## 5 Conclusions  
By measuring the performance of piston-radial pumps, it was concluded that their efficiency can generally be evaluated according to their maximum working pressure capacity and flow rate at a certain drive speed.  
The parameters of the hydrodynamic process of the piston-radial pump (pressure flow, suction flow and compression flow) cannot be determined accurately enough purely experimentally, nor purely mathematically. Sufficiently accurate parameters can be obtained by the combined application of pressure flow measurement in the cylinder, mathematical modeling of the actual hydrodynamic process and nonlinear optimization methods, whereby systematic measurement errors and unknown parameters can be simultaneously determined.  
Radial piston pumps are commonly used in mobile machinery due to their efficiency and compact design. Understanding their mechanical, volumetric, and overall efficiency is essential to optimizing performance. Mechanical efficiency measures how effectively a pump converts input power into hydraulic power, taking into account losses due to friction, wear, and mechanical components. The mechanical efficiency of radial piston pumps typically ranges from 85% to 95%. Volumetric efficiency measures the pump's efficiency in moving liquid compared to its theoretical displacement. It calculates losses due to leakage and compressibility of liquids. The volumetric efficiency of radial piston pumps can vary widely, generally falling between 90% and 98%. Overall efficiency combines both mechanical and volumetric efficiency, providing a comprehensive measure of pump performance. Overall efficiency can be quite high for radial piston pumps, often exceeding 80% when both mechanical and volumetric efficiency are optimized. This efficiency can  
Figure 7: Results of harmonic analysis of measured pressures, vibrations and time intervals for one cycle at \(n=875.6\) min\({}^{-1}\) and \(p=200\) bar with a graphic display of 80 harmonics.  
be affected by design factors, operating conditions and the quality of materials used in construction. Regular maintenance and proper operation are also critical to maintaining these levels of efficiency in mobile machines.  
The piston-radial pump is an important component in hydraulic systems in mobile applications, from construction and agricultural equipment to heavy trucks, because of its sufficient power density for a range of work functions. Optimizing the operating and structural parameters of piston-radial pumps can directly influence the efficiency of mobile machines.  
Further directions of research are possible in the construction of piston pumps in terms of: separation of the working fluid, dynamics of the cylinder block and hydrodynamic processes in the gaps between the piston and the cylinder in the cylinder block.  
Conceptualization, M.R. and R.P.; Methodology, R.P., B.Z. and S.C.; Software, M.R., R.P. and S.C.; Validation, R.P.; Formal analysis, M.R., R.P. and B.Z.; Investigation, R.P.; Resources, R.P.; Data curation, R.P.; Writing--original draft, M.R., R.P., B.Z. and D.B.; Writing--review & editing, M.R., R.P. and B.Z.; Visualization, R.P.; Supervision, R.P.; Project administration, R.P.; Funding acquisition, R.P. All authors have read and agreed to the published version of the manuscript.  
This paper is funded by the University \"Union-NikolaTesla\", Faculty of Information Technology and Engineering.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflict of interest.