The role and working principle of automotive high pressure fuel pump

What is the role of the high pressure fuel pump?

The high pressure fuel pump oil is exported into the oil cooler, and the oil cooler comes out and then enters the oil filter. After coming out of the oil filter, it is divided into two ways. After decompression, the lubricating oil is supplied, and all the way becomes the control oil. There may be one or two accumulators in the oil circuit.

Its function is to improve fuel pressure, high pressure injection to achieve atomization effect, the main purpose of high pressure fuel pump is as a power source for hydraulic devices such as jacks, hoes, extruders, and tying machines.

The high pressure fuel pump is the interface between the high pressure oil circuit and the low pressure oil circuit. Its function is to generate fuel pressure in the common rail by controlling the fuel output. In all cases, it is primarily responsible for providing sufficient high pressure fuel to the common rail.

The main purpose of the high pressure fuel pump is as a power source for hydraulic devices such as jacks, hoes, extruders, and tying machines. The installation sequence of the high pressure fuel pump is as follows: In the process of installing the high pressure fuel pump, in order to prevent debris from falling into the machine, all the holes of the unit should be covered. Place the unit on the foundation with the anchor bolts, and use the pair of wedge pads for calibration between the base and the foundation. Correct the concentricity of the motor shaft of the pump shaft. The deviation of the outer diameter of the coupling shaft is 0.1 mm. The clearance of the plane of the two couplings should be 2~4 mm. (The small pump takes a small value) The gap should be even and the deviation is allowed. 0.3 mm.

How high pressure fuel pumps work?

1. oil absorption stroke

During the oil suction process, the oil suction is provided by the downward direction of the pump piston, and the oil inlet valve is opened, and the fuel is sucked into the pump chamber. In the last 1/3 of the stroke of the pump piston, the fuel pressure regulating valve is energized, so that the oil inlet valve is still open for oil return when the pump piston moves upward.

2. oil return stroke

In order to control the actual fuel supply, the inlet valve is still open at the beginning of the upward movement of the pump piston, and the excess fuel is pushed back to the low pressure end by the pump piston. The role of the retarder is to absorb the pressure fluctuations generated during this process.

3. pump stroke

At the beginning of the pumping stroke, the fuel pressure regulating valve is de-energized, so that the inlet valve is closed under the action of the increased pressure in the pump chamber and the closing spring in the valve.

The pump piston moves up to generate pressure in the pump chamber. When the pressure exceeds the pressure in the rail, the outlet valve is opened and the fuel is pumped into the fuel rail.