SPARK-IGNITION DIESEL ENGINES : AN ACOUSTIC COMPARISON

After briefly describing the test procedures developed during the research, and their application to two versions (one SI and one compression-ignition) of the same twin-cylinder engine, the article reveals the various noise sources and their contribution to the total noise associated with the combustion characteristics and with those induced in the moving mechanical parts. Finally, the possible repercussions these can have on the noise inside the vehicle are considered.