Mobility and Vehicle Mechanics

Number 4, 40

7-27
TURBOCHARGING OF IC ENGINES: AN OVERVIEW OF THE HISTORY, CURRENT STATE, AND THE DEVELOPMENT TRENDS

Authors: Dobrivoje Ninković

Abstract

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Number of views: 398

Since the first patent granted in 1905 to the Swiss engineer A. Büchi for utilizing the IC engine exhaust gas energy for driving a turbine compounded with the engine, which is generally understood as the basis for the introduction of turbocharging, the latter has enjoyed a steady development first in the large Diesel engine segment, where it brought about efficiencies of 55%, becoming nowadays the indispensable technology for further progress in the field of IC engines in general. Surveyed in the lecture is the development of the turbocharging concepts and realizations in the large engine field, where it matured and formed thus the basis for the introduction of the technology to the engines used to propel road vehicles. Although turbocharging is still an active R&D subject in the large engine segment, it is apparent that the main activities are now to be found in the field of small engines. The role of turbocharging as a means for further increasing the specific engine power, reducing both the production of CO2 and the emission of pollution gases detrimental to the environment while simultaneously improving driveability of the vehicles, is also discussed. Finally, an overview is presented of the current development trends in this area.

29-46
A CONTRIBUTION TO RESEARCH OF SOME PHYSICAL CHARACTERISTICS OF DISC BRAKES IN LABORATORY CONDITIONS

Authors: Jasna Glišović Miroslav Demić Jovanka Lukić Danijela Miloradović Jasmina Blagojević Sandra Veličković

Abstract

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Number of views: 363

It has been proved in literature that there is no generally accepted method for the evaluation of characteristics and output parameters of the disc brake mechanism. This paper presents experimental research of disk brake subsystem with brake fluid pressure in the brake cylinder and disc speed as input quantities and brake torque and brake noise (expressed as sound pressure level) as output quantities. The work of disc brakes during the braking process is defined with physical output parameters: activation force, brake torque, brake noise, thermal load, etc. The aim of this paper was to determine the minimum number of mutually independent physical parameters that represent, with reasonable accuracy, the braking characteristics of disc brakes.

47-59
THE CAR IN THE YEAR 2014

Authors: Josip Vlahović

Abstract

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Number of views: 551

The passenger vehicle today is modern and highly equipped. Already in the basic version, it has a servo steering, power brakes, Antilock Braking System, Electronic Stability Control, air bag, etc. It has crash safe and dynamically robust body. Body corrosion resistance is significantly better. Engines consume less, and yet (and nevertheless) the emission is nearly 100 times cleaner than 30 years ago. In any case, the passenger cars today are much better, safer, more reliable and environmentally friendly. They became larger and heavier, but they are fulfilling all requirements. All this is possible through the application of new methods of body construction, by application of the know-how in new production technologies and through application of the new metallurgical classes of Steel and Aluminium. There are also new plastics and composites, too. Great progress has been made in electronic monitoring and control of vehicle systems. Today, on the market, there are vehicles with automatic control. Future cars will soon not need a driver. On the other hand, new limitations on the road, like speed limits, are coming more and more. Congestions on roads would lead toward more speed limits. Because of these, it is quite difficult to say how would passenger cars look like in the future? It could happen that private cars would be controlled from some control centre.

61-77
THE EFFECT OF INTERMODAL TRANSPORT ON THE REDUCTION OF CO2 EMISSION

Authors: Branko Davidović, Miroslav Božović

Abstract

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Number of views: 445

In October 2013 at the demand of Germany, The European Union postponed the adoption of regulations that stipulate that the average carbon dioxide emission of newly-manufactured passenger vehicles would be reduced from 130 gCO2/km in 2015 to 95 gCO2/km until 2020, which does not understate the importance of the need to reduce the emission of pollutants in road transport. European Automobile Manufacturers Association (ACEA) considers that crediting is necessary and they remind that credits should be used as incentives to technological innovations concerning reduction of carbon dioxide emission. In freight transport more and more carriers deliver monthly reports about carbon dioxide emission and inform their clients about the emission of pollutants and the savings generated in transport. The aims of EU-28 are directed towards the reduction of existing CO2 emission by 20% until 2020 and by 80-95% by 2050 in comparison to 2010. One of the possibilities for CO2 emission reduction is the application of intermodal transport which would meet all basic goals of relevant national and international treaties. Many studies have shown that the application of intermodal transport can reduce CO2 emission in road transport by 13% or more, especially on distances over 250 km long. This paper shows possible reductions of CO2 emission depending on the vehicle load and distance according to various intermodal technologies.

79-88
APPLICATION OF HIGH STRENGTH STEELS TO RESPONSIBLE WELDED STRUCTURES ON MOTOR VEHICLES

Authors: Dušan Arsić Vukić Lazić Srbislav Aleksandrović Dragan Milosavljević Božidar Krstić Petar Marinković Milan Đorđević

Abstract

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Number of views: 349

There is constant tendency of engineers to decrease a weight of vehicles and to increase their capacity and mobility. Parallel with development of high strength steels, which starts in 90's years of last century, starts their application in industry for producing motor vehicles with special purpose (construction mechanization vehicles, fire and military vehicles, etc.). With increase of strength of used materials there are conditions for using lower thickness of cross sections what have direct influence to the weight reduction. With respect to that, one of the most used method for producing that kind of structures is welding, in this paper is analysed the weldability of used HS steel and it is proposed the optimal welding technology for welding HSS class S690QL. The assemblies and parts on one military vehicle are made of that steel. The optimal welding technology should preserve good mechanical properties in weld metal, transition zone and in HAZ as the most critical zone of the welded joint.