Ship management personnel are very important for the ma […]
Ship management personnel are very important for the maintenance and management of diesel engines. Only by fully understanding the functions of the various components of the fuel system and maintaining and adjusting according to their characteristics can the high-pressure oil pump be effectively prevented from being stuck. In general, the operation management should proceed from the viewpoint of keeping the high-pressure oil pumping parts evenly heated.
The common fuel return valve is just a normal stop check valve, which acts as a fuel check, but some diesel engine fuel return outlets are provided with constant pressure valves. When the constant pressure valve is working at the set pressure, it is constant. The oil inlet of the pressure valve is open, so that the oil pressure and the spring thrust acting on the variable piston are equal, and the variable piston balance works at a certain position.
If the diesel engine load is increased, the oil return pressure rises, and the pressure difference acting on the variable piston causes the variable piston to move, and the flow rate of the valve increases until the pressure drops to the set constant pressure, and the variable piston returns to the equilibrium position. Therefore, the fuel inlet pressure recommended by the main engine supplier can be obtained by adjusting the spring preload on the constant pressure valve body as needed.
If the constant pressure valve is operated from high load to stop after the high pressure oil pump is running, if the opening of the constant pressure valve is not adjusted in time, when the ship is in the stop state, the high pressure oil pump will not be cooled by the effective circulation of the fuel, and will gradually cool down. When it is put into operation again, the high-temperature fuel suddenly enters the already-cooled high-pressure oil pump. Once the plunger and the sleeve are heated unevenly, the expansion speed will be inconsistent. At this time, it is inevitable that the oil pump will die.
Temperature and viscosity control during light and heavy oil conversion and heavy oil conversion is also very important. Avoid mixing oil and try to maintain oil stability. The recommended values of the viscosity and temperature of the different fuels are different. The hysteresis of the viscosity meter and the hysteresis of the temperature control system often cause the viscosity of the machine to be improperly pulled and the plunger is pulled, and the metal particles that are ground will continue. Pulling the plunger, the pull marks caused by such reasons are mostly concentrated in the lower part of the plunger.