The operation of the internal combustion engine leads to the production of exhaust gases harmful to the natural environment. The introduced standards of the European exhaust emission standard aim, among other things, to reduce CO2 emissions. Such assumptions are related to the reduction of fuel consumption of internal combustion engines in vehicles. This means the need to make structural changes in the produced engines, and thus reduce the displacement while maintaining high power and torque. Engines constructed in this way require the use of individually selected oils and maintaining appropriate service intervals for their replacement.

In this study, the influence of the geometrical surface structure shape on wear process of friction pairs elements with conformal contact was analyzed. Characteristics of the machine elements surface layer were described with special distinction of importance of the surface structure directivity and isotropy in terms of the surface layer transformation. This work presents the results of experimental tests in which the following input factors were used: specimen and counter-specimen ridge angle of intersection (0°; 30°; 45°; 60°; 90°) and specimen and counter-specimen clamp (1.0; 1.5; 2.0 MPa). The changes of the surface layer were recorded as a function of a specimen mass changes. Based on the conducted research, it was found that the ridge angle of intersection on the specimen and counter-specimen has a significant impact on the wear process intensity. The changes were uttermost for 0° angle and slightest for 9°. It was also found that the observed changes have a larger gradient for higher specimen load values. Thus, the significance of the geometrical surface structure directivity influence on the friction pair elements wear process intensity was confirmed.

The Ti6Al4V alloy produced by additive methods is the most studied material, which can be attributed to its wide application and the resulting need for a thorough understanding of this material and its behavior under static and fatigue loads. For this reason, the paper presents the results of tests of the Ti6Al4V alloy produced by the additive method and in the standard smelting process. The publication contains the results of the alloy tests under static and variable loads based on strain control.

For the purpose of measuring the flow and pressure characteristics of oil filters used in vehicles with internal combustion engines, a laboratory test equipment was used, which was designed at the Department of Transport and Handling of the Slovak University of Agriculture in Nitra. The target information from the given measurement is the obtained data on the change of flow and pressure, based on the type of oil filter used. The contribution of this paper is information that can be used in the future in the design of new filtration equipment, as well as the creation of a system for evaluating the technical life of motor oils, in order to extend the service intervals of motor oil, monitored set of motor vehicles.

This article focuses on the challenges and problems facing road transport nowadays. The main aspect discussed in the paper is the ecological aspect. As the demand for transport services has been constantly growing for the last 20 years, solving the problem has become a great challenge. In the further part of the study, an attempt was made to indicate solutions applied in the European Union. Another solution is presented in this paper, which is the introduction of European Modular Systems to road transport. Their characteristics were presented and countries in which such solutions are used were indicated. Based the analysis of studies in the field of the discussed issues, a comparison of fuel consumption and CO₂ and NO_x emissions of standard sets with EMS sets was carried out.

Fuel injectors are the most damage-sensitive component of the diesel fuel injection system in self-ignition engines. Therefore, an important issue is their diagnosis for the proper assessment of their wear condition. The paper presents a method involving the use of an image from a thermal imaging camera to assess the technical condition of injectors used in common rail injection systems. Four injectors, whose technical condition was known, were tested. Three of them were characterized by a common fault they had damaged control valve seats, while one of the injectors was fully functional. In order to precisely assess their technical condition, the injectors were tested on a test bench. While the injectors were working, the temperature of the body in the place of the control valve was measured at a constant time interval. The conducted research has shown that there is a relationship between the rate of temperature rise of the damaged injectors’ body and their maximum temperatures, and the injection dose expenditure and the overflow expenditure.

Increasingly, with the purchase of a new vehicle, users want to protect their vehicle from exploitation, but also use it to advertise their activities. While the application of the foil on a new vehicle after factory painting is much simpler, a bigger problem occurs in the event of a loss due to third party liability of the perpetrator. In relation to such a vehicle, the cost of settling the repair is much higher than in the case of an unsealed vehicle. It is related, inter alia, with the costs of renting a replacement vehicle. The period between varnishing and the possibility of re-application of the foil may constitute a significant part of the total lease. The article presents the issues related to the settlement of rental costs in relation to a wrapped vehicle after damage.

The paper presents a numerical analysis of thick-walled PA66 GF30 moldings with the addition of a chemical blowing agent with a content of 1-3 wt%, and the obtained results were compared with the real object. Computer simulations were performed using Moldex3D^® software. Based on the numerical analysis, it was found that regardless of the dose of the blowing agent used, the largest pores were place in the core of the sample. Moreover, it was found that the size of the pores depends on their number in the cross-section of moldings. Compositions containing a higher cross-sectional pore density were characterized by smaller pore sizes. The results of the computer simulation also showed that increasing the blowing agent dose above 2 wt% does not significantly affect the size of the pores in the structure. The experimentally determined pore size of the composition containing 3 wt% chemical blowing agent slightly differs from the pore size obtained based on numerical analysis.

The paper presents a semi-Markow model of a preventive repair system by age, implemented in hydroelectric power plants with Kaplan turbines. In the case of the analyzed technical objects, the profit per time unit is considered as the criterion of the quality of functioning. On the basis of the adopted assumptions, for the developed mathematical model, formulas describing the criterion function were determined and the conditions for the existence of the extreme (maximum) of this function were formulated. The proposed method makes it possible to determine the optimal time for preventive repair of the considered technical objects. The theoretical considerations presented in the work are illustrated by a computational example developed on the basis of data obtained from the actual operating system of Kaplan water turbines with a rated power of 120 kW.

The paper presents the effect of gas dosing parameters on the microporous structure of physically foamed polyamide 66 reinforced with 30 wt% of glass fibers (PA66 + 30% GF). The thick-walled molding was used as the research object. To realize the research aim, simulation software was applied. The variable parameter in a research program was a dose of supercritical fluid, in this case, nitrogen. The tested properties of a cellular structure were: cell size, cell density and local density of a material. All the parameters were considered based on 30 measurement points evenly distributed in the central zone of the sample’s cross-sectional area. The largest size of pores was observed in the core region of molding for every amount of supercritical (SCF) fluid used. It was shown that regardless of the amount of gas, the pore size increases as a function of the distance from the mold cavity surface until it achieves a constant value. However, the most rapid increase was observed in the case of the smallest amount of gas dosed (0.25 wt%) which also resulted in the largest pore size in the core zone of a molding. The lowest value of cell density was noticed for 0.25 wt% of gas used. In the case of 0.5 wt%, 0.75 wt% and 1 wt% of gas dosed, results of cell size, as well as cell density, were comparable. However, dosing 1 wt% of gas resulted in obtaining the finest structure, characterized by the smallest pore size and highest cell density. As a parameter resulting from a cell size and cell density, the local density of material was analyzed. The lowest value of local density in the core area was noticed for 0.25 wt% of SCF dosed.