What is a Pilot Operated Solenoid Valve and How Does it Work

What is a pilot operated solenoid valve?

Pilot operated solenoid valve is a device used to control the flow of fluid (liquid or gas), which controls the opening and closing of the valve through electromagnetic force. Compared with direct-control solenoid valves, pilot-operated solenoid valves utilize a more sophisticated control method that allows for more reliable control under high differential pressure.

Pilot operated solenoid valves usually consist of two main parts: the main valve and the pilot valve. The main valve is responsible for controlling the main passage of fluid, while the pilot valve is responsible for controlling the opening and closing of the main valve. When the solenoid valve receives a control signal, the solenoid coil generates an electromagnetic force that causes the position of the pilot valve to change. This change in position causes the spool of the pilot valve to move, thus changing the flow state of the main valve passage. This way makes the pilot operated solenoid valve able to realize accurate control under large pressure difference.

Pilot operated solenoid valves have a wide range of applications in construction machinery, especially in hydraulic systems. They are commonly used to control the movement of hydraulic cylinders, regulate the pressure and flow of hydraulic systems, and realize complex motion control. For example, the hydraulic arm of excavator, the movement control of bucket rod and bucket head, as well as the lifting and telescopic operation of crane may involve the application of pilot operated solenoid valves, so pilot operated solenoid valves is a very important part in diesel engine parts.

Pilot operated solenoid valves offer the following advantages over direct control solenoid valves:

High differential pressure control: Pilot operated solenoid valves are suitable for control in high differential pressure situations, enabling more consistent and accurate flow control.

Fast Response: Pilot-operated solenoid valves have a faster response time, allowing for quick adjustments in flow and pressure, making them suitable for conditions that require rapid changes.

Precision Control: Pilot-operated solenoid valves allow for precise flow and pressure control, making them ideal for applications that require accurate operation.

Energy Savings: Pilot operated solenoid valves can reduce energy consumption in some applications due to their ability to operate at high differential pressures.

How does a pilot operated solenoid valve work?

The core idea of pilot operated diesel solenoid valve is to control the movement of the valve by electromagnetic force, so as to regulate the flow and pressure of the fluid. It consists of two main parts: the main valve and the pilot valve. The main valve controls the main passage of the fluid, while the pilot valve controls the opening and closing of the main valve. This design allows pilot operated solenoid valves to achieve more accurate and reliable fluid control under high differential pressure and high flow rates.

The specific workflow is as follows:

1.Signal Input: When the system needs to adjust the fluid flow, the starter motor is turned on and other components start to operate after a control signal is sent to the solenoid coil of the pilot operated solenoid valve.

2.Electromagnetic Force Generation: When the solenoid coil receives the signal, it generates an electromagnetic force that affects the position of the pilot valve. The magnitude and direction of the electromagnetic force depends on the characteristics of the signal.

3.Pilot Valve Control: A change in the position of the pilot valve affects the position of the pilot valve spool, which changes the flow condition of the main valve passage. If the pilot valve is open, the main valve passage will also open, allowing fluid to pass. Conversely, if the pilot valve is closed, the main valve passage will also be closed, thus preventing the flow of fluid.

4.Main Valve Control: The opening or closing of the main valve passage determines whether or not fluid can pass through the main valve passage. This further regulates the flow and pressure of the entire system.