The rapid development of digital technology makes it possible to expand the sustainability of the transport sector. With the development of digitalization, virtual tests play an increasingly important role in product design. With the development of computer technology, there is a more accurate and faster opportunity to save time, energy, and costs before the product is introduced to the market. In the early stages, vehicle simulation can be effectively used, which is a cost- and time-efficient solution. This study presents the transfer of a vehicle simulation model to an internal combustion engine dynamometer. Dynamometers allow the behavior of the real engine to be tested before the complete vehicle is available. Building the simulation model of the complete system including the dynamometer and the engine makes it possible to setup the variables of the real test environment resulting in decreased time and cost on the dynamometer. Furthermore, the system constructed in this way can be suitable for carrying out the tests that were previously carried out on the entire vehicle. With a vehicle simulation model, the level of simulation can be changed as needed during development until the developed real vehicle is fully realized.

This article presents the results of an experimental investigation of different nanoforms of graphene used as a nano additive in engine lubricating oil. The experiments were carried out on a pin-on-disc tribometer at the Department of Internal Combustion Engines and Propulsions at Széchenyi István University. The paper introduces the experimental equipment and the experimental method and presents the research findings. The paper concludes that fullerene can decrease friction by 7% on average when used as a nano additive in engine lubricating oil. Furthermore, fullerene did not present a sedimentation problem when used as an additive up to 0.25 wt% in lubricant instead of graphene and multiwalled carbon nanotubes. The paper attempts to explain the friction decreasing effect and the possible roles of carbon nano additives in tribological systems.

This study presents an experimental analysis of a turbocharger with semi-floating ring bearings, focusing on hysteresis in subsynchronous vibrations. Four automotive oils (SAE 0W-20, SAE 0W-30, SAE 5W-30, SAE 5W-40) were tested across six oil inlet temperatures from 20 °C to 120 °C during ramp-up and ramp-down cycles to examine the effects of lubricant viscosity and temperature on rotor dynamics. Hysteresis and bifurcation points were observed at distinct rotational speeds in both directions, with subsynchronous components providing insights into rotor–lubrication interactions. This study applies the concept of hysteresis loop width for turbocharger rotors, highlighting its nonlinear dependence on oil temperature, an unexpected and unexplained phenomenon. Additionally, the results suggest that vibration sensors could provide real-time feedback on oil supply conditions, offering potential enhancements for turbochargers and other rotating machinery.

This study presents an experimental analysis of a turbocharger equipped with a semi-floating bearing system, with a particular focus on the bifurcation phenomenon within the subsynchronous vibration spectrum. A predefined design of experiments (DoE) methodology was employed to determine the measurement domains to be analyzed, where the primary input parameters included the lubricant supply temperature and pressure values. The bifurcation phenomenon in relation to the physical parameters of the system is observed via vibration and displacement sensors in two directions, enabling the collection of subsynchronous frequency data for further insights into the influence of lubricant parameters on the rotor system. While the nonlinear effect of oil temperature is well studied in the literature. However, the combined effect of oil supply temperature and pressure was not yet examined, which was the focus of the present study. This paper aims to investigate its coupled effects on the bifurcation phenomenon associated with both lubricant temperature and pressure. The occurrence of the introduced phenomenon is further examined to enhance the understanding of the uncharted behavior of turbocharger rotors and other rotor-bearing-based machinery.

This study presents a comparative analysis of the water droplet erosion resistance of three compressor wheels coated with Ni-P and Si-P layers. The tests were conducted using a custom-developed experimental apparatus in accordance with the ASTM G73-10 standard. The degree of erosion was monitored through continuous precision mass measurements, and structural changes on the surfaces of both the base materials and the coatings were examined using a Zeiss Crossbeam 350 scanning electron microscope (SEM). Hardness values were determined using a Vickers KB 30 hardness tester, while the chemical composition was analysed using a WAS Foundry Master optical emission spectrometer. Significant differences in erosion resistance were observed among the various compressor wheels, which can be attributed to differences in coating hardness values, as well as to the detachment of the Ni-P layer from the base material under continuous erosion. In all cases, water droplet erosion led to a reduction in the isentropic efficiency of the compressor—measured using a hot gas turbocharger testbench—with the extent of efficiency loss depending upon the type of coating applied. Although blade protection technologies for turbocharger compressor impellers used in the automotive industry have been the subject of only a limited number of studies, modern technologies, such as the application of certain alternative fuels and exhaust gas recirculation, have increased water droplet formation, thereby accelerating the erosion rate of the impeller. The aim of this study is to evaluate the resistance of three different coating layers to water droplet erosion through standardized tests conducted using a custom-designed experimental apparatus.