Improving the design of combine harvesters by harmonizing their basic technical parameters

Introduction. The article presents the results of statistical analysis of basic technical parameters of modern combine harvesters, comprising a sample of 150 models. A new complex criterion for assessing the technical level of combine harvesters called the harmonization coefficient is proposed, which makes it possible to evaluate the perfection degree of combine harvester design and identify the ways to improve them. Aim of the Article. The aim of the study is to propose a methodology for calculating the harmonization coefficient of each combine harvester and to identify the way for its improvement, based on the degree of compliance with global trends. The article continues to develop the idea of harmonization of combine harvester parameters outlined in the previous publications on this topic. Materials and Methods. There was applied statistical analysis identifying homogeneous statistical samples by harvester classes from 4 to 12 kg/sec. Results. On the example of a sample of 16 different combine harvester models, the harmonization coefficients of combine harvester design were calculated. The applied statistical equations for calculating combine harvester parameters reflect global trends in the development of combine harvester design and were called theoretical parameters, then they were compared with the actual parameters of combine harvesters. The difference between the theoretical and actual parameters affected the identifying of the ways of improvement. There were identified the combine harvester brands with high harmonization coefficient and a number of combine harvesters requiring modernization. Discussion and Conclusion. A technique for digital assessment of the technical level of combine harvesters is proposed. It is based on three design criteria: parametric index, regression dependencies between combine parameters reflecting global trends in the combine harvester design, and the harmonization coefficient of the combine harvester design in terms of threshing and separating device parameters. There was identified a group of combine harvesters with a very high harmonization coefficient 0.93-0.94. We mean first of all German harvesters of Claas company (Medion 340, Dominator 150, Lexion 580), Russian harvester of Rostselmash company (TORUM 740) and American Massey Ferguson (MF 7278). There is a large group of combine harvesters, which have a harmonization coefficient of their design in terms of parameters below 0.9, therefore, they may be improved in accordance with global trends, for example, the 5270 C-AL combine harvester of the German company Fendt needs the increase in engine power from 180 HP to 252 HP, reducing the concave area from 1.3 to 0.81 m2, increasing the area of the straw separator from 5.7 to 7.2 m2 and reducing the area of the cleaning sieves from 6.0 to 5.4 m2. At the same time, the combine harvester throughput efficiency will remain at the level of 9.1 kg/s. Based on the proposed methodology, there are given recommendations for improving a number of the most famous combine harvesters of domestic and foreign production, taking into account global trends in their development.