Changes in fuel injection pressures and fuel spray quantity of marine diesel engines

摘要

When four-stroke diesel engines operate over long durations, it is well known that the fuel injection pressure decreases steadily, and then often followed by incomplete combustion in engine. Poor combustion in engine caused by the pressure drop is a big problem because it causes environmental pollution. However, changes in the exhaust temperature in four-stroke diesel engines occur more slowly than that in the fuel injection pressure. So, the effects of the fuel-injection-pressure drop on the exhaust gas temperature and maximum pressure do not appear in the operating data. It is difficult to grasp the combustion state from the operating data of an actual machine. This study aimed to observe and investigate carefully the phenomena that were accompanied with a drop in the fuel injection pressure.