This work is focused on the design of a hydraulic device on which simulations of pressure shocks can be performed. The hydraulic device was constructed to allow simulations of pressure shocks transferred directly in operating conditions because simulation programs for hydraulic accumulators have only theoretical values while simulation on the designed hydraulic device enables obtaining specific readings directly in operating conditions that can be set. At the first control measurement on the hydraulic device, there occurred pressure shocks generated by the hydraulic device itself, these pressure shocks being undesirable in hydraulic circuits. In order to eliminate pressure shocks in the circuit, a diaphragm accumulator was added to the hydraulic device and was used to verify the function of simulating pressure shocks and eliminating undesirable pressure shocks. During the second control measurement on the hydraulic device, a reduction of unwanted pressure shocks was shown with the help of added diaphragm accumulator, thus the function of the hydraulic device to simulate pressure shocks was confirmed, which may also refect practical application in hydraulic circuits of mobile machines.

This paper deals with the importance of fuel economy in road freight transport. It provides the calculation of financial savings for fuel savings of 0.5 l per 100 km. In the subsequent part, some factors that influence the fuel consumption are specified, e.g. aerodynamic resistance, rolling resistance, and tyre inflation pressure. The effect of tyre inflation pressure on fuel economy has been tested on four selected towing vehicles. Based on the results obtained, it can be stated that tyre pressure has a great impact on fuel consumption. A one-bar pressure reduction of tyres can increase the fuel consumption by 0.5 l per 100 km.

Our study focuses on individual methods of measuring the fuel consumption of lorries. We have verified the difference between the consumption calculated from fuelling records and consumption listed by the Infomax information system. Based on obtained results, we can state that the difference between presented consumption measurement methods reached the maximum value of 5 %.

Vehicle emissions inspection represents a fast, relatively efective in terms of time and cost, and mainly comprehensive estimation of vehicle emissions. Procedurally, emissions inspection includes those inspection operations that focus not only on analysing exhaust gases but also on detecting the functionality and tightness of other engine components directly afecting the ecological friendliness of inspected vehicle‘s engine. Our study describes the results of vehicles inspected at an emissions inspection station for the reporting period. Based on the analysis of information obtained from the National Transport Authority of the Slovak Republic concerning the evaluation of vehicles according to individual categories, it can be alleged that the technical condition of vehicles of M1 and N1 categories is gradually improving.