CN112196710A

CN112196710A - Fuel injector

Info

Publication number: CN112196710A
Application number: CN202011072382.0A
Authority: CN
Inventors: 吕宏美
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2020-10-09
Filing date: 2020-10-09
Publication date: 2021-01-08

Abstract

The invention relates to the field of engines, in particular to a fuel injector, which comprises an injector shell and a needle valve, wherein a high-pressure cavity, a plurality of first input flow passages and a plurality of injection ports are formed in the injector shell, fuel enters the high-pressure cavity through the first input flow passages, the needle valve can move to conduct or cut off the high-pressure cavity and the injection ports, damping blocks are arranged on part of the first input flow passages, damping holes are formed in the damping blocks, or part of the first input flow passage comprises damping holes to reduce the pressure fluctuation in the high-pressure cavity, thereby improving the injection stability and consistency of the injection port, being beneficial to realizing the accurate control of the injection quantity, injecting the fuel into the combustion chamber of the internal combustion engine in fixed time and quantity, improving the combustion efficiency and the standard reaching rate of the engine emission, meanwhile, the service life of the fuel injector is prolonged, and the fuel injector is particularly suitable for a high-power internal combustion engine with large fuel injection quantity.

Description

Fuel injector

Technical Field

The invention relates to the field of engines, in particular to a fuel injector.

Background

Common rail fuel injection systems are widely used for fuel supply for both vehicular and off-road engines. Common rail fuel injection systems provide compressed fuel in a rail by means of a high pressure pump and inject the fuel into the combustion chambers of an engine by means of injectors, improving combustion efficiency.

However, due to the influence of the fuel flow rate and pressure, the pressure fluctuation in the high-pressure chamber is large, which causes difficulty in controlling the consistency and stability of the injection amount, affects the combustion efficiency, increases the possibility of the engine emission failing to reach the standard, and affects the service life of the injector.

Disclosure of Invention

The invention aims to provide a fuel injector which has good consistency and stability of injection quantity, improves combustion efficiency, improves the standard reaching rate of engine emission and prolongs the service life of the fuel injector.

In order to realize the purpose, the following technical scheme is provided:

the utility model provides a fuel injector, includes injector housing and needle valve, be constructed with high-pressure chamber, jet orifice and a plurality of first input flow channel in the injector housing, fuel warp first input flow channel gets into in the high-pressure chamber, the needle valve is mobile in order to switch on or cut off the high-pressure chamber with the jet orifice, part be provided with the damping piece on the first input flow channel, the damping hole has been seted up on the damping piece, or part first input flow channel includes the damping hole, in order to reduce pressure oscillation in the high-pressure chamber.

As a preferable mode of the fuel injector, the orifice is gradually increased in size in a flow direction of the fuel.

As a preferable mode of the fuel injector, the orifice includes a first orifice and a second orifice that communicate, the first orifice having a smaller sectional area than the second orifice, and the second orifice communicating between the first orifice and the high pressure chamber.

As a preferable mode of the fuel injector, a ratio of a sectional area of the first hole to a sum of sectional areas of all the injection ports is 0.2 to 1.2.

As a preferable mode of the fuel injector, a plurality of the first input flow passages are provided, one of the first input flow passages is provided with the damping block, the damping block is provided with the damping hole, or one of the first input flow passages includes the damping hole.

As a preferable mode of the fuel injector, the fuel injector further includes:

a control chamber associated with the needle valve;

control valve subassembly, including orifice plate subassembly and valve module, second input flow way and output flow way have been seted up on the orifice plate subassembly, second input flow way intercommunication the high pressure chamber with the control chamber, output flow way with the control chamber intercommunication, valve module can shutoff or open output flow way's delivery outlet, in order to change control intracavity control fluid's pressure, in order to arouse the needle valve motion.

As a preferable mode of the fuel injector, the second input flow path includes an inlet and an outlet, the inlet is communicated with the high pressure chamber, the outlet is communicated with the control chamber, the second input flow path is inclined toward the needle valve, and the outlet is lower than the inlet.

As a preferable scheme of the fuel injector, the output port of the output flow passage is a tapered hole, and the output flow passage includes a primary oil outlet throttling structure and a secondary oil outlet throttling structure, so as to reduce cavitation erosion of the fuel on the hole wall of the tapered hole.

As a preferable mode of the fuel injector, the primary oil outlet throttling structure is a first throttling block arranged in the output flow passage, and a first throttling hole is formed in the first throttling block, or the primary oil outlet throttling structure is a first throttling hole, and the output flow passage comprises the first throttling hole; or the like, or, alternatively,

the second-stage oil outlet throttling structure is a second throttling block arranged in the output flow channel, a second throttling hole is formed in the second throttling block, or the second-stage oil outlet throttling structure is a second throttling hole, and the output flow channel comprises the second throttling hole.

As a preferable aspect of the fuel injector, the throttle plate assembly includes a first throttle plate and a second throttle plate, the second input flow passage and the primary oil outlet throttle structure are both disposed on the first throttle plate, and the secondary oil outlet throttle structure and the output port are both disposed on the second throttle plate.

The invention has the beneficial effects that:

in the fuel injector provided by the invention, the damping block is arranged on the first input flow passage, the damping hole is formed in the damping block, or the first input flow passage comprises the damping hole, so that the pressure fluctuation in the high-pressure cavity is reduced, the injection stability and consistency of the injection port are improved, the accurate control of the injection quantity is facilitated, the fuel is injected into a combustion chamber of an internal combustion engine in a timed and quantitative manner, the combustion efficiency is improved, the standard reaching rate of the engine emission is improved, the service life of the fuel injector is prolonged, and the fuel injector is particularly suitable for a fuel injector for a high-power internal combustion engine with large fuel injection quantity.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

FIG. 1 is a cross-sectional view of a fuel injector provided in accordance with an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the lower body of the injector provided in accordance with an embodiment of the present invention;

FIG. 3 is a cross-sectional view of a damping mass provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of pressure fluctuations within the high pressure chamber with and without the first damping structure provided by an embodiment of the present invention;

FIG. 5 is a cross-sectional view of a first throttle plate provided in accordance with an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a second throttle plate provided in accordance with an embodiment of the present invention.

Reference numerals:

100-an injector housing;

1-needle valve; 2-a control valve assembly; 3-an injector upper body; 4-injector lower body; 5-valve sleeve; 6-needle valve body; 7-high pressure chamber; 8-a control chamber; 9-pressure regulating elastic parts; 10-a damping block;

31-a material conveying channel; 32-a material storage cavity;

41-a first input flow channel;

411-first input flow channel one; 412-first input flow channel two;

21-a throttle plate assembly; 22-a valve assembly; 23-a second input flow channel; 24-an output flow channel;

211-a first throttle plate; 212-a second throttle plate;

221-a leaf spring; 222-a baffle; 223-an electromagnet; 224-an electromagnet spring; 225-an armature; 226-steel ball;

241-output flow channel I; 242 — a second orifice;

2411 — a first orifice; 2421-an output port;

61-an ejection port;

101-a damping hole;

1011-first hole; 1012-second hole.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection or a removable connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, the present embodiment provides a fuel injector including an injector housing 100, and a needle valve 1 and a control valve assembly 2 provided therein. The injector housing 100 includes an injector upper body 3, an injector lower body 4, a valve housing 5, and a needle valve body 6, which are sequentially disposed from top to bottom.

The valve housing 5 is provided with a first boring hole. The control valve component 2 is arranged in the first boring hole and is embedded in the inner wall of the first boring hole. The needle valve body 6 is provided with a second boring hole communicated with the first boring hole. The needle valve 1 is arranged in the second boring hole in a penetrating mode, and a high-pressure cavity 7 is formed between the needle valve 1 and the inner wall of the second boring hole. The bottom of the needle valve body 6 is provided with a penetrating jet orifice 61. The top of the needle valve 1 extends into the first boring hole, and a control cavity 8 is formed between the top end surface of the needle valve 1 and the control valve component 2. The bottom of the needle valve 1 is seated on the inner wall of the second bore under the pressure of the control fluid in the control chamber 8 to shut off the high-pressure chamber 7 and the injection port 61.

A pressure regulating elastic part 9 is connected between the needle valve 1 and the control valve component 2. The pressure-regulating elastic member 9 is preferably a spring, which is sleeved on the top of the needle valve 1, and two ends of the spring are respectively connected to the needle valve 1 and the control valve assembly 2.

The ejector upper body 3 is internally provided with a material conveying runner 31 and a material storage cavity 32 which are communicated. The injector lower body 4 is provided with a first input flow passage 41, and the first input flow passage 41 penetrates through the valve sleeve 5. The two ends of the first input flow channel 41 are respectively communicated with the material storage cavity 32 and the high pressure cavity 7. The fuel enters the material storage chamber 32 through the material delivery channel 31 and then flows into the high pressure chamber 7 through the first input channel 41. When the high pressure chamber 7 communicates with the injection ports 61, the fuel in the high pressure chamber 7 is injected through the injection ports 61 toward the combustion chamber of the internal combustion engine.

It is preferable that the first introduction flow path 41 is provided in plural number to increase the cross-sectional area of fuel flow and further increase the injection amount. Referring to fig. 2, in the present embodiment, four first input flow passages 41 are provided, the four first input flow passages 41 are circumferentially arranged around the axis of the injector lower body 4, and the injector lower body 4 and the valve sleeve 5 are both subjected to a relatively uniform impact force from the fuel, thereby improving the service life of the injector lower body 4 and the valve sleeve 5.

Further, referring again to fig. 1, the control valve assembly 2 described above includes a throttle plate assembly 21 and a valve assembly 22. The throttle plate assembly 21 is provided with a second input flow passage 23 and an output flow passage 24.

The second inlet channel 23 connects the high pressure chamber 7 and the control chamber 8, and part of the fuel in the high pressure chamber 7 enters the control chamber 8 through the second inlet channel 23, i.e. the fuel is used as the control fluid in the control chamber 8. Of course, in other embodiments, the control chamber 8 may not be provided to communicate with the high pressure chamber 7, and other control fluids than fuel may be injected into the control chamber 8.

The input of the output flow channel 24 communicates with the control chamber 8. The valve assembly 22 is capable of closing off or opening the output port 2421 of the output flow passage 24 to vary the pressure of the control fluid in the control chamber 8 to cause movement of the needle 1.

When the valve assembly 22 blocks the output port 2421 of the output flow passage 24, the pressure in the control chamber 8 is increased continuously until the pressure in the control chamber 8, the pressure in the high pressure chamber 7 and the pressure regulating elastic element 9 are balanced. When the valve assembly 22 opens the output port 2421 of the output flow passage 24, the control fluid in the control chamber 8 flows out of the control chamber 8 through the output port 2421, the pressure in the control chamber 8 is reduced, the needle valve 1 moves upwards under the pressure of the fuel in the high-pressure chamber 7, the needle valve 1 is separated from the inner wall of the first bore, the high-pressure chamber 7 is communicated with the injection port 61, and the fuel is injected into the combustion chamber of the internal combustion engine through the injection port 61.

Specifically, the valve assembly 22 includes a plate spring 221, a baffle 222, an electromagnet 223, an electromagnet spring 224, an armature 225, and a steel ball 226, which are sequentially arranged from top to bottom. The plate spring 221 presses against the stop 222 and the stop 222 further presses the electromagnet 223 axially against the inner wall of the first bore of the valve housing 5. When the electromagnet 223 is powered off, the electromagnet spring 224 presses against the armature 225, and the armature 225 further presses the steel ball 226 against the output port 2421 of the output flow channel 24 to close the output port 2421. When the electromagnet 223 is electrified, the armature 225 is attracted and lifted upwards, the steel ball 226 moves upwards under the pressure of the control fluid in the control chamber 8, the output port 2421 of the output flow channel 24 is opened, and the control fluid in the control chamber 8 flows out from the output port 2421. The electromagnet 223 is built in the valve housing 5, so that the control precision and the service life of the electromagnet 223 are improved.

In this embodiment, at least a part of the first input flow passage 41 is provided with a damping structure to change the phase of pressure fluctuation in the high pressure chamber 7 and reduce the pressure fluctuation in the high pressure chamber 7, thereby improving the injection stability and consistency of the injection port 61, facilitating the realization of accurate control of the injection amount, injecting the fuel into the combustion chamber of the internal combustion engine at regular time and quantity, improving the combustion efficiency, improving the standard reaching rate of the engine emission, and simultaneously improving the service life of the fuel injector, and is particularly suitable for the fuel injector for the high-power internal combustion engine with large fuel injection amount.

For convenience of description, the first input flow channel 41 opened on the injector lower body 4 is set as a first input flow channel 411, and the first input flow channel 41 opened on the valve sleeve 5 is set as a second input flow channel 412.

In this embodiment, referring to fig. 1 and 3, the damping structure is a damping block 10, the damping block 10 is disposed at an input end of the first input flow channel 411, accordingly, the input end of the first input flow channel 411 is disposed in a step shape to accommodate the damping block 10, and the damping block 10 is provided with a damping hole 101 to reduce pressure fluctuation in the high pressure chamber 7.

Fig. 4 shows a schematic diagram of the pressure fluctuation in the high-pressure chamber with and without the damping structure, and it can be seen that the damping structure is arranged to effectively reduce the amplitude of the pressure fluctuation in the high-pressure chamber 7.

Obviously, in other embodiments, the damping block 10 may also be disposed at the output end of the first input flow channel 411, the input end of the second input flow channel 412, or the output end of the second input flow channel 412, which is not limited herein, on the premise of convenient processing.

Illustratively, the damping orifice 101 includes a first orifice 1011 and a second orifice 1012 in communication, the first orifice 1011 having a smaller cross-section than the second orifice 1012, the second orifice 1012 communicating between the first orifice 1011 and the high pressure chamber 7.

Through a large number of experiments, the pressure fluctuation in the high-pressure cavity 7 can be effectively suppressed when the ratio of the cross-sectional area of the first hole 1011 to the total cross-sectional area of all the injection ports 61 is 0.2 to 1.2.

In other embodiments, it is also possible to provide that the orifice 101 gradually increases in size in the flow direction of the fuel, and thus, the pressure fluctuation in the high-pressure chamber 7 can also be suppressed.

In this embodiment, the damping block 10 is interference-mounted on the input end of the first input flow passage 411 on the lower injector body 4, and the upper injector body 3 compresses the damping block 10. In other embodiments, the damping mass 10 may also be screwed or fastened to the injector lower body 4 by fasteners. The first damping structure is set to be the damping block 10, the damping hole 101 is formed in the damping block 10, the failed damping block 10 can be replaced conveniently, and the damping block 10 with the damping hole 101 of different sizes can be replaced conveniently to adapt to different injection pressures.

It should be noted that the above-mentioned damper block 10 may also be eliminated, and the damper hole 101 is directly used as a section of the first input flow passage 41, that is, the first input flow passage 41 includes the damper hole 101, and a partial section of the first input flow passage 41 is directly processed into a hole expansion to form the damper hole 101. The damping block 10 is adopted, so that the machining process and the assembling process are more mature and reliable, the machining precision is easy to control, the requirement on machining setting is reduced, and the machining cost is low.

It should be noted that, referring to fig. 2, the number of the first input flow passages 41 of the present embodiment is four, and only one of the first input flow passages 41 is provided with the damping structure, so that the injection amount and the injection speed are ensured while the pressure fluctuation in the high-pressure chamber 7 is ensured to be reduced. If the damper structure is provided in each of the four first input flow passages 41, the injection amount and the injection speed of the fuel may be reduced. In other embodiments, the number of the first input flow channels 41 of the damping structure may be selected according to specific situations, and is not limited herein.

Further, referring to fig. 1, 5 and 6, the second input flow channel 23 of the throttle plate assembly 21 is inclined toward the needle valve 1, and the vertical impact force generated by the high-speed flow of the fuel directly acts on the top of the needle valve 1, so that the rapid closing of the injector is facilitated, the closing delay is reduced, and the injection characteristic of the fuel injector is improved.

The output port 2421 of the output flow channel 24 is a tapered hole, so that the contact area between the tapered hole and the steel ball 226 is increased, and the sealing performance of the steel ball 226 on the output port 2421 is improved. When the steel ball 226 moves upwards, the output port 2421 is opened, and the control fluid in the control chamber 8 flows out of the throttle plate assembly 21 through the output port 2421. In this embodiment, the output flow passage 24 includes a primary oil outlet throttling structure and a secondary oil outlet throttling structure to reduce cavitation of the liquid control fluid on the tapered output port 2421, and improve the service life of the throttle plate assembly 21. When the control fluid in the control cavity 8 flows out through the output flow passage 24, the control fluid is throttled twice through the primary oil outlet throttling structure and the secondary oil outlet throttling structure, so that the cavitation erosion effect of the liquid control fluid on the output port 2421 is reduced.

In this embodiment, the throttle plate assembly 21 is a split structure, and includes a first throttle plate 211 and a second throttle plate 212. The second inlet flow channel 23 opens onto the first throttle plate 211. The output flow channel 24 includes a first output flow channel 241 and a second output flow channel. The first output flow channel 241 is opened on the first throttle plate 211, and the second output flow channel is opened on the second throttle plate 212. The primary oil outlet throttling structure is a first throttling hole 2411, and the first output flow passage 241 comprises the first throttling hole 2411. The second-stage oil outlet throttling structure is a second throttling hole 242, the second output flow passage comprises the second throttling hole 242, and the output end of the second output flow passage is an output port 2421. The output port 2421 is a cavitation erosion risk surface which is most prone to cavitation erosion, the throttle plate assembly 21 is arranged in a split structure, the output port 2421 is arranged on the second throttle plate 212, when cavitation erosion occurs on the output port 2421, the second throttle plate 212 can be independently replaced without replacing the first throttle plate 211 with the second input flow channel 23 and the first output flow channel 241, and maintenance and replacement cost is reduced.

Obviously, in other embodiments, the primary oil outlet throttling structure may also be a first throttling block disposed in the first output flow channel 241, and the first throttling block is provided with the first throttling hole 2411. Similarly, the two-stage oil outlet throttling structure may also be a second throttling block disposed in the second output flow channel, and the second throttling block is provided with the second throttling hole 242.

It should be noted that the fuel in this embodiment may be a liquid fuel, such as gasoline or diesel, or a gaseous fuel, such as natural gas.

In the fuel injector provided by the embodiment, the damping structure is arranged on the first input flow passage 41 to change the phase of pressure fluctuation in the high-pressure cavity 7, so that the amplitude of the pressure fluctuation in the high-pressure cavity 7 is reduced, the injection stability and consistency of the injection port 61 are improved, the accurate control of the injection quantity is facilitated, fuel is injected into a combustion chamber of an internal combustion engine at regular time and quantity, the combustion efficiency is improved, the standard reaching rate of engine emission is improved, the service life of the fuel injector is prolonged, and the fuel injector is particularly suitable for a fuel injector for a high-power internal combustion engine with large fuel injection quantity. Further, the second input flow channel 23 comprises an inlet and an outlet, the inlet is communicated with the high pressure cavity, the outlet is communicated with the control cavity, the second input flow channel 23 is obliquely arranged towards the needle valve 1, and the outlet is lower than the inlet, so that fuel in the second input flow channel 23 flows from top to bottom, the vertical impact force generated by high-speed flow of the fuel directly acts on the top of the needle valve 1, the quick closing of the injector is facilitated, the closing delay is reduced, and the injection characteristic of the fuel injector is improved. When the control fluid in the control cavity 8 flows out through the output flow passage 24, the control fluid is throttled twice through the primary oil outlet throttling structure and the secondary oil outlet throttling structure, so that the cavitation erosion effect of the liquid control fluid on the output port 2421 is reduced. The throttle plate assembly 21 is of a split structure, the output port 2421 which is most susceptible to cavitation erosion is arranged on the second throttle plate 212, and when cavitation erosion occurs on the output port 2421, the second throttle plate 212 can be independently replaced without replacing the first throttle plate 211 which has the second input flow channel 23 and the primary oil outlet throttle structure, so that the maintenance and replacement cost is reduced. In addition, in the fuel injector of this embodiment, whole valve body does not have static structure of revealing, can reduce the pump oil requirement to the fuel feed pump, and is good to the adaptability of oil, has improved the reliability.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. The utility model provides a fuel injector, characterized in that, includes injector housing (100) and needle valve (1), be constructed high-pressure chamber (7), injection port (61) and a plurality of first input runner (41) in injector housing (100), fuel warp first input runner (41) get into in high-pressure chamber (7), needle valve (1) is movable in order to switch on or cut off high-pressure chamber (7) with injection port (61), part be provided with damping block (10) on first input runner (41), damping hole (101) have been seted up on damping block (10), or part first input runner (41) include damping hole (101), in order to reduce pressure fluctuation in high-pressure chamber (7).

2. A fuel injector according to claim 1, characterized in that the size of the orifice (101) increases gradually in the direction of flow of the fuel.

3. A fuel injector according to claim 1, characterized in that the damping orifice (101) comprises a communicating first orifice (1011) and second orifice (1012), the first orifice (1011) having a smaller cross-sectional area than the second orifice (1012), the second orifice (1012) communicating between the first orifice (1011) and the high pressure chamber (7).

4. The fuel injector as claimed in claim 3, wherein a ratio of a sectional area of the first hole (1011) to a sum of sectional areas of all the injection ports (61) is 0.2 to 1.2.

5. A fuel injector according to claim 1, characterized in that the first inlet flow channel (41) is provided in plurality, wherein one of the first inlet flow channels (41) is provided with the damping mass (10), wherein the damping orifice (101) is provided in the damping mass (10), or wherein one of the first inlet flow channels (41) comprises the damping orifice (101).

6. The fuel injector of claim 1, further comprising:

a control chamber (8) associated with the needle valve (1);

the control valve assembly (2) comprises a throttling plate assembly (21) and a valve assembly (22), a second input flow channel (23) and an output flow channel (24) are formed in the throttling plate assembly (21), the second input flow channel (23) is communicated with the high-pressure cavity (7) and the control cavity (8), the output flow channel (24) is communicated with the control cavity (8), and the valve assembly (22) can block or open an output port (2421) of the output flow channel (24) so as to change the pressure of control fluid in the control cavity (8) and cause the needle valve (1) to move.

7. A fuel injector according to claim 6, characterized in that the second inlet channel (23) comprises an inlet communicating with the high pressure chamber (7) and an outlet communicating with the control chamber (8), the second inlet channel (23) being arranged obliquely towards the needle valve (1) and the outlet being lower than the inlet.

8. The fuel injector of claim 6, wherein the outlet port (2421) of the outlet flow passage (24) is a tapered bore, and the outlet flow passage (24) includes a primary oil outlet throttling structure and a secondary oil outlet throttling structure to reduce cavitation of a bore wall of the tapered bore by the fuel.

9. The fuel injector of claim 8,

the primary oil outlet throttling structure is a first throttling block arranged in the output flow channel (24), a first throttling hole (2411) is formed in the first throttling block, or the primary oil outlet throttling structure is a first throttling hole (2411), and the output flow channel (24) comprises the first throttling hole (2411); or the like, or, alternatively,

the secondary oil outlet throttling structure is a second throttling block arranged in the output flow channel (24), a second throttling hole (242) is formed in the second throttling block, or the secondary oil outlet throttling structure is a second throttling hole (242), and the output flow channel (24) comprises the second throttling hole (242).

10. The fuel injector of claim 9, wherein the throttle plate assembly (21) includes a first throttle plate (211) and a second throttle plate (212), the second inlet flow passage (23) and the primary oil outlet throttle structure are disposed on the first throttle plate (211), and the secondary oil outlet throttle structure and the outlet port (2421) are disposed on the second throttle plate (212).