| 摘要 |
The subject of the invention is a non-invasive method of diagnosing injection systems of self-ignition engines, marine engines in particular. The diagnostic method of the fuel injection process in a self-ignition engine in this invention is characterized by the fact that, without disturbing the injection system, in a close proximity of the injector, we measure energy pulses of an AE elastic wave signal, generated by the injection system, then the signal is recorded in a form of 50000 digital samples, after which twice more samples are created by inserting samples with mean values of the nearest samples. In the next step the whole set is divided into segments of 50 samples each, called time windows, with a length of half millisecond, then 150 zero samples are added at the beginning and end of each segment, next step being the addition of Hanning window function in the segments, in which then Fourier transformation is applied in order to find 50 spectral lines 0.5 kHz wide in each segment. The next step consists in deleting the time and frequency spectrogram, and thus obtained characteristics is analyzed in specific frequency bands, in which the highest signal energy occurs. The system for diagnosing the fuel injection process in a self-ignition engine is characterized by an AE measurement sensor /2/, that is placed possibly close to the injector / 1 /, and pressed to the point of measurement with a constant force value, whereas the sensor / 2 / is connected to a logger / 3 / comprising a built-in spectral analyzer / 4 / and a supply unit / 5 /, whose output is connected to a computer/ 6 /.
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