ANALYSIS OF THE EXPERIMENTAL MEASUREMENT OF ELECTRIC VEHICLE SOUND

The number of automobiles tends to increase in the world, which leads to an increase in the consumption of fossil fuels. Alternative energy sources are sought for automobiles to reduce environmental pollution. One of the alternative sources of energy for automobiles is electricity. Electric automobiles have many advantages over internal combustion vehicles, and one of them is quiet engine operation. However, using electric automobiles in city traffic can create a lot of situations where quiet vehicles can endanger pedestrians, because pedestrians are accustomed to the sound of conventional vehicles, and electric automobiles might not be noticed by them. The main aim of the present research is to develop a methodology for measuring the sound of an electric automobile and define preconditions for the measurement under specific urban conditions. The research developed a specific methodology for measuring the sound of individual vehicles moving past the microphone, as well as a specific methodology for measuring the sound at various intersections with pedestrian crossings. The test of the methodology in non-urban traffic revealed that the converted Renault Clio generated the highest sound level - 88.6 dBA - at a speed of 90 km.h(-1), whereas the lowest sound level - 71.8 dBA - was recorded at the point closest to the microphone at a speed of 30 km.h(-1). At a distance of 30 m from the position of the microphone, the sound level decreased to 54.2 dBA at a speed of 30 km.h(-1 )and to 67.9 dBA at a speed of 90 km.h(-1). At the next stages, the research intends to analyse the operation of special sound devices and the usefulness of equipping electric vehicles with the devices to improve pedestrian safety.