Vibration measuring method of engine speed by applying four-point energy centrobaric correction method

Abstract

The invention discloses a vibration measuring method of engine speed by applying a four-point energy centrobaric correction method, which comprises the steps of: discrete-sampling a vibration acceleration signal on the surface of an engine block to obtain a time series; obtaining a frequency domain signal X1(f) through fast Fourier transformation of Zn(t); correcting the peak frequency fi of X1(f) by adopting a four-point energy centrobaric correction method, and obtaining a corrected frequency; obtaining a time spectrum signal ZZn(t) through carrying out self-related transformation and fast Fourier transformation on the frequency domain signal X1(f); correcting the time ti corresponding to the peak of ZZn(t) by adopting the four-point energy centrobaric correction method again, and obtaining the corrected time; and finding the accurate 1 / 2 harmonic frequency value of the rotating speed w of the four stroke engine according to the corrected frequency and time, and calculating the rotating speed w of the engine through a relational expression. The vibration measuring method of engine speed can solve the problem that the rotating speed of the engine cannot be detected when the number of engine blocks cannot be determined; and the method has the advantages of better universality, high noise-proof performance and accurate and reliable result.

Description

technical field [0001] This aspect relates to the field of power machinery and signal processing, in particular to a vibration measurement method for engine speed using a four-point energy center of gravity correction method, which is a method for testing the engine speed when the number of engine cylinders is unknown. Background technique [0002] Since the vast majority of vehicles currently in use are four-stroke engines, for a four-stroke engine, a four-stroke engine refers to the period in which the crankshaft rotates 720°, and the engine completes the four strokes of intake, ignition, power, and exhaust; 1 / 2 harmonic The order is the most basic simple harmonic order; at the same time, through the torque analysis of the engine, it can be known that for an engine with i cylinder number, its main harmonic order is (i×m) / 2 (same as above, m is any positive integer). Since the amplitude of each harmonic decreases rapidly with the increase of the harmonic, ideally, for an en...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to address the defects of existing engine speed measurement methods, and propose an engine speed measurement method using the four-point energy center of gravity correction method to solve the problem that the engine speed cannot be measured when the number of engine cylinders cannot be predicted, and the test Better speed versatility, high noise resistance, accurate and reliable results

Images