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The basic knowledge of HP4
Structure and characteristics
1) HP4 pump basic structure and HP3 similar to the composition is the same with the HP3, by the pump unit (eccentric cam + ring cam + plunger), oil control valve SCV, oil temperature sensor and pre-supply pump composition. Unlike HP3, HP4 has three plungers.
2) Because there are three plungers, the three plungers are arranged on the Common Rail outside of the annular cam every 120 degrees. In addition, the oil supply capacity is HP times 1.5 times.
3) As with HP3, the oil supply is also controlled by the oil suction control valve SCV.
2. Each component function
HP4 parts and functions and HP3 basically the same, the following is only concerned with HP3 is not the same place.
1) HP4 drive shaft eccentric cam is equipped with a triangular ring, three plungers were 120 degrees angular distribution in the lateral triangle. Similar to the arrangement of Bosch CP3.3 and CP1H.
2) The circular motion of the camshaft drives the eccentric cam eccentric rotation Common Rail Injector , and the triangular ring follows the three plunger reciprocating motion to achieve the pump function (the triangular ring itself does not rotate).
4. Working principle
1) Fuel flow
The pre-fuel pump draws fuel from the tank to the oil suction control valve SCV, while the regulator valve regulates the oil pressure below a certain value. The amount of oil from the pre-supply pump has been adjusted by the oil-absorbing control valve SCV, which is then fed into the pump unit, which pumps the compressed high-pressure fuel into the oil rail.
2) work process
The pump oil is controlled by the oil suction control valve SCV. As with HP3, the opening of the valve is controlled by Common Rail Shim controlling the duty cycle. The only difference from HP3 is the shape of the pump unit. The work process, principle and control are basically the same. With