Jonas Sapragonas

The role of a tire in vehicle and road interaction

Abstract Major difficulties in road surface description lies in the evaluation of the tire and road interaction. Main purpose of this paper is to analyse the influence of the tire in vehicle and road interaction with the purpose to choose more commons, but enough precise tire models. Data of profile used in investigations were measured in real roads. For the investigation of the tires smoothing function two models were used: flexible narrow ring-2D estimates the tire and road contact in a line and flexible band-3D estimates dimensional contact between the road and tire. Results of computations are presented in figures. There were determinate that tire does not fully smooth irregularity of surface texture level.

Analysis of exhaust gas composition of internal combustion engines using liquefied petroleum gas

Abstract The problems of implementation of liquefied petroleum gas (LPG) supply systems are related with the fact that they are alternative systems used in engines constructed and optimized for work with other kinds of fuel. So assemblers of the systems have to evaluate power losses and at the same time ecological requirements. The experiment is devoted to the analysis of gas composition of engines working at different modes in order to specify the particularity of LPG system tuning and to obtain data for the evaluation of environmental pollution by numerical car dynamics models. It is estimated that the algorithms of current LPG systems balance between ecological requirements and optimization of external characteristics of engines, and the gas systems are characterized by a great inertia. Also, it is determined that more precise tuning algorithms must be constructed, and more tuning points and tuning, when an engine works in standard modes, must be foreseen.

Research of the influence of tire hydroplaning on directional stability of vehicle

AbstractVehicle use is inherently linked to the risks. While transport means are being constantly improved, active and passive safety issues appeared to be more and more complex what makes experimental testing and numerical modelling problems of safety – sensitive structures considerably actual. In case of hydroplaning phenomenon to keep the vehicles stable direction its movement becomes more difficult. Selection of the safe speed is one of the main objectives in order to ensure greater traffic safety and reduce the possibility of an accident. The aspects of tire simulation by finite element method were revealed and analysis of the impact of a vehicles speed on the appearance of hydroplaning process was performed. The peculiarities of Euler–Lagrange formulation of dynamical problems and modelling of fluid – structure interaction by finite element method are presented in the research. The article describes preliminary models developed using the PATRAN and DYTRAN software packages. On the basis of these m...