1. Partition plunger chamber and high-pressure oil pipe: When the oil outlet valve is not supplying oil, it can partition the plunger chamber and high-pressure oil pipe to prevent the fuel in the high-pressure oil pipe from being sucked back into the oil pump chamber.
2. Maintain residual pressure: The fuel outlet valve can control a certain residual pressure in the high-pressure fuel pipe, so that the fuel pressure in the high-pressure fuel pipe can quickly increase during the next fuel injection.
3. Quickly reduce oil pressure: At the end of fuel supply by the fuel injection pump, the oil outlet valve can quickly reduce the oil pressure in the high-pressure fuel pipe, ensuring a crisp and clean fuel cut-off and eliminating the dripping phenomenon of the fuel injector.
The working principle of the oil outlet valve:
The oil outlet valve is tightly fitted with the valve seat on its upper conical surface through the action of spring pressure. After the plunger presses the oil, the oil outlet valve opens from the seat surface and fuel enters the high-pressure fuel pipe. After the oil supply stops, the oil outlet valve descends. When the control edge of the valve completely closes the side oil hole, the return oil passage is cut off, and the unloading effect of the oil outlet valve begins until it is seated, and the unloading effect ends.
Classification and structure of oil outlet valves:
There are mainly two types of oil outlet valves: equal volume and non equal volume. The equal volume oil outlet valve is widely used, and its working principle is to achieve fuel inlet and outlet and unloading through the guide holes of the cylindrical unloading flange and valve seat. Non constant volume oil outlet valves achieve rapid pressure reduction in high-pressure oil pipes through the cooperation of pressure reducing rings and valve seats.
