Experimental Research On Monitoring Wear Conditions Of Main Moving Parts For Diesel Engine

The development of diesel engines goes ahead with lightweight, integrationand intellectualization. Along with the thermal load and the mechanical load ofdiesel engine increases, the requirements of the safety and the reliability of dieselengine also increase respectively. The modern diesel engines have their complexstructures and hard working conditions. If a fault occurs in diesel engine, it not onlyaffects the heat efficiency, but also seriou damage occure in diesel engine. So, it isimportantly significent of researching on the monitoring and the diagnosingmethods, and developing the online monitoring systems for diesel engine in order toprevent the occurrence of the faults, to improve the heat efficiency and to increasethe reliability of diesel engine. In the thesis, marine diesel engine selected as theresearch object, the wear faults of the piston ring, the cylinder, and the main bearingwere simulated,and the corresponding experimental researches on monitoring anddiagnosis technology were realized. The main contents are as follows:6DK20diesel engine and4120SD diesel engine are selected as the researchobjects in the thesis, the wear faults simulated of the piston rings, the cylinders, andthe main bearings are experimented respectively. The main conclusions are asfollows:1. The methods of the vibration monitoring for the diesel engine were analyzedin the thesis. The monitoring principles of the wear conditions of the piston rings,the cylinders and the main bearings are elaborated, the theoretical basis isestablished for guiding the fault experiment simulatd.2.The wear faults of the main bearing was simulated on4120SD diesel engine.The temperature of the lower bearing cap is measured and analyzed; the featureparameters are extracted; the fault diagnoses rule is obtained through the analysis ofresults.3.The wear faults of the piston ring and the cylinder are simulated on6DK-20diesel engine.The cylinder pressure signals, Top Dead Center（TDC）signals, and thevibration signals on the surface of the diesel engine are measured; the surfacevibration signals of the diesel engine on combustion section are analyzed; the feature parameters of the vibration signals are extracted; the rule between the featureparameters and the faults is obtained.