PROPOSAL OF A TEST TO MEASURE VEHICLE NOISE EMISSIONS IN REAL DRIVING CONDITIONS

摘要

Traffic noise is one of the main sources of noise pollution in cities. Around an 80% of the cityrnnoise is produced by vehicles. One of the current technological challenges is to achieve arnsustainable acoustic environment in constantly growing cities with a rising quantity of vehicles.rnCurrent legislation obliges to determine the noise level of a vehicle according to a test procedurernshown in Directive 70/157/EEC.rnThe maximum noise level has been declining gradually; however, this reduction has not affectedrnthe overall traffic noise. One of the reasons for this fact is that the approval test does not representrnproperly the real noise level emitted by a real car in real driving conditions. To determine thernnoise emission level more realistically, it is necessary to establish a pattern test that allows twornthings: controlling the main parameters that may affect such noise emission and reproducing thernmeasurement conditions any time the test is performed.rnIn this work, a sample of vehicles has been instrumented to obtain physical measurements of thernvariables that can influence the noise emission level. Positions, velocities, accelerationsrn(longitudinal and lateral) and time have been analyzed using a GPS sensor. Engine speed, enginernload, throttle position and engine temperature have been studied through the vehicle CAN BUSrnand a battery of microphones has measured emitted noise in several points of the vehicle.rnA circuit that represents the usual circulation in a big city like Madrid has been defined, as wellrnas several vehicle models with great presence in existing fleet of cars. Several drivers haverncovered the circuit at different times of the day and previous parameters have been measured inrneach test in order to determine average values of behavior.rnWith these average values, it has been possible to define a pattern test that allows to estimate thernnoise emissions produced by a vehicle in real driving conditions. This pattern test will also allowrnto establish acceptable limits of such emissions.