Analysis of the level of sound noises imitted into the passenger compartment by road vehicles

This scientific paper presents an analysis carried out by the authors in order to implement some concepts, in which technical aspects (theoretical and practical) are presented concerning sound noises, imitated in the passenger compartment by road vehicles, determined on the basis of the second order active type experiment, under the conditions of their running in urban and extraurban environment at different speed regimes (30, 50 and 130 km/h). For the research, a sample of passenger cars from the national fleet of road vehicles, with spark ignition engines, with European pollution standard in the range [Euro 3 - Euro 6], cylinder capacities (cylinders displacement) in the range [1,400 – 1,600] cm3 and manual and continuously variable transmissions (CVT), which includes all vehicles belonging to owners (natural persons) and legal persons (road transport organisations) at national level. Finally, the conclusions in the field are presented.