CN211950714U - Oil injector for high-pressure common rail system - Google Patents

Abstract

The utility model discloses a sprayer for high pressure common rail system, the sprayer includes: an injector body (1), the injector body (1) including a central bore and an oil inlet, the oil inlet being in fluid communication with the central bore; the oil nozzle (2) is connected with the oil injector body (1) in a sealing mode, and the oil nozzle (2) also comprises a central hole; a plunger (8) mounted in a central bore of the injector body (1); and a needle valve (9) installed in a central hole of the oil nozzle (2), wherein a fluid passage is formed between the injector body (1) and the plunger (8), the fluid passage being configured such that high-pressure fuel, which enters the central hole of the injector body (1) from the oil inlet, flows into the oil nozzle (2) therethrough. The fuel injector has the advantages of simple structure, lower manufacturing cost and higher mechanical strength.

Description

Oil injector for high-pressure common rail system

Technical Field

The utility model relates to a sprayer for high pressure common rail system.

Background

The high pressure common rail system generally includes a high pressure oil pump, a common rail, an injector, a pressure sensor, and the like, the injector and the pressure sensor being in electrical communication with an electronic control unit. The high-pressure oil pump delivers fuel oil to the public oil rail at high pressure, the oil injector is communicated with the public oil rail, and the electronic control unit controls the oil injection quantity and the oil injection timing by controlling the lifting of a needle valve of the oil injector.

Current injectors for high pressure common rail systems generally comprise an injector body and an injector nozzle, and a plunger, a needle valve, a ball valve, etc. mounted in central through holes of the injector body and the injector nozzle, the plunger and the needle valve being connected together, a control chamber being above the plunger, and the lower end of the needle valve being tapered for closing an injection hole. High-pressure fuel oil from a common fuel rail enters the fuel injector through an oil inlet in the fuel injector body, one part of the fuel oil enters the control chamber through the oil inlet hole, and the other part of the fuel oil enters the needle valve pressure bearing chamber through the high-pressure deep hole in the fuel injector body. Because the high-pressure fuel oil in the oil injector is continuously leaked to the low-pressure space through gaps among all parts, an oil return channel is also arranged in the oil injector body so as to lead out the fuel oil leaked to the low-pressure space.

However, the injector body of the above injector has a complex structure, especially including a high-pressure deep hole and an oil return passage, which are difficult to machine, and thus the manufacturing cost is too high.

Therefore, there is a need to develop a fuel injector having a simple structure and a low manufacturing cost.

Disclosure of Invention

The utility model aims to overcome the not enough of prior art, provide a sprayer for high pressure common rail system based on brand-new design concept.

The utility model discloses a sprayer for high pressure common rail system, the sprayer includes: an injector body including a central bore and an oil inlet in fluid communication with the central bore; the oil spray nozzle is hermetically connected with the oil spray body and also comprises a central hole; a plunger mounted in a central bore of the injector body; and a needle valve installed in a central hole of the injector, wherein a fluid passage is formed between the injector body and the plunger, the fluid passage being configured such that high-pressure fuel, which enters the central hole of the injector body from the oil inlet, flows into the injector therethrough.

The utility model discloses a structure of sprayer through changing injector, plunger and needle valve for need not to set up high-pressure deep hole and oil return channel in the injector, thereby simplified the manufacturing process of sprayer, reduced its manufacturing cost.

Drawings

The accompanying drawings are provided to assist the reader in a more thorough understanding of the invention. Throughout the specification, like reference numerals designate like parts, in which:

fig. 1A is a cross-sectional view of a fuel injector for a high pressure common rail system according to an embodiment of the present invention, wherein the fuel injector is in a closed state; FIGS. 1B and 1C are enlarged partial views of portions indicated by blocks I and II in FIG. 1A, respectively;

FIGS. 2A and 2B are enlarged fragmentary views of corresponding portions of the fuel injector of FIG. 1A during opening thereof, respectively; and

fig. 3A and 3B are enlarged partial views of corresponding portions of the fuel injector of fig. 1A during closing, respectively.

Reference numbers in the figures: 1. an injector body; 2. an oil jet; 3. a locking cap; 4. locking the nut; 5. sealing gaskets; 6. a ball valve; 7. a plunger sleeve; 8. a plunger; 9. a needle valve; 10. an electromagnetic coil; 11. an armature; 12. an oil outlet metering hole; 13. a control room; 14. a baffle ring; 15. a spring; 16. a coupling chamber; 17. an oil passage; 18. a through hole; 19. a needle valve pressure bearing chamber; 20. an oil return port; 21. groove

Detailed Description

The present invention will be described below with reference to specific embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration only. Accordingly, the following examples are illustrative only, and the scope of the invention is to be limited only by the following claims.

Fig. 1A shows a fuel injector for a high-pressure common rail system according to an embodiment of the present invention, which includes a fuel injector body 1 and a fuel injector nozzle 2, wherein the fuel injector body 1 and the fuel injector nozzle 2 are hermetically connected by a locking cap 3 and a locking nut 4, and a sealing gasket 5 is further disposed between the fuel injector body 1 and the fuel injector nozzle 2. The fuel injector also comprises a ball valve 6, a plunger sleeve 7, a plunger 8, a needle valve 9, an electromagnetic coil 10, an armature 11 and the like. The plunger 8, the plunger sleeve 7 and the ball valve 6 are sequentially arranged in a stepped central hole of the oil injector body 1, a fluid passage is formed between the plunger 8 and the oil injector body 1, and the needle valve 9 is arranged in the central hole of the oil nozzle 2. Plunger sleeve 7 is fixedly installed in oil injector body 1, and ball valve 6 is located above plunger sleeve 7 and can move up and down relative to plunger sleeve 7 along with armature 11 under the action of electromagnetic coil 10 to open or close oil outlet hole 12 in plunger sleeve 7. The upper end of the plunger 8 is mounted in the plunger barrel 7 and thus defines, together with the plunger barrel 7, a control chamber 13, the control chamber 13 being in fluid communication with an oil inlet (not shown) and an oil outlet 12 in the plunger barrel 7. The plunger 8 is provided with a stopper ring 14, and a spring 15 is provided between the stopper ring 14 and the lower end portion of the plunger sleeve 7. The spring 15 is biased upwardly to apply a downward force to the plunger 8. The lower end of the plunger 8 projects into the central bore of the injection nozzle 2 and, together with the upper end of the needle valve 9, delimits a coupling chamber 16. However, the present invention is not limited thereto, and for example, the plunger 8 and the needle valve 9 may be connected together. The oil jet 2 comprises an oil channel 17, which oil channel 17 may be inclined. The lower end of the injector body 1 comprises a groove 21 arranged around a part of the central hole thereof, the upper end of the oil duct 17 is in fluid communication with the groove 21 of the injector body 1 through a through hole 18 in the sealing gasket 5 and further in fluid communication with the central hole of the injector body 1, and the lower end thereof is in fluid communication with the needle valve pressure chamber 19. The needle pressure bearing chamber 19 is disposed around the center hole of the injector 2, and the high-pressure fuel therein applies an upward force to the pressure bearing surface of the needle 9.

The injector body 1 further comprises an oil inlet (not shown) located at an upper portion of the injector body 1 near the oil inlet port and in fluid communication with the central bore of the injector body 1, through which high pressure fuel from a common rail of a high pressure common rail system enters the injector and flows downward.

As shown in fig. 1A to 1C, when the injector is in a closed state, the electromagnetic coil 10 is not energized, the ball valve 6 closes the fuel outlet hole 12 under the action of an upper spring, high-pressure fuel enters the central hole from the fuel inlet of the injector body 1, a part of the high-pressure fuel enters the control chamber 13 through the fuel inlet hole in the plunger sleeve 7, the pressure in the control chamber 13 is increased to a high pressure in a common rail, and another part of the high-pressure fuel flows downward through the fluid passage between the plunger 8 and the injector body 1 and enters the needle valve pressure receiving chamber 19 through the groove 21, the through hole 18 and the oil passage 17, further enters the coupling chamber 16 through a gap between the needle valve 9 and the injector 2, and the pressure in the coupling chamber 16 is increased to an equal high pressure. In this closed state, the combined downward force of the high-pressure fuel in the control chamber 13 and the spring 15 acting on the plunger 8 is greater than the upward force of the high-pressure fuel in the coupling chamber 16 acting on the plunger 8, so that the plunger 8 presses downward against the needle valve 9. Further, since the resultant downward force of the high-pressure fuel in the plunger 8 and the coupling chamber 16 acting on the needle valve 9 is greater than the upward force of the high-pressure fuel in the needle valve pressure bearing chamber 19 acting on the needle valve 9, the needle valve 9 is pressed against the injection hole of the injection nozzle 2, so that the injector is kept in a closed state.

As can be seen from the above description, when the injector is in the closed state, the high-pressure fuel fills the entire internal space of the injector, and there is no problem that the high-pressure fuel leaks from the gap between the parts to the low-pressure space, and therefore, there is no need to provide an oil return passage on the injector body 1, so that a large amount of fuel does not flow back into the fuel tank from the oil return passage, and thus, the efficiency of the high-pressure oil pump is significantly improved. In addition, since the high-pressure fuel directly enters the fuel injector 2 through the fluid passage between the injector body 1 and the plunger 8, it is not necessary to provide a deep high-pressure hole in the injector body 1. Compared with the prior art, the utility model discloses an oil sprayer body 1 does not include return oil channel and high-pressure deep hole, therefore simple structure, manufacturing cost are lower, and have higher mechanical strength. It is worth noting that each part of the oil sprayer can be processed and manufactured on the existing production line, so that a new production line is not needed to be invested.

The operation of the fuel injector according to the embodiment of the present invention is described in detail below.

When the electromagnetic coil 10 is energized, the armature 11 moves upward under the action of the attraction force and drives the ball valve 6 to move upward, thereby opening the oil outlet hole 12, as shown in fig. 2A and 2B. Therefore, the high-pressure fuel in the control chamber 13 flows out through the fuel outlet port 12 and finally returns to the fuel tank through the fuel return port 20 (see fig. 1A) located at the upper portion of the injector, which causes the pressure in the control chamber 13 to rapidly decrease, the plunger 8 rapidly rises (as indicated by an arrow in fig. 2A) by the high-pressure fuel in the coupling chamber 16, which in turn causes the pressure in the coupling chamber 16 to rapidly decrease, and the needle valve 9 rapidly rises (as indicated by an arrow in fig. 2B) by the high-pressure fuel in the needle valve pressure receiving chamber 19, whereby the fuel injection hole of the fuel injection nozzle 2 is opened, and the high-pressure fuel between the needle valve 9 and the fuel injection nozzle 2 is rapidly ejected from the fuel injection hole.

Compared with the technical scheme that the plunger 8 and the needle valve 9 are connected together, the coupling chamber 16 defined between the plunger 8 and the plunger 9 can improve the reaction rate of the fuel injector, so that accurate control of the fuel injector is facilitated.

As shown in fig. 3A and 3B, when the electromagnetic coil 10 is de-energized, the attraction force disappears, and the armature 11 moves downward under the action of the upper spring and drives the ball valve 6 to move downward, thereby closing the oil outlet hole 12. At this time, the pressure in the control chamber 13 rises again to the high pressure in the common rail, whereby the plunger 8 moves downward (as shown by the arrow in fig. 3A) and pushes the needle valve 9 downward (as shown by the arrow in fig. 3B), thereby closing the injection hole of the injection nozzle 2 and stopping the injection.

Although specific embodiments of the present invention have been disclosed, those skilled in the art will appreciate that various modifications, substitutions and changes may be made without departing from the spirit and scope of the invention. Accordingly, the scope of the present invention is not limited to the specific embodiments described above, but is only limited by the appended claims.

Claims (10)

1. A fuel injector for a high pressure common rail system, the fuel injector comprising:

an injector body (1), the injector body (1) including a central bore and an oil inlet, the oil inlet being in fluid communication with the central bore;

the oil nozzle (2) is connected with the oil injector body (1) in a sealing mode, and the oil nozzle (2) also comprises a central hole;

a plunger (8) mounted in a central bore of the injector body (1); and

a needle valve (9) arranged in the central hole of the oil nozzle (2),

characterized in that a fluid passage is formed between the injector body (1) and the plunger (8), the fluid passage being configured such that high-pressure fuel entering a central bore of the injector body (1) from the oil inlet flows into the injection nozzle (2) therethrough.

2. Injector for a high pressure common rail system according to claim 1, characterized in that the injector (2) comprises an oil channel (17), the upper end of the oil channel (17) being in fluid communication with the central bore of the injector body (1) and the lower end thereof being in fluid communication with a needle pressure chamber (19) arranged around the central bore of the injector (2).

3. A fuel injector for a high pressure common rail system according to claim 2, characterized in that a lower end portion of the injector body (1) includes a groove (21) provided around a part of a center hole thereof, and an upper end of the oil passage (17) is in fluid communication with the center hole of the injector body (1) via the groove (21).

4. Injector for a high pressure common rail system according to claim 3, characterized in that a sealing gasket (5) is provided between the injector body (1) and the injector nozzle (2), the sealing gasket (5) comprising a through hole (18), the through hole (18) being in fluid communication with the oil channel (17) and the groove (21).

5. Injector for a high pressure common rail system according to claim 2, characterized in that the lower end of the plunger (8) projects into a central bore of the injector (2) and defines a coupling chamber (16) together with the upper end of the needle valve (9).

6. Injector for a high pressure common rail system according to claim 5, characterized in that the high pressure fuel in the needle bearing chamber (19) can flow into the coupling chamber (16) via a clearance between the needle (9) and the injector (2).

7. A fuel injector for a high pressure common rail system according to claim 1, characterized in that the fuel injector further comprises a plunger barrel (7) fixedly mounted in a central bore of the injector body (1), the upper end of the plunger (8) being mounted in the plunger barrel (7) and thereby defining together with the plunger barrel (7) a control chamber (13), the control chamber (13) being in fluid communication with a fuel inlet and a fuel outlet (12) in the plunger barrel (7), the fuel inlet being located at an upper portion of the injector body (1) and close to the fuel inlet.

8. A fuel injector for a high pressure common rail system according to claim 7, characterized by further comprising a ball valve (6) located above said plunger barrel (7), said ball valve (6) being capable of performing an elevating movement with respect to said plunger barrel (7) to open/close said fuel outlet hole (12) in said plunger barrel (7).

9. A fuel injector for a high pressure common rail system according to claim 8, characterized in that when the fuel outlet port (12) is opened, the high pressure fuel in the control chamber (13) flows out through the fuel outlet port (12) and is returned to a fuel tank through a fuel return port (20) located at an upper portion of the fuel injector.

10. A fuel injector for a high pressure common rail system according to claim 7, characterized in that a retainer ring (14) is provided on the plunger (8), and an upward biasing spring (15) is provided between the retainer ring (14) and a lower end portion of the plunger sleeve (7).

Images