Abstract Analysis of noise level from engines is important from point of view of customer satisfaction. Accurate prediction of noise is important for planning, design and target setting decisions for meeting customer satisfaction goals. In this work an analytic model has been described to break diesel engine noise data into various components in order to plan a strategy for condition monitoring of engine. Introduction Optimization techniques adopted in engines to reduce excitation sources are effective way to control noise emissions. Hence exact contribution of each source of excitation towards total noise is necessary. Previous works have shown that combustion and mechanical noise contribute a major portion towards noise emitted from diesel engines[1, 2, 3, 4, 5, 6, 7].Based on these works a methodology has been developed to analyze noise emitted from diesel engines. This is based on assumption that that engine noise emissions (TN)are sum of noise due to combustion process(CN), noise during motored condition (MN)and increased motoring noise due to mechanical excitation(IMN).i.e. (1) Experimental Setup Tests were done on a dual cylinder Lombardini LDW442CRS engine having a common rail injection system. The engine as presented in Figure no 1 has specifcations as in Table no 1. Table 1. Engine Specification Table 2. Pressure Transducer Specification Table 3. Testing Conditions A fully opened electronic control unit connected to computer was used to manage the injection system with aim to control operational parameters. The engine was coupled with an a synchronous motor of SIEMENS 1PH7 make thus allowing to control speed and load. This engine test rig has a piezo electric type Kistler 6056A make pressure transducer for in cylinder pressure measurements having features presented in table no 2. An optical crank angle encoder of AVL 364C make was used for detection of TDC position. The given system can do maximum of 2 injections per cycle. All signals were simultaneously acquired by NI boards of 6110 type(for analog type)& 6533 type(for optical encoder signals) using LabVIEW 10 software. During the tests the sampling rate was varied in order to guarantee a fxed crank angle resolution of 0.25°. The signals obtained were fltered using a B&K Nexus device which is a combination of an amplifer and a low pass flter. The sampling rate varied with engine speed in order to have a fxed resolution. During the tests the injection parameters were varied with different injection methods, variations in injection timings and duration of injection. Various engine testing speeds (1600RPM,2000 RPM & 3000 RPM) and load Modeling of Noise Radiated from Engines 2015-01-0107 TSAE-15IC-0107 Published 03/30/2015 Sunny Narayan Roma Tre CITATION: Narayan, S., "Modeling of Noise Radiated from Engines," SAE Technical Paper 2015-01-0107, 2015, doi:10.4271/2015- 01-0107. Copyright © 2015 SAE International and Copyright © 2015 TSAE Downloaded from SAE International by Sunny Narayan, Wednesday, September 23, 2015