A common rail injector control valve

Abstract

The invention discloses a control valve for a common-rail oil injector. According to the control valve, when a control piston ascends and descends, a high-pressure oil cavity communicates with a low-pressure oil passage through an oil cavity B, a throttling ring belt between a sealing ring surface and the top plane of the control piston, a throttling groove in the sealing ring surface and an oil cavity A, wherein the oil cavity A and the oil cavity B in the oil passage are connected in series; in the ascending process of the control piston, the throttling effect of the throttling ring belt canbe continuously increased, the leakage amount can be effectively decreased, meanwhile, the flow ratio of an oil outlet quantity hole to an oil inlet quantity hole can be larger, the time when the control piston ascends can be earlier, and the oil spraying delay can be reduced; and after the control piston lift reaches the maximum value, the oil cavity A and the oil cavity B are connected throughthe throttling groove only, the flowing resistance can be improved, the leakage amount can be decreased, the oil cavity B can be kept higher pressure, when an electromagnetic valve is powered off, thepressure of a control cavity can be restored faster, the oil injection delay of the oil injector can be reduced, meanwhile, the closing delay can be reduced, and the oil injection sensitivity of theoil injector can be improved.

Description

technical field [0001] The invention belongs to the field of fuel injection systems of internal combustion engines, and in particular relates to a control valve of a common rail fuel injector. Background technique [0002] From the working principle of the common rail injector, it can be seen that the movement of the armature is controlled by the solenoid valve to control the change of the fuel pressure in the control chamber, so as to control the force of the pressure difference between the upper and lower pistons, and realize the control of fuel injection and seating of the control piston. And the control chamber has an oil inlet orifice and an oil outlet orifice, the oil inlet orifice is connected to the high pressure oil passage, and the oil outlet orifice is connected to the low pressure oil passage, such as patents CN102282354A, CN201210199068.8, CN200820014041. 6. [0003] During the fuel injection process, both the inlet and outlet orifices are open, and the high-pr...

AI Technical Summary

Problems solved by technology

With the increase of the fuel injection pressure of the common rail system, the leakage of the fuel injector will increase significantly, which will cause the power loss of the common rail system to be obvious, the efficiency will decrease, and the economy of the fuel system will be reduced

At the same time, more high-pressure fuel leaks into the low-pressure oil circuit, which will lead to a higher temperature of the low-pressure oil circuit in the injector, which will affect the stability and reliability of the injector, making it difficult to increase the injection pressure.

[0004] In addition, in order to reduce the closing delay of the fuel injector in the design of the fuel injector, the flow rate of the fuel outlet hole and the oil inlet hole of the fuel injector should not be larger than the designed one.

This causes the fuel pressure in the control chamber to decrease slowly, resulting in a slow decrease in the fuel pressure in the control chamber at the beginning of fuel injection, and a longer delay in opening the injector, resulting in poor fuel injection sensitivity of the injector , which limits the improvement of the injector's multiple injection capability

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