Mobility and Vehicle Mechanics

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.