High Quality Diesel engine Parts 6 Cyl VE diesel pump rotor head 1468376028 1 468 376 028

The main function of the fuel pump safety valve is to limit the maximum pressure at the fuel pump outlet, prevent the hydraulic system from being overloaded, and play a safety role. The safety valve opening and closing characteristics are the relationship between the safety valve opening pressure, closing pressure and the pressure when the safety valve reaches the nominal flow rate. It is an important static performance of the safety valve. It is required that the system pressure should be maintained as constant as possible after the safety valve is opened, and the closing pressure should be as consistent as possible. The opening pressure is equal, but in fact it is impossible. We can only try to ensure that the pressure difference under different flow rates is as small as possible. It is generally required that the opening pressure of the safety valve is not less than 95% of the maximum set pressure, and the closing pressure is not less than 90% of the maximum set pressure. The opening and closing characteristics of a certain fuel pump safety valve do not meet the requirements. The fuel pump safety valve is a two-stage safety valve with a pilot stage, which is mainly composed of a main valve, a pilot valve, a main valve spring and a pilot valve pressure regulating spring. When the pressure behind the fuel pump reaches the pre-pressure of the pressure regulating spring of the pilot valve, the pilot valve opens and the main valve spring chamber is passed to low pressure. Therefore, the pressure difference between the front and rear of the main valve increases. The main valve opens and releases the fuel after the pump into the diesel return chamber, reducing the pressure after the diesel pump ensures the safety of the system, that is, the opening and closing of the main valve is controlled by the pilot valve. Opening the main valve to drain diesel reduces the pressure after the pump and prevents the system from overloading.