A Guide to Common Rail System
Time:2023-02-08 Read:622
Reading guide: What is Common Rail System and how does it work? Learn more now.

What is Common Rail System?

Common Rail System is a diesel fuel injection system that uses electronically controlled injection. It was originally developed by Robert Bosch GmbH in the late 1990s. It is composed of a fuel pump, rail, injectors, and electronic control unit (ECU). The ECU controls the timing and quantity of fuel injection and is programmed to maximize efficiency and minimize exhaust emissions. Common Rail Systems provide more precise fuel delivery than traditional diesel fuel systems, resulting in more consistent engine performance and lower exhaust emissions. They are used in many modern diesel engines, ranging from passenger cars to heavy-duty commercial vehicles.

Working principle of high-pressure common rail

(1) The high-pressure common rail system uses a large-volume common-rail cavity to accumulate the high-pressure fuel output by the oil pump, eliminate pressure fluctuations in the fuel, and then deliver it to each injector. By controlling the electromagnetic on the injector The valve enables the initiation and termination of injection.

The high-pressure common rail system is mainly composed of an electronic control unit, a high-pressure oil pump, a pressure accumulator (common rail pipe), an electronically controlled fuel injector, and various sensors. The low-pressure fuel pump feeds the fuel into the high-pressure fuel pump, and the high-pressure fuel pump pressurizes the fuel into the high-pressure fuel rail (accumulator), and the pressure in the high-pressure fuel rail is adjusted by the electronic control unit according to the fuel rail pressure measured by the fuel rail pressure sensor and needs The fuel in the high-pressure fuel rail passes through the high-pressure fuel pipe. According to the operating state of the machine, the electronic control unit determines the appropriate fuel injection timing and fuel injection duration. The electronic fuel injector controlled by electro-hydraulic injects fuel into the cylinder.

Working principle of high-pressure common rail

The fuel injection pressure is the common rail pressure, and the characteristics of the common rail pressure are as follows.

(1)The common rail pressure can be controlled by the high-pressure oil supply pump according to the common rail pressure command issued by the ECU.

(2)Common rail pressure is closed-loop controlled.

Arrangement on the diesel engine of the common rail system


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