Papers by Krzysztof Parczewski
Badania stateczności samochodów ciężarowych, szczególnie podczas wykonywania manewrów skrętu, stw... more Badania stateczności samochodów ciężarowych, szczególnie podczas wykonywania manewrów skrętu, stwarzają niebezpieczeństwo wywrócenia pojazdu. Aby temu zapobiec stosuje się specjalne belki zabezpieczające przed wywrotem lub dąży się do wyznaczania stateczności metodami obliczeniowymi lub przy wykorzystaniu modeli pojazdów. Przedstawiona praca stanowi opis przeprowadzonych prób modelu pojazdu a także porównanie ich zachowania się z ruchem rzeczywistych pojazdów. Poniżej przedstawiono porównanie zachowania się modelu i pojazdów podczas jazdy po okręgu. Słowa kluczowe: stateczność pojazdu, badania pojazdu, model pojazdu, tor krzywoliniowy, przyspieszenie poprzeczne. The testing of the stability of large weight vehicles, particularly while executing the manoeuvres of the turn, creates the emergency of the overturn of the vehicle. To prevent this, he complies special anti-roll beams mounted to vehicles or one proceed to determine stability using computational methods. We can also carry over tests on models of vehicles. The introduced work makes up the description of the carried over tests of the model of the vehicle and also the comparison of their behaviour oneself with the motion of real vehicles. Below is presented the comparison of behaviour presented truck model and vehicle during the drive after the circle track.
Combustion Engines
Article introduces and discusses the sensors used in autonomous cars. The reliability of these de... more Article introduces and discusses the sensors used in autonomous cars. The reliability of these devices is crucial for the proper operation of autonomous driving systems. The research works related to the issue of the performance of autonomous sensors in adverse weather conditions is discussed and critically analysed. The negative effects caused by bad weather conditions are characterised. The paper presents the result of author's own research concern on the effects of rain, snow and fog on lidar measurments. The results obtained are presented, detailing the most important threats from each weather phenomenon. Attempts currently being made to address these issues are presented as well. The paper concludes with a summary of the research results, the current state of knowledge and suggestions for future developments.
Combustion Engines, 2015
Methods of testing of vehicles lateral stability based on the study of physical models The paper ... more Methods of testing of vehicles lateral stability based on the study of physical models The paper presents a methodology that allows the use of vehicles physical models on scale to analyze the stability of real vehicles. The geometric parameters of the model and the kinematics and dynamics of motion were determined using the theory of similarity and dimensional analysis. The problems related to the construction of models and their parts and to the steering system, taking into account the scale of similarity. Issues concerning the construction were not only the parameters derived from the theory of similarity but also the structural similarity of powertrain, suspension, steering system and tires. An additional problem is the increasing requirements for the control model. Assessed the performed studies was developed algorithm for testing vehicle lateral stability on the study of the physical model in dynamic traffic conditions to allow the representation of the full size vehicle dynamics.
IOP Conference Series: Materials Science and Engineering, 2018
The increase in interest in electric vehicles is associated primarily with the actions of states ... more The increase in interest in electric vehicles is associated primarily with the actions of states that seek to sell new vehicles with low emissions of harmful compounds into the atmosphere. This is codified by emission standards. One of the solutions of the exhaust emission problem is the use of the electric drive (assuming that electricity comes from renewable sources). The electric drive system can be developed in several ways, depending on how the drive torque is transmitted: by gears or directly to each wheel. These constructional solutions affect the largeness of unsprung masses and require proper selection of vehicle suspensions. Series of tests and simulations has been carried out to verify the mathematical model proposed for the rear suspension system with electric motors mounted in the wheels. The simulation model has been prepared in the MSC.Adams package. This model was (tuned) verified by comparison the dynamic response of the system with the experimental results. The verified model was used to analyse the impact of the shock absorber damping characteristics on tire deflection and contact forces acting between the road and tire.
Akademia Techniczno-Humanistyczna w Bielsku-Białej eBooks, Dec 1, 2022
BADANIE WPŁYWU NIESPRZYJAJ CYCH WARUNKÓW ATMOSFERYCZNYCH NA LIDAR Z WYKORZYSTANIEM SZTUCZNEJ MGŁY... more BADANIE WPŁYWU NIESPRZYJAJ CYCH WARUNKÓW ATMOSFERYCZNYCH NA LIDAR Z WYKORZYSTANIEM SZTUCZNEJ MGŁY Streszczenie: W artykule przedstawia si wpływ sztucznej mgły na działanie LiDARu. Wykazuje si , e nawet g sta mgła nie parali uje całkowicie działania urz dzenia. Przeprowadzone eksperymenty potwierdzaj przewag LIDARu nad kamer pod k tem działania w złych warunkach atmosferycznych. Badania sygnalizuj obni enie wska nika odblaskowo ci celów o wietlanych LiDARem z powodu wzrostu zadymienia.
Praca przedstawia analizę wpływu położenia środka masy i jej rozkładu na stateczność samochodu ci... more Praca przedstawia analizę wpływu położenia środka masy i jej rozkładu na stateczność samochodu ciężarowego. Z uwagi na znaczny koszt badań i niebezpieczeństwo przewrócenia pojazdu starano się odwzorować zachowanie się rzeczywistego pojazdu, wykorzystując podobieństwo a badania przeprowadzono na mobilnym modelu pojazdu. W pracy przedstawiono analizę wpływu takich parametrów masowy moment bezwładności względem osi wzdłużnej i pionowej przy zachowaniu położenia środka masy pojazdu. Analizę przeprowadzono w oparciu o próby drogowe. Przedstawiono porównanie z wyników dla różnych rozkładów mas. Słowa kluczowe: stateczność ruchu samochodu ciężarowego, badania mobilnych modeli pojazdów, badania stateczności pojazdów.
Combustion Engines, 2008
The majority of published data on exhaust gas emissions is cited based on the test results from t... more The majority of published data on exhaust gas emissions is cited based on the test results from the NEDC driving cycle. This paper specifies the methodology of how to develop dynamic characteristics of the emissions, based on the aggregated data from the measurement of modal emissions obtained in the course of NEDC and FTP-75 driving cycles for gasoline and CNG fuelling. The presented characteristics concern a real passenger car which was tested, then the characteristics were used to calculate the exhaust gas emissions during a specially developed driving test comprising four main motion resistances and engine braking. The effect of fuel type on selected emissions of exhaust gas components has also been compared and assessed.
Make use of the friction coefficient during braking the vehicle Wykorzystanie przyczepności podcz... more Make use of the friction coefficient during braking the vehicle Wykorzystanie przyczepności podczas haMoWania pojazdu* In this publication is presented use the tyre-road friction during vehicle braking. Results presented in this publication are based on the road tests of the vehicle equipped in the anti-lock brake system (ABS). Two kinds of tests applied were carried out- the road tests of vehicle making the manoeuvre of braking on the straight section of the road and on the curve of the road. The braking forces and the friction coefficients for the individual wheels of the vehicle were defined on the basis of road tests, including the border values of the friction coefficient.
Rollover of the vehicle is about 2.5% of the total number of accidents, but they have about 20% o... more Rollover of the vehicle is about 2.5% of the total number of accidents, but they have about 20% of the total number of victims [5]. Such overturning of the vehicle occurs when the vehicle is rotated by ninety degrees or more relative to its longitudinal axis. Agency NHTSA (National Highway Traffic Safety Administration USA) [7] has evaluated a number of manoeuvres that may cause wheels lift on the road and rollover the vehicle. The results did not indicate in detail the manoeuvres that cause the loss of lateral stability of the vehicle. It should be noted that the study of large-scale test vehicle especially, are dangerous and costly. Attempts were made to determine the conditions of “limit” at which the vehicle is likely to rollover. To assess the vehicle stability both indicators are based on the mass and geometrical parameters of vehicles with varying degrees of simplicity and road tests are performed using standardized procedures vehicles developed by ISO and recommended by NHTS...
Energies, 2021
The influence of mounting motors in wheels’ hubs and flexibility of the twist beam rear suspensio... more The influence of mounting motors in wheels’ hubs and flexibility of the twist beam rear suspension on their dynamics and strength is presented in the paper. The international roughness indicator (IRI) is applied to assess the overcoming of road unevenness. This indicator is a combination of a shape of the road unevenness and of overcoming velocity. The movement of a wheel’s axis during obstacles overcoming is described. For the needs of the dynamics analysis, the mathematical model of the rear suspension system with embedded motors is developed using the MSC.Adams-ANSYS interface. The discrete model of the twist beam is prepared in the ANSYS software, which is used in the next step to construct the dynamics model of the rear suspension system using the MSC.Adams program. The vertical components of displacement and acceleration of the wheel’s centre, forces in the suspension’s springs and dampers, as well as forces in the joints are analyzed. The analysis of the suspension beam’s str...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The paper presents results of research and thermal analysis of valves made of various materials. ... more The paper presents results of research and thermal analysis of valves made of various materials. Monolithic (of valve steel) and bimetallic valves produced with the same technology have been compared, the external layer of bimetallic valves being of the valve steel and the internal of steel 45. Results of valve heating research and measured temperatures on the surface of a valve and a guide have been presented. Model computations have been carried out using the finite elements method, temperatures distribution in a valve placed on the measuring position and during operation of an engine. Also, the impact of a crevice between a guide and a valve on the carrying away of heat have been analyzed (width of the crevice and its lubrication). For the purpose of the analysis a model of a guide together with a guide has been built. On the basis of analysis of heat emitted in the combustion chamber and the outlet channel, the conditions of heat transfer have been determined. The results of the...
The condition of shock-absorbers is one of factors influencing the in active-safety technology wh... more The condition of shock-absorbers is one of factors influencing the in active-safety technology which help drivers to control of their vehicles in the motion. It stuck in the drivers ' consciousness, that the damage of the shock-absorber causes the elongation the braking path and the lowering of the drive comfort. The remaining consequences of the worse conditions of shock-absorbers they are not known for the drivers ' generality. This impinges on the vehicle motion parameters, its steerability and directional stability. The results of investigations and the analyses of the inefficient shock-absorber influence on vibration damping and the motion of the car were introduced in the presented work. The damping coefficients of the shock-absorber and their change during the exploitation were defined on the basis of test-bed investigations. Road tests were carrying over, on the basis which, try to catch the influence of fault on steerability and the directional stability of the ve...
Projektowanie, badania i eksploatacja
Celem artykułu jest objaśnienie wpływu niekorzystnych warunków pogodowych na najbardziej popularn... more Celem artykułu jest objaśnienie wpływu niekorzystnych warunków pogodowych na najbardziej popularne sensory wykorzystywane w samochodach autonomicznych. W pracy przedstawiono typowe sensory takie jak: kamera, LiDAR oraz RADAR, a następnie wskazano zakłócenia jakie w ich pracy wywołują niekorzystne warunki pogodowe. Przedstawiono wpływ: deszczu, śniegu oraz mgły. Ponadto omówiono próby zmierzające do ograniczenia tego wpływu. Proponowane działania dotyczą zarówno usprawnień samego sprzętu jak i rozwijania metod analizy obrazu. Podsumowaniem opracowania jest konkluzja, że najlepsze efekty otrzymuje się podczas wykorzystywania różnych sensorów, które mogą się wzajemnie uzupełniać.
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Papers by Krzysztof Parczewski