阅读说明：本技术 一种大流量共轨喷油器喷油嘴用针阀、喷油嘴偶件及其工作方法 (Needle valve for large-flow common rail oil injector oil injection nozzle, oil injection nozzle matching part and working method of oil injection nozzle matching part ) 是由 李汝宁 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种大流量共轨喷油器喷油嘴用针阀,所述针阀的下段为喷油段,所述喷油段的侧面上轴向均匀设置有多个凸起的喷针导向,每一所述喷针导向的顶面与喷油嘴的喷油道内壁过渡配合,相邻两个所述喷针导向之间形成供高压燃油通过的喷油凹槽。可在保证燃油充分雾化的前提下,提高燃油流通面积,增大喷油速率,满足大功率柴油机对共轨喷油器供油特性的需求。此外,喷油嘴的上端面为微内凹面,在压力作用下产生形变与所述流量控制板的下表面形成高压密封,该密封方式效果长期稳定,能适应较大的燃油压力。(The invention discloses a needle valve for a fuel injection nozzle of a large-flow common rail fuel injector, wherein the lower section of the needle valve is a fuel injection section, a plurality of raised needle guides are axially and uniformly arranged on the side surface of the fuel injection section, the top surface of each needle guide is in transition fit with the inner wall of a fuel injection passage of the fuel injection nozzle, and a fuel injection groove for high-pressure fuel to pass through is formed between every two adjacent needle guides. On the premise of ensuring the sufficient atomization of fuel, the fuel flow area is increased, the fuel injection rate is increased, and the requirement of a high-power diesel engine on the fuel supply characteristic of the common rail fuel injector is met. In addition, the up end of fuel sprayer is little interior concave surface, produce deformation under the pressure effect with the lower surface of flow control board forms high-pressure seal, and this sealing mode effect is stable for a long time, can adapt to great fuel pressure.)

1. The needle valve for the oil injection nozzle of the large-flow common rail oil injector is characterized in that the lower section of the needle valve is an oil injection section, a plurality of raised injection needle guides are axially and uniformly arranged on the side surface of the oil injection section, the outer side surface of each injection needle guide is in transition fit with the inner wall of an oil injection channel of the oil injection nozzle, and an oil injection groove for high-pressure fuel oil to pass through is formed between every two adjacent injection needle guides.

2. The needle valve of claim 1 wherein the number of needle guides is 6; the connection between the spray needle guide and the oil injection groove is a fillet.

3. The needle valve of claim 2, wherein the needle valve comprises a needle valve column section, a guide column section and an oil injection section from top to bottom; a spring seat is arranged at the joint of the needle valve column section and the guide column section for limiting; the diameter of the lower part of the guide column section is reduced to form a plurality of conical surfaces, the conical surface at the lowest part is a sealing surface, and the sealing surface is matched with a sealing seat of an oil nozzle to form high-pressure sealing.

4. The needle valve of claim 3 wherein said guide post segment is provided axially on its side with one or more needle valve oil slots for the passage of high pressure fuel therethrough, said needle valve oil slots having an arcuate cross-section.

5. A high-flow common rail injector nozzle matching part is characterized by comprising a flow control plate, an injector, the needle valve according to any one of claims 1 to 4, a control sleeve, a needle valve spring and a needle valve spring seat.

6. The fuel injection nozzle matching part of the large-flow common rail fuel injector according to claim 5, wherein the upper surface of a boss at the top of the fuel injection nozzle is uniformly recessed from the outer edge to the center to form a slightly concave surface, and the slightly concave surface deforms under the action of pressure to form high-pressure sealing with the lower surface of the flow control plate.

7. The fuel injection nozzle matching part of the large-flow common rail fuel injector according to claim 6,

the middle part of the oil nozzle is axially communicated to form an internal cavity, and the internal cavity sequentially comprises a needle valve cavity, a guide cavity and an oil injection duct from top to bottom;

the control sleeve, the needle valve spring and the needle valve spring seat are sequentially sleeved on the needle valve column section from top to bottom and are positioned in the needle valve cavity, and the needle valve spring seat is limited by the spring seat;

the needle valve spring is positioned between the control sleeve and the needle valve spring seat, provides upward elastic force for the control sleeve, provides downward elastic force for the needle valve spring seat and further provides downward elastic force for the needle valve;

two high-pressure fuel oil inlet holes are formed in the flow control plate so that high-pressure fuel oil can enter the needle valve cavity;

the inner surface of the control sleeve is in transition fit with the outer surface of the needle valve column section, and the upper end surface of the needle valve column section, the inner surface and the lower surface form a control cavity; the control sleeve is radially provided with a control cavity oil inlet, and the flow control plate is provided with a control cavity oil outlet;

the inner wall of the guide cavity and the guide column section are in transition fit to form a matching part, a fuel oil cavity is formed between the inner wall of the guide cavity and the conical surfaces at the lower part of the guide column section, and high-pressure fuel oil in the needle valve cavity enters the fuel oil cavity through the needle valve oil groove;

and the lower end of the guide cavity is provided with a sealing seat which is matched with the sealing surface to form high-pressure sealing.

8. The fuel injector nozzle matching part of the large-flow common rail fuel injector of claim 7, characterized in that the concave degree of the slightly concave surface is 0.0008-0.0015 mm.

9. The fuel injector nozzle matching part of the high-flow common rail fuel injector of claim 7, characterized in that the needle valve cavity is connected with the guide cavity through a first conical surface; the guide cavity is connected with the oil injection channel through a second conical surface, and the sealing seat is arranged between the second conical surface and the oil injection channel;

the two ends of the control cavity oil inlet hole are respectively provided with a horn mouth and a cylindrical hole, and high-pressure fuel oil in the needle valve cavity sequentially passes through the horn mouth, the control cavity oil inlet hole and the cylindrical hole to enter the control cavity;

the diameter of the cylindrical hole is larger than that of the oil inlet hole of the control cavity;

the joint of the control cavity oil inlet and the bell mouth and the joint of the control cavity oil inlet and the cylindrical hole are rounded corners to improve the fuel oil circulation coefficient;

the upper end and the lower end of the control cavity oil outlet are respectively an upper cylindrical hole and a lower cylindrical hole, and the diameters of the upper cylindrical hole and the lower cylindrical hole are equal and larger than that of the control cavity oil outlet;

the diameter of the control cavity oil outlet hole is smaller than that of the control cavity oil inlet hole, so that high pressure is quickly built in the control cavity.

10. The working method of the fuel injection nozzle matching part of the large-flow common rail fuel injector according to any one of claims 5 to 9,

in the initial state, under the action of the elastic force of a needle valve spring, a sealing surface at the lower end of the needle valve is contacted with a sealing seat at the lower end of the guide cavity to form sealing; high-pressure fuel enters the needle valve cavity through the high-pressure fuel inlet hole and enters the fuel cavity through the needle valve oil groove; simultaneously, high-pressure fuel enters the control cavity through the control cavity fuel inlet;

when oil is injected, the oil outlet of the control cavity is opened, the fuel pressure in the control cavity is reduced, the sum of the downward fuel pressure provided by the control cavity and the downward elastic force provided by the needle valve spring, which is borne by the needle valve, is smaller than the upward fuel pressure provided by the fuel cavity, the needle valve moves upwards, the sealing surface is separated from the sealing seat, and high-pressure fuel enters the cylinder through an oil injection channel;

when the fuel is cut off, the control chamber oil outlet is closed, and high-pressure fuel gets into the control chamber via the control chamber inlet port, control intracavity fuel pressure increases, the sum of the downward fuel pressure that the control chamber that the needle valve received provided and the downward elasticity that the needle valve spring provided is greater than the fuel pressure that makes progress that the fuel chamber provided, the needle valve downstream, sealed face with the seal receptacle contact forms high-pressure seal, stops the oil spout.

Technical Field

The invention relates to the technical field of common rail oil injectors for diesel engines, in particular to a needle valve for an oil nozzle of a large-flow common rail oil injector, an oil nozzle matching part and a working method of the oil nozzle matching part.

Background

After high-pressure fuel oil enters a needle valve cavity through an oil way, an oil nozzle matching part of the conventional common rail oil sprayer is provided with an oil nozzle hole, and then the high-pressure fuel oil enters a cylinder of a diesel engine through the oil nozzle hole to be combusted. However, with the increase of the power of the diesel engine, the requirement on the oil injection rate of the common rail oil injector is higher and higher, and on the basis of the basic invariance of the structure of the oil injection nozzle of the existing oil injector, the method of increasing the diameter of the oil injection hole and increasing the number of the oil injection holes is generally adopted to improve the oil injection rate.

However, the method has limited capability of improving the oil injection rate, and simultaneously, the erosion corrosion of the nozzle tip is aggravated, so that the requirements of a high-power diesel engine on the high oil injection rate and the reliability of the large-flow common rail oil injector cannot be met.

Meanwhile, along with the increase of the oil injection pressure, especially when the oil injection pressure is more than or equal to 180MPa, the existing oil injector parallel plane sealing structure is not enough to ensure the effective sealing of high-pressure fuel oil, and further the reliability of the large-flow common rail oil injector is influenced.

Disclosure of Invention

The invention aims to provide a needle valve for a fuel injection nozzle of a large-flow common rail fuel injector, aiming at the technical defect that the conventional fuel injection nozzle matching part cannot meet the requirements of a high-power diesel engine on high fuel injection rate and reliability of the large-flow common rail fuel injector.

The invention further aims to provide a fuel injection nozzle matching part of the large-flow common rail fuel injector.

The invention further aims to provide a working method of the fuel injection nozzle matching part of the large-flow common rail fuel injector.

The technical scheme adopted for realizing the purpose of the invention is as follows:

the utility model provides a large-traffic common rail sprayer needle valve for fuel sprayer, the hypomere of needle valve is the oil spout section, the axial evenly is provided with a plurality of bellied nozzle needle direction on the side of oil spout section, each the lateral surface of nozzle needle direction and the oil spout way inner wall transition cooperation of fuel sprayer, adjacent two form the oil spout recess that supplies high-pressure fuel to pass through between the nozzle needle direction.

In the technical scheme, the number of the spray needle guides is 6; the connection between the spray needle guide and the oil injection groove is a fillet.

In the technical scheme, the needle valve sequentially comprises a needle valve column section, a guide column section and an oil injection section from top to bottom; a spring seat is arranged at the joint of the needle valve column section and the guide column section for limiting; the diameter of the lower part of the guide column section is reduced to form a plurality of conical surfaces, the conical surface at the lowest part is a sealing surface, and the sealing surface is matched with a sealing seat of an oil nozzle to form high-pressure sealing.

In the technical scheme, one or more needle valve oil grooves for high-pressure fuel to pass through are axially formed in the side surface of the guide column section, and the cross section of each needle valve oil groove is of an arch structure.

In another aspect of the invention, a fuel injection nozzle matching part of a high-flow common rail fuel injector comprises a flow control plate, a fuel injection nozzle, the needle valve, a control sleeve, a needle valve spring and a needle valve spring seat.

In the technical scheme, the upper surface of the top boss of the oil nozzle is uniformly recessed from the outer edge to the center to form a micro-concave surface, and the micro-concave surface deforms under the action of pressure to form high-pressure sealing with the lower surface of the flow control plate.

In the technical scheme, the middle part of the oil nozzle is axially communicated to form an internal cavity, and the internal cavity sequentially comprises a needle valve cavity, a guide cavity and an oil injection duct from top to bottom;

the control sleeve, the needle valve spring and the needle valve spring seat are sequentially sleeved on the needle valve column section from top to bottom and are positioned in the needle valve cavity, and the needle valve spring seat is limited by the spring seat;

the needle valve spring is positioned between the control sleeve and the needle valve spring seat, provides upward elastic force for the control sleeve, provides downward elastic force for the needle valve spring seat and further provides downward elastic force for the needle valve;

two high-pressure fuel oil inlet holes are formed in the flow control plate so that high-pressure fuel oil can enter the needle valve cavity;

the inner surface of the control sleeve is in transition fit with the outer surface of the needle valve column section, and the upper end surface of the needle valve column section, the inner surface and the lower surface form a control cavity; the control sleeve is radially provided with a control cavity oil inlet, and the flow control plate is provided with a control cavity oil outlet;

the inner wall of the guide cavity and the guide column section are in transition fit to form a matching part, a fuel oil cavity is formed between the inner wall of the guide cavity and the conical surfaces at the lower part of the guide column section, and high-pressure fuel oil in the needle valve cavity enters the fuel oil cavity through the needle valve oil groove;

and the lower end of the guide cavity is provided with a sealing seat which is matched with the sealing surface to form high-pressure sealing.

In the technical scheme, the concave degree of the micro concave surface is 0.0008-0.0015 mm.

In the technical scheme, the needle valve cavity is connected with the guide cavity through a first conical surface; the guide cavity is connected with the oil injection passage through a second conical surface, and the sealing seat is arranged between the second conical surface and the oil injection passage.

In the technical scheme, two ends of the oil inlet hole of the control cavity are respectively provided with a horn mouth and a cylindrical hole, and high-pressure fuel oil in the needle valve cavity sequentially passes through the horn mouth, the oil inlet hole of the control cavity and the cylindrical hole to enter the control cavity;

the diameter of the cylindrical hole is larger than that of the oil inlet hole of the control cavity;

and the joint of the control cavity oil inlet hole and the horn mouth and the joint of the control cavity oil inlet hole and the cylindrical hole are rounded corners so as to improve the fuel circulation coefficient.

In the technical scheme, the upper end and the lower end of the control cavity oil outlet are respectively an upper cylindrical hole and a lower cylindrical hole, and the diameters of the upper cylindrical hole and the lower cylindrical hole are equal and larger than that of the control cavity oil outlet;

the diameter of the control cavity oil outlet hole is smaller than that of the control cavity oil inlet hole so that high pressure is quickly built in the control cavity.

In another aspect of the invention, the working method of the fuel injection nozzle matching part of the large-flow common rail fuel injector,

in an initial state, under the action of the elastic force of a needle valve spring, a sealing surface at the lower end of the needle valve is contacted with a sealing seat at the lower end of the guide cavity to form sealing; high-pressure fuel enters the needle valve cavity through the high-pressure fuel inlet hole and enters the fuel cavity through the needle valve oil groove; simultaneously, high-pressure fuel enters the control cavity through the control cavity fuel inlet;

when oil is injected, the oil outlet of the control cavity is opened, the fuel pressure in the control cavity is reduced, the sum of the downward fuel pressure provided by the control cavity and the downward elastic force provided by the needle valve spring, which is borne by the needle valve, is smaller than the upward fuel pressure provided by the fuel cavity, the needle valve moves upwards, the sealing surface is separated from the sealing seat, and high-pressure fuel enters the cylinder through the oil injection channel;

when fuel cut-off, the control chamber delivery port is closed, and high-pressure fuel gets into the control chamber via the control chamber inlet port, the fuel pressure increases in the control chamber, the sum of the downward fuel pressure that the control chamber that the needle valve received provided and the downward elasticity that the needle valve spring provided is greater than the fuel pressure that makes progress that the fuel chamber provided, the needle valve downstream, sealed face with the seal receptacle contact forms high-pressure seal, stops the oil spout.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the needle valve for the oil nozzle of the large-flow common rail oil sprayer, the plurality of needle guides are axially distributed at the oil injection section, the oil injection grooves are formed between every two needle guides, the needle guides are in transition fit with the inner wall of the oil injection passage to form the coupling part, and the plurality of oil injection passages for high-pressure fuel oil to pass are formed between the oil injection grooves and the inner wall of the oil injection passage.

2. According to the high-flow common rail oil sprayer nozzle matching part provided by the invention, the upper end surface of the oil sprayer is a slightly concave surface and is in contact with the lower surface of the flow control plate, and the slightly concave surface at the upper end of the oil sprayer deforms under certain pressure to form high-pressure sealing with the lower surface of the flow control plate.

Drawings

FIG. 1 is a schematic front view of a needle valve;

FIG. 2 is an isometric view of the needle valve;

FIG. 3 is an enlarged view of a portion of FIG. 2;

FIG. 4a is a schematic sectional view of an assembly structure of a fuel injection nozzle matching part of the large-flow common rail fuel injector;

FIG. 4b is a schematic view of an assembly structure of a fuel injection nozzle matching part of the large-flow common rail fuel injector;

FIG. 5a is an enlarged view of a portion of FIG. 4 a;

FIG. 5b shows a partial enlarged view of FIG. 4 b;

FIG. 6 shows a view from the direction A of FIG. 5 a;

FIG. 7 is a schematic cross-sectional view of an oil jet;

FIG. 8 is a schematic view of a needle spring;

FIG. 9 is a schematic cross-sectional view of a needle valve spring seat;

FIG. 10 is a schematic cross-sectional view of a control sleeve;

fig. 11 is a schematic cross-sectional view of the flow control plate.

In the figure: 1-an oil nozzle, 1-1-a slight concave inner surface, 1-2-a needle valve cavity, 1-3-a guide cavity, 1-4-a first conical surface, 1-5-a second conical surface, 1-6-a seal seat, 1-7-an oil spray channel, 2-a needle valve, 2-1-an upper end surface, 2-2-a needle valve column section, 2-3-a spring seat limit, 2-4-a needle valve oil groove, 2-5-a guide column section, 2-6-a seal surface, 2-7-a needle guide, 2-8-an oil spray groove, 3-a needle valve spring, 3-1-an upper end, 3-2-a lower end, 4-a needle valve seat, 5-a control sleeve, 5-2-bell mouth, 5-3-control chamber oil inlet hole, 5-6-cylindrical hole, 6-flow control plate, 6-1-high pressure fuel oil inlet hole, 6-2-upper cylindrical hole, 6-3-lower cylindrical hole, 6-4-lower surface, and 6-5-control chamber oil outlet hole.

Detailed Description

The present invention will be described in further detail with reference to specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.