Military University of Technology, Institute of Vehicle and Transportation, Faculty of Mechanical Engineering, gen. Sylwestra Kaliskiego 2 Street, 00-908 Warsaw, Poland
Prof. Dr. Jerzy Jackowski
Military University of Technology, Institute of Vehicle and Transportation, Faculty of Mechanical Engineering, gen. Sylwestra Kaliskiego 2 Street, 00-908 Warsaw, Poland
The rapid transition to electric-drive vehicles is taking place globally. Most automakers are adding electric models to their lineups to prepare for the new electric future. From the analysis of the automotive market, it is evident that there is a growing interest in such vehicles. They are expected to account for half the models released after 2030. Electric-drive vehicles include battery-electric vehicles. As indicated in the research literature and emphasized by experts, electric vehicles (EVs) are supposed to be an environmentally friendly alternative to conventional vehicles. The rising number and variety of EVs contribute to a better understanding of their performance. With more EVs on the market, there are problems to be solved and challenges to overcome. This article is the first part of a two-article series reviewing the strengths and weaknesses of EVs. The article analyzes the environmental effects of EVs at each stage of their life cycle, compares large- and small-scale recycling methods, and explores the potential applications of second-life batteries. This article is an attempt to find out how environmentally friendly EVs are.
The non-pneumatic tire (NPT) is a type of wheel whichdevelopment is related to the beginning of automotive development. The non-pneumatic tire (NPT) is a type of tire that does not contain compressed gases or fluid to provide directional control and traction. Nowadays, this type of wheel is more and more often used in special purpose vehicles, e.g., in military vehicles and working machines. The main feature of the non-pneumatic tire is a flexible support structure (including the part of the wheel between the tread and the rim). This paper presents the results of research aimed at determining the influence of the geometry of the NPT’s (intended for All-Terrain Vehicle–ATV/Utility Task Vehicle–UTV) load-bearing structure on its quasi-static directional characteristics. The experimental tests included the determination of the radial stiffness of research objects on a non-deformable flat surface and on a single obstacle, as well as the determination of the degree of deformation for the elastic structure and belt. The significant influence of the elastic structure’s shape and the elastomer, as the material forming the NPT, on its radial stiffness was revealed.
The electrification of road transport is developing dynamically around the world. Many automotive companies are introducing electric vehicles to the market, and their popularity is constantly growing. The increasing popularity of electric vehicles is caused by individual countries’ governments encouraging people to switch to electric vehicles and their lower operating costs. In 2022, the number of electric vehicles in China will exceed 10 million. Europe and the USA rank second and third in global electric car stock, respectively. The number of available electric vehicle models is constantly growing, remaining approximately 2.5 times smaller than the case of vehicles with an internal combustion engine. Among others, a significant limitation to the popularity of electric cars is users’ fear of range and the density of the charging infrastructure network. This paper presents the objectives regarding public areas and charging stations around the European Union’s comprehensive and core transport network. It is worth noting that the vehicle and charging point’s charging connectors vary depending on the geographical region. Therefore, the currently used charging connectors for different regions are presented. Charging time depends significantly on the charging current, the power of the charging point, and the devices installed in the vehicle. The paper analyzes the limitations of charging power resulting from the onboard charger’s power and the charging point’s power. It presents the charging time of selected electric vehicles. The second aspect that is also the subject of user concerns and discussed in this article is issues related to the safety of electric vehicles. General safety indicators of such vehicles based on Euro-NCAP tests are characterized. Attention was also paid to more detailed problems related to active and passive safety and functional safety analyses. The issue of the fire hazard of electric vehicles was discussed together with modern experiences regarding post-accident procedures in the event of fires.
This article presents the results of a study of the braking process in terms of assessing the longitudinal loading condition of transported cargo. The existing methods of securing cargo do not take into consideration the type of vehicle used to transport the cargo. This may result in cargo not being transported in compliance with the principles of proper cargo protection. This paper discusses the differences in maximum deceleration values achieved by different types of vehicles that are structurally suitable for freight transport. As a result of these differences in deceleration values, the values of forces acting on the transported cargo are also different. This paper presents and analyses the results of road tests that entailed the heavy braking of two vehicles structurally suitable for freight transport. One of them was a delivery vehicle, while the other was a semi-trailer truck. The experiment was carried out in six measurement series. Four of them were performed on an asphalt pavement, while the other two on a concrete pavement. One series included ten brake tests. Deceleration values registered during the tests were later used to determine the values of coefficient Cx, which were then compared with standardised values. It has been shown that failure to take into account in the selection process of cargo securing equipment, vehicle category, and type and condition of the pavement can result in cargo displacement and even traffic incidents.
This paper deals with the issues of the impact of vertical vibrations on a child seated in a child seat during a journey. Its purpose was to assess the impact of fastening the child seats and road conditions on the level of vibrations recorded on child seats. The paper describes the tested child seats, the methodology of the tests and the test apparatus included in the measuring track. The tests were carried out in real road conditions where the child seats were located on the rear seat of a passenger vehicle. One was attached with standard seat belts, and the other with the ISOFIX base. When driving on roads with three types of surface, the following vertical accelerations were measured: seat of the child seats, the rear seat of the vehicle and the ISOfix base. The recorded accelerations were first analyzed in the time domain and then in the frequency domain. Three indexes (r.m.s, rmq and VDV) were used to assess the vibration comfort. Research has shown that the classic method of fastening a child seat with standard seat belts is more advantageous in terms of vibration comfort. Calculated indicators confirmed the negative impact of separating the child seat from the rear seat of the vehicle using the IQ ISOFIX base.