1. The diagram of Bosch Fuel System reference metering valve 0928400752 with pressure relief valve

0928400752 MEASURING UNIT, HIGH-PRESSURE PUMP 0445020509

                       

Parts Catalogue  Model : RK55H / RK55HC file.pdf  download

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Tractor 4JH45 2.2 L with pump assy 129A00-51000 including metering valve 129A00-51100 0928400752

Fuel is now forced into the high-pressure chamber, which moves the pump plunger downwards (intake stroke).

If the BDC position of the pump plunger is exceeded, the inlet valve closes due to the increasing pressure in the high-pressure chamber. The fuel in the high-pressure chamber can no longer escape.

As soon as the pressure in the high-pressure chamber exceeds the pressure in the fuel rail, the outlet valve opens and the fuel is forced into the fuel rail via the high-pressure connection (delivery stroke).

The pump plunger delivers fuel until TDC is reached.

The pressure then drops so that the outlet valve closes.

As the pressure on the remaining fuel is reduced, the pump plunger moves downward.

      

Rail pressure relief valve 111 001 0020

2. The diagram of Denso Fuel Injection System

  

Diesel components from DENSO

Operation

The fuel pressure on the fuel rail is given by

Fuel rail pressure sensor. If the fuel pressure becomes

Too large, the pressure limiting valve opens,

Drain excess pressure into the fuel drain circuit.

Move

The fuel pressure limiting valve is located at

Top of fuel rail (Figure 20).

3. Pic. of Scania High-pressure pump with the metering valve 2024377

Pressure Limiter Valve location

Operation of the high-pressure common rail

Various rail assembled components are fitted on the high-pressure rail depending on the system configuration. The rail pressure sensor (RPS) installed on the high-pressure rail communicates with the control unit. The transmitted pressure values serve to regulate the system pressure and control the injectors. The pressure control valve (PCV, PCVN) sets the system pressure supplied by the control unit in the rail. The pressure limiting valve (PLV) reduces the system pressure in case of overload and thus protects the other injection components from damage.

If abnormally high pressure is generated, the pressure limiter opens to relieve the pressure. If the pressure inside the rail becomes abnormally high, the pressure limiter will work (open). Operation resumes (shutdown) after the pressure drops to a certain level. Fuel released by the pressure limiter returns to the fuel tank.

The working pressure of the pressure limiter varies with the model, the valve opening pressure is about 140-230MPa, and the valve closing pressure is about 30-50MPa.

Pressure Limiter Valve located in Engine 1KD-FTV & 2KD-FTV for Toyota Hilux/Kijang Innova

Rail

 outline

 *stores pressurized fuel (0 to 160 MPa) that has been delivered from the supply pump and distributes the fuel to each cylinder injector. A rail pressure sensor and the pressure discharge valve (low-pressure valve) are adopted in the rail.

*The rail pressure sensor (PC sensor) detects fuel pressure in the rail and sends a signal to the engine ECU, and the pressure limiter controls the excess pressure. This ensures optimum combustion and reduces combustion noise.

Reference Pressure Limiter Valve 095420-0422 with common rail 23810-0L010

Pressure Limiter

The the pressure limiter opens to release the pressure if an abnormally high pressure is generated

The Pressure limiter valve 095420-0422 Exploded View

Common rail 23810-0L010 Henshine Precision

Pressure relief valve fitted on Common rail 23810-0L010 Henshine

The common rail system consists primarily of a supply pump, rail, injectors, and engine ECU.

CRDI P.R.V(pressure relief valve) WORKING EXPLAINED

4.  The diagram of Fuel Injection System on the engine LNP Z20D1 2000CC for Opel/Chevrolet

The common rail system in LNP Z20D1 2000CC

The fuel pump 25184341 common rail system in LNP Z20D1 2000CC

Actually, there is no pressure limiting valve on this high-pressure common rail and through the cutaway in EPC catalog, we can see that the metering valve is 28233374(refer to letering) , the OEM are GM 25187791/OPEL 48 19 468 & etc. noted in our system. The following OE list is all reference with this kind “Inlet Metering Valve”. Under same egnine LNP Z20D1 2000CC, the rail pressure sensor is 9307Z528A and sensor letering is 55PP30-01 (in the following pc.)

All the information courtesied of Ningbo Henshine Precision Machinery Co., Ltd.

FLOW CONTROL VALVE 28233374 fitted on FUEL PUMP OEM 28343143

Fuel pump A6510701801-28343143 including fuel flow control valve A 651 074 00 84

Rail pressure sensor 55PP30-01 OE 9307Z528A-Henshine Precision Machinery

No pressure limiter valve on Fuel common rail 96868901 with pressure sensor 55PP30-01 - Henshine Precision Machinery

For example common rail location in Engine D4CB Euro V for Hyundai including metering valve 28233374 & rail sensor 55PP30-01

Common Rail Direct Fuel Injection is a direct fuel injection system for gasoline and diesel engines.

On diesel engines, it uses a high pressure (over 1,000 bar or 100 MPa or 15,000 psi) fuel rail to feed the individual solenoid valves instead of the low pressure fuel pump feed unit injectors (or pump nozzles). The third-generation common rail diesel engine is now equipped with piezoelectric injectors for increased precision, with fuel pressures up to 3,000 bar (300 MPa; 44,000 psi).

In common rail direct injection, the onset of combustion occurs directly in the main combustion chamber located within the cavity at the top of the piston crown. Today, CRDi technology is widely used to overcome some of the shortcomings of conventional diesel engines, especially slow, noisy and poor performance when implemented in passenger cars. CRDi technology works in conjunction with the engine ECU that takes input from various sensors to calculate precise fuel quantity and injection timing. In CRDi, the fuel system components are smarter and electrically/electronically controlled. Traditional fuel injectors are replaced by advanced electric solenoid injectors. The injectors are turned on by signals from the ECU, depending on variables such as engine speed, load, engine temperature, etc.

In a common rail system, the "common to all cylinders" fuel rail or simply the fuel distribution line is used to maintain optimal residual fuel pressure and acts as a shared fuel tank for all injectors. Fuel is continuously supplied at the pressure required for injection. In modern engines, high-pressure fuel is stored in this single line, which is then supplied to solenoid valve injectors, rather than the fuel injection pump supplying diesel fuel to the injectors in earlier designs through a separate fuel line. Components of the CRDi system. Courtesied of Ningbo Henshine Precision Machinery Co., Ltd. Pressure limiting valve production also including suction control valve, fuel flow control valve & inlet metering valve.

1. High pressure fuel pump

2. Universal fuel rail

3. Fuel injector

4. The work of the engine control unit CRDi

Pressure is created in the high pressure pump. The pump compresses the fuel at a pressure of about 1,000 bar or about 15,000 bar and then supplies the fuel to the inlet of the rail through a high pressure line. From there, the fuel is distributed to individual injectors, which inject it into the combustion chambers of the cylinders.

Production by Ningbo Henshine Precisison Machinery

6C1Q9H321AB Diesel Common Rail Denso Pressure Relief Valve Limiting Valve

Pressure limiter valve 6C1Q_9H321_AB Diesel Common Rail

Used on:

    Ford Transit MK7 2006 > 2.2 TDCI 2.4 TDCI

    Land Rover Defender 2.4

    LR006866, 1497165

*Condition:  Brand NEW

*Manufacturer Number:  6C1Q9H321AB

*Other Number:  1920NL, 1497165

    6C1Q-9H321-AB, 6C1Q9H321AB

*Brand:  HENSHINE

The pressure limiter valve is located on the fuel common rail in the fuel system with then main parts: the fuel pump & the common rail. Usually, the high-pressure pump(fuel pump) is fitted on the side of the engine.  Meanwhile,

（PRV）Pressure Relief Valve in the Common Rail System

Stores pressurized fuel (0 to 160 MPa) delivered from the fuel supply pump and distributes the fuel to each cylinder injector. Rail Pressure Sensor and Pressure Relief Valve

The guide rail adopts (low pressure valve).

RE536274 Pressure limiting valve fitted on John Deere common rail RE543322

RE536274 Pressure limiting valve for John Deere common rail RE543322

Pressure limiter valve fitted on John Deere common rail RE543322

Through compared with different engine types we can know about the position of the common rail clearly. Then, against the high-pressure fuel rail, which types the corresponding rail limiter valve will be fitted on.

N98-ND6091E engine display the common rail including rail pressure control valve

The latest developments in diesel technology have given us direct injection, common rail technology, multi-stage injection and variable geometry turbochargers.

The engine management system controls the fuel pressure produced by the high pressure pump, the precise timing of electronically controlled fuel injectors, the operation of the EGR system, and the output of the turbocharger.

Compared with the advancement of gasoline engine fuel injection and management systems, the development of diesel engines, especially engine management systems, has been relatively slow. In recent years, however, electronic diesel engine control systems have been developed to improve diesel engine efficiency and reduce exhaust emissions.

Almost all modern engines use some form of electronic engine control system. In order for a diesel engine to operate efficiently, the right amount of fuel must be injected at the right pressure and at the right time.

Even small deviations can lead to increased exhaust emissions, increased noise and increased fuel consumption. In a typical diesel engine, the injection process takes only a thousandth of a second and only a very small amount of fuel is injected.