Mobility and Vehicle Mechanics

Number 1, 39

7-24
NATURAL GAS AS A SAFE TECHNOLOGY FOR CLEAN URBAN VEHICLES

Authors: Saša Milojević, Radivoje Pešic, Dušan Gordić

Abstract

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Number of views: 557

A motor vehicle fuel can be dangerous if handled improperly. Like liquefied petroleum gas, gasoline and diesel fuel are potentially dangerous fuels, but over time we are learned to use them safely. The same is true with natural gas. It safely generates our electricity, heats our homes and cooks our meals. Natural gas from the gas field to the vehicle's engine, requires very little processing to make it suitable for the use as a fuel. Usually, at a reciprocating compressor's fueling station, the natural gas is compressed and provided to vehicles, where it is stored at 200 bar pressure like Compressed Natural Gas (CNG). In the paper, the solutions for the safe conversion of gasoline powered car and local articulated bus to dedicated Natural Gas Vehicle (NGV) are shown. In addition to safety, the paper demonstrates also ecological benefits, regarding to the use of NGVs in urban transport. In the paper, shortly is presented a look in the natural gas market and safety regulations.

25-38
INVESTIGATION OF PARAMETERS AFFECTING HYDRAULIC BRAKE LOAD SENSING VALVE PERFORMANCE

Authors: Saeed Abu Alyazeed Albatlan

Abstract

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Number of views: 352

Some of hydraulic brake systems for passenger cars and light trucks are provided with load sensing proportioning valve. The behavior of this valve is important to improve the braking performance. This study presents the development and validation of a mathematical model of the change of valve design parameters on its performance according to application requirements. Experiments have been performed to measure the behavior of line pressure before and after the valve. The model results have good agreement with the experimental results.

39-49
COMPOSITE MATERIALS IN AUTOMOTIVE ENGINEERING – MECHANICAL BEHAVIOR OF ANISOTROPIC MEDIA

Authors: Gordana Bogdanović, Dragan Milosavljević, Ljiljana Veljović, Aleksandar Radaković, Mirjana Lazić

Abstract

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Number of views: 393

In recent engineering practice composite materials are widely used. In such materials two or more materials are combined to obtain a new one with new properties, while individual properties of constituents remain distinguished. Such materials have notable feature that are anisotropic, having different mechanical properties in different directions. Here is special attention devoted to their mechanical behavior. Small changes of preferred direction have significant influence to stress strain relations in fibre reinforced layers. Fibre reinforced medium is here treated as homogeneous transversally isotropic. Here is formed Riemann-Christoffel’s equation leading to three homogeneous linear algebraic equations, from which displacements amplitudes may be determined. In such way problem may be analyzed as system of homogeneous algebraic equations. Developed constitutive relations are accommodated for complete analysis of dynamical behavior of plates and laminates, which is one of the basic requirement of actual technical practice.

51-46
THE INFLUENCE OF VARIATION IN POSITION OF OUTPUT SHAFT TO LOAD ON THE CARDAN JOINT CROSS SHAFT

Authors: Boris Rakić, Lozica Ivanović, Danica Josifović, Blaža Stojanović, Andreja Ilić

Abstract

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Number of views: 504

In this paper, the analysis of the influence of variation in position of output shaft to load on the Cardan joint cross shaft in power transmitters is shown. Cardan shafts are the systems that provide alterations of angles between axes of the shafts, which are involved in the power transmission, so as theirs relative translations. Those properties make Cardan shafts very suitable for using in power transmitters, especially at motor vehicles. The kinematic of power transmitters with Cardan joints is highly specific in relation to variation in position of the axis of the output and input shafts. Those variations in positions cause the alterations of the maximal stresses at the branches of the Cardan joint cross shaft and, also, at its bases. The analysis of the motions at this power transmitter is presented in the first part of the paper and also, the diagrams of relations between the specific kinematic values are given. The analytical calculation of the stresses at the cross shaft of the Cardan joint, as function of the angular position of the shaft is done. The second part of the paper deals with forming of the analytic, so as with numeric calculation of stresses in the critical section of the cross shaft. The results obtained by numeric and analytic method are evaluated and the conclusions about stress concentration and stress distribution for different positions of Cardan joints are done.