International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The paper describes the urban passenger transport system which is a set of interdependent subsystems: «city», «transport», «passengers». The urban passenger transport performance indicators have been determined for all system participants. The objective functions of an optimization problem of urban passenger transport are given in general terms. The optimization criterion for traffic routing of urban passenger transport has been determined, which takes account of mutual influence of the interests of all system participants has been determined. The passenger traffic flow density on the studying road section, has been suggested as such optimization criterion. The formulation of an optimization problem of urban passenger transport have been defined as well.

One of the most critical components of an engine in particular, the connecting rod, has been analyzed. Being one of the most integral parts in an engine’s design, the connecting rod must be able to withstand tremendous loads and transmit a great deal of power. This study includes general properties about the connecting rod, research about forces upon crank angle with corresponding to its working dependencies in a structural mentality, study on the stress analysis upon to this forces gained from calculations and optimization with the data that gained from the analysis. In conclusion, the connecting rod can be designed and optimized under a given load range comprising tensile load corresponding to 360^o crank angle at the maximum engine speed as one extreme load, and compressive load corresponding to the peak gas pressure as the other extreme load.

This paper comprises an analysis of an automotive industry company in order to identify whether it has an effective quality assurance system, by monitoring the manner business processes are managed (identification, documentation and control) and whether system efficiency documentation has been developed. The application of different standards/systems for: quality, environment, employee health and safety, corporative social responsibility, food products safety, etc., requires new manager proactive management style and system orientation, as well as reengineering of business processes. However, for successful operation, it is not enough to develop a system that will provide designed quality, but also the costs to implement business processes are significant. In this paper, by applying the Pareto method for detection of points where most defects occur, the Ishikawa approach which reveals the causes of errors, checklists, as well as the Quick Response Quick Control methodologies; 8D (Eight disciplines); PFMEA, the business processes for procurement of raw and repro materials was optimized. The obtained results show that the implementation of these methodologies to optimize business processes leads to the defined quality and better productivity at the lowest costs in operation.

A mathematical model has been derived to assess the potential of the rail passenger transport to increase his capacity and efficiency. This potential has been evaluates in comparison with the competition of the bus transportation. A specific transportation route has been chosen from Sofia to Varna and the potential for increase of the rail transport has been evaluated. The mathematical model uses optimization problem, related to the evaluation of a maximal flow in a transportation network.

The basic features of calculating the reliability of agricultural machinery are shown, in contrast to industries such as mechanical engineering, radio and television equipment, automation systems and etc., in which machines and apparatus operate in steady modes, while agricultural machines do in difficult soil and climatic and dynamic conditions.

Еconomic aspect of reliability is substantiated and patterns of change in the efficiency of use of agricultural machinery in time are established, the economic parameters of reliability are determined. With the help of the theory of similarity and dimensions as well as the planning of multifactor experiments, through the original installation manufactured by us, the basic physical and mechanical properties of metal coatings are studied, obtained by welding under flux, there are relevant similarity criteria determined that characterize the process of restoration of worn parts and, after processing of experimental data an analytical view of criterion equation is formed and rational modes of the restoration of parts under submerged arc welding are set. Further, to optimize the process, the scheduling theory of extreme experiments has been used and as factors in the regression equation there have been chosen most significant similarity criteria. In methodics elaborated by us, it was obtained an adequate equation and by a method of steep ascent (movement along the gradient), there were determined optimal modes of recovery for metal coatings with high physical and mechanical properties (hardness, wear resistance).

Under these regimes there were recovered worn ploughshares and their operational check showed an increase of resource as many as 1.4…1.5 times. For surfacing worn parts with complex configurations (ploughshare plows, cultivators paws), we have manufactured a special copier allowing to recover the items automatically, in a continuous mode. The feasibility study of the developed resource-saving innovative technology has shown that the restoration of 800 ploughshares provides an yearly economic effect of EURO 1,462.

Among cavity pumps used in hydraulic drive systems as energy generators, gear pumps are the most widespread. Apart from their numerous advantages from the point of view of noisiness and the delivery fluctuation coefficient, they are inferior to others. Steps are undertaken to decrease the noisiness. According to the research results, own acoustic parameters of the pump depend on the technology and performance quality as well as on the geometrical features of the tooth profile. The paper is restricted to the analysis of acoustic properties of an innovative gear unit after tooth root undercutting. Acoustic properties have been described with taking into consideration induction of decision trees and decision rules.

The paper presents the characteristics of a modern software system for modeling and optimization of technological processes MOTP_VTU. It outlines the possibilities also to use the system at the design stage. A comparative analysis is performed of three characteristics to apply the new software system MOTP_VTU related to a similar existing one – DSAT-16. via similar systems it is possible to expand the basis of constructions and of functional materials in low technological level during exploration of the set of properties of these materials. This process of realization of scientific and technical ideas is a process to search via multi criteria support of decision making between the project task and the actual possibility, determined by the chemical composition and the processing-mode parameters.

In the article is considered traffic management system in urban networks. Presented analysis of the criteria in the transport network management techniques. Showed results achieved in the implementation and management of traffic flows in the cities, their advantages and benefits. Development of mathematical dynamic models for calculating working parameters of the transport unit allows t create a well-functioning traffic management system. These systems allow to solve optimization problems, to regulate traffic flows in populated areas, thereby allowing the full potential of the existing route network, as well as it will ensure an adequate level of safety, convenience and efficiency of transportation with the least environmental impact.

The paper presents the characteristics of a modern software system for modeling and optimization of technological processes MOTP_VTU. It outlines the possibilities also to use the system at the design stage. A comparative analysis is performed of three characteristics to apply the new software system MOTP_VTU related to a similar existing one – DSAT-16. via similar systems it is possible to expand the basis of constructions and of functional materials in low technological level during exploration of the set of properties of these materials. This process of realization of scientific and technical ideas is a process to search via multi criteria support of decision making between the project task and the actual possibility, determined by the chemical composition and the processing-mode parameters.

The article describes software modules of computer-aided design of vehicle power supply systems: analysis of modes of power supply systems operation, optimal choice of wire sizes, selection and verification of protective devices.

This paper demonstrates a systematic approach for achieving comprehensive mathematical models for electrochemical machining (ECM) of 321-stainless steel based on the response surface methodology (RSM). Machining voltage, tool feed rate, electrolyte flow rate and concentration of NaNO3 solution were considered as the machining parameters while material removal rate (MRR) and surface roughness (Ra) were considered as the process responses. Experimental plan was performed by a central composite design (CCD).

The proposed mathematical models statistically have been evaluated by analysis of variance (ANOVA). Analysis shows that the RSM method has been appointed properly as the design of experiments (DOE) method for resolving curvature in ECM process responses. Also, the optimal machining parameter for single optimization of MRR and Ra is determined by desirability function. The results showed that the proposed approach is an effective and suitable way for modeling and optimization of the ECM machining process.

We are witnessing the rapid growth of the energy prices and there are expectations that they will continue to grow in the future. Consequently, there is a constant need of energy efficiency improvements that could be achieved by decreasing of energy losses, smart and efficient energy utilization and conservation of energy resources.

The water supply systems are large energy consumers. So, the investments in the increasing of their energy efficiency will not only have an economic dimension, but also they could have large positive effect on the environment protection. In this paper, an analysis of the degree of efficient usage of the energy and the appropriate techno-economic analysis of the energy consumption for a real water supply system is presented. Few methods for increasing the energy efficiency of water supply pump stations and an analysis of the potential benefits of this method are proposed and discussed too.