Leakage-free double-spring high-pressure common rail fuel injector

Abstract

The invention belongs to the field of electronic control fuel injection systems of diesel engines and relates to a leakage-free double-spring high-pressure common rail fuel injector. The leakage-free double-spring high-pressure common rail fuel injector comprises a needle valve body, the upper end face of the needle valve body is connected to the lower end face of a fuel injector body in a sealed mode through an adjusting cushion block, a piston needle valve is arranged inside the needle valve body, and a valve body of the piston needle valve is provided with an upper limiting step and a lower limiting step; an inner cavity of the fuel injector body is divided into an upper cavity body and a lower cavity body communicating with the upper cavity body, a high-pressure oil inlet channel is formed in the side part of the upper cavity body, the piston needle valve extends into the fuel injector body, double springs are adopted by the fuel injector for realizing subsection control over the two-stage stroke of the piston needle valve, and the timing function, the quantifying function and the multiple injection function can be realized at any pressure; the pressure storage function is realized, injection is stable, the characteristic curve of the fuel capacity is good, static high-pressure leakage is eliminated, the high-pressure fuel return amount is effectively reduced, the power loss is lowered, and the requirements for emissions, the economical efficiency and the low noise of the diesel engines can be met.

Description

technical field [0001] The invention belongs to the field of electronically controlled fuel injection systems for diesel engines, and relates to a non-leakage double-spring high-pressure common rail fuel injector. Background technique [0002] As the automotive industry has higher and higher requirements for emission, economy and low noise, diesel engine fuel injection systems are developing towards high pressure, high precision and flexible control. Affected by the structural principle, the existing common rail injector mainly has the following problems: After the needle valve is opened, the force on the sealing cone surface becomes larger, and the rising speed of the needle valve increases, which causes the piston to hit the valve assembly and cause impact and wear; the high-pressure oil passage hole Arranged on the side of the injector body, the pressure is not easy to stabilize during injection. At the same time, it is difficult to process the elongated hole, and the man...

AI Technical Summary

Problems solved by technology

Affected by the structural principle, the existing common rail injector mainly has the following problems: After the needle valve is opened, the force on the sealing cone surface becomes larger, and the rising speed of the needle valve increases, which causes the piston to hit the valve assembly and cause impact and wear; the high-pressure oil passage hole Arranged on the side of the injector body, the pressure is not easy to stabilize during injection. At the same time, it is difficult to process the elongated hole, and the manufacturing cost is high; the two ends of the needle valve coupler are respectively high-pressure and low-pressure areas, and the coupler leaks no matter it is static or working. The high-pressure fuel consumption is large, and the manufacturing cost is high at the same time; the two ends of the piston couple are high-pressure and low-pressure areas, and there is leakage in static state, and the high-pressure fuel consumption is large; because the diameter of the piston is different from that of the needle valve, the force in the control chamber is greater than that of the needle. The force on the cone surface of the valve, and the higher the rail pressure, the greater the force, resulting in a large impact force when the needle valve is closed, which is prone to wear; the valve sleeve of the valve assembly is arranged with an oil inlet and outlet orifice, and the middle hole is blind. Hole, difficult to process, high manufacturing cost

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