2025 Volume 60 Issue 3 Pages 353-359
We are focusing on methods for measuring and monitoring engine and its component conditions using vibration sensors installed around the cylinders of marine diesel engines. Measurement targets include exhaust valve motion, fuel injection timing, ignition timing and maximum combustion pressure. In this study, vibration characteristics of a low-speed two-stroke marine diesel engine was investigated during operations of exhaust valve and fuel injection valve. Vibrations of the engine were measured by operating the exhaust valve or fuel injection valve when the engine was stopped. As a result of experiments, it was found that the timing at which the exhaust valve closes and the start and end of fuel injection from the fuel injection valve can be detected using vibration measurement signals. Furthermore, the fuel oil pressure rise in fuel injection pipe can be detected separately from vibration signal of the injection start timing by FFT analysis.
