Common Rail Diesel - Accumulator Injection - Sensors
The common rail system is currently the most common injection system in diesel engines. Realizing injection pressures of up to 2500 bar is no longer a problem in the 4th generation of the common rail system from Bosch. In this article I will understand the path of the fuel and go into some details of the individual components separately.
The components of the 4th generation common rail system include: the supply lines with pre-supply pump and fuel filter, the high-pressure pump, also called HP pump, with quantity control valve, the rail with lines to the injectors, the rail pressure sensor, the rail pressure control valve, the piezo injectors and the return line with filter.
The fuel is pumped from the tank by a pre-supply pump and approx. 3 bar pressure to the high-pressure pump. In this way, the fuel is filtered at least once. Arriving at the HP pump, the fuel first lubricates the area between the cam and tappet before flowing through the quantity control valve and to the high pressure chamber in the pump; This ensures that the pump does not run without lubrication. Since the quality control principle applies to the diesel engine, a so-called quantity control valve controls the amount of fuel fed to the rail. A return line is installed in front of the quantity control valve in order to discharge the excess quantity and to counteract unwanted heating of the fuel.
From the HP pump, the remaining fuel flows under high pressure to the rail, which acts as a pressure accumulator. The pressure in the rail is recorded by the rail pressure sensor and optimally adjusted by the rail pressure control valve. If the pressure is too high, the pressure control valve opens and allows fuel to flow into the return line, the pressure drops and the pressure control valve closes again. It must be mentioned here that the quantity control valve and the rail pressure control valve are both monitored by the control unit and controlled by a PWM signal. Important control variables would be the rail pressure for the rail pressure control valve or the load condition and the engine speed for the quantity control valve.
After that, the remaining amount of fuel flows through the lines into the injectors where the fuel is divided into two chambers. The fuel in one chamber is injected while the fuel in the other chamber flows into the return line. In the return, the fuel is filtered again and then flows back into the tank.
Common Rail Diesel - Accumulator Injection - Sensors
The common rail system is currently the most common injection system in diesel engines. Realizing injection pressures of up to 2500 bar is no longer a problem in the 4th generation of the common rail system from Bosch. In this article I will understand the path of the fuel and go into some details of the individual components separately.
The components of the 4th generation common rail system include: the supply lines with pre-supply pump and fuel filter, the high-pressure pump, also called HP pump, with quantity control valve, the rail with lines to the injectors, the rail pressure sensor, the rail pressure control valve, the piezo injectors and the return line with filter.
The fuel is pumped from the tank by a pre-supply pump and approx. 3 bar pressure to the high-pressure pump. In this way, the fuel is filtered at least once. Arriving at the HP pump, the fuel first lubricates the area between the cam and tappet before flowing through the quantity control valve and to the high pressure chamber in the pump; This ensures that the pump does not run without lubrication. Since the quality control principle applies to the diesel engine, a so-called quantity control valve controls the amount of fuel fed to the rail. A return line is installed in front of the quantity control valve in order to discharge the excess quantity and to counteract unwanted heating of the fuel.
From the HP pump, the remaining fuel flows under high pressure to the rail, which acts as a pressure accumulator. The pressure in the rail is recorded by the rail pressure sensor and optimally adjusted by the rail pressure control valve. If the pressure is too high, the pressure control valve opens and allows fuel to flow into the return line, the pressure drops and the pressure control valve closes again. It must be mentioned here that the quantity control valve and the rail pressure control valve are both monitored by the control unit and controlled by a PWM signal. Important control variables would be the rail pressure for the rail pressure control valve or the load condition and the engine speed for the quantity control valve.
After that, the remaining amount of fuel flows through the lines into the injectors where the fuel is divided into two chambers. The fuel in one chamber is injected while the fuel in the other chamber flows into the return line. In the return, the fuel is filtered again and then flows back into the tank.
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