Fulltext search in archive

The paper is focused on fuels, their users - engines and the end-user, the vehicles, from an environmental and economic point of view. The basic characteristics of potential fuels for internal combustion engines, as well as possible sources of electricity, are analysed. A comparative analysis of characteristics of vehicle propulsion with gasoline, diesel fuel, compressed natural gas, liquefied petroleum gas and electricity was performed. The research has shown that the application of vehicles with an electric motor is ecologically justified only in cases of obtaining electricity in an environmentally friendly way and that in other cases there is no profit in an ecological sense. From an economic point of view, if there were no subsidies to manufacturers and buyers of electric cars, they would not be competitive with internal combustion engines now. Within the research, potential solutions for reducing air pollution and improving the quality of life in cities have been proposed.

This study provides a teaching-learning-based optimization (TLBO) path planning method for an autonomous vehicle in a cluttered environment, which takes into account path smoothness and the possibility of collision with nearby obstacles. The path planning problem is tackled as a multiobjective optimization in order to plan an efficient path that allows the vehicle to travel autonomously in crowded settings. The TLBO algorithm is used to find the ideal path, with the goals of finding the shortest path to the target site and maximizing path smoothness, while avoiding obstacles and taking into account the vehicle's dynamic and algebraic properties.

Bike-sharing systems are an important element in development of the smart cities and datasets from these systems are one of the ways to obtain large amount of information on bicycle traffic. These usually contain data on the origin and destination of each trip, as well as its time and duration. Alongside the basic data, some operators also provide information on the exact route picked by each user. This allows researchers to study stopovers, which may serve as a source of interesting information on human behaviour in public spaces and, as a consequence, help improve its analysis and design. However, using the raw data may lead to important errors because most stops occur in the vicinity of bike stations or are related to traffic problems, as evidenced by the case study of Cracow. The data filtering method proposed below opens up the possibility for using such datasets for further research on bike user behaviour and public spaces.

This paper deals with the noise level of power transformers operating at a middle frequency from 800 Hz to 2000 Hz. The factors that influence the noise produced by power transformers are size, design and operating conditions. The research shows that the noise level of power transformers can vary widely depending on these factors. The paper discusses an overview of different types of power transformers core and their impact on the transformer's noise performance. This paper describes the design of a middle-frequency power transformer, its material composition and the design of the magnetic circuit and windings, operating in the frequency range 800 to 2000 Hz, with a capacity of 200 kVA, air-cooled, to be fed from a suitable frequency converter, characterized by reduced noise. The proposed solution allows implementation of galvanically isolated DC-DC converters for auxiliary traction drives and other DC-DC converters.

The methodology for selecting the main force parameters of nonlinear non-conservative suspension for the main performance characteristics of wheeled vehicles has been developed based on the longitudinal-angular oscillations. The following has been established: a) change limits of static deformation of the elastic suspension system and its other parameters at which the basic operational characteristics for various ranges of amplitude change are satisfied; b) the amplitude of the initial perturbation of oscillations depending on the shape of the inequality and its entry speed; c) the influence of the main characteristics of damping devices on the amplitude-frequency characteristics. The results of this work can be a basis for the choice of such parameters of the considered controlled suspension, which ensure the stability of the vehicle along the curved sections of the road, its controllability, etc.

The COVID-19 pandemic has significantly affected the development of road transport, not only in Poland, but also worldwide. Limited mobility, especially at the beginning of the pandemic, had a large impact on the number of road accidents. The aim of the present study is to predict the number of road accidents in Poland and to assess the impact of the COVID-19 pandemic on variability of the number of road accidents. To attain the objective, annual data on the road accidents for every province in Poland were collected and analysed. Based on historical crash data, obtained from the police, the number of road accidents was forecasted for both pandemic and non-pandemic scenarios. Selected time series models and exponential models were used to forecast the number of accidents.

This paper deals with the use of modern technology for security purposes, focusing on the situation in cities (urban noise and shooting) and in transport (passenger rail). The authors aimed to highlight the possibilities and capabilities of installation of technology in the field of applied physical acoustics (sensors, evaluation system with the possibility of setting sensitive sensing filters, end output) and the possibilities of monitoring, including the response of security forces or security measures to the detected danger. In the paper, the authors also include graphical representations of the energy-normalized spectra of the different sound backgrounds and classification classes of acoustic events and types of acoustic events to clarify the differences of the selected monitored events.

This study discusses the automated visual inspection of electronic boards used in the mass production of power electronics equipment. Soldering splashes, produced during the necessary manufacturing stages, can affect the hybrid power semiconductor modules' quality, specifications and lifespan. Splashes from soldering may appear in some electronic boards areas when they may cause decreasing of quality of these boards and need to be removed. Image analysis algorithms are used to search for such areas. The automated inspection is based on neural network YOLO. The images of electronic boards, acquired by authors in SEMIKRON Slovakia company, were used as training, testing and validation dataset for the YOLO network. The custom recording system was designed to acquire those images. The implementation of this method may increase the object search success and then thereby increase the overall quality of module production.

Electric car does not supply all the electric energy, obtained from the electric network, to the wheels in the form of mechanical energy. During such a transformation, a part of this energy is lost. The article endeavours to determine the energy efficiency of selected electric car. The electric car used for measurements is not from the batch production since that is a vehicle designed at University of Zilina. The efficiency has been observed while driving under the conditions of amended methodology of New European Driving Cycle (NEDC). The measured value of electric car's efficiency is being analyzed from the energy consumption, as well as emission production, points of view.

For the developed system of public transport, the passengers, as the customers, have a variety of alternatives when choosing the transport mode or even the route for the given mode of public transport. The estimation of the passengers' preference is the key task for transportation planners for solving the wide range of optimization problems in the field of public transport. A methodology for estimation of the passengers' preference when choosing the bus line within a public transport system is developed in this paper. The proposed approach is based on the fuzzy-logic mathematical apparatus and uses the surveys' data to calculate the membership functions defining the passengers' preference. The case study of the passengers' survey, held in Talas (Kazakhstan), is used to illustrate the developed methodology.

The article presents results of the overpass condition survey, technical survey, static tests and assessment of the structure operational reliability, a double-decker overpass on Almaty-Kapshagai highway section in Kazakhstan.

Models developed in Highway Capacity Manual (HCM) are not suitable to cater to the effects of mixed traffic conditions and hence, its use is unjustifiable. This research investigates such a challenging problem as the effect of undesignated pedestrian crossings on the entry capacity of roundabouts. For the present study, field survey data were collected using video cameras from three roundabouts such that the base section (roundabout without pedestrian influence) and non-base sections (with pedestrian influence), both scenarios, were captured. A modified HCM equation was developed to estimate entry capacity and further, the reduction in capacity with respect to pedestrian volume is determined. Lastly, a relationship was developed to check the effect of pedestrian crossflow on the entry capacity. The relation shows that capacity reduced to 1841 Passenger Car Unit (PCU/h) when the pedestrian flow increased to 288 pedestrians/hour.

In this paper, the authors discuss the method of deformations compensation (resulting from the impact of variable temperatures and pressure) in pipelines intended for fluids transport (liquids and gases). Classical methods of compensation through the so-called "natural compensation" and using special devices called expansion joints. In this paper authors present research work on a new type of the metal expansion joints, called bellow-lens expansion joints. The mechanically assisted laser forming method, which was used to manufacture the bellow-lens expansion joints, was presented. The method uses CO₂ laser radiation to heat the element from which the expansion joint will be made and the proprietary system consists of an actuator and swivel handle.

One of the most important directions of intensification and increasing the efficiency of the transportation process is to improve the use of the carrying capacity and capacity of vehicles. For this, it is necessary to the choose rational schemes for loading the cargo into cargo places of the rolling stock. The possible options for loading the vehicle body with cylindrical loads, which are transported when they are installed on the end, are considered. The conducted analysis showed that there are several typical schemes for loading such cargoes. Analytical dependencies have been obtained that allow choosing a rational loading scheme when transporting such cylindrical loads, considering their parameters and the characteristics of cargo places of vehicles. Based on the performed research, the best variant is proposed, i.e. the option with the clearance of 0.2 m, allowing transportation of 125 cylindrical cargo units in the space of a vehicle.

This paper presents a redundant multi-object detection method for autonomous driving, exploiting a combination of Light Detection and Ranging (LiDAR) and stereocamera sensors to detect different obstacles. These sensors are used for distinct perception pipelines considering a custom hardware/software architecture deployed on a self-driving electric racing vehicle. Consequently, the creation of a local map with respect to the vehicle position enables development of further local trajectory planning algorithms. The LiDAR-based algorithm exploits segmentation of point clouds for the ground filtering and obstacle detection. The stereocamera-based perception pipeline is based on a Single Shot Detector using a deep learning neural network. The presented algorithm is experimentally validated on the instrumented vehicle during different driving maneuvers.

In this paper is given the definition of e reliability of a transport information system, with features of transport information systems listed. Equations for calculating reliability indicators are given, as well. The developed hierarchical graph model for assessing the reliability of transport information systems and an algorithm for analyzing the graph model, which allows taking into account the specifics of the reliability of the operation of system elements at different levels of the hierarchy, are presented. Using the graph model and the graph model analysis algorithm, it is possible to reasonably predict the strategy for the creation and development of transport information systems.

The article deals with the problem of estimating the rational number and utilization rate of the vehicles' fleet. According to the analysis results of the state-of-the-art literature it has been revealed that the issue of substantiating the rational fleet size and the rate of its utilization were not fully solved. The purpose of the study was to increase the efficiency of servicing transportation orders by determining the required number of vehicles. The goal of the research was the influence of the transportation process parameters on the truck utilization rate. Originating from the probabilistic nature of the transportation process, it has been proposed to use the AnyLogic software product to develop a simulation model for vehicle orders' servicing. From the processing of the experimental results by the regression analysis methods, it has been found that the dependence of changes in the vehicle utilization rate is of a linear form.

This paper describes the optimization of dimensions of the individual injection mold runner system of the plastic part used as the frame for various devices in transport means. Nowadays, the great emphasis is placed on the production time and finances associated with design and production. As a result, simulations are being employed increasingly. This paper aims to describe the design the optimum size and shape of the sprues and runners required for proper filling and to simulate the injection molding process to avoid problems and defects that tend to be caused by an incorrectly sized runner system. As a result, some adjustments were made to the size of the runner system to eliminate problems with underfilling, overfilling, air traps and weld lines. The difficulties with the original design were fixed by the optimized solution, which improved the monitored parameters. Additionally, the technological parameters of the injection process were modified, resulting in lower stress on the injection mold in the injection process.

The article deals with the analysis of selected technical and economic aspects that influence decision making process when choosing a car with an electric drive - an electric car. Environmental friendliness is beginning to be one of the key aspects in the context of electric vehicle selection, but its final choice is still affected by the standards offered by internal combustion vehicles. In our case, the relevant standards were defined when using the results of a questionnaire survey, the criteria of scales, which are used to compare selected types of electric passenger cars in the conditions of the Czech Republic. The aim of the article is to select an appropriate electric car by using specific techniques of multi-criteria decision making - the Basic Variant method and the Analytic Hierarchy Process (AHP). The scientific value of the article lies primarily in its applicability to the global environment and the variability possibilities of criteria set and their significance.

The number of vehicles on the road is growing every year and each year too many people lose their lives and health on Polish roads. The number of accidents, including at level crossings, is very high. Despite the construction of new, safer roads, the number of collisions continues to grow and about three thousand accident participants die each year. The main causes of accidents are inadequate speed to the prevailing road conditions or regulations, driving under the influence of alcohol and random events. For this reason, the article analyzes the safety at railroad crossings in Poland. In the next stage, an exemplary system improving safety at railroad crossings is presented. The new solution was analysed using a survey. The research results presented may be applicable to other countries.

The purpose of the research was an experimental study of the dynamic processes of interaction between a TE33A diesel locomotive and a railway track when passing along a curved section with a radius of 290 m. To study the dynamic and driving properties of the rolling stock, the analysis of the experimental data obtained was carried out. When performing the study, the following results were obtained: the indicators of the frame forces of each wheel were determined when moving the TE33A locomotive along a curve with a radius of 290 m; the coefficients of the vertical dynamics of the second suspension stage when moving the TE33A locomotive along a curve with a radius of 290 m are determined; axial stresses in the rails under the influence of the TE33A locomotive on the track with rails of grades R50 and R65 are determined.

The paper aims to present an analysis of the component sizes of commercially available vehicles with electrified powertrains. The paper provides insight into how the powertrain components (an internal combustion engine, an electric motor and a battery) of mass production electrified vehicles are sized. The data of wide range of mass production electrified vehicles are collected and analyzed. Firstly, the main requirements to performance of a vehicle are described. The power values to meet the main performance requirements are calculated and compared to the real vehicle data. Based on the calculated values of the power requirements the minimum sizes of the powertrain components are derived. The paper highlights how the sizing methodologies, described in the research literature, are implemented in sizing the powertrain of the commercially available electrified vehicles.

The issue of spatial data visualization is currently an important element in the positioning and navigation process. The constant trend in increasing the accuracy and availability of position modules affects the widespread use of the mobile devices in transport. The paper presents creation of a three-dimensional visualization model based on ground tracks recorded in NMEA (National Marine Electronics Association) and GPX (GPS Exchange Format) formats. Additionally, the study presents an analysis of the positioning accuracy including the sky obstructions presence and the instantaneous state of the satellite constellation. The significant deterioration in positioning accuracies was noted due to the presence of sky obstructions and low movement speed during data recording. The analysis of these parameters showed the dependence of the positioning accuracy with the number of visible satellites and the HDOP (Horizontal Dilution of Precision) parameter.

Traffic congestion is one of the most significant problems in urban transportation. It has been increasing, especially in regions close to intersections. Several methods have been developed to reduce the traffic congestion. One of the analysis methods is social network analysis (SNA). This method, which has increased use in transportation, can quickly identify the most central intersections in transportation networks. Improvements to central intersections, identified in a road network structure, speed up the traffic flow across the entire network structure. In this study, the Istanbul highway transportation network has been examined and values for a series of network centrality measures have been calculated using the SNA. The accuracy and error scales of the centrality values were compared using a machine learning algorithm. The Bonacich power centrality has been the best performance. Based on the study results the most central intersections in Istanbul have been determined.

This research study provides a new framework to optimize pedestrian simulation parameters required to replicate emergency evacuation conditions specifically observed in high rise buildings, passenger vehicles and transport terminals. The simulation experiments are performed with generalised social force model in VISWALK simulation environment. The data required for optimization are obtained by conducting several evacuation experiments. The results indicate that pedestrian behavioural aspects, such as the relaxation time, distance from the other pedestrian and force exerted by closest pedestrians, have a significant impact on total evacuation time. The outcomes are in consistence with field observations and the calibrated parameters would help in simulating future scenarios including building level simulations and further simulating emergency evacuation of passengers from transport terminals and vehicles.

In this paper, the focus is given on the potential use of the supercapacitor component for peak power delivery, required during operation. Potential application use considered here is electric drive for robotic arm motorization. Automatization of industrial and manufacturing processes requires increasing demands on the use of industrial robots. The motion profiles of such system, requires within the operation peak power demand. The supply system can be composed from DC bus power supply, or combined with energy storage system. Combination with proper energy storage component, can improve energy efficiency and provide peak power for the requirements of the system operation. In this paper, design approach for supercapacitor (SC) module is presented for certain motion profile, which is defined by power requirement here. SC module design reflects input to output electrical specifications, while the most optimal configuration is being identified according to SC operation. This approach refers also to the identification of the operational performance of DC-DC bidirectional converter and its proper topological configuration.

Road transport is the primary source of atmospheric air pollution, thus posing a threat to human health and life. The aim of the study was to determine the impact of fuel obtained from plants on the ecological properties of a compression ignition engine. The article reports the results of investigations into a modern engine with a Common Rail system, powered by the RME (rapeseed methyl esters) biodiesel and their blends with diesel. For comparison, the engine was also fuelled with conventional diesel oil without ester addition. When powering the engine with blends and pure biodiesel, brake specific fuel consumption increased. The concentrations of nitrogen oxides and carbon dioxide in the engine exhaust gas also slightly increased. At the same time, a clear reduction in average concentrations of carbon monoxide, hydrocarbons and particulates matter was obtained.

While introducing into a system of passenger traffic the ecologically clean vehicles, namely the electric buses, a task of providing them with a rational move margin is actual. This problem is especially acute while using the trolleybuses with an autonomous move at urban and suburban routes.

The article provides an analysis of the classical design of the apron conveyor, which revealed the significant disadvantages. The study is devoted to the improvement of the plate conveyor design, which would provide an increase in the speed and performance of the conveyor, and allow to create conveyors of any required length and installation angle.

This paper presents experimental and theoretical work, analyzing the performance of single slope solar still with and without a floating lid, conducted in Cairo, Egypt. A Comparison of the experimental output yield with the theoretical one was carried out. The experimentations without the lid were conducted for 7 days and the daily output yield ranges from (2.8 l/day to 3.15 l/day) with an average output yield of 52.8 % when compared to the theoretical output yield. To improve the output yield of the still, a black fibrous lid was placed on the water surface and its effect on the output yield was studied. Because of its porosity the evaporation surface area of the still was improved, water depth is considered small above its surface. The experimentations with the lid were conducted for 6 days and the daily output yield ranges from (3.1 l/day to 3.3 l/day) with an average output yield of 57.95 % when compared to the theoretical yield.