Introduction of High Pressure Common Rail Direct Injection Diesel Engine

F-DIESEL FIE SYSTEM 12/18/2020 3:35:30 AM

[Key Words] 20201218-Introduction of High Pressure Common Rail Direct Injection Diesel Engin Piezo injector Diesel common rail pump DCP Built-in transfer pump ITP Volume control valve VCV High pressure pump HPP

Piezo injector

Piezo injectors have extremely fast and precise fuel distribution. The response time of the Piezo injector is 4 times that of the original system, allowing for shorter and more variable distance injections between pre-injection and main injection.

Due to the possibility of obtaining the necessary trigger energy through energy recovery, the necessary trigger energy will be considerably reduced. In addition, through simple electrical control, it can tolerate larger electromagnetic and basically reduce induction errors.

Piezo injectors are installed on the fuel rail to inject fuel into the combustion chamber. The injection volume per stroke is composed of the pre-injection volume and the main injection volume. This stratified injection softens the combustion process of the diesel engine. Due to the configuration of the Piezo injector, it has an extremely fast response speed (time). Therefore, the amount and dosage of fuel injected can be controlled very accurately, and an excellent cycle is ensured.

The injector is controlled by the engine control unit (ECU). Compared with the previous system, the Piezo ejector requires a relatively small trigger energy, which can be obtained through possible energy recovery.

Note: When the engine is working, connect the harness connector to the engine control device, and the injector must be connected reliably, otherwise there is a danger of engine damage.

During maintenance work, the injector should not be disassembled. Each piece must not be loosened or not tightened, otherwise it will cause damage to the injector.

Diesel common rail pump DCP

The diesel common rail pump consists of the following components arranged in a single casing:

Built-in transfer pump ITP

The function of the built-in vane pump is to pump the fuel from the fuel tank through the fuel filter and supply it to the high-pressure fuel pump with diesel. In addition, there is the purpose of lubricating the high-pressure oil pump.

The diesel common rail pump DCP is the demand control center. The cam disc drives the plunger pump with three displacement devices with a difference of 120°. The DCP provides the volume flow to ensure the normal high pressure of the fuel rail. It also provides the fuel volume and the fuel pressure in the DCP necessary for the injector under all operating conditions of the engine.

The complete built-in transfer pump ITP of diesel in the fuel tank is drawn out through the fuel filter. Fuel is also sent to the lubrication valve and volume control valve. The pre-pressure control valve, which is located in parallel in the fuel supply pump, opens when the volume control valve is closed, allowing the fuel to reach the suction side of the fuel pump again. The fuel passes through the lubrication valve to the pump, and from there to the fuel return pipe.

The volume control valve is controlled by the engine control device and measures the amount of fuel delivered to the high-pressure element and at the same time to the high-pressure pump HPP.

The high-pressure output ports of the three pump elements will be recombined and delivered to the high-pressure outlet of the DCP and the high-pressure control valve. The fuel quantity from the volume control valve to the high-pressure outlet, while ensuring the pressure in the fuel rail, is located between the high-pressure passage and the oil return line.

Volume control valve VCV

The volume control valve controls the fuel flow ratio input to the high-pressure pump and ensures accurate input to the high-pressure pump according to requirements. The volume control valve VCV regulates the delivery of fuel from the built-in transfer pump to the high-pressure pump element. The built-in transfer pump is installed in the diesel common rail pump.

Then, on the low-pressure side of the system, the amount of fuel delivered by the high-pressure pump HPP can be adjusted according to the requirements of the engine. The suction function of the high-pressure pump can be reduced, thereby improving the efficiency of the engine. The volume control valve VCV is directly screwed to the diesel common rail pump DCP.

Note: If maintenance is necessary, the volume control valve must not be removed from the diesel common rail pump DCP.

High pressure pump HPP

The high-pressure pump is a plunger pump driven by a 3-cylinder cam disc to provide the necessary system pressure for the fuel rail.

Pressure control valve PCV

The pressure control valve controls the outlet pressure of the high-pressure pump.

The pressure control valve PCV controls the fuel pressure of the diesel common rail pump DCP at the high-pressure outlet and the fuel rail. In addition, the pressure control valve attenuates pressure fluctuations that occur during the fuel supply period of the diesel rail pump and during injection.

The pressure control valve is controlled by the ECU device, so that there is an optimal pressure in the fuel rail under each operating condition of the engine. The pressure control valve is directly flanged to the diesel common rail pump DCP.

High-pressure pipeline

The high-pressure fuel pipe connects the diesel common rail pump and the fuel rail, the fuel rail and the injector.

Note: When the high-pressure oil pipe must be repaired, the high-pressure oil pipe is always replaced because the seal ring has been crimped during the tightening process.

Our Bosch Piezo Valve recommend for you: F00VX40042, F00VX20054, F00VX20017

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