How do you release pressure on common rail?
You don’t need to disconnect the fuel rail to pull the motor, just unbolt it from the manifold and set it to the side. You can bleed it by slowly releasing pressure via the Schrader valve under the green cap on the fuel line. Wrap a rag around it as you will get fuel spray until the pressure is released.
What is high pressure common rail?
In common rail systems, a high-pressure pump stores a reservoir of fuel at high pressure — up to and above 2,000 bars (200 MPa; 29,000 psi).
What pressure does a common rail diesel run at?
29,000 PSI
Common rail direct fuel injection is a direct fuel injection system for petrol and diesel engines. On diesel engines, it features a high-pressure (2,000 BAR – 29,000 PSI) fuel rail feeding individual solenoid valves, as opposed to a low-pressure fuel pump feeding unit injectors or pump nozzles.
How does a common rail relief valve work?
This can be located either on the high-pressure pump or on the common rail itself. The pressure relief valve simply allows more or less high pressure fuel to flow into the back leak system thus increasing or decreasing the fuel pressure in the rail. Excess fuel returns to the fuel tank. It’s controlled from the ECM.
Where is the pressure discharge valve fitted in CRDI system?
A pressure control valve (PCV) for controlling rail pressure can be located at one rail extremity (pump-external PCV), Figure 1, or at the pump outlet (pump-integrated PCV), Figure 2.
What is the difference between common rail and direct injection?
Simply, common rail injection sprays fuel into the port before the intake valve. Direct injection sprays fuel after the intake valve, directly into the combustion chamber. Direct injection relies on much higher fuel pressure besides. This pertains to gasoline engines.
How does a Bosch high pressure fuel pump work?
The pump camshaft is driven by belts, chains, or cogwheels and moves the pump pistons to generate the required high pressure. The fuel is delivered as required using an integrated cogwheel pump or electric fuel pump. The engine control unit enables the delivery of the required quantity of fuel.
What is the main function of the high pressure rail on a common rail diesel engine?
The high-pressure rail binds the pump and injectors together as the central hydraulic component. It stores the compressed fuel and supplies this to the injectors. Pressure pulses occur in the high-pressure rail as a result of the injection process. The stored high-pressure volume reduces these to a minimum.
How does a common rail high pressure pump work?
At engine start and for preheating the fuel when temperatures are low, the rail pressure is controlled by the PCV. To heat up the fuel quickly, the high-pressure pump delivers and compresses more fuel than is needed and the excess fuel is discharged by the PCV into the fuel return.
