Application of vibration signals in the diagnosis of combustion engines - exploitation practices

Changes in operating properties of the internal combustion engine, for various reasons, may manifest themselves with similar symptoms. An example is the drop in engine power, which may be caused by malfunctioning of the system such as power supply, or excessive wear geometric kinematic pairs as the piston-crankshaft. Identification of the causes of malfunction is the basis for carrying out corrective action. In practice, the workshop frequent disability are different manifestations of the drive units having identical symptoms. An alternative to iterative repair methods is the introduction of diagnostic tools that will help identify causes of failure, without having to remove the individual motor units. These provisions comply with the method of vibration analysis. The vibration signals provide information about the technical condition of the object. The paper presents examples of applying the methods of vibration in the identification of changes in the technical condition of the engine, which confirm their usefulness in identifying sources of failure. During the process of investigations, time courses of vibration accelerations were recorded with piezoelectric transducer mounted at half height of the first cylinder, perpendicular to its axis. The worked out method is based on vibration signals recorded at engine operation. The dominant amplitude components of time courses are strongly connected with air- fuel mixture ignition as well as with kinetic pairs of the engine.