Ústav automobilního a dopravního inženýrství

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    The Potential of Using Birotor Machines in Modern Transport Means
    (2025-10-29) Fomin, Oleksij; Chubykalo, Mikhaylo; Lohvinenko, Oleksandr; Píštěk, Václav; Kučera, Pavel
    The transport sector requires compact, reliable, and energy-efficient power units for modernization of road, rail, maritime, and aerial systems. Conventional piston and rotary machines often face limitations related to vibration, sealing losses, and manufacturing complexity. This study investigates birotor machines (BM), a class of positive-displacement devices combining synchronized rotation of the rotor and housing. This configuration ensures smooth kinematics, near-complete dynamic balance, and simplified design. The working principle enables continuous volumetric transformation with reduced friction and leakage, enhancing efficiency and durability. Using generalized mathematical models (GMM) developed through statistical experimental design, optimal geometric parameters were determined with a root-mean-square error below 3%. A prototype birotor compressor (BC) designed for subway rolling stock achieved equivalent output performance (0.43 m3/min at 0.8 MPa) with 82% efficiency and a mass reduction from 130 kg to 32 kg. Comparative simulations and preliminary testing of BM-based internal combustion engines (BRICE) demonstrated 3–4 times smaller and lighter units with improved reliability and environmental characteristics. The results confirm that BM technology provides a feasible and manufacturable alternative to conventional designs, suitable for integration into next-generation transport and unmanned vehicle systems.
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    Requirements for Hybrid Technology Enabling the Production of High-Precision Thin-Wall Castings
    (MDPI, 2022-05-26) Krutiš, Vladimír; Novosad, Pavel; Záděra, Antonín; Kaňa, Václav
    Prototypes and small series production of metal thin-walled components is a field for the use of a number of additive technologies. This method has certain limits related to the size and price of the parts, productivity, or the type of requested material. On the other hand, conventional production methods encounter the limits of shape, which are currently associated with the implementation of optimization methods such as topological optimization or generative design. An effective solution is employing hybrid technology, which combines the advantages of 3D model printing and conventional casting production methods. This paper describes the design of aluminum casting using topological optimization and technological co-design for the purpose of switching to new manufacturing technology. It characterizes the requirements of hybrid technology for the material and properties of the model in relation to the production operations of the investment casting technology. Optical roughness measurement compares the surface quality in a standard wax model and a model obtained by additive manufacturing (AM) of polymethyl methacrylate (PMMA) using the binder jetting method. The surface quality results of the 3D printed model evaluated by measuring the surface roughness are lower than for the standard wax model; however, they still meet the requirements of prototype production technology. The measurements proved that the PMMA model has half the thermal expansion in the measured interval compared to the wax model, which was confirmed by minimal shape deviations in the dimensional analysis.
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    Prototyping a System for Truck Differential Lock Control
    (MDPI, 2019-08-20) Kučera, Pavel; Píštěk, Václav
    The article deals with the development of a mechatronic system for locking vehicle differentials. An important benefit of this system is that it prevents the jamming of the vehicle in difficult adhesion conditions. The system recognizes such a situation much sooner than the driver and is able to respond immediately, ensuring smooth driving in off-road or snowy conditions. This article describes the control algorithm of this mechatronic system, which is designed for firefighting, military, or civilian vehicles with a drivetrain configuration of up to 10 × 10, and also explains the input signal processing and the control of actuators. The main part of this article concerns prototype testing on a vehicle. The results are an evaluation of one of the many experiments and monitor the proper function of the developed mechatronic system.
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    Method for Maintaining Technical Condition of Marine Diesel Engine Bearings
    (MDPI, 2025-03-25) Sagin, Sergii; Sagin, Arsenii; Zablotskyi, Yurii; Fomin, Oleksij; Píštěk, Václav; Kučera, Pavel
    The aim of the research was to determine the impact of antifriction coatings on the technical condition of marine diesel engine bearings. Various epilams were used as antifriction coatings, with a thin layer applied to the surfaces of the bearings of the marine diesel engines 12V32/40 MAN-Diesel&Turbo. The thickness of the epilam coating adsorbed on the metal surface was controlled by ellipsometry. It was found that the thickness of the epilam layer on the surfaces of marine diesel engine bearings could reach 11.2 nm to 17.0 nm. The adsorption time required does not exceed 10 min. It was shown that the epilam nanolayer applied to the metal surface led to an increase in the structural characteristics of the oil boundary layer (thickness: from 12.3 µm to 15.2–18.3 µm; contact angles: from 10.2 deg to 15.8–17.4 deg). It was experimentally confirmed that the epilam coating of bearing surfaces significantly reduced their wear. For the 12V32/40 MAN-Diesel&Turbo marine diesel engine, in the case of epilaminating, the wear of the bearing shell surface was reduced by 6.1–27.6%, with the greatest reduction in wear occurring for the stern (most loaded) bearings. This helped to maintain the technical condition of the bearings of marine diesel engines.
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    On the Effectiveness of Optimisation Algorithms for Hydrodynamic Lubrication Problems
    (MDPI, 2025-05-08) Kocman, František; Novotný, Pavel
    In many applications, it is necessary to optimise the performance of hydrodynamic (HD) bearings. Many studies have proposed different strategies, but there remains a lack of conclusive research on the suitability of various optimisation methods. This study evaluates the most commonly used algorithms, including the genetic (GA), particle swarm (PSWM), pattern search (PSCH) and surrogate (SURG) algorithms. The effectiveness of each algorithm in finding the global minimum is analysed, with attention to the parameter settings of each algorithm. The algorithms are assessed on HD journal and thrust bearings, using analytical and numerical solutions for friction moment, bearing load-carrying capacity and outlet lubricant flow rate under multiple operating conditions. The results indicate that the PSCH algorithm was the most efficient in all cases, excelling in both finding the global minimum and speed. While the PSWM algorithm also reliably found the global minimum, it exhibited lower speed in the defined problems. In contrast, genetic algorithms and the surrogate algorithm demonstrated significantly lower efficiency in the tested problems. Although the PSCH algorithm proved to be the most efficient, the PSWM algorithm is recommended as the best default choice due to its ease of use and minimal sensitivity to parameter settings.