# Impact of Combine Harvester Technological Operations on Global Warming Potential
## 3 Results and Discussion
### Results of the Telematics Data Analysis
A decrease in GWP per ton of wheat processed was realized by significantly increasing the running speed of the CH during harvesting; a comparison between running speeds of 1 and 5 km h\({}^{-1}\) at a threshing cylinder speed of 950 min\({}^{-1}\) resulted in a significant decrease in GWP by 60.08%. In fact, the driving speed during harvesting (or, more precisely, the supplied wheat crop flow in the threshing apparatus and the engine load) is the most important economic and environmental factor. If the selected driving speed is too low, the GWP per ton of raw material processed will be very high. Conversely, if the speed is too high (at the same time overloading the engine), we will lose part of the crop due to grain damage and grain separation losses. The latest CH models have built-in technologies that automatically select the driving speed (at the same time, the supplied crop in the threshing apparatus and the engine load) in order to achieve optimal fuel consumption and reduce the environmental impact. In our study, assessing these factors and making decisions depend on the CH driver. That is why it is important to research and publicize research results and properly educate CH drivers. Link between Global Warming Potential in Threshing Mode and Exhaust Gas Concentrations and Engine Load  
Figure 4 presents the results of the integrated field research conducted in 2020. The data show a connection between the GWP per ton of wheat processed, the exhaust gas content/concentration, the driving speed during harvesting, the feed rate, and the engine load  
Figure 3: Relation between combine harveseter (CH) speed in harvesting mode and global warming potential (GWP) per ton of wheat mass processed in the 2019 tests (engine crankshaft speed \(n=2200\) min\({}^{-1}\)): \(B_{1}\)—threshing cylinder rotational speed \(nt=950\) min\({}^{-1}\)\(B_{2}\)—\(nt=850\) min\({}^{-1}\) The value of each point was obtained from an average of 20 replicates. factor. The most obvious result is that both NO content and CO2 concentration increased commensurately with harvesting speed (and thus engine load), while the concentration of O2 decreased. When comparing the values obtained at the slowest and fastest harvesting speeds (1 and 4.5 km h\({}^{-1}\), respectively), the following differences are noted:  
* O2 concentration decreased by 23.4%
* CO2 concentration increased by 26.7%
* NO concentration increased by 118.9%  
These variations are attributed to the fact that, as the speed of the CH increases, the amount of wheat flow per unit of time also increases. Simultaneously, there is an increase in engine load and corresponding rises in both gas compression and temperature inside the internal combustion engine's cylinder. Increases also occur in the interactions between N, O, and C in both ambient air and diesel fuel. The consequences of heat and pressure cause O2 in the exhaust gases to decrease and CO2 and NO levels to rise [48]. Despite the research estimates indicating that the lowest GWP per ton of wheat processed during harvesting is achieved at top operational speeds (Figures 3 and 4), there is no definitive conclusion or solution. Furthermore, when a CH reaches a certain critical speed during harvesting, there is an increase in both grain damage and grain separation losses [32]; therefore, other researchers indicate the need to include evaluations of both grain damage and grain loss [49]. Future research should investigate the determination of optimal harvesting speeds by comprehensively estimating GWP, grain damage, and grain losses. After analyzing the accumulated multi-year telematics data and conducting field tests on a specific CH, we clearly see that there is potential for a more efficient use of the machine. We can propose a process that would allow continuous improvement to achieve economic and environmental goals (Figure 5).