Abstract:
The article presents the acoustic method of marine low-speed engine turbocharger parameter estimation under operating conditions when a prompt assessment of instantaneous turbocharger
speed and rotor vibration level is required. The method lies in the analysis of the acoustic signal that
is generated by the compressor of the turbocharger with the diesel engine running under load. The
spectral analysis reveals that the compressor blades generate acoustic oscillations that are always
present in the overall acoustic spectrum of the turbocharger regardless of its technical condition.
The harmonic components corresponding to the blades can be detected in the spectrum using the
limit method. The calculated instantaneous turbocharger speed makes it possible to analyze the
main harmonic amplitude in the spectrum. The method presented in this paper helps eliminate
discrete Fourier transform (DFT) spectral leakage so that the amplitude of the main harmonic can be
estimated. Further analysis of the amplitude of the main harmonic allows for efficient estimation
of the turbocharger rotor vibration level when in operation. The method can be practically applied
by means of a smartphone or a computer that has the dedicated software installed. The proposed
method lays the foundations for a permanent monitoring system of turbocharger speed and vibration
in industrial and marine diesel engines.
