A Shock Feature Extraction Method of Variable Load Piston Engine Based on emd and Teager Operator

Abstract

The invention relates to a method for extracting shock features of a variable-load piston engine based on EMD and Teager operator. First, the engine cylinder vibration shock signal is processed by using EMD and teager operator to obtain a reconstructed vibration waveform; then, for the engine In the case of variable load conditions, the impact judgment threshold value under normal working conditions is extracted by using the signal data change rate, which solves the problem that the previous single fixed threshold value is greatly affected by the load and has deviations in identifying shocks; finally, the vibration signal of the engine is used according to the fixed Due to the characteristics of phase distribution, the vibration signal is processed in segments, and the impact peak value of each segment is compared with the impact judgment threshold to effectively identify the number of impacts in the entire cycle, which can be used for impact fault judgment and alarm such as engine valves, cylinder collisions, and connecting rod fractures. .

Description

technical field [0001] The invention belongs to the technical field of engine fault monitoring and diagnosis, and relates to a method for extracting shock features of a variable-load piston engine based on EMD and a Teager operator. Background technique [0002] Piston engines are widely used as power equipment in the fields of ships, naval vessels, petroleum and petrochemical and nuclear power, and are of great significance to the monitoring and diagnosis of engines. Compared with rotating machinery, the most essential feature of the engine vibration signal is the impact feature, the system structure is complex, and there are many vibration excitation sources; the signal is time-varying, which belongs to a typical time-varying system. Due to the large number of shocks, the signal as a whole shows strong non-Gaussian characteristics; in the vibration signals collected at different measuring points of the same unit, the vibration shocks are mixed with each other, and the exci...

AI Technical Summary

Problems solved by technology

Due to the large number of shocks, the signal as a whole shows strong non-Gaussian characteristics; in the vibration signals collected at different measuring points of the same unit, the vibration shocks are mixed with each other, and the excitation is complex, so it is difficult to extract and identify the vibration shocks, determine the shock source, and diagnose faults happened

[0003] With the development of engine fault diagnosis technology at home and abroad, the research on vibration and shock identification is relatively lacking; most units currently focus on thermal parameter monitoring, which cannot meet the needs of on-site unit inspection and maintenance

However, the method of vibration signal monitoring and diagnosis still has problems such as variable signals, multiple sources of impact, complex components, and difficulty in extracting fault symptoms.

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