Mobility and Vehicle Mechanics

1-15

Authors: Valentina Golubović-Bugarski, Snežana Petković, Željko Đurić, Goran Jotić

Research of the human body vibrations, carried out under controlled laboratory conditions, shows that human body is the most sensitive to vibrations in the frequency range that matches the biomechanical resonance. In the vertical direction, the resonance of the body is approximately 5 Hz, while in the horizontal direction the resonance occurs at frequencies less than 2 Hz. The vibrations of the vehicle have been transferred to the driver and passengers over the seats, which have the ability to attenuate or to amplify vibrations which human body is exposed to while driving. One way to determine the vibration behaviour of the seat is to measure the SEAT (seat effective amplitude transmissibility) factor, which represents the ratio between the vibrations measured on the seat and vibration measured directly on the floor under the seat. Measurement of vibrations in these two positions must be performed simultaneously. If the value of SEAT is less than 1, a seat attenuates vibrations and meets vibrational comfort, the value of SEAT greater than 1 indicates that a seat amplifies vibration, reducing vibration comfort. This paper gives results of SEAT factor investigation done on a hybrid vehicle, for different types of road surface and different modes of driving (electric power and internal combustion engine).

29-37

Authors: Nenad Kostić, Nenad Petrović, Vesna Marjanović, Nenad Marjanović

This research allows for a selection of gearbox according to minimal dimensional criteria from automated analytical calculations. An automation of the calculation process for four different analytical approaches from literature. The results achieved in the software are compared according to various criteria, minimal length, height, width, and volume. The automation of the process allows for a selection of gearbox concept depending on the chosen criteria. For specific input values, a verification of the automated software operation was conducted, and the resulting values are compared and discussed. Differences in calculated volumes of gearboxes, depending on choice of calculation, reach over 50%. This approach allows for adequate choice of gearbox for specific cases and speeds up the calculation process.

49-63

Authors: Radivoje Pešić, Saša Milojević, Dragan Taranović, Milan Stanojević

Natural gas and liquefied petroleum gas represent the most practical, realistic and easiest way to reduce pollution coming from road transportation. In practice, natural gas vehicles are as safe as any other vehicles (gasoline, diesel, liquefied petroleum gas, etc.) operating on the roads. However, safety incidents sometimes occur where a natural gas system, primarily storage cylinders, have failed. Recent incidents involving natural gas vehicles have shown that cylinders may explode through compliant with current UN ECE 110R regulation. In the paper are systematized regulations and technical requirements relating to the installation of devices and equipment on vehicles powered by natural gas. The main objective of the research is to present a good practice related to inspection of motor vehicles on natural gas. It was also shown the several options for the reconstruction of vehicles to drive on gas fuel, as well as logistics.