| Popis: |
Noise source identification on a V‐6 diesel engine has been performed by means of the “coherence function method.” The multiple coherence function between the cylinder pressure and the engine noise has been measured. Utilizing the measured coherence function, the engine “combustion noise” is separated from the mechanical impact noise. The frequency response function between the excitation (cylinder pressure) and the response (engine noise) has also been measured. Utilizing the measured frequency response, the engine “combustion noise” has been predicted for some specific cylinder pressure diagrams. A digital Fourier analyzer has been used for measuring the auto‐ and cross‐spectrum of the signals. Calibrations of the transducers and the instrumentation for this particular experiment are discussed. [Work performed under a grant from the National Science Foundation, Washington, D. C.] |
