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In this article passenger car suspensions are analyzed, depending on the type of shock absorber. Introduced typical suspension components and semi-active suspension control called “Skyhook”. An overview of the literature is provided also presented the research of passive and semi-active suspension. A quarter-car model simulation has been performed using Matlab/Simulink software package. In results are analyzed sprung and unsprung masses displacements and suspension deflection rates when vehicle are moving over speed lowering bump. Article in Lithuanian. Lengvųjų automobilių pasyvių ir pusiau aktyvių pakabų tyrimas Santrauka.Šiame darbe analizuojamos lengvųjų automobilių pakabos priklausomai nuo amortizatoriaus tipo. Pateikiamos tipinės sudedamosios pakabos dalys ir pusiau aktyvios pakabos, veikiančios „Skyhook“ valdymo principu. Pateikiama literatūros apžvalga, taip pat atliekamas pasyvios ir pusiau aktyvios pakabos tyrimas. Atliekamas ketvirčio automobilio modeliavimas „Matlab/Simulink“ programiniu paketu. Analizuojami amortizuotos ir neamortizuotos masių poslinkiai ir pakabos eigos greičiai, modeliui judant per nelygumą su skirtingomis pakabomis. Reikšminiai žodžiai:pasyvi pakaba, pusiau aktyvi pakaba, „Skyhook“ valdymo principas, slopinimo elementas, standumo elementas, ketvirčio automobilio modelis, modeliavimas.

With the technologies of the autonomous vehicles improving, one of the biggest tasks is safe and effective integration of the autonomous vehicles into the transport system. The safety of such vehicles depends on their ability to move stably and accurately in the desired trajectory. The intellectual control algorithm is the most important system, controlling the movement of the autonomous vehicle. That is why the formulation and analysis of the rational intellectual control algorithms based on different methods is a significant element when seeking that the autonomous vehicles become a valuable road user. A theoretical version of an intellectual control algorithm, which is designed to ensure an accurate following of the desired movement trajectory under different movement conditions, is presented and described in the work. The operation of the algorithm is based on the comparison of the mathematical models of two vehicles and the solution of the optimization task. The described control algorithm is presented in the environment of the software package MATLAB/Simulink, the analysis of the rational operation of the designed algorithm is done. Santrauka Tobulėjant autonominių transporto priemonių technologijoms, vienas didžiausių uždavinių – užtikrinti saugią ir efektyvią autonominių transporto priemonių integraciją į transporto sistemą. Tokių transporto priemonių saugumas priklauso nuo jų galimybės stabiliai ir tiksliai judėti pageidaujama trajektorija. Intelektinis valdymo algoritmas yra svarbiausia sistema, kontroliuojanti autonominės transporto priemonės judėjimą. Todėl skirtingais metodais paremtų racionalių valdymo algoritmų formulavimas bei jų analizė yra reikšmingas dėmuo siekiant, kad autonominės transporto priemonės taptų visaverčiais eismo dalyviais. Straipsnyje aprašomas teorinis intelektinio valdymo algoritmo prototipas, skirtas tiksliam pageidaujamos judėjimo trajektorijos sekimui užtikrinti skirtingomis judėjimo sąlygomis. Algoritmo prototipo veikimas paremtas dviejų transporto priemonių matematinių modelių tarpusavio lyginimu ir optimizavimo uždavinio sprendimu. Aprašomas valdymo algoritmo prototipas pateikiamas programinio paketo MATLAB / Simulink aplinkoje, atliekama algoritmo racionalaus veikimo analizė. Reikšminiai žodžiai: autonominis automobilis; genetinis algoritmas; judėjimo trajektorijos sekimas; nuokrypis.

The paper analyses the effect of road roughness on the variation of the vertical oscillations’ frequency of the sprung and unsprung masses of a vehicle driving at varying speed. The research aims to determine the regularity with which the wheel of a vehicle moving at varying speed reproduces the roughness of road pavement texture. The theory of mathematical statistics is used to define the distribution law of road defects measured during the experiment. In the present investigation, the displacements of the wheel and suspension of the vehicle, driving at varying speed over the defects of the selected road section pavement, have been evaluated. Based on the frequency characteristic obtained from the measured data, the frequency variation of the displacements of the sprung and unsprung masses in a vehicle moving on a rough road has been determined. The vertical acceleration of the wheel and the body of a vehicle has been measured, and the frequency characteristic of vertical acceleration of the sprung and unsprung vehicles’ masses has been analysed. The schematic view of the wheel’s axis displacement model is presented.

In this paper, the parameters important for lateral dynamics of vehicles are analyzed in order to establish the values of its critical speed on the moment of losing the stability. The values of the vehicle’s speed yaw rate, the steering wheel angle, the lateral acceleration, and the roll angle obtained from experimental tests are filtered according to the set conditions and only the general values that mean the beginning of the vehicle slipping are selected. For more precise assessment of the selected values, a statistical analysis is carried out. The Normal distribution law describes scattering of the selected values in the most relevant way and concretizes the critical speed being established. In the end of the paper, the obtained values of the speed are compared to the results of the theoretical calculations. Conclusions assessing the developed technique of selection of the parameters are provided.

The article analyzes the movement of the car on the curve on the slippery and snowy road surface with asphalted ruts. The paper reviews literature related to lateral and longitudinal vehicle acceleration and dynamics of vehicle movement. The experimental facts of vehicle lateral acceleration are given in graphical charts. The article also describes the acceleration values and stability of the automobile depending on the speed in the curve. The findings are given based on the results. Article in Lithuanian. Automobilio judėjimo posūkyje tyrimas žiemos sąlygomis Santrauka.Straipsnyje nagrinėjamas automobilio judėjimas posūkyje esant slidžiai ir snieguotai su asfaltuotomis provėžomis kelio dangai. Apžvelgiama literatūra, susijusi su automobilių skersiniais ir išilginiais pagreičiais, automobilių judėjimo dinamika. Eksperimentinėje dalyje pateikiami automobilių skersinių pagreičių grafikai. Nagrinėjamas pagreičių dydis ir automobilio stabilumas priklausomai nuo judėjimo greičio tame kelio posūkyje. Remiantis gautais rezultatais pateikiamos išvados. Raktiniai žodžiai: automobilis, automobilio dinamika, kelio danga, skersinis pagreitis.

Knygoje pateikiami laboratorinių darbų aprašymai, apimantys teorinę dalį ir darbų atlikimo metodiką, aprašytos pagrindinės degalų, alyvų ir kitų techninių skysčių savybės ir jas apibūdinantys rodikliai, jų nustatymo priemonės ir metodai. Leidinys skirtas sausumos transporto inžinerijos krypties automobilių transporto, transporto technologinių įrenginių ir geležinkelių transporto specializacijų studentams, studijuojantiems transporto priemonių ir stacionarių variklių degalus, variklių ir kitų agregatų, mechanizmų bei mazgų alyvas ir tepimo medžiagas. Knyga tinka ir transporto priemonių techninės priežiūros bei remonto specialistams.

The article provides a closer look into the quality properties of fuels, analyses the merits and demerits of using biocomponents in petrol and diesel and overviews the ways of improving the quality of fuels. The work carried out by the authors covers the determination of the basic quality properties (density, kinematic viscosity and flash point) in petrol, diesel, methanol, ethanol, buthanol as well as rape methyl and rape ethyl esters, the investigation on how these qualities influence the operational performance of the engine and the age-dependence analysis of diesel quality properties.

The present article depicts the results of the investigation into automobile braking parameters and traction characteristics on the different road surfaces. The results of the investigation into automobile braking (the automobile deceleration and coefficient of traction), while braking in winter conditions, i.e. on ice and snow, are presented. The values of deceleration of the automobile while braking on various non‐typical surfaces, on the asphalt, covered with the motor oil or resin, while driving across the petrol spot, and on other surfaces of the road, are presented. Such data are necessary while modelling the automobile's movement in various road conditions and while carrying out the examination of traffic accidents. First Published Online: 27 Oct 2010

The present paper describes the results of an investigation into the braking parameters of automobiles equipped with an antilock brake system (ABS) and without an ABS. The values of the automobile deceleration, the time of the deceleration increase and the time of disbraking, while braking on a dry asphalt-concrete surface, which has been fixed in the course of the experimental investigation, are presented. The dependence of the deceleration of the automobiles, equipped with an ABS and without an ABS, upon the primary driving speed is reflected and substantiated. The results of the investigation of the braking of the automobiles, equipped with an ABS and without an ABS, in winter conditions, i.e., on ice and snow, are presented. The cohesion characteristics and the automobile decelerations while braking onother road surfaces are presented. V prispevku smo opisali rezultate raziskave zavornih lastnosti avtomobilov, opremeljenih s protiblokirnim zavornim sistemom (ABS) in brez njega. Predstavili smo vrednosti zaviranja avtomobila, od trenutka zaviranja do konca zaviranja, na suhi asfaltno-betonski površini, ki je bila nespremenjena med raziskavo. Prikazali in dokazali smo odvisnost zaviranja avtomobilov, opremljenih z ABS in brez njega, od začetne hitrosti voznje. Predstavili smo tudi rezultate preizkusov zaviranja avtomobilov, opremljenih z ABS in brez njega, v zimskih razmerah, na ledu in snegu. Opisali smo tudi stične lastnostiin zaviranja avtomobilov pri zaviranju na drugih povrsinah cestisča.

The present article depicts the results of the investigation of braking parameters of the automobiles, equipped with ABS and without ABS. The values of the automobile deceleration, increase of the deceleration time and the time of disbraking, while braking on dry asphalt-concrete surface, which was fixed in the course of the experimental investigation, are presented. Dependence of deceleration of the automobiles, equipped with ABS and without ABS, upon the primary driving speed is reflected and substantiated. The results of the investigation of automobiles, equipped with ABS and without ABS, braking in winter conditions, i.e. on ice and snow, are presented. Collision of the automobile wheels with vertical obstacle, as a result of which the wheel tire gets dismantled, is considered in the present article. The required force and the automobile s minimal speed of driving, which is equivalent to its kinetic energy loss at dismantling of the lire from the wheel rim after collision with the obstacle, are shown. The values of this force and speed, typical of the automobiles, attributed to different classes, their dependence upon the obstacle height and collision with the obstacle angle are fixed. More precise methods for the calculation of the automobile speed prior to the traffic accident, by taking into consideration its kinetic energy, necessary for dismantling of the wheel at its collision with the vertical obstacle, is suggested.

Transport traffic safety depends on many factors; one of them being the efficiency of the vehicle braking. The efficiency of the vehicle depends on the reaction of the driver, the braking system, the quality of tires, the characteristics of the road surface. The vehicle with the hydraulic braking system and a disc brake with the wheel has been investigated. The dynamic models of the disk brake assembly and the wheel have been constructed. The braking distances of the vehicle with a hydraulic ABS on the asphalt concrete pavement with shortwave roughness and different initial velocity are obtained. Straipsnyje nagrinėjamas stabdomos transporto priemonės judėjimas, kai kuriems ratams nestabdant arba atitrūkus nuo kelio paviršiaus. Nustatyti transporto priemonės lėtėjimo pagreičiai ir važiavimo greičiai, ekvivalentiniai tam tikram ratų stabdymo pėdsako ilgiui, kai visi ratai yra stabdomi, ir atitrūkus nuo kelio paviršiaus ar dėl kitų priežasčių nestabdant ratams. Pateikti kompiuterinio eksperimento rezultatai. Исследовано движение заторможенного транспортного средства в случае, когда некоторые его колеса не тормозят или потеряли контакт с поверхностью дороги. Определено замедление торможения и скорости движения транспортного средства, эквивалентное определенной длине следа торможения колес в случае, ког�����а заторможены все колеса или потеряли контакт с поверхностью дороги, а также по другим причинам не тормозят некоторые колеса заторможенного транспортного средства. Представлены результаты компьютерного эксперимента.

The graphic analytical modelling and the computer modelling of collisions of the automobiles are compared in this article. The examples of modelling of collisions of the automobiles are given. The computer modelling of collision of the automobiles with the help of the program PC CRASH is introduced. The possibilities and advantages of this computer program, the inserted parameters and their optimization are investigated. The possibilities of applying the computer modelling program in the experts' examination of traffic accidents while modelling collisions of the automobiles, the items and requirements raised towards the experts, who work with such programs, on reliability of the obtained results are considered. Straipsnyje lyginami automobilių susidūrimų grafinis analitinis ir kompiuterinis modeliavimas. Pateikta automobilių susidūrimų modeliavimo pavyzdžių, automobilių susidūrimo kompiuterinis modeliavimas remiantis programa PC CRASH. Nagrinėjamos šios kompiuterinės programos galimybės ir privalumai, pasitelkiami parametrai ir jų optimizavimas. Aptariamos galimybės taikyti kompiuterinio modeliavimo programas eismo įvykių ekspertizei, modeliuojant automobilių susidūrimus, gaunamų rezultatų patikimumą, taip pat reikalavimai, keliami tokiomis programomis dirbantiems specialistams. Сравнены графо-аналитическое и компьютерное моделирование столкновений автомобилей. Представлены примеры моделирования столкновений автомобилей, а также компьютерное моделирован�����е столкновений автомобилей, выполненное с помощью программы PC CRASH. Исследованы возможности и преимущества этой компьютерной программы, вводимые параметры и их оптимизация. Обсуждены возможности использования программ компьютерного моделирования при выполнении экспертиз дорожных происшествий для моделирования столкновения автомобилей, вопросы надежности получаемых результатов и требования, предъявляемые специалистам, работающим с такими программами.