Table of Contents

  • NATURE, TOPICAL ISSUES AND GUIDELINES TOWARDS RESEARCH OF FUNCTIONAL RELIABILITY OF TRANSPORT SYSTEMS

    pg(s) 13-15

    One of the most important characteristics of transport systems is the reliability of their performance. Significant global efforts are being made in this direction, both by the relevant government structures, and individual transport operators. These efforts are justified because improvements in the sphere of safety and reliability entail considerable benefits to transport users (reducing the waiting time of passengers, improving the quality of service in general, increasing supply chains reliability level, etc.) and for operators offering such a service (higher level of competitiveness, more revenues, etc.). This article examines the nature, existing problems and opportunities for improvement of approaches and methods of analysis, evaluation and management of exploitation reliability (and respectively transport service quality) of transport systems.

  • ROAD INFRASTRUCTURE AND TRAFFIC PARAMETERS – MAIN FACTORS AFFECTING TRAFFIC SAFETY

    pg(s) 16-19

    Within the transport process there is continuous interaction between the three main factors: behaviour of road users, infrastructure conditions and characteristics and vehicles. As a matter of fact, the aforementioned factors are key sources of causes for traffic accidents.
    The purpose of the present article is to propose such a road traffic organization that would reduce congestions, minimize the number of road accidents and the risk to health and life and would enhance safety. In this context certain characteristics of a specific road section in Bulgaria will be examined. Furthermore measures for improving traffic conditions and safety will be defined.

  • THE EFFECT OF FUEL VARIATION ON FLAME PROPAGATION IN IC ENGINES WITH STRONG MACRO FLOWS

    pg(s) 20-23

    In this paper some results concerning the evolution of flame propagation through unburnt mixture of two different hydrocarbon fuels,such as CH4 and C8H18, in engines with strong macro flows were presented. Flame propagation was represented by the evolution of spatial distribution of temperature in various cutplanes within combustion chamber. Flame front location was determined in zones with maximum temperature gradient. All results were obtained by dint of multidimensional modeling of reactive flows in arbitrary geometry of IC engine combustion chamber with moving boundaries. In 4.-valve engines the fluid flow pattern during intake is characterized with organized tumble motion pursued by small but clearly legible deterioration in the vicinity of BDC. During compression the fluid flow pattern is entirely three-dimensional and fully controlled by vortex motion located in the central part of the chamber. For that reason these engines are designated as IC engines with strong macro flows (swirl, squish, tumble) yielding non-spherical flame shapes usually encountered in quiescent flows. Flame propagation results for both fuels were obtained with eddy-viscosity model i.e. with standard k-ε model of turbulence.
    The interplay between fluid flow pattern and flame propagation is entirely invariant as regards fuel variationindicating that flame propagation through unburnet mixture of CH4 and C8H18 hydrocarbon fuels is not chemically controlled but controlled by dint of turbulent diffusion.

  • PROECOLOGICAL ENERGETIC SYSTEMS FOR FISHING CUTTERS

    pg(s) 24-27

    In view of the hazards to the environment resulting from operating fishing cutters, a proposal for energy saving and proecological energetic systems for these vessels is presented in this paper. It also demonstrates the significance of the proecological energetic systems, includes a review of the impact of fuel type, renewable energy sources and energy conversion methods on the degree of the hazards to the environment. The proposed solutions regarding the energetic systems refer to the fishing cutters of the length from 15 to 30 m. The solutions are divided into two groups according to currently available technologies and future technologies allowing for alternative energy sources to be applied.

  • FUNCTIONAL DESIGN, MODELING AND NUMERICAL ANALYSIS OF THE REGENERATOR OF STIRLING ENGINE WITH UNCONVENTIONAL MECHANISM FIK

    pg(s) 28-31

    The paper deals with a design of a regenerator of Stirling engine with unconventional mechanism of engine FIK. The final design of the regenerator is based on previous simulations of flowing of a working fluid, created in software Fluent. The paper presents basic requirements to be followed in the design of the regenerator. The contribution also contains a dimensional computation of the regenerator, which describes basic procedures and boundary conditions in the computation of the designed shape of the regenerator.

  • MODELLING OF REMOTE CONTROL WORKING PROCESS OF CONSTRUCTION AND ROAD MACHINES OPERATED IN AGGRESIVE ENVIROMENT

    pg(s) 3-5

    It is evident from the experience of operating the construction machinery (excavators, bulldozers, loaders etc.) that quite often the machinery and its operators are working under severe conditions. When the operators are at risk, it is advisable to deploy remote process control technologies on the work sites. This is what brings research and development of modern remote control systems to the top of the chart in order to improve the productivity of machinery, enhance the safety and quality of the jobs carried out.

  • TRANSPORT PLANNING ON THE LIBERALIZED MARKET OF PUBLIC SERVICES

    pg(s) 32-36

    The importance of transport planning in public services gradually becomes to be fully appreciated in the context of the Czech Republic. Public transport such as investment and operationally intensive industries require a guaranteed long-term strategy, not only in the field of transport infrastructure, but also in the field of transport services. The first prerequisite for successful transport planning is the most accurate description of passenger flows, including the parameters affecting the choice of transport mode. These inputs are an important basis for additional steps: the creation of a line network, timetable design, creating circulation of vehicles and courses of staff, controlling, and any requests for infrastructure improvements. At the end of this article are referred specific practical examples, where thank to a compliance with the rules of theoretical transport planning it has been achieved the increased operational efficiency of public passenger rail-transport.

  • INTEGRATED TECHNOLOGY AND MULTIMODULE TRACKED VEHICLES UNIT FOR WETLANDS PROTECTION

    pg(s) 37-40

    Integrated technology and new generation of multimodule tracked vehicles unit was designed by PIMR- Industrial Institute of Agricultural Engineering in Poznan within the research project WND-POIG.01.03.01-00-164/09. The Tracked Vehicles Unit (TVU) was built as a part of cooperation with Polish firm Hydromega. TVU is dedicated to work on wetlands and should have positive impact on ecology and better environment protection thanks to use of biodegradable oils and lubricants, diesel engine with Stage III emission standard, innovative tracks which have different internal and external speeds during turns. A single-phase technology is designed for harvesting/collecting and transporting biomass (reeds, grass, bushes, small trees) on wetlands, especially these that are located in National Parks and Nature 2000 areas. The TVU is designed to work with different tool modules for cutting, shredding and transporting collected biomass on wetlands. Amphibian type of the TVU’s hulls allows for work in inlands water (rivers, lakes, canals).

  • THE QUALITY OF THE BRAKE COMPONENTS AND ITS IMPACT ON THE BASIC PARAMETERS OF BRAKING

    pg(s) 6-8

    One of the most important characteristics of the vehicle, which characterizes the behaviour of the vehicle while driving, is the ability to reduce vehicle´s speed to stop point. Brake system requirements are set by statute ECE 13 and each EU Member State is obligated to implement them into their legislation. The brake system consists of a set of parts that serve to gradually reduce the speed of the vehicle to stop it and the system must keep it stationary if it has already been stopped. The quality of the brake discs and brake pads is decisive during braking as well as in removing heat from the brake area. This article discusses about the basic parameters compared during braking in changing the quality of brake components which impact road safety and the safety of passengers in vehicles.

  • PROCEDURE FOR THE SEPARATION SEQUENCE OF VERTICES IN DIFERENT ROUTES

    pg(s) 9-12

    The objective of vehicle routing problem (VRP) is to deliver a set of customers with known demands on minimum-cost routes originating and terminating at the same depot. Similar to most GA that a chromosome S is a permutation of n positive integers, such that each integer is corresponding to a customer without trip delimiters. Christian Prins proposed an optimal splitting procedure to get the best solution, respecting to a given chromosome. In this paper, application of this splitting procedure to get the best solution, respecting to a sequence of vertices, produced by the heuristic approaches(or a new chromosome produced by the mutation procedure), is considered.