Characteristic study of Principal parts in High pressure Fuel system of the Common rail diesel engine

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KeunSang Lee, HaengMuk Cho


In the past, a lot of research on internal combustion engines performance and fuel efficiency has been carried out. The most ideal goal was to increase the engine power and lower the fuel consumption rate, but in general, the higher the power, the higher the fuel consumption rate. It was one of the important tasks to have complete combustion the fuel that was injected into the combustion chamber while reducing the fuel consumption rate at the same horsepower. Which would reduce the toxic exhaust gas emitted to the atmosphere. In addition, as the engine of the vehicle ages, these air pollutants become more severe.  There are the main parts of Common Rail Diesel Engine such as High-Pressure pump, common rail, rail pressure sensor and EFC actuator which plays an important role in making and controlling high pressure of the fuel. When these parts fail, there will be make problem in controlling the fuel at high pressure under engine is running. This leads to incomplete combustion and causes toxic gases to be emitted into the atmosphere.

In this paper, it was confirmed that the HP Pump of Common Rail Diesel Engine does not have a big problem in engine cranking even when the pumping capacity is reduced by 1/3. In addition, when signal of the fuel pressure sensor was not input to the ECU, the ECU displays the default value of 460 bar, and it was confirmed that engine does not rise more than 2,900 RPM even when the engine is accelerated in this state, which is call the fail-safe mode controlling. It was also confirmed that the high-pressure fuel in the fuel line in the common rail drops to 0 bar within 4-5 seconds without continuing to maintain the high pressure when the engine is stopped

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