engleski

Spectrum Analysis Technique in Road Vehicles Diagnostics

This work present the possibility of diagnosing the cylinder-piston assembly of engines based on the analysis of the vibration signal. The basis of this method is to determine the condition of the assemblies and the engine as a whole without disassembling. One of the basic parameters for determining the technical condition of the cylinder-piston assembly is the clearance between the piston and the cylinder. Along with other parameters, the clearance has extreme significance because its change affects directly the irregularities in the operation of the assemblies and the engine as a whole. By increasing the operating clearance, which is precisely defined by design, the technical condition and the operatiting capacities of the assemblies and the engine as a whole will change. The cylinder wear increses the operatating clearance. The cylinder wear-increse of the operatating clearance, one of the basic parameters for diagnosing technical condition. It is almost impossible to determine any rules regarding cylinder wear, but it is possible, based on experiment, to determine the symptoms which indicate the engine condition. One of the symptoms is the change in vibrations. By processing the vibrations acceleration measured on the cylinder, and by more precise usage of spectral analysis, it is possible to determine the spectral components the spectral density of the vibrations potential. The increse of the spectral components amplitude is the consequence of the increasing clearance between the cylinder and the piston. For some spectral components this rule is linear and for the other it is non-linear.

Cylinder-piston; Diagnostics; Engine; Vibration Signal

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