Mobility and Vehicle Mechanics

1-15

Authors: Mohamed Ali Emam

An off-road vehicles` mobility program that predicts off-road vehicles mobility has been created to meet requirements for both research and educational programs. The program allows quick prediction of off-road vehicles` performance prior to their usage in sites as it checks whether soil properties are compatible with vehicles` parameters and configuration. The program also may be helpful in comparing and assessing the results of vehicles` mobility investigation obtained by using different methods and concluding the parameters affecting vehicles` mobility. The program has been written in Microsoft Visual Basic.net 2008 and can be considered as a new tool for predicting off-road vehicles` mobility. The program provides an intuitive user interface by linking databases such as off-road vehicles` specifications, soil parameters, and empirical equations to predict the wheel formula, motion resistance ratio, torque ratio, net traction ratio and the traction efficiency. It has been proven that the program is easily to use, simple, and efficient.

37-52

Authors: Mikhail G. Shatrov Leonid N. Golubkov, Andrey U. Dunin, Pavel V. Dushkin, Andrey L. Yakovenko

Fuel injection by Common Rail type fuel system results in hydrodynamic effects presenting considerable interest in case of multiple injections. After injection, fuel pressure oscillations at the injector inlet originate which influence considerably the injection rate and characteristic of consequent injection in case of multiple injections. The article presents the results of various factors influence experimental research on pressure oscillations at the injector inlet in case of single and doubles injections of different fuels. With this, such factors as fuel pressure, injection rate value, interval between injections, physical properties of fuel and design features of the injector were taken into account. The aim of the research: to evaluate the influence of pressure oscillations caused by the preliminary injection of fuel to the main injection. Analysis of the experimental data obtained is useful for selection of main design solutions for Common Rail Injectors (CRI).

67-74

Authors: Nenad Kostić, Nenad Marjanović, Nenad Petrović

Gear train optimization is a constant subject of research with the goals of its adequate and justified use. One of the more important segments of optimization is the criteria of gear train volume. This paper is oriented on the analysis of the problem of decreasing gear train volume from a gear shaft axis position aspect. A heuristic approach has been developed for positioning shaft axes along a golden spiral contour, and the methodology for this alternative solution of optimization problems was defined. This approach represents an imitation of natural occurrences and development processes in nature. Nature itself achieves optimal processes, therefore this research started under the assumption of convergence towards optima. The process is verified on examples as functional, and results were compared to optimal solutions from literature. Achieved results of volume decrease are directly linked to savings, not only on space, but on housing material for the gear train, costs, speed of forming construction documentation, etc.