Development of High-resolution Exciting Source Identification System

We have developed an excitation source identification system that can distinguish excitation sources on a sub-assembly level (around 30mm) for vehicle components by combining a measurement and a timing analysis. Therefore, noise and vibration problems can be solved at an early stage of development and the development period can be shortened. This system is composed of measurement, control, modeling, and excitation source identification parts. The measurement and the excitation source identification parts are the main topics of this paper. In the measurement part, multiple physical quantities can be measured in multi-channel (noise and vibration: 48ch, general purpose: 64ch), and these time data can be analyzed by using a high-resolution signal analysis (Instantaneous Frequency Analysis (IFA)) that we developed. The main difference from the conventional method (Short Time Fourier Transform Analysis (STFT)) is the calculation of the instantaneous frequency from temporal changes in phase. The advantage of IFA is that it has higher resolution than STFT. On the other hand, in the excitation source identification part, the excitation sources can be identified by using a measurement technique such as IFA and an analysis technique such as 1D modeling and timing analysis. We applied this system to high pressure fuel pumps to identify the excitation sources. In the results, six excitation sources were almost all distinguished. Furthermore, the impact noise of the inlet valve and the pressure pulsation noise of the outlet valve were distinguished correctly. These results show that the inlet and outlet valves can be identified as excitation sources.