Measurement of the acoustic internal source impedance of an internal combustion engine

The standing wave tube technique has been adapted to measure the acoustic internal source impedance of an internal combustion engine. In order to implement this technique an extensive experimental facility was designed and constructed and simple test cases were evaluated for validity. In addition an adaptation of the standing wave tube method incorporating a random signal as the external driver sound source and digital data analysis techniques were introduced to reduce the experimental difficulty and time consumption. Normalized specific acoustic impedance data at a constant engine speed of 2200 rpm show little change with varying engine load conditions. Similar data at a constant engine load condition of 254‐mm Hg exhibit more significant dependence on engine speed.

[1]  E. K. Bender,et al.  Measurement of the acoustic impedance of an internal combustion engine , 1975 .

[2]  A. Craggs,et al.  A finite element method for damped acoustic systems: An application to evaluate the performance of reactive mufflers , 1976 .

[3]  J. W. Sullivan.  A method for modeling perforated tube muffler components. I. Theory , 1979 .

[4]  J. Schwinger,et al.  On the Radiation of Sound from an Unflanged Circular Pipe , 1948 .

[5]  D. F. Ross.  A finite element analysis of parallel-coupled acoustic systems using subsystems , 1980 .

[6]  Malcolm J. Crocker,et al.  Insertion loss studies on models of automotive exhaust systems , 1981 .

[7]  Malcolm J. Crocker,et al.  Prediction of transmission loss in mufflers by the finite−element method , 1975 .

[8]  Cheng-I James Young.  ACOUSTIC ANALYSIS OF MUFFLERS FOR ENGINE EXHAUST SYSTEMS. , 1973 .

[9]  Anthony J. Brammer,et al.  Internal‐Combustion Engine Induction and Exhaust System Noise , 1973 .

[10]  Malcolm J. Crocker,et al.  Acoustical analysts, testing, and design of flow‐reversing muffler chambers , 1975 .

[11]  Malcolm J. Crocker,et al.  A scheme to predict the sound pressure radiated from an automotive exhaust system , 1981 .

[12]  David P. Egolf,et al.  Experimental scheme for analyzing the dynamic behavior of electroacoustic transducers , 1977 .

[13]  M. J. Crocker,et al.  Analysis of concentric‐tube resonators having unpartitioned cavities , 1978 .

[14]  Don D Davis,et al.  Theoretical and experimental investigation of mufflers with comments on engine-exhaust muffler design , 1952 .

[15]  W. Soedel,et al.  A mathematical model of Helmholtz resonator type gas oscillation discharges of two-stroke cycle engines , 1976 .

[16]  D. Karnopp,et al.  COMPUTER PREDICTION OF POWER AND NOISE FOR TWO-STROKE ENGINES WITH POWER TUNED SILENCED EXHAUSTS , 1975 .

[17]  P.O.A.L. Davies.  The design of silencers for internal combustion engines , 1964 .