Ústav automobilního a dopravního inženýrství

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    Methodology for Measuring Forces in Motorcycle Suspension Using a System Based on Analogue Potentiometers
    (Slovak University of Technology in Bratislava, 2024-06-01) Míša, Jiří; Tobiáš, Martin; Repka, Martin; Straka, Tomáš; Gregor, Lukáš
    This study explores the quest for a more cost-effective and practical method of measuring forces in motorcycle suspension systems by utilizing simple potentiometers as an alternative to sophisticated strain gauges. The research delves into the feasibility of potentiometers to provide accurate and reliable force measurements, offering potential advantages in terms of affordability, accessibility, and ease of implementation. Through empirical testing and verification, this investigation aims to establish potentiometers as a viable and economical solution for enhancing motorcycle suspension performance monitoring and tuning.
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    Comparative study of engine dynamics for rolling and selective cylinder deactivation
    (PERGAMON-ELSEVIER SCIENCE LTD, 2024-09-15) Fridrichová, Kateřina; Drápal, Lubomír; Raffai, Peter; Böhm, Michael
    Strict emission limits have forced the automotive industry to reduce the carbon dioxide emissions produced by internal combustion engines. Emissions can also be reduced by increasing the efficiency of internal combustion engines by implementing technologies such as cylinder deactivation, the main benefit of which is a reduction in fuel consumption. However, there are some negative effects associated with this technology. There are two approaches to cylinder deactivation - selective and rolling. This paper focuses on the constraints of the technology and compares the two methods of cylinder deactivation in terms of torsional vibration, friction losses and load on the main bearings. The results for the selective and rolling cylinder deactivation are obtained from a verified multibody simulation of a four-cylinder engine.
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    Experimental Investigation of Microcontroller-Based Acoustic Temperature Transducer Systems
    (MDPI, 2023-01-12) Al-Rawashdeh, Ayman Y.; Younes, Tariq M.; Dalabeeh, Ali; Al_Issa, Huthaifa; Qawaqzeh, Mohamed; Miroshnyk, Oleksandr; Kondratiev, Andrii; Kučera, Pavel; Píštěk, Václav; Stepenko, Serhii
    Temperature transducers are commonly used to monitor process parameters that are controlled by various types of industrial controllers. The purpose of this study is to design and model a simple microcontroller-based acoustic temperature transducer based on the variations of resonance conditions in a cylindrical resonance tube. The transducer’s operation is based on the generation of an acoustic standing wave in the free resonance mode of generation within a cylindrical resonance tube which is converted into a train of pulses using Schmitt trigger circuit. The frequency of the generated standing wave (i.e., the train of pulses) is measured by the Arduino Uno microcontroller, where a digital pin is used to acquire pulses that are counted using a build-in software function in an Arduino IDE environment. Experimental results are performed for three sizes of diameters to investigate the effect of the diameter of resonance tube on the obtained results. The maximum nonlinearity error according to Full-Scale Deflection (FSD) is about 2.3 percent, and the relative error of the transducer is evaluated using experimental findings and the regression model. The circuit simplicity and design of the suggested transducer, as well as the linearity of its measurements, are notable.
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    Methodological Approach in the Simulation of the Robustness Boundaries of Tribosystems under the Conditions of Boundary Lubrication
    (MDPI, 2023-01-04) Al-Quraan, Tareq M. A.; Alfaqs, Fadi; Alrefo, Ibrahim F. S.; Vojtov, Viktor; Voitov, Anton; Kravtsov, Andrey; Miroshnyk, Oleksandr; Kondratiev, Andrii; Kučera, Pavel; Píštěk, Václav
    In the presented work, a methodical approach was developed for determining rational operation modes of tribosystems, taking into account their design. This approach makes it possible in the designing stage, according to the predicted operating modes, to calculate the limits and margins of stable work in operation. The definition of the robustness of the tribosystem and the criteria for assessing the robustness are formulated based on the theory of stability of technical systems. It is shown that such a methodical approach allows for determining the modes of the rational operation of the designed structures without damaging the friction surfaces. Experimental studies have proven that not all designs of tribosystems lose stability due to the appearance of friction surface burrs. There are designs where the loss of stability occurs upon the appearance of accelerated wear. The developed criteria take into account two options for the loss of stability. An experimental verification of the modes of loss of stability of tribosystems was performed by the appearance of a burr or the beginning of accelerated wear with the calculated values of the robustness criteria. The obtained results allow us to conclude that the modeling error is within 8.3–18.7%, which is a satisfactory result in the study of friction and wear processes. Robustness criteria is based on the coefficient of friction RRf and wear rate RRI, and must be used when designing new constructions of tribosystems. Theoretical calculations of such criteria and the dependence of their change on changing the predicted operating modes will allow for justifying rational operating modes within their stability.
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    Ensuring Reliable and Safe Operation of Trunk Diesel Engines of Marine Transport Vessels
    (MDPI, 2022-09-26) Sagin, Sergii; Madey, Volodymyr; Sagin, Arsenii; Stoliaryk, Tymur; Fomin, Oleksij; Kučera, Pavel
    In this study, a method for ensuring reliable and safe operation of marine trunk diesel engines is considered. The research was carried out on 5L23/30 MAN-B&W diesel engines of a Bulk Carrier class vessel. The objective of the study was to determine the effect of the structural characteristics of the oil layer (wetting angle and thickness) on the operational parameters of a marine diesel engine (compression pressure, concentration of nitrogen oxides in exhaust gases and temperature of exhaust gases after the cylinder) and performance characteristics of the oil (base number, wear and contaminant elements). It has been established that an increase in the degree of the contact angles of wetting and in the thickness of the oil layer improves the heat and power and environmental performance of a diesel engine. At the same time, the decrease in compression pressure in the cylinder slows down, the temperature of gases after the cylinder decreases, and the emission of nitrogen oxides with exhaust gases decreases. Also, it was found that wear of diesel parts and oil oxidation are reduced. The study confirms the possibility of improving the reliable and safe operation of trunk-type diesel engines of maritime vessels by effective control of variables relating to the characteristics of engine oil.