Three-way valve control assembly for electronic fuel injector

Abstract

The present invention discloses a three-way valve control assembly for an electronically controlled fuel injector, the three-way valve control assembly comprising a needle valve, a three-way valve, a metering valve, a sealing hemisphere, a compression screw sleeve, and an armature shaft. The present invention has the beneficial technical effect of providing a three-way valve control assembly for an electronically controlled fuel injector, which can simultaneously solve the needle valve lift error problem and the opening variation problem caused by oil pressure fluctuation.

Description

Technical Field

[0001] The present invention relates to an electronically controlled fuel injector technology, in particular to a three-way valve control assembly for the electronically controlled fuel injector. Background Art

[0002] With the gradual improvement of National V and National VI emission requirements, the high-pressure common rail fuel injection system is moving towards a higher working rail pressure, which puts higher requirements on the control performance of the injector. On the one hand, it is necessary to ensure the stability of the low rail pressure stage, and on the other hand, it is also necessary to ensure the consistency under high rail pressure. The control assembly used by the electronically controlled injector in the existing technology is limited by the structure, which leads to the needle valve not moving smoothly when it is upward and not moving fast enough when it is downward. In particular, when the needle valve is moving upward, the upper end face usually does not contact other structures. Due to factors such as oil pressure fluctuations, there is a certain error in the needle valve lift. In order to solve the lift error problem, some technologies also need to add additional limiting structures, resulting in a large number of parts and a complex structure. Summary of the Invention

[0003] In response to the problems in the background technology, the present invention proposes a three-way valve control assembly for an electronically controlled fuel injector. The innovation of the three-way valve control assembly is that the three-way valve control assembly includes a needle valve, a three-way valve, a metering valve, a sealing hemisphere, a compression screw sleeve, and an armature shaft;

[0004] The needle valve body is provided with a guide section in the middle, and the structure on the upper side of the guide section forms a sealing section. The outer diameter of the sealing section is smaller than that of the guide section, and a step surface is formed between the sealing section and the guide section; the upper end surface of the sealing section is a spherical surface;

[0005] The outer contour of the three-way valve is cylindrical; a mounting groove is provided on the lower end surface of the three-way valve, a first control cavity is formed on the upper part of the mounting groove, and a guide cavity is formed at the lower part of the mounting groove, the inner diameter of the guide cavity matches the guide section, and the inner diameter of the first control cavity is larger than the inner diameter of the guide cavity; a connecting groove is provided on the upper end surface of the three-way valve, an oil outlet hole is provided at the bottom of the mounting groove, the oil outlet hole connects the connecting groove and the mounting groove, and the lower end of the oil outlet hole is a tapered mouth with a larger bottom and a smaller top; a regular through hole is provided on the outer wall of the upper part of the three-way valve, the regular through hole connects the connecting groove and the outer wall of the upper part of the three-way valve; an oil inlet hole is provided at a position corresponding to the first control cavity on the three-way valve, and the oil inlet hole connects the outer wall of the three-way valve and the first control cavity; the guide section of the needle valve is sleeved in the guide cavity, and the oil inlet hole and the step surface are always in a connected state; when the spherical surface contacts the tapered mouth, the oil outlet hole can be closed.

[0006] The metering valve is provided with a metering hole axially penetrating the metering valve, the lower end of the metering hole is a bell mouth with a larger bottom and a smaller top, and the size of the lower end of the bell mouth matches the connecting groove; the metering valve is arranged on the upper side of the three-way valve, the lower end face of the metering valve contacts the upper end face of the three-way valve, the bell mouth is positioned opposite to the connecting groove, and the area enclosed by the bell mouth and the connecting groove forms a second control chamber;

[0007] The compression screw sleeve is arranged on the upper side of the metering valve, and the compression screw sleeve presses the metering valve against the supporting surface; an axial through hole is arranged in the middle of the compression screw sleeve;

[0008] The sealing hemisphere is arranged in the axial through hole with the spherical surface facing upward, and the position of the sealing hemisphere matches the upper port of the metering hole; the armature shaft is sleeved in the axial through hole, and the lower end surface of the armature shaft is provided with a tightening groove matching the spherical surface of the sealing hemisphere. When the armature shaft presses the sealing hemisphere, the sealing hemisphere closes the upper port of the metering hole.

[0009] The principle of the aforementioned scheme is as follows: the outer end of the permanent through hole is connected to the oil passage inside the injector body, allowing fuel to continuously flow into the communication groove through the permanent through hole. At the same time, the outer end of the oil inlet hole is also connected to the oil passage inside the injector body, allowing fuel to continuously flow into the first control chamber through the oil inlet hole. When the armature shaft presses the sealing hemisphere against the upper end face of the metering valve, the metering hole is in a closed state. Under the action of the fuel pressure in the first control chamber, the needle valve is pressed downward, and the nozzle is in a closed state.

[0010] Based on the existing technology, it is known that the lower part of the needle valve is also continuously subjected to the upward force of the high-pressure fuel, and this upward force is recorded as the pushing force; the downward force acting on the needle valve in the first control chamber is recorded as the lower pushing force; during the nozzle opening process, the armature shaft is first lifted upward, the upper part of the sealing hemisphere loses its support, and the high-pressure fuel in the second control chamber pushes up the sealing hemisphere, the pressure in the second control chamber drops rapidly, and the fuel in the first control chamber also flows to the second control chamber, resulting in a decrease in the pressure in the first control chamber and a decrease in the lower pushing force. At this time, the needle valve will move upward under the action of the pushing force. When the needle valve rises and the spherical surface at the upper end of the needle valve contacts the tapered port, the oil outlet is closed. At this time, due to the continuous action of the top force, the needle valve will be pressed tightly against the tapered port. By designing the size of the structure, the nozzle is in the maximum opening state in this state, which effectively solves the problem of needle valve lift error. At the same time, because the top force presses the needle valve against the tapered port, the needle valve will not shake even if the oil pressure fluctuates, thereby ensuring that the nozzle opening can be stably maintained at the maximum opening state, which effectively solves the problem of needle valve opening changes due to oil pressure fluctuations.

[0011] The beneficial technical effect of the present invention is that a three-way valve control assembly for an electronically controlled fuel injector is proposed, which can simultaneously solve the needle valve lift error problem and the opening change problem caused by oil pressure fluctuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 , a schematic cross-sectional view of the present invention;

[0013] Figure 2 , schematic cross-sectional view of the needle valve upper structure;

[0014] Figure 3 、 three Schematic diagram of the cross-section structure of the valve;

[0015] Figure 4 , a schematic cross-sectional view of a fuel injector using the solution of the present invention;

[0016] The names corresponding to the various marks in the figure are: needle valve 1, guide section 11, sealing section 12, three-way valve 2, first control chamber 21, connecting groove 22, guide chamber 23, metering valve 3, second control chamber 31, sealing hemisphere 4, tightening screw sleeve 5, armature shaft 6, solenoid valve 7, oil outlet hole A, normal through hole B, oil inlet hole C. DETAILED DESCRIPTION

[0017] A three-way valve control assembly for an electronically controlled fuel injector, the innovation of which is that the three-way valve control assembly includes a needle valve 1, a three-way valve 2, a metering valve 3, a sealing hemisphere 4, a compression screw sleeve 5 and an armature shaft 6;

[0018] The needle valve 1 has a guide section 11 in the middle of its body. A sealing section 12 is formed on the upper side of the guide section 11. The outer diameter of the sealing section 12 is smaller than that of the guide section 11, and a step surface is formed between the sealing section 12 and the guide section 11. The upper end surface of the sealing section 12 is a spherical surface.

[0019] The outer contour of the three-way valve 2 is cylindrical; the lower end surface of the three-way valve 2 is provided with a mounting groove, the upper part of the mounting groove forms a first control cavity 21, and the lower part of the mounting groove forms a guide cavity 23, the inner diameter of the guide cavity 23 matches the guide section 11, and the inner diameter of the first control cavity 21 is larger than the inner diameter of the guide cavity 23; a connecting groove 22 is provided on the upper end surface of the three-way valve 2, and an oil outlet hole A is provided at the bottom of the mounting groove, and the oil outlet hole A connects the connecting groove 22 and the mounting groove, and the lower end of the oil outlet hole A is larger than the lower end. A small tapered opening; a normally open hole B is provided on the outer wall of the upper portion of the three-way valve 2, which connects the connecting groove 22 with the upper outer wall of the three-way valve 2; an oil inlet hole C is provided on the portion of the three-way valve 2 corresponding to the first control chamber 21, which connects the outer wall of the three-way valve 2 with the first control chamber 21; the guide section 11 of the needle valve 1 is sleeved in the guide chamber 23, and the oil inlet hole C is always in communication with the step surface; when the spherical surface contacts the tapered opening, the oil outlet hole A can be closed;

[0020] The metering valve 3 is provided with a metering hole axially extending therethrough. The lower end of the metering hole is a bell-shaped mouth with a larger bottom and a smaller top. The size of the lower end of the bell-shaped mouth matches the size of the connecting groove 22. The metering valve 3 is arranged on the upper side of the three-way valve 2. The lower end surface of the metering valve 3 contacts the upper end surface of the three-way valve 2. The bell-shaped mouth is positioned opposite to the connecting groove 22. The area enclosed by the bell-shaped mouth and the connecting groove 22 forms a second control chamber 31.

[0021] The compression screw sleeve 5 is arranged on the upper side of the metering valve 3, and the compression screw sleeve 5 presses the metering valve 3 against the supporting surface; an axial through hole is provided in the middle of the compression screw sleeve 5;

[0022] The sealing hemisphere 4 is arranged in the axial through hole with the spherical surface facing upward, and the position of the sealing hemisphere 4 matches the upper end of the metering hole; the armature shaft 6 is sleeved in the axial through hole, and the lower end surface of the armature shaft 6 is provided with a tightening groove that matches the spherical surface of the sealing hemisphere 4. When the armature shaft 6 presses the sealing hemisphere 4 tightly, the sealing hemisphere 4 closes the upper end of the metering hole.

Claims

1. A three-way valve control assembly for an electronically controlled fuel injector, characterized in that: The three-way valve control assembly comprises a needle valve (1), a three-way valve (2), a metering valve (3), a sealing hemisphere (4), a compression screw sleeve (5) and an armature shaft (6); A guide section (11) is provided in the middle of the needle valve (1) body, and a structure on the upper side of the guide section (11) forms a sealing section (12). The outer diameter of the sealing section (12) is smaller than the outer diameter of the guide section (11), and a step surface is formed between the sealing section (12) and the guide section (11); the upper end surface of the sealing section (12) is a spherical surface; The outer contour of the three-way valve (2) is cylindrical; a mounting groove is provided on the lower end surface of the three-way valve (2); a first control cavity (21) is formed at the upper portion of the mounting groove; a guide cavity (23) is formed at the lower portion of the mounting groove; the inner diameter of the guide cavity (23) matches the inner diameter of the guide section (11); the inner diameter of the first control cavity (21) is larger than the inner diameter of the guide cavity (23); a connecting groove (22) is provided on the upper end surface of the three-way valve (2); an oil outlet hole (A) is provided at the bottom of the mounting groove; the oil outlet hole (A) connects the connecting groove (22) and the mounting groove; the lower end of the oil outlet hole (A) is larger at the bottom and smaller at the top. Conical port; a normally open hole (B) is provided on the outer wall of the upper portion of the three-way valve (2), and the normally open hole (B) connects the connecting groove (22) and the outer wall of the upper portion of the three-way valve (2); an oil inlet hole (C) is provided on the portion of the three-way valve (2) corresponding to the first control chamber (21), and the oil inlet hole (C) connects the outer wall of the three-way valve (2) and the first control chamber (21); the guide section (11) of the needle valve (1) is sleeved in the guide chamber (23), and the oil inlet hole (C) is always in a connected state with the step surface; when the spherical surface contacts the conical port, the oil outlet hole (A) can be closed; The metering valve (3) is provided with a metering hole axially penetrating the metering valve (3), the lower end of the metering hole being a bell mouth with a larger bottom and a smaller top, the size of the lower end of the bell mouth matching the connecting groove (22); the metering valve (3) is provided on the upper side of the three-way valve (2), the lower end face of the metering valve (3) contacts the upper end face of the three-way valve (2), the bell mouth is positioned opposite to the connecting groove (22), and the area enclosed by the bell mouth and the connecting groove (22) forms a second control chamber (31); The compression screw sleeve (5) is arranged on the upper side of the metering valve (3), and the compression screw sleeve (5) presses the metering valve (3) against the support surface; an axial through hole is provided in the middle of the compression screw sleeve (5); The sealing hemisphere (4) is arranged in the axial through hole with its spherical surface facing upward, and the position of the sealing hemisphere (4) matches the upper end of the metering hole; the armature shaft (6) is sleeved in the axial through hole, and the lower end surface of the armature shaft (6) is provided with a tightening groove that matches the spherical surface of the sealing hemisphere (4). When the armature shaft (6) presses the sealing hemisphere (4) tightly, the sealing hemisphere (4) closes the upper end of the metering hole.

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