Injector and engine
By optimizing the nozzle and chamber design of the injector, the problems of backflow erosion and wall adhesion in methanol injectors were solved, resulting in higher reliability and stability, reduced failure probability, and improved performance of the injector and engine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- WEICHAI POWER CO LTD
- Filing Date
- 2025-08-07
- Publication Date
- 2026-07-10
AI Technical Summary
The existing pressure chamber design of methanol injectors leads to methanol backflow that erodes the needle valve, has a large nozzle length-to-diameter ratio, and poses a risk of adhesion to the wall, increasing the probability of failure.
The valve body of the injector is designed with a first nozzle and a first chamber. The nozzle and the chamber are connected. The nozzle has a small size in the axial direction and forms an angle with the axis of the chamber. Multiple nozzles and chambers are provided. The shape of the nozzle matches the shape of the chamber to reduce the length-to-diameter ratio and the through-span. A needle valve structure is used to form a fuel passage to avoid backflow and wall adhesion.
It reduces the probability of injector and engine failure, improves the reliability of injectors and engines, makes methanol injection more stable, reduces energy loss and eddies, and improves injection volume and uniformity.
Smart Images
Figure CN224478997U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of automotive technology, and in particular relates to an injector and an engine. Background Technology
[0002] The methanol injector is an important component of the methanol engine fuel supply system. Its main function is to inject methanol fuel into the engine cylinder in the form of atomized particles to ensure the normal operation of the engine.
[0003] The methanol injector has a pressure chamber for storing methanol, providing a stable supply of methanol for the injection process.
[0004] The pressure chambers of existing methanol injectors are mostly annular or conical, and their dimensions are relatively small in the direction of the injector orifice axis. This not only causes methanol to flow back along the orifice after injection stops, causing erosion of the internal needle valve, but also results in a relatively large length-to-diameter ratio and a large penetration distance of the orifice, increasing the risk of methanol adhering to the wall. Utility Model Content
[0005] This utility model aims to at least partially solve one of the technical problems in the related art.
[0006] On one hand, embodiments of this application provide an injector, including:
[0007] A valve body having a first cavity, a first nozzle, and a first chamber, one end of the first nozzle communicating with the first chamber, and the other end of the first nozzle communicating with the outside of the valve body; and
[0008] A first needle valve is located in the first cavity. When the first needle valve is in the first position, the outer wall of the first needle valve contacts the inner wall of the valve body to form a first contact portion and a second contact portion. The outer wall of the first needle valve located between the first contact portion and the second contact portion defines a second chamber portion with the inner wall of the valve body. The second chamber portion communicates with the first chamber portion, and the first chamber portion and the second chamber portion form a first pressure chamber.
[0009] In some embodiments, the axis of the first nozzle and the axis of the first chamber form an angle of 0°-30°.
[0010] In some embodiments, the first nozzle is circular in shape on a cross-section perpendicular to its axial direction, and the first chamber is circular in shape on a cross-section perpendicular to its axial direction.
[0011] In some embodiments, a first fuel passage is formed between the first needle valve and the valve body, and the first fuel passage and the second chamber are arranged along the axial direction of the valve body;
[0012] When the first needle valve is in the first position, the first fuel passage and the second chamber are not connected. When the first needle valve leaves the first position, the first fuel passage and the second chamber are connected.
[0013] In some embodiments, the injector further includes a second needle valve, the first needle valve having a second inner cavity, the second needle valve being disposed in the second inner cavity, and when the second needle valve is in a second position, a portion of the outer wall of the second needle valve is in contact with a portion of the inner wall of the first needle valve, the second needle valve and the first needle valve forming a third chamber, the third chamber being semi-circular in shape along the axial direction of the valve body.
[0014] In some embodiments, a second fuel passage is formed between the second needle valve and the first needle valve, and the second fuel passage and the third chamber are arranged along the axial direction of the valve body;
[0015] When the second needle valve is in the second position, the second fuel passage is not connected to the third chamber. When the second needle valve is away from the second position, the second fuel passage is connected to the third chamber.
[0016] In some embodiments, the first needle valve is further provided with a second nozzle, one end of which is connected to the third chamber and the other end of which is connected to the outside of the valve body.
[0017] In some embodiments, the first needle valve is further provided with a fourth chamber, which is located between the second nozzle and the third chamber, with one end of the fourth chamber communicating with the second nozzle and the other end of the fourth chamber communicating with the third chamber.
[0018] In some embodiments, the second nozzle is circular in shape on a cross-section perpendicular to its axial direction, and the fourth chamber is circular in shape on a cross-section perpendicular to its axial direction.
[0019] On the other hand, embodiments of this application also provide an engine, including an injector and a cylinder as described above, wherein the injector is disposed in the cylinder.
[0020] The injector provided in this embodiment has a valve body with a first nozzle and a first chamber. One end of the first nozzle communicates with the first chamber, and the other end communicates with the outside of the valve body. This makes the size of the first nozzle in its axial direction relatively small, which not only prevents the first fuel from flowing back along the first nozzle and causing erosion of the first needle valve, but also reduces the length-to-diameter ratio and penetration distance of the first nozzle, reducing the risk of first fuel adhering to the valve wall. This, in turn, reduces the probability of injector and engine failure and improves the reliability of the injector and engine. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the structure of an injector provided in one embodiment of the present invention;
[0023] Figure 2 This is a cross-sectional view of an injector provided in one embodiment of the present invention.
[0024] The annotations in the attached figures are explained as follows:
[0025] 10. Injector;
[0026] 1. Valve body; 11. First nozzle; 12. First chamber;
[0027] 2. First needle valve; 21. First nozzle;
[0028] 3. Second Chamber;
[0029] 4. Second needle valve;
[0030] 5. The Third Department;
[0031] 6. First fuel passage;
[0032] 7. Second fuel passage;
[0033] 8. First contact part;
[0034] 9. Second contact part;
[0035] θ, included angle. Detailed Implementation
[0036] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the application. Similarly, the following embodiments are only some, not all, embodiments of the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.
[0037] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.
[0038] Please see Figure 1 and Figure 2 On one hand, this application provides an injector 10, which includes a valve body 1 and a first needle valve 2. The valve body 1 has a first cavity, a first nozzle 11, and a first chamber 12. The first needle valve 2 is located in the first cavity. When the first needle valve 2 is in a first position, the outer wall of the first needle valve 2 contacts the inner wall of the valve body 1 to form a first contact portion 8 and a second contact portion 9. The outer wall of the first needle valve 2 located between the first contact portion 8 and the second contact portion 9 and the inner wall of the valve body 1 define a second chamber 3, which communicates with the first chamber 12.
[0039] Specifically, the valve body 1 has a first cavity, and the first needle valve 2 can move axially within the first cavity along the valve body 1. When the first needle valve 2 moves to the first position, the outer wall of the first needle valve 2 contacts the inner wall of the valve body 1, and a second chamber 3 is formed between the first needle valve 2 and the valve body 1.
[0040] The valve body 1 has an opening at one end along its axial direction, and the first needle valve 2 has the opening blocked at one end along its axial direction.
[0041] Furthermore, the first needle valve 2 includes an exposed portion that extends out of the opening and is located outside the first cavity.
[0042] The volume of the second chamber 3 is greater than the volume of the first chamber 12. Of course, in other embodiments, the volume of the second chamber 3 may be equal to or slightly less than the volume of the first chamber 12.
[0043] The injector 10 provided in this embodiment has a valve body 1 with a first nozzle 11 and a first chamber 12. One end of the first nozzle 11 communicates with the first chamber 12, and the other end of the first nozzle 11 communicates with the outside of the valve body 1. This makes the size of the first nozzle 11 smaller in its axial direction, which not only avoids the first fuel flowing back along the first nozzle 11 and causing erosion of the first needle valve 2, but also reduces the length-to-diameter ratio and penetration distance of the first nozzle 11, reducing the risk of first fuel adhering to the wall. This reduces the failure probability of the injector 10 and the engine, and improves the reliability of the injector 10 and the engine.
[0044] The first fuel is methanol (as an example of the first fuel). Of course, in other embodiments, the first fuel may also be high-pressure oil.
[0045] In some embodiments, the area of the first chamber 12 in a cross-section perpendicular to its axis gradually decreases along a direction away from the second chamber 3. By setting the area of the first chamber 12 in a cross-section perpendicular to its axis to gradually decrease along a direction away from the second chamber 3, the flow rate of methanol can be increased, and the injection distance of methanol can be increased.
[0046] In some embodiments, the axis of the first nozzle 11 and the axis of the first chamber form an angle θ, which is 0°-30°. By setting the axis of the first nozzle 11 to form an angle θ with the axis of the first chamber 12, the pressure generated by methanol in the first chamber 12 can directly act along the axis of the first nozzle 11, and the flow direction of methanol is basically consistent with the inlet direction of the first nozzle 11. This reduces turbulence and eddies of methanol at the connection between the first chamber 12 and the first nozzle 11, allowing methanol to enter the first nozzle 11 more smoothly. On the other hand, the pressure in the first chamber 12 can be directly transmitted to the first nozzle 11 without generating additional resistance or pressure loss due to changes in direction.
[0047] The included angle θ can be 0°, 10°, 20°, 30° or any range of two of the above values.
[0048] Furthermore, the axis of the first nozzle 11 coincides with the axis of the first chamber 12. By aligning the axis of the first nozzle 11 with the axis of the first chamber 12, the flow direction of methanol is made completely consistent with the inlet direction of the first nozzle 11, further reducing the turbulence and eddies of methanol at the connection between the first chamber 12 and the first nozzle 11, allowing methanol to enter the first nozzle 11 more smoothly.
[0049] Multiple first nozzles 11 are provided, and these multiple first nozzles 11 are evenly spaced along the circumference of the valve body 1. By providing multiple first nozzles 11, methanol can be injected simultaneously. Compared to a single first nozzle 11, more methanol can be injected per unit time, thus significantly increasing the injection volume. Providing multiple first nozzles 11 also disperses the injection energy, allowing for a more stable methanol injection and preventing strong turbulence from impacting or damaging the valve body 1. Furthermore, by evenly distributing multiple first nozzles 11 along the circumference of the valve body 1, methanol can be injected from each nozzle 11 at a relatively consistent flow rate and velocity, resulting in a uniform methanol distribution in the target area. This also prevents damage caused by localized overload of the valve body 1.
[0050] Multiple first chambers 12 are provided, and the multiple first chambers 12 are evenly spaced along the circumference of the valve body 1. Multiple first nozzles 11 are provided in a one-to-one correspondence with the multiple first chambers 12.
[0051] In some embodiments, the shape of the first nozzle 11 on a cross-section perpendicular to its axial direction is the same as the shape of the first chamber 12 on the same cross-section perpendicular to its axial direction. By setting the shape of the first nozzle 11 on the same cross-section perpendicular to its axial direction as the shape of the first chamber 12 on the same cross-section perpendicular to its axial direction, on the one hand, the flow path of methanol is smoother when it enters the first nozzle 11 from the first chamber 12, reducing the abrupt change of methanol at the boundary connecting the first chamber 12 and the first nozzle 11, and achieving a smoother transition of methanol from the first chamber 12 to the first nozzle 11, thus reducing energy loss. On the other hand, the distribution of methanol from the first chamber 12 into the first nozzle 11 is more uniform, reducing methanol fluctuations during injection, and achieving methanol ejection from the first nozzle 11 at a more uniform speed and direction, forming a more stable jet flow.
[0052] In some embodiments, the first nozzle 11 is circular in shape on a cross-section perpendicular to its axial direction, and the first chamber 12 is circular in shape on a cross-section perpendicular to its axial direction. By setting the first nozzle 11 and the first chamber 12 to be circular in shape on a cross-section perpendicular to their axial direction, methanol can have a more uniform streamline distribution when flowing in the first chamber 12 and the first nozzle.
[0053] Of course, in other embodiments, the first nozzle 11 is elliptical in shape on a cross-section perpendicular to its axial direction, and the first chamber 12 is elliptical in shape on a cross-section perpendicular to its axial direction; alternatively, the first nozzle 11 may be polygonal in shape on a cross-section perpendicular to its axial direction, and the first chamber 12 may be polygonal in shape on a cross-section perpendicular to its axial direction.
[0054] In some embodiments, on a cross-section perpendicular to the axial direction of the first nozzle 11, the areas of the second chamber 3, the first chamber 12, and the first nozzle 11 decrease sequentially. By setting the areas of the second chamber 3, the first chamber 12, and the first nozzle 11 to decrease sequentially on a cross-section perpendicular to the axial direction of the first nozzle 11, methanol can be accelerated to a very high speed, thereby achieving efficient injection.
[0055] In some embodiments, the shape of the first chamber 12 on a cross-section perpendicular to its axial direction is the same as the shape of the second chamber 3 on the same cross-section perpendicular to its axial direction. By setting the shape of the first chamber 12 on a cross-section perpendicular to its axial direction to be the same as the shape of the second chamber 3 on the same cross-section perpendicular to its axial direction, the flow path of fuel is smoother when it enters the first chamber 12 from the second chamber 3, reducing the abrupt change of fuel at the boundary connecting the second chamber 3 and the first chamber 12, and enabling a smoother transition of fuel from the second chamber 3 to the first chamber 12, thus reducing energy loss.
[0056] The shape of the first chamber 12 on a cross-section perpendicular to its axial direction and the shape of the second chamber 3 on a cross-section perpendicular to its axial direction are both circular. Of course, in other embodiments, the shape of the first chamber 12 on a cross-section perpendicular to its axial direction and the shape of the second chamber 3 on a cross-section perpendicular to its axial direction may also be elliptical or polygonal.
[0057] In some embodiments, a first fuel passage 6 is formed between the first needle valve 2 and the valve body 1, and the first fuel passage 6 and the second chamber 3 are arranged axially along the valve body 1. When the first needle valve 2 is in the first position, the first fuel passage 6 and the second chamber 3 are not in communication; when the first needle valve 2 is out of the first position, the first fuel passage 6 and the second chamber 3 are in communication. In practical applications, when the first needle valve 2 is not in the first position, the first fuel passage 6 and the second chamber 3 are in communication, and methanol can enter the second chamber 3 from the first fuel passage 6. When the first needle valve 2 is in the first position, the first fuel passage 6 and the second chamber 3 are not in communication, and methanol cannot enter the second chamber 3 from the first fuel passage 6.
[0058] In some embodiments, the injector 10 further includes a second needle valve 4. The first needle valve 2 has a second inner cavity, and the second needle valve 4 is disposed in the second inner cavity. When the second needle valve 4 is in a second position, a portion of the outer wall of the second needle valve 4 contacts a portion of the inner wall of the first needle valve 2. The second needle valve 4 and the first needle valve 2 form a third chamber 5, and the third chamber 5 has a semi-circular shape along the axial direction of the valve body 1. By setting the third chamber 5 to have a semi-circular shape along the axial direction of the valve body 1, the pressure can be distributed more evenly. When pressure is applied to the inner surface of the third chamber 5, the pressure is transmitted along the curvature direction of the sphere, making the stress on each part of the third chamber 5 relatively uniform.
[0059] Of course, in other embodiments, the third chamber 5 may also be polygonal in shape along the axial direction of the valve body 1.
[0060] In some embodiments, a second fuel passage 7 is formed between the second needle valve 4 and the first needle valve 2, and the second fuel passage 7 and the third chamber 5 are arranged axially along the valve body 1. When the second needle valve 4 is in the second position, the second fuel passage 7 and the third chamber 5 are not in communication; when the second needle valve 4 is away from the second position, the second fuel passage 7 and the third chamber 5 are in communication. In practical applications, when the second needle valve 4 is not in the second position, the second fuel passage 7 and the third chamber 5 are in communication, and the second fuel can enter the third chamber 5 from the second fuel passage 7. When the second needle valve 4 is in the second position, the second fuel passage 7 and the third chamber 5 are not in communication, and the second fuel cannot enter the third chamber 5 from the second fuel passage 7.
[0061] The second fuel is high-pressure oil (as an example of a second fuel). Of course, in other embodiments, the second fuel may also be methanol.
[0062] In some embodiments, the first needle valve 2 is further provided with a second nozzle 21, one end of which communicates with the third chamber 5, and the other end of which communicates with the outside of the valve body 1. By providing a second nozzle 21 on the first needle valve 2, and making one end of the second nozzle 21 communicate with the third chamber 5 and the other end of the second nozzle 21 communicate with the outside of the valve body 1, high-pressure oil can enter the first nozzle 21 through the third chamber 5 and then be sprayed from the first nozzle 21 to the outside of the valve body 1.
[0063] Furthermore, the second nozzle 21 has a circular shape on a cross-section perpendicular to its axis. Of course, in other embodiments, the second nozzle 21 may also have an elliptical or polygonal shape on a cross-section perpendicular to its axis.
[0064] Multiple second nozzles 21 are provided, and these multiple nozzles 21 are evenly spaced along the circumference of the first needle valve 2. By providing multiple second nozzles 21, high-pressure oil can be injected simultaneously. Compared to providing a single second nozzle 21, more high-pressure oil can be injected per unit time, thus significantly increasing the injection volume. Providing multiple second nozzles 21 also disperses the injection energy, making the high-pressure oil ejected more stably and preventing the strong turbulence generated by the injection from impacting or damaging the first needle valve 2. By providing multiple second nozzles 21 evenly spaced along the circumference of the first needle valve 2, high-pressure oil can be ejected from each nozzle 21 at a relatively consistent flow rate and speed, thus forming a uniform high-pressure oil portion in the target area, while also preventing damage caused by localized overload of the first needle valve 2.
[0065] In some embodiments, the first needle valve 2 is further provided with a fourth chamber, which is located between the second nozzle 21 and the third chamber 5. One end of the fourth chamber communicates with the second nozzle 21, and the other end communicates with the third chamber 5. By providing the fourth chamber, the size of the second nozzle 21 in its axial direction is reduced, which not only prevents high-pressure oil from flowing back along the second nozzle 21 and causing erosion of the second needle valve 4, but also reduces the length-to-diameter ratio and penetration distance of the second nozzle 21, reducing the risk of high-pressure oil adhering to the wall. This reduces the probability of failure of the injector 10 and the engine, and improves the reliability of the injector 10 and the engine.
[0066] In some embodiments, the second nozzle 21 is circular in shape on a cross-section perpendicular to its axial direction, and the fourth chamber is circular in shape on a cross-section perpendicular to its axial direction. By setting the second nozzle 21 and the second chamber to be circular in shape on a cross-section perpendicular to its axial direction, a more uniform streamline distribution can be achieved when the high-pressure oil flows within the second chamber and the second nozzle 21.
[0067] On the other hand, embodiments of this application also provide an engine, including the aforementioned injector 10 and cylinder, with the injector 10 disposed in the cylinder. Since this engine includes the aforementioned injector 10, it also has the advantages of low failure probability and high reliability.
[0068] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0070] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0071] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0072] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0073] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. An injector, characterized in that, include: A valve body having a first cavity, a first nozzle, and a first chamber, one end of the first nozzle communicating with the first chamber, and the other end of the first nozzle communicating with the outside of the valve body; and A first needle valve is located in the first cavity. When the first needle valve is in the first position, the outer wall of the first needle valve contacts the inner wall of the valve body to form a first contact portion and a second contact portion. The outer wall of the first needle valve located between the first contact portion and the second contact portion defines a second chamber portion with the inner wall of the valve body. The second chamber portion communicates with the first chamber portion.
2. The injector according to claim 1, characterized in that, The axis of the first nozzle and the axis of the first chamber form an angle of 0°-30°.
3. The injector according to claim 2, characterized in that, The first nozzle is circular in shape on a cross-section perpendicular to its axial direction, and the first chamber is circular in shape on a cross-section perpendicular to its axial direction.
4. The injector according to claim 1, characterized in that, A first fuel passage is formed between the first needle valve and the valve body, and the first fuel passage and the second chamber are arranged along the axial direction of the valve body; When the first needle valve is in the first position, the first fuel passage and the second chamber are not connected. When the first needle valve leaves the first position, the first fuel passage and the second chamber are connected.
5. The injector according to any one of claims 1-4, characterized in that, It also includes a second needle valve, the first needle valve has a second inner cavity, the second needle valve is disposed in the second inner cavity, when the second needle valve is in the second position, a portion of the outer wall of the second needle valve contacts a portion of the inner wall of the first needle valve, the second needle valve and the first needle valve form a third chamber, the third chamber is semi-circular in shape along the axial direction of the valve body.
6. The injector according to claim 5, characterized in that, A second fuel passage is formed between the second needle valve and the first needle valve, and the second fuel passage and the third chamber are arranged along the axial direction of the valve body; When the second needle valve is in the second position, the second fuel passage is not connected to the third chamber. When the second needle valve is away from the second position, the second fuel passage is connected to the third chamber.
7. The injector according to claim 5, characterized in that, The first needle valve is also provided with a second nozzle, one end of which is connected to the third chamber and the other end of which is connected to the outside of the valve body.
8. The injector according to claim 7, characterized in that, The first needle valve is also provided with a fourth chamber, which is located between the second nozzle and the third chamber. One end of the fourth chamber is connected to the second nozzle, and the other end of the fourth chamber is connected to the third chamber.
9. The injector according to claim 8, characterized in that, The second nozzle is circular in shape on a cross-section perpendicular to its axial direction, and the fourth chamber is also circular in shape on a cross-section perpendicular to its axial direction.
10. An engine, characterized in that, It includes the injector and cylinder as described in any one of claims 1-9, wherein the injector is disposed in the cylinder.