Hot Sale Solenoid Valve 312-5620 ELECTROVALVE for Caterpillar CAT 320D

Function
The fuel pump solenoid valve is mainly used to control the working state of the fuel pump. It receives signals from the engine control unit (ECU) to accurately control the power supply circuit of the fuel pump, thereby realizing the start, stop and fuel pressure regulation of the fuel pump. When the engine starts, the fuel pump solenoid valve will open quickly, so that the fuel pump can be powered on to pump the fuel from the fuel tank, build up sufficient fuel pressure and provide a stable fuel supply for the injector. During the operation of the engine, according to the changes in the engine's operating conditions, such as load and speed, the ECU will adjust the duty cycle of the fuel pump solenoid valve in real time, and then adjust the speed of the fuel pump to accurately control the fuel pressure and flow to meet the fuel demand under different engine conditions. When the engine stops running, the fuel pump solenoid valve will cut off the power supply of the fuel pump, stop the fuel pump from working, prevent the fuel from continuing to supply, and avoid fuel leakage and waste.

Working principle
The fuel pump solenoid valve is usually composed of electromagnetic coils, valve cores, springs and other components. When the ECU sends a control signal, current passes through the electromagnetic coil to generate a magnetic field. The magnetic field force attracts the valve core to overcome the spring force to move, thereby opening or closing the power supply circuit of the fuel pump. By controlling the on-off and duty cycle of the current in the electromagnetic coil, the position of the valve core can be controlled, thereby achieving precise control of the working state of the fuel pump. For example, when the fuel pressure needs to be increased, the ECU will increase the duty cycle of the solenoid valve, so that the electromagnetic coil is powered on for a longer time, the valve core is opened more, the fuel pump gets more power supply time, the speed increases, and the fuel pressure increases; conversely, when the fuel pressure needs to be reduced, the ECU will reduce the duty cycle, the fuel pump speed decreases, and the fuel pressure decreases accordingly.

Common faults and effects
Solenoid valve coil failure: The electromagnetic coil may be damaged due to overheating, short circuit, open circuit, etc. If the coil is short-circuited or open-circuited, the solenoid valve will not work properly, and the fuel pump will not receive the correct control signal, which may cause the fuel pump to not work or work abnormally, and then the engine cannot start or there will be insufficient fuel supply, such as engine shaking, weak acceleration, etc.
Valve core stuck: Due to impurities, moisture in the fuel or wear and tear after long-term use, the valve core may become stuck. The valve core is stuck, which will cause the solenoid valve to be unable to accurately control the power supply of the fuel pump, making the working state of the fuel pump unstable, and the fuel pressure fluctuates greatly, affecting the normal operation of the engine. For example, if the valve core is stuck in the open position, the fuel pump may be in a working state all the time, resulting in excessive fuel pressure, increasing the burden on the fuel system, and even causing fuel leakage; while if the valve core is stuck in the closed position, the fuel pump will not work properly, causing the engine fuel supply to be interrupted.
Poor sealing: Aging or damage of the seal of the oil pump solenoid valve will cause fuel leakage. Fuel leakage will not only cause fuel waste, but also may cause safety hazards such as fire. At the same time, the leaked fuel will affect the normal operation of the solenoid valve, causing the solenoid coil to be damp and short-circuited, further damaging the solenoid valve.

Detection and maintenance
Detection method: Use a multimeter to detect the resistance value of the solenoid coil, compare it with the standard value, and determine whether the coil is normal. You can also use professional diagnostic equipment to read the fault code in the ECU to check whether there is any fault information related to the oil pump solenoid valve. In addition, you can also indirectly judge whether the oil pump solenoid valve is working properly by observing the pressure changes in the fuel system and the working state of the fuel pump. For example, during the start-up and operation of the engine, use a fuel pressure gauge to detect the fuel pressure. If the pressure is abnormal and the fuel pump itself and other fuel system components are excluded, it is likely that there is a problem with the fuel pump solenoid valve.
Repair measures: For solenoid coil failure, a new solenoid valve is generally required. For valve core stuck problems, you can try to clean and lubricate the solenoid valve to remove impurities and dirt. If the stuck is serious, the solenoid valve also needs to be replaced. If the fuel leak is caused by poor sealing, it is necessary to replace the seal and check the surrounding pipes and connecting parts to ensure that the entire fuel system is well sealed. After repairing or replacing the fuel pump solenoid valve, it is necessary to use professional equipment to calibrate and match it to ensure that it can communicate and work with the engine control unit normally to ensure the normal operation of the fuel system.