Controllable needle valve lift electronic fuel injector

Abstract

The invention provides a controllable needle valve lift electronic fuel injector which comprises a fuel injector high-pressure oil path, a control cavity, a control cavity oil inlet channel, a control cavity oil outlet channel, a fuel spray nozzle and a fuel spray nozzle needle valve, wherein the control cavity oil inlet channel and the control cavity oil outlet channel are communicated with the control cavity. The fuel injector high-pressure oil path is communicated with the control cavity oil inlet channel and the fuel spray nozzle at the same time. The fuel spray nozzle needle valve is connected with the control cavity and the fuel spray nozzle. The control cavity oil outlet channel is communicated with a fuel injector low-pressure oil path. A variable stroke executor achieving the stop function on the stroke of the fuel spray nozzle needle valve is added in the control cavity. The variable stroke executor is added in the control cavity, the fuel spray nozzle needle valve which is started and moves is stopped under different engine work conditions, active control over the motion rule of the fuel spray nozzle needle valve is achieved, and fuel injection stability and consistency are improved. The machining size and precision of the fuel spray nozzle needle valve, the control cavity, a control cavity oil inlet metering hole, a control cavity oil outlet metering hole and other parts related to the work of the needle valve can be improved, and therefore manufacturing cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of electronically controlled fuel injectors, in particular to a controllable needle valve lift electronically controlled fuel injector. Background technique [0002] Electronically controlled injector is one of the most critical components in the common rail system, and it is also the most difficult component to design and process. The ECU controls the opening and closing of the solenoid valve to inject the fuel in the high-pressure rail into the combustion chamber at the optimum injection timing, quantity and rate. [0003] In the prior art, a general electronically controlled fuel injector uses a two-position two-way solenoid valve and a two-position three-way solenoid valve to control the fuel injection process. like figure 1 As shown, the feature of this structure is that both the opening movement and the closing movement of the needle valve of the fuel injection nozzle are affected by the matching bet...

AI Technical Summary

Problems solved by technology

[0004] During the multi-cycle fuel injection process of a single fuel injector, affected by various factors, the pressure in the control chamber and the fuel injector is out of control, resulting in uncontrolled movement of the needle valve of the fuel injector, which eventually leads to multiple The cycle fuel injection performance is unstable, the fuel injection duration is poor, and the fuel injection volume is poor; in addition, machining errors are inevitable during the fuel injector manufacturing process, and the control cavity and fuel injection between the individual injectors caused by machining errors The pressure difference in the nozzle leads to poor injection consistency among multiple injectors

[0005] The existing improvement idea is: in order to improve the stability of multi-cycle injection of a single injector and the consistency of injection between multiple injectors, it is necessary to take a lot of optimization and matching work on the injector and the fuel supply system, through Improve the machining accuracy of the parts of the injector, which will greatly increase the cost of research and development time and funds

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