A double-needle valve electronically controlled fuel injector with double-layer injection holes

Abstract

The invention relates to a double-needle-valve electronically-controlled fuel injector with double layers of orifices and belongs to the technical field of internal combustion engines. According to the invention, the upper end of an upper body is connected with a locking nut, the lower end of the upper body is fixedly connected with the upper end of a middle body, the lower end of the middle body is connected with the upper end of the lower body; a ball valve a and an armature a are arranged in a cavity a of the upper body together; a ball valve b and an armature b are arranged in an oil return cavity a of the upper body and an oil return cavity b of the middle body together; an internal needle valve is arranged in a cavity d of an external needle valve, the internal needle valve and the external needle valve are arranged in a pressure chamber of the upper body, a cavity b of the middle body and a cavity c of the lower body together and are in sliding connection with the side wall. According to the invention, double electromagnetic valves are adopted to precisely control the injection timing of the two groups of orifices, the situation that one group of orifices is opened in low load and two groups of orifices are opened in heavy load can be realized, the requirements of different loads of the engine on the orifice number and apertures of the fuel injectors can be met, good atomizing characteristics can be achieved no matter in heavy load or low load, and relatively large fuel injection quantity can be met in heavy load, and therefore, mutual interference and overlapping of fuel sprays can be effectively avoided, and the combustion and discharge characteristic of the engine can be improved.

Description

technical field [0001] The invention belongs to the technical field of internal combustion engines, and in particular relates to a double-needle valve electronically controlled fuel injector with double-layer injection holes. Background technique [0002] The fuel injector is an important component of the diesel engine. Its main function is to atomize the high-pressure diesel oil from the fuel injection pump according to certain requirements, and distribute it to the combustion center to form a good combustible mixture. The performance of the injector directly affects the combustion performance, fuel consumption and service life of the diesel engine. For the fixed hole number injector of a general diesel engine, the injector is required to have a smaller pore diameter to meet a better atomization degree under a small load, and the injector is required to have a larger pore diameter to meet a better atomization degree under a large load. Large fuel injection volume. Using a...

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Problems solved by technology

Using a larger nozzle hole diameter cannot meet the atomization requirements under small loads, and under small loads a shorter fuel injection duration and lower injection pressure are required to maintain a smaller fuel injection volume, while a lower injection The pressure is not conducive to the atomization and fragmentation of the oil beam; the use of a smaller nozzle hole diameter cannot meet the demand for large-load fuel injection. If more nozzle holes are used, the fuel oil beams will interfere with each other and overlap, resulting in economical damage. decreased performance and soot generation

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