An Objective Evaluation Method of Diesel Engine Impulse Noise

Abstract

The invention relates to the technical field of diesel engine starting, in particular to an objective evaluation method for pulse noise of a diesel engine. The method comprises the following specificsteps: 1, respectively filtering a certain sound signal by adopting 24 groups of critical frequency band filters within the range of 20-16000Hz to obtain 24 groups of sound pressure signals, calculating the time-varying characteristic loudness of each group of signals under the condition that frequency domain and time domain masking effects are considered, and finally obtaining 24 groups of characteristic loudness time sequences, called uncompressed signals for short, of the sound signal within 24 critical frequency bands; 2, dividing the pulse sound calculation and identification process intotwo parallel signal processing processes, namely a log2 compressed signal pulse relative amplitude pickup process and a non-compressed signal pulse absolute amplitude pickup process; and 3, calculating a pulse index. An objective evaluation method is provided for the pulse noise of the diesel engine, and the method not only can calculate the total impulse index of the engine noise, but also can analyze the contribution degree of the pulse indexes of critical frequency bands of the pulse noise.

Description

technical field [0001] The invention relates to the technical field of diesel engines, in particular to an objective evaluation method of diesel engine impulse noise. Background technique [0002] The internal combustion engine is prone to pulse noise (such as rattling, rattling) due to the impact of the valve system, crankshaft mechanism, high-pressure fuel injection system and other mechanisms. Even if the sound pressure level of this kind of impulsive noise is not high, it will seriously deteriorate the overall sound quality of the engine, cause the driver's displeasure, and seriously reduce the sense of vehicle quality. The overall sound pressure level of impulse noise is not large, and the frequency distribution is in the wide frequency band of 1000Hz-12000Hz, so the energy distribution is very scattered in the spectrogram. The traditional objective measurement method of impulse noise is the frequency slice sound pressure level method based on spectrum analysis. In th...

AI Technical Summary

Problems solved by technology

This frequency slice sound pressure level method is greatly affected by background noise and the selected slice interval

The conditions of use of this traditional method must be limited to the same model and the same working conditions

Different workshops often have different engine noise characteristics, and the objective indicators and subjective evaluations cannot correspond

Therefore, in the actual evaluation of impulse noise, it still can only rely on subjective evaluation

Subjective evaluation is limited by the evaluator's experience, technical ability, and psychological factors, and the subjective randomness is large and the stability is poor.

In addition, subjective evaluation is not conducive to technology accumulation and inheritance, and the project process often leads to evaluation confusion due to personnel turnover and inconsistent standards

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