Micro-dynamic oil return resonance bypass type electronic fuel injector with hydraulic feedback function

Abstract

The invention aims to provide a micro-dynamic oil return resonance bypass type electronic oil injector with a hydraulic feedback function. The fuel injector comprises a fuel injector head, a fuel injector body, a flow limiting valve assembly, an electromagnetic valve assembly, a needle valve stop collar, a nozzle and a needle valve body. A pressure accumulation cavity is formed in the fuel injector body and communicates with a main oil supply hole and the flow limiting valve assembly, and the stability of the fuel injection process of all cylinders is ensured under the large fuel injection amount condition. The flow limiting valve assembly is arranged under the pressure accumulation cavity, and abnormal fuel injection is stopped from continuing. A resonance through hole and a resonance throttling hole are machined in the bottom of the flow limiting valve assembly, and fluctuation of fuel passing through the flow limiting valve assembly is reduced through a wave superposition principle. A control sliding block is arranged in a control cavity and makes contact with an intermediate block, and the functions of decreasing the fuel injection rate at the early injection stage and accelerating needle valve seating response are achieved. The effect is further strengthened through a hydraulic feedback circuit machined in the intermediate block. Static pressure difference in the fuel injector is avoided, the characteristic that the fuel injector is free of static leakage is ensured, and the system hydraulic efficiency is improved.

Description

technical field [0001] The invention relates to an engine fuel injection device. Background technique [0002] In order to optimize the fuel economy and emission indicators of diesel engines, the electronically controlled fuel injectors of diesel engines on the current market begin to adopt high-speed electromagnetic switch valve control, which has the advantages of fast system response, high control precision, flexible control strategy and reliable working performance Etc. However, with the gradual increase of fuel injection pressure, the disadvantages of conventional electronically controlled injectors are also revealed. [0003] First of all, the fuel injector must reduce the emission of nitrogen oxides on the one hand, which requires controlling the instantaneous fuel injection rate during the fuel injection process and reducing the fuel injection rate at the initial stage of injection. On the other hand, at the end of the injection process, the injector must cut off t...

AI Technical Summary

Problems solved by technology

However, it is difficult for conventional electronically controlled injectors to achieve this

Secondly, at present, most domestic electronically controlled fuel injectors use a two-position two-way high-speed solenoid valve to control the fuel injection process. The two-position two-way valve is always open during the fuel injection process. Large oil volume, resulting in energy loss

At the same time, the limitation of the diameter of the oil inlet and outlet damping holes and the existence of dynamic oil return also make it difficult to achieve a fast seat response of the needle valve.

In addition, the water hammer pressure fluctuation caused by the rapid opening and closing of the injector will make the fuel injection process unstable, especially when a large amount of fuel is injected, the fluctuation of the fuel pressure of the high-pressure common rail will cause the inconsistency of the injection process of each cylinder

Images