Surface Intensity Measurements on a Diesel Engine

Abstract

The use of surface intensity measurements as an alternative to the conventional selective‐wrapping technique of noise source identification and ranking on diesel engines was investigated. A six‐cylinder, in‐line, turbocharged, 350 horsepower diesel engine was used. Sound power was measured under anechoic conditions for eight separate parts of the engine at steady‐state operating conditions using the conventional technique. Sound power measurements were repeated on five separate parts of the engine using the surface intensity technique at the same steady‐state operating conditions. The results were compared by plotting sound power level against frequency, overall sound power level, and noise source rankings for the two methods. A specialized piston‐tube experiment was developed to alleviate the phase shift problems encountered with the surface intensity method by earlier researchers. The results of the experiments demonstrate that the surface intensity method is a viable alternative to the selective‐wrappi...