Bosch Pressure Limiting Valve

1.Product Introduction

The Bosch pressure limiting valve is a component used in fuel injection systems to regulate and control the fuel pressure within the system. It is designed to maintain a constant pressure at the fuel injectors, ensuring optimal fuel delivery to the engine.

The pressure limiter valve is typically located in the fuel rail, which is a pipe or rail that supplies fuel to the injectors. Its primary function is to limit the maximum fuel pressure within the system, preventing it from exceeding a predetermined threshold. This is important because excessive fuel pressure can lead to poor fuel atomization, fuel leakage, or damage to the fuel injectors.

The pressure limiter valve operates by using a spring-loaded mechanism and a diaphragm. As fuel pressure increases, it pushes against the diaphragm, compressing the spring and causing the valve to open. Once the pressure reaches the predetermined limit, the valve begins to restrict the flow of fuel, maintaining a steady pressure.

The pressure limiter valve is crucial for maintaining fuel system performance and ensuring proper combustion in the engine. By regulating the fuel pressure, it helps achieve consistent fuel atomization, which is essential for efficient combustion and optimal engine power output. It also protects the fuel injectors from potential damage caused by excessive pressure.

There are two main types of common rail pressure limiting valves from Bosch: PLV2 and PLV4.

a.How to work of PLV2

Under normal operating conditions, the common rail pressure limiting valve is closed without fuel leakage, and the common rail pressure limiting valve will only open actively or passively when a fault occurs.

First, the first stage piston is opened, the oil pressure in the oil rail drops until the secondary piston opens, and the balance between the rail pressure and the discharge flow is reached. The rail pressure is stabilized at a lower pressure and enters the limp home mode.

b.How to work of PLV4

Under normal operating conditions, the common rail pressure limiting valve is closed without fuel leakage, and the common rail pressure limiting valve will only open actively or passively when a fault occurs.

When a fault occurs, the piston moves up and down, and the flow cross section of the piston changes accordingly. The rail pressure is adjusted together with the spring until the balance between the rail pressure and the discharge flow is reached, and the rail pressure is stabilized at a lower pressure and enters the limp home mode.

2.Model of Common Rail Pressure Limiting Valve