.75 & 7.63 \\ \hline VH\({}_{2}\)O & 1.62 & 1.61 & 1.60 & 1.58 & 1.57 & 1.56 & 1.54 & 1.53 & 1.51 & 1.50 & 1.49 \\ \hline VRO\({}_{2}\) & 1.62 & 1.60 & 1.58 & 1.56 & 1.54 & 1.53 & 1.51 & 1.49 & 1.47 & 1.45 & 1.43 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Combustion product volume results.  
Figure 12: Maximum temperatures in the combustion chamber with the B5 mixture: (**a**) temperature in the chamber of 174.12 \({}^{\circ}\)C; (**b**) temperature in the chamber of 174.37 \({}^{\circ}\)C.  
With the B10 mixture (Figure 13), there was a maximum temperature of 175.6 \({}^{\circ}\)C in the combustion chamber. The block reached a maximum temperature of 64 \({}^{\circ}\)C. Compared to the previous iteration (B5), the temperature in the combustion chamber increased with the B10 mixture; a summary of these results is shown in Table 8. The importance of this analysis is to corroborate the combustion efficiency through the combustion temperature; the results show an increase in the combustion temperature by increasing the percentage of biodiesel. This has the same trend as the analysis in Table 7.  
This work reveals a decrease in carbon monoxide and a considerable increase in nitrogen oxides. On the other hand, another study carried out with canola biodiesel, with proportions of 5%, 10%, 15%, and 20% (% blends) and conventional diesel under different loads in a single-cylinder engine, showed, among several results, that ignition was delayed. However, there was a minimal delay with canola biodiesel; NOx emissions decreased, as well as the generated smoke and CO\({}_{2}\) in all charges [37]. Additionally, a recent study by [PERSON] and [PERSON] (2018) analyzed and proposed effective strategies for injection time and pressure in the combustion chamber. The results of the proposed strategies were long ignition delay, finer atomization, lower cylinder temperature, lower gas pressure, and rapid combustion [38]. Based on the results obtained and other scientific studies, it can be concluded that there are many factors that affect the combustion process in a compression engine, and this is reflected in exhaust emissions. These factors are mainly biofuel raw material, injection delay, and the physical characteristics of the combustion chamber, among others.