Mobility and Vehicle Mechanics

15-27

Authors: Perić Sreten Nedić Bogdan Stoiljković Mile Antunović Ranko

The basic function of the lubricant is the lubrication i.e. the diminishing of the friction between two surfaces in relative motion. Besides, they are also used to transfer power, heat transfer, cooling, corrosion protection and so on. Lubricating oils and greases are the third tribology element and their use is necessary for the proper function of almost every mechanical system. This paper presents development and testing of the biodegradable universal tractor oil based on the vegetable oils. The agricultural equipment is ideal for the use of biodegradable oils based on vegetable oils because it is used in the very proximity of the environment where the lubricant can come into contact with the soil, water and crops. This is the ideal opportunity to create permanent cycle where the agricultural equipment is lubricated by the oil from the plants grown in the fields cultivated by the very same equipment. Universal tractor oil (UTTO) is the multipurpose oil for the lubrication of the transmission, rear axle, differential, wet brakes, and hydraulic system fed by the common oil reservoir.

41-50

Authors: Marko Denić, Zorica Đorđević, Vesna Marjanović, Nenad Petrović, Nenad Kostić

Composite materials are still not in widespread use in the industry due to their unexplored potential. One of the uses of composite materials can be in drive shafts. Using lightweight materials for propulsion components can potentially significantly decrease their weight in comparison to their metal counterparts, while maintaining performance characteristics. Drive shafts are subjected to torsion and in rare cases they are subjected to bending. This paper explores the angle of twist in case of torsion, deflection in case of bending, mass, and eigenfrequencies (1st mode) in three cases of frequently used composites (E Glass, High Strength Carbon, and Kevlar-49), and compares the results to those of conventional material shafts. Numerical testing of examples was conducted in Autodesk Helius Composites 2016. The research also covers possible variations of composite shafts to include the influence of the number of layers in the composite, their directions, and possible combination of composite and metal in shaft design and their respective influences on shaft characteristics.

13-22

Authors: Isak Karabegović, Ermin Husak

Year after year, installations of industrial robots in manufacturing processes in the world have been increasing, and especially in recent years in continents Asia/Australia. Sales of industrial robots and their application in all industry branches in 2014 have increased compared to 2013 for 29 % so that in 2014 sales and installation of industrial robots reached 229.261 units. Two industrial branches: automotive and electro/electronics are significant for industrial robot applications. Since 2010 demand for industrial robots and their installations in automation of manufacturing processes have significantly accelerated. One of the reasons is innovative technical improvement of the robots. From 2010 to 2014 average increase of industrial robot installation in automation and modernization of manufacturing processes at the annual level was 17 % (CAGR-Compound Annual Growth Rate). China is a world leading country in the last two years in industrial robot installations. Almost 25 % of annual supply of industrial robots in the world belongs to China. Taking into consideration that China in the last several years is leading country in production of motor vehicles, it is easy to conclude that these industrial robot applications are aimed to automation and modernization of manufacturing processes in automotive industry.

35-51

Authors: N. Ramesh Babu, Harish Mahadevappa

Providing transport facilities to rural people are very important in order to improve the economic lot of the people. In Mysore and Chamarajanagar Districts, transportation is provided by both KSRTC (Public Organisation) and Private Bus Operators. The objective was to study the rural transportation system of these two districts provided by KSRTC and private bus operators and do a comparative analysis and see which organization provides better transportation in the rural areas and also to give some suggestions to improve it. Data were collected by administering questionnaire to the commuters of both public and private bus service.

17-35

Authors: Dimitrios Koulocheris, Georgios Papaioannou, Dimitrios Christodoulou

Suspension systems of vehicles influence the overall performance of the vehicle by receiving the loads created by the road. In the past, researchers introduced many types of suspension systems studying them with the use of vehicle models, such as passive, active, semi-active etc. Many studies turned their attention to the optimization of the suspension systems, so as to facilitate the influence of design parameters in order to get the minimum or the maximum of an objective function. This allowed researchers to investigate ways to combine important parameters of a vehicle in the objective function, so as to achieve the optimum combination of its important parameters, such as the ride comfort and the road holding; the most common trade off in the automotive industry. In this paper, not only the efficiency of different optimization methods is investigated but also the efficiency of various fitness and objective functions so as to achieve the optimum result in the dynamical behaviour of a heavy vehicle model.

53-65

Authors: Vanja Šušteršič, Dušan Gordić, Mladen Josijević, Vladimir Vukašinović

In the recent years, there has been a great progress in the development and practical application of hydro transmission in all industries. In particular, they are widely used in mobile machines in the construction, mining, agriculture and forestry for starting the working parts (manipulators) which perform technological operations and for driving power. The basic advantages and disadvantages of hydraulic power transmission are explained in this paper, with examples of application of both types - hydrostatic and hydrodynamic power transmission for tractors. Calculation of both types of hydraulic power transmission for tractors was made along with a 3D model based on the calculated size.

9-16

Authors: Nadica Stojanović, Jasna Glišović

The effect of temperature and mechanical loads that occur when the vehicle is slowing down or stopping is shown in this paper. In the first section of paper, it is shown that with increasing temperature leads to decrease of the coefficient of friction i.e. the brake efficiency characteristics fade. The structural and thermal analysis is carried out on the model of brake disc and the brake pads, and the deformation and stress states of these elements are shown.

29-44

Authors: Saša Milojević, Radivoje Pešić, Dragan Taranović, Aleksandar Davinić

Lowering fuel consumption and exhaust emissions continue to be prime targets in the development of technology applied for Motor Vehicles and their equipment. Into the focus of attention are the reduction of the vehicle weight as well as, in the field of internal combustion engine technology, more efficient combustion system and accessory components. As a complex system, the internal combustion engine accounts for a major part of the vehicle mass. The key components, the cylinder head and the cylinder block, for heavy loaded diesel engines, are today almost exclusively produced from aluminium. Also, by application of the aluminium pistons, it reduces engines’ weight and inertial forces, as well as the engine vibrations. According to the later, the use of lightweight materials for construction of engine’s accessories as it is small air reciprocating compressor for braking system of trucks and buses, has significant contributions to the reduction of equipped vehicle mass. The advantage of aluminium with regard to the specific weight is notable, but exist the problem because it has considerable disadvantages in terms of the thermal expansion coefficient. The greater thermal expansion would cause unacceptable deformation and higher clearances during reciprocating machine operations. These high clearances would drastically increase the oil consumption and worsen the acoustic excitation. With additional coating on the cylinder liner surfaces it overcoming of poor aluminium strain properties. The application of tribological inserts towards lowering friction resulting in higher performance. The authors hope to obtain more measurement data on the test rig for small air reciprocating compressors in the Engine Laboratory at the Faculty of Engineering University of Kragujevac, which is currently being brought into operation.