Diesel engine fuel injection monitoring using acoustic measurements and independent component analysis

Abstract

Air-borne acoustic based condition monitoring is a promising technique because of its intrusive nature and the rich information contained within the acoustic signals including all sources. However, the back ground noise contamination, interferences and the number of Internal Combustion Engine ICE vibro-acoustic sources preclude the extraction of condition information using this technique. Therefore, lower energy events; such as fuel injection, are buried within higher energy events and/or corrupted by background noise.This work firstly investigates diesel engine air-borne acoustic signals characteristics and the benefits of joint time-frequency domain analysis. Secondly, the air-borne acoustic signals in the vicinity of injector head were recorded using three microphones around the fuel injector (120° apart from each other) and an Independent Component Analysis (ICA) based scheme was developed to decompose these acoustic signals. The fuel injection process characteristics were thus revealed in the timefrequency domain using Wigner-Ville distribution (WVD) technique. Consequently the energy levels around the injection process period between 11 and 5 degrees before the top dead center and of frequency band 9 to 15 kHz are calculated. The developed technique was validated by simulated signals and empirical measurements at different injection pressure levels from 250 to 210 bars in steps of 10 bars. The recovered energy levels in the tested conditions were found to be affected by the injector pressure settings.

Characterisation of acoustic emissions for the frictional effect in engines using wavelets based multi-resolution analysis

“…In particular, the valve events from air intake exhaust and fuel injections can cause strong impacts. Hence, a number of acoustic emission based studies have been carried out to detect the faults of valve opening and closing impacts [4] [12] and needle impacts of injection [13] [14].…”

Automobile engine condition monitoring using sound emission

“…Therefore, the development of an automobile engine condition monitoring system capable of providing early warning about the engine's state of operation is needed. Both the vibration [1,2] and sound signals [3,4] have been widely used for fault diagnosis. Xian et al [2] used a wavelet packet transform (WPT) for feature extraction in their reported work; however, the authors were targeting a vibration frequency band less affected by environment noise compared to sound.…”

The Use of Denoising and Analysis of the Acoustic Signal Entropy in Diagnosing Engine Valve Clearance

“…Papers [5][6][7][8][9] present the application of the measurements of combustion engine noise and vibration in the analysis of damage to the injection system. This type of research was also conducted by the authors of [10], which analysed various types of damage to fuel injectors as well as damage to one or two injectors.…”