Piezoelectric-electromagnetic hybrid control injector with variable injection schedule

Abstract

The invention aims at providing a piezoelectric-electromagnetic mixed control oil injector with the variable oil injection law. The piezoelectric-electromagnetic mixed control oil injector comprises apressurizing control valve part, a three-stage piston assembly, an oil injection control valve part, a needle valve part, a tightening cap, a fastening cap and an oil injector body. According to thepiezoelectric-electromagnetic mixed control oil injector with the variable oil injection law, a two-stage electromagnetic valve structure is adopted to control the pressurizing area of a three-stage piston, different pressurizing ratios can be effectively achieved, and the oil injection law is more flexible; the action process of a needle valve is driven by a piezoelectric stack, the needle valveresponse speed is high, the control freedom degree is high, the oil injection law is flexible and controllable, the power performance of a diesel engine and the economical efficiency of fuel oil are effectively improved, and the diesel engine can meet the stricter emission regulation; and meanwhile, a pressurizing control valve is soaked in low-pressure oil to achieve the cooling effect on an electromagnetic valve, and the safe and reliable work is guaranteed. An adopted hydraulic compensation piston structure is used for supplementing oil when a control cavity is depressurized and achieving the two-way oil inlet effect when the control cavity is pressurized, therefore, the oil injection law achieves the characteristics of being slow firstly and quick secondly, and the oil injection performance is improved.

Description

technical field [0001] The invention relates to a fuel system, in particular to a marine diesel engine fuel system. Background technique [0002] The traditional mechanically controlled fuel injector has the advantages of high reliability and simple structure. However, because its fuel injection characteristics such as fuel injection timing, fuel injection pressure and fuel injection rate are restricted by the cam profile of the high-pressure fuel supply pump, it has disadvantages such as inflexible fuel injection characteristics, slow response, and poor control accuracy of fuel injection volume. . With the increasingly stringent emission regulations, it is difficult to further improve the economy and emission performance of the engine, nor can it meet the requirements of the current market for the engine. [0003] Compared with the mechanically controlled injector, the electromagnetically controlled injector used in the electronically controlled fuel injection system of a...

AI Technical Summary

Problems solved by technology

Although the electromagnetic control injector has improved the emission performance of the diesel engine, there are still some shortcomings: the injector usually adopts the form of single-way oil inlet, and the response speed of the needle valve seat is slow, and due to the balance of the diameter of the inlet and outlet holes relationship, it is difficult to further improve the response characteristics; the dynamic oil return in the form of a two-position two-way valve is large, which affects fuel utilization; the axial gap between the needle valve and the control plunger causes static leakage in the injector Fuel problem; due to the inductance of the solenoid valve coil, there is a certain lag time in its response, which leads to the limitation of the further increase in the number of fuel injections, and the repeatability of fuel injection needs to be improved, etc.

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