• Energy control principles in an automotive active suspension system

    pg(s) 107-110

    In the paper, energy recuperation and management in automotive suspension systems with linear electric motors controlled using a proposed H∞ controller to obtain a variable mechanical force for a car damper is presented. Vehicle suspensions in which forces are generated in response to feedback signals by active elements obviously offer increased design flexibility compared to the conventional suspensions using passive elements such as springs and dampers. The main advantage of the proposed solution using a linear AC motor is the possibility to generate desired forces acting between the unsprung and sprung masses of the car, providing good insulation of the car sprung mass from the road surface disturbances. In addition, under certain circumstances using linear motors as actuators enables to transform mechanical energy of the vertical car vibrations to electrical energy, accumulate it, and use it when needed. Energy flow control (management) enables to reduce or even eliminate the demands concerning the external power source.

  • Finding the optimal compensator control matrix in the longitudinal chanel for developed MUAV

    pg(s) 103-106

    The presented report examines the isolated longitudinal movement of a mini unmanned air vechicle type flying wing. The overall dimensions and the mass characteristics are taked from the developed MUAV. These features are introduced into the software environment of the virtual aerodynamic tunnel. The resulting mathematical model is statically balanced in the isolated longitudinal movement and the openloop system has been stability examined. The received state matrix is introduced into the state space model of the isolation longitudinal movement and the system is tested for stability and controlability. A matrix of the compensator is synthesized, and its optimal coefficients are found by two methods.

  • Features of hybrid electric vehicle (HEV) transmission

    pg(s) 95-98

    The transmissions of HEVs or so-called hybrid transmissions (HT) are essentially power split transmissions, which almost always require planetary gears to split or sum up power. An essential prerequisite for reading and studying hybrid transmissions is the knowledge of planetary gear function and calculation. For example, the Toyota hybrid system can only be clarified using the principles of the planetary mechanism. In addition to Toyota’s decision, there are two modes of transmission (BMW, Daimler and GM) and many patent applications with similar ideas.
    Technically speaking, these solutions are power split transmissions that turn into a hybrid system by adding an electric motor (EM), a generator (G) and an electric storage battery (SB). These transmissions perform the functions required for vehicles with an internal combustion engine, such as the HEV.
    These functions are launching, torque and speed conversion, reverse gear, and rapid gear-shifts in ascending or descending order. In addition, the requirements for HT are realized with the help of electronic control. For parallel HEV, a conventional gearbox plus EM is used. The automatic transmissions used in the mixed HEVs are designed with planetary gearboxes and are also known as automatic HTs. This article discusses the features of planetary gearboxes used in HEVs transmissions.

  • Approach of calculating the automotive gasoline injector electromagnetic parameters

    pg(s) 91-94

    The electromagnetic fuel injectors automotive are the gasoline injection systems main elements. The injectors perform the gasoline injection and its time of open condition, i.e injection duration determines the fuel quantity per working cycle [1]. The injectors are activated by solenoid and inject the gasoline in the engine manifold at the system pressure [2]. The gasoline injectors ensure precise fuel metering according to engine work state. The injectors are controlled by control signals, whose parameters are defined by the engine management system. The control devices are power transistors (drivers) in the electronic control unit (ECU). The injectors synchronizing and speed activating has a special significance and influence upon the increasing of the power and efficiency and the decreasing of the harmful emissions of the automotive engines. The synchronization of the electromagnetic gasoline injectors is connected by one hand of the injection according engine work order and by the other – with equal fuel injection duration and injection quantity. Meanwhile the injectors work at such conditions, which imposed constant compensation and adaptation activities by the ECU. This circumstance is connected with requirements of speed activating, which is measured by indicators, such as minimal electromagnetic activating force and minimal opening and closing time. This paper is considered the method of calculating the electromagnetic parameters of the automotive electromagnetic gasoline injectors for manifold gasoline injection.

  • Objectification and determination of hand-arm vibrations

    pg(s) 87-90

    The paper is devoted to objectification and determination of the influence of hand-arm vibrations with selected machinery. We permanently meet with vibrations, but especially when performing work activities. When working with machinery, a person is constantly exposed to vibrations and they can very negatively affect the health of the person. The aim of the paper is to compare measured vibration values with the manual of the device and then to determine the maximum time exposure for work activities to avoid the employee being at risk of working with the device. Comparison of a final hand-arm vibration will be assessed by means of the hand-arm exposure calculator and software for a specific measuring device – vibration analyzer of the 4447 type. The proposed method – an extended risk matrix – is used to assess the risks of hand-arm vibration.

  • COMPARISON BETWEEN THE PURSUIT GUIDANCE AND THE PROPORTIONAL NAVIGATION GUIDANCE LAWS REGARDING A PREDETERMINED SCENARIO

    pg(s) 162-165

    In tactical missile design, it is highly crucial to select the proper guidance method in order to meet the scenario requirements. As it is applicable in every aspect of life, trade-off conditions should be measured meticulously to reach the most advantageous and economical outcome. In this study, a particular scenario with a manoeuvring target is taken into consideration. Two of the guidance laws, namely, the pursuit guidance and the proportional navigation guidance are then implemented and compared. Lastly, the effect of the missile acceleration is examined within the proportional navigation guidance to consolidate the study.

  • THREE-DIMENSIONAL SIMULATION OF THERMAL STRESSES IN DISCS DURING AN AUTOMOTIVE BRAKING CYCLE

    pg(s) 158-161

    In this study, a 3-Dimensional finite element simulation of a braking cycle including braking and cooling steps is presented. In order to induce thermal stresses, thermo-mechanical material behaviour and interactions between pad and discs are considered in the simulation. The results reveal that compressive and tensile stresses are happening in the braking and cooling steps respectively. Cyclic tensile stresses in the disc of heavy trucks would lead to the initiation of superficial radial cracks in them. The occurrence of hot spot phenomenon in the discs are also observed and discussed thoroughly. The proposed model could be utilized to estimate fatigue life of the braking discs in the automobiles and heavy vehicles..

  • VEHICLES FOR THE FUTURE – DILLEMAS AND PERSPECTIVES

    pg(s) 155-156

    The homeland of the first modern electrical car is Greece. Legendary Enfild 8000 is one of the first electrical cars in the world, and that small two-seater was also extremely economical. It originated from the Greek island of Syros, where it is exhibited today at the Industrial Museum in Hermoupolis.It is believed that electrical cars are the real small revolution, because we replaced one type of engine with the other, while the autonomous vehicles resistant to human errors will represent the first real big transport revolution of the 21st century. Experts believe that new models of cars will have the best test in Norway1, where during the last year drivers mostly (52%) voted for electric cars and hybrids. Electrified icons: Ford Mustang and Ford F-150 hybrids are coming by 2020. Porsche plans to sell 20,000 cars E mission per year. Also the French are planning to present 8 new electric cars (record holder is the model “zoe”2, and soon the EV version of the “Quid”, a small SUV that is sold on developing markets should join) before year 2022. In Serbia there is a plan to set up more charging stations for electrical vehicles. It will be initially only 3 stations within the project “Green Balkanica”, while it is cited that in China there are even 5 million of these stations.

  • DEVELOPMENT AND RESEARCH OF TEMPERATURE CONTROL SYSTEM OF A HIGH-VOLTAGE BATTERY OF A PERSPECTIVE ELECTRIC VEHICLE

    pg(s) 151-154

    The development of temperature control system of high-voltage batteries is an actual and important task in the development of modern electric and hybrid vehicles. There are a large number of designs and types of temperature control systems. In this article, we propose to consider a temperature control system based on a liquid cooling system and designed for both cooling and heating the battery in a wide range of ambient temperatures. In the development process of temperature control system for high-voltage batteries were carried calculations, 3D modelling of the design and tests.

  • INTERACTION BETWEEN ROLLING STOCK AND RAILWAY TRACK WITH OF THE ELASTIC PROPERTIES OF THE BASE

    pg(s) 113-115

    The main trend in considering the interaction of the railway track and the rolling stock is the studying of the parameters of the rigidity of the interaction. For the study, a model of the track design, described using the basic concepts of the theory of elasticity and the propagation of elastic waves was developed. The study of the peculiarities of the interaction of the rolling stock and the track, taking into account the elastic properties of the base, allows to expand the possibilities of solving the problems of ensuring their functionally safe operation with a certain level of operational efficiency.

  • AN ALTERNATIVE DESIGN OF TESTING BENCH FOR DYNAMIC WHEEL CORNERING FATIGUE TESTS

    pg(s) 110-112

    Worldwide test laboratories use complex equipment with high level of automated testing processes due to the larger quantity of samples processed. In order to facilitate the testing of products in domestic, accredited test laboratories, the Center for IC Engine and Vehicles of Vinca Institute developed a testing bench adapted to requirements of the domestic producers. This article presents an examination device designed for cornering fatigue testing of wheels in laboratory conditions. Furthermore, this testing bench allows testing of a wide range of elements and systems associated with the wheel, e.g. hubs, bearings, screw connectors, axles etc. Upon construction, the test bench was evaluated through a number of tests of various wheel specimens. The obtained results confirm the pertinence of this method in the development of the vehicle suspension systems.