Analysis of injector spring damage to determine maintenance management diesel engine at PLTD Ampenan

Abstract

The injector spring in cylinder #2 of a diesel engine in Ampenan PLTD which is operated by PT. X damaged. After visual inspection, a helical spring of the injector was broken. The spring broke in the lower part, in winding 2 of the spring. Before the damage was known, with a diesel load of 1100 kW, the exhaust manifold the cylinder #2 was glowing. Root cause analysis of the broken spiral spring was carried out by visual observation, metallography, and maintenance management analysis. Results indicated that the damaged of the broken injector spring based on visual observation of the helical spring was due to alternating bending loads. The fracture angle was at 450 indicated a bending load. Benchmark shows the beginning of the fault, followed by a static fracture. Metallographic and microstructure examination results found too many sulphides possibly making the formation of the onset of the fatigue. To minimize the damage, the sulphide amount of the spring must be reduced, and the spring injector material must be redesigned. Maintenance management must check every time the new spring is received and the cam lobe dimensions and wear of the roller must be lifted every 1000 hours.