Fuel injector and engine

Abstract

The invention relates to the technical field of automobile power devices, and particularly discloses a fuel injector and an engine, a control valve is adopted to drive a needle valve to move so as to open a fuel injection hole, mixed fuel at the bottom of a mixing cavity enters an engine combustion chamber from the fuel injection hole, and at the moment, oil pressure at the bottom of the mixing cavity is rapidly reduced; the second fuel overflows into the mixing cavity through the oil inlet passage and the fuel cavity in sequence, forms mixed fuel with the first fuel from the upper part of the mixing cavity, and is injected into an engine combustion chamber along with the first fuel; mixed injection of two different kinds of fuel can be achieved in the same fuel injector, the complexity of an injection system is reduced, and the economical efficiency, the dynamic property and the emission performance of an engine are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive power devices, and particularly to a fuel injector and an engine. Background Art

[0002] A fuel injector is used to directly inject fuel into a cylinder or an intake passage under a certain pressure, and is an important structural component in an engine fuel supply system. Its fuel injection performance has a very important impact on the engine performance.

[0003] In order to ensure the sustainable development of energy, the existing automotive field has begun to seek alternative energy sources available for vehicles. And with the gradual deepening of the environmental protection concept, the application of low-carbon and zero-carbon fuels in vehicles has become increasingly urgent. Among them, natural gas, methanol, etc. are used as alternative energy sources, with relatively low costs, relatively easy to prepare, and relatively environmentally friendly emission products. Hydrogen, as a zero-carbon fuel, has emission products that do not contain greenhouse gases and has a high energy density. Therefore, the dynamic performance, economic performance, and emission performance of an engine can be further improved by the flexible mixing ratio of various types of fuels. However, the existing fuel injectors cannot be applied to the injection of multiple fuels, have poor flexibility, and to a certain extent affect the dynamic performance, economic performance, and emission performance of the engine.

[0004] Therefore, there is an urgent need for a fuel injector and an engine to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a fuel injector and an engine, which can realize the mixed injection of two different fuels and effectively improve the economic performance, dynamic performance, and emission performance of the engine.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a fuel injector, comprising:

[0008] An injection body, wherein the injection body is provided with a first fuel passage and a second fuel passage;

[0009] A needle valve assembly, wherein the needle valve assembly includes a valve body and a needle valve. The valve body is fixedly connected to the injection body and is located downstream in the fuel flow direction. The valve body is provided with a mixing chamber and a fuel injection hole communicating with the mixing chamber. The mixing chamber communicates with the first fuel passage. The needle valve is slidably disposed in the valve body, and a fuel chamber and an oil inlet passage are provided in the needle valve. The oil inlet passage communicates the fuel chamber with the second fuel passage, and the fuel chamber communicates with the mixing chamber;

[0010] A one-way valve, wherein the one-way valve is disposed in the fuel chamber and is configured to open or close the oil inlet passage;

[0011] A control valve configured to be able to drive the needle valve to move so as to open or close the fuel injection hole.

[0012] As a preferred technical solution of the above fuel injector, a control cavity is provided in the injection body, one end of the needle valve is arranged in the control cavity, and the control valve can regulate the fuel pressure in the control cavity to drive the needle valve to move, so that the other end of the needle valve opens or closes the fuel injection hole.

[0013] As a preferred technical solution of the above fuel injector, the fuel injector further includes a first elastic member configured to always have a tendency to drive the needle valve to move towards the position of closing the fuel injection hole.

[0014] As a preferred technical solution of the above fuel injector, the first elastic member is a compression spring.

[0015] As a preferred technical solution of the above fuel injector, the needle valve includes a main body portion and a blocking portion. One end of the main body portion is placed in the control cavity, the other end of the main body portion is connected to the blocking portion. The fuel cavity and the oil inlet passage are provided in the main body portion. The blocking portion is provided with an oil outlet passage and a fuel hole. The oil outlet passage communicates with the fuel cavity, and the fuel hole communicates with the mixing cavity and the oil outlet passage. The blocking portion is used to open or close the fuel injection hole.

[0016] As a preferred technical solution of the above fuel injector, the one-way valve includes a second elastic member and a sealing member. The two ends of the second elastic member respectively abut against the blocking portion and the sealing member, and the second elastic member is configured to always have a tendency to drive the sealing member to move towards the position of closing the oil inlet passage.

[0017] As a preferred technical solution of the above fuel injector, the valve body is provided with a first oil inlet passage and a second oil inlet passage. The first oil inlet passage communicates the first fuel passage with the mixing cavity, and the second oil inlet passage communicates the second fuel passage with the oil inlet passage.

[0018] As a preferred technical solution of the above fuel injector, an oil fuel groove is provided on the inner side wall of the valve body. The oil fuel groove communicates the oil inlet passage with the second oil inlet passage, and the oil pressure in the oil fuel groove is greater than the oil pressure in the mixing cavity.

[0019] As a preferred technical solution of the above fuel injector, the fuel injector further includes a fastener fixedly connected between the valve body and the injection body.

[0020] On the other hand, the present invention also provides an engine, including a combustion chamber and the fuel injector in any of the above solutions, and the fuel injection holes communicate with the combustion chamber.

[0021] The beneficial effects of the present invention are as follows:

[0022] The present invention provides a fuel injector and an engine. The fuel injector includes an injection body, a needle valve assembly, a one-way valve and a control valve. The injection body is provided with a first fuel passage and a second fuel passage. The needle valve assembly includes a valve body and a needle valve. The valve body is fixedly connected to the injection body and is located downstream in the fuel flow direction. The valve body is provided with a mixing chamber and a fuel injection hole communicating with the mixing chamber. The mixing chamber communicates with the first fuel passage. The needle valve is slidably disposed in the valve body, and a fuel chamber and an oil inlet passage are provided in the needle valve. The oil inlet passage communicates the fuel chamber with the second fuel passage, and the fuel chamber communicates with the mixing chamber. The one-way valve is disposed in the fuel chamber and is configured to be able to open or close the oil inlet passage. The control valve is configured to be able to drive the needle valve to move so as to open or close the fuel injection hole. With such a setting, the control valve is used to drive the needle valve to move to open the fuel injection hole. The mixed fuel at the bottom of the mixing chamber enters the engine combustion chamber from the fuel injection hole. At this time, the oil pressure at the bottom of the mixing chamber drops rapidly, and the pressure difference with the oil inlet passage increases. The one-way valve automatically opens, and the second fuel sequentially overflows into the mixing chamber through the oil inlet passage and the fuel chamber, forms mixed fuel with the first fuel from the upper part of the mixing chamber, and is jointly injected into the engine combustion chamber with the first fuel. It can realize the mixed injection of two different fuels in the same fuel injector, reduce the complexity of the injection system, and effectively improve the economy, power performance and emission performance of the engine. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the fuel injector provided by the present invention.

[0024] Wherein:

[0025] 1. Injection body; 101. First fuel passage; 102. Second fuel passage; 103. Control chamber; 104. Pressure regulating passage;

[0026] 2. Needle valve assembly; 21. Valve body; 22. Needle valve;

[0027] 3. Mixing chamber; 4. Fuel injection hole; 5. Fuel chamber; 6. Oil inlet passage;

[0028] 7. Control valve; 8. First elastic member; 9. Oil outlet passage; 10. Fuel hole; 11. Second elastic member; 12. Sealing member; 13. First oil inlet passage; 14. Second oil inlet passage; 15. Fuel tank; 16. Fastener. Detailed Embodiments

[0029] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0031] Unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Unless otherwise clearly defined and limited, the fact that the first feature is "above" or "below" the second feature may include direct contact between the first feature and the second feature, or may include the situation where the first feature and the second feature are not in direct contact but in contact through other features between them. Moreover, the fact that the first feature is "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The fact that the first feature is "below", "under" and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments.

[0034] As Figure 1As shown in the figure, this embodiment provides a fuel injector, which includes an injection body 1, a needle valve assembly 2, a check valve and a control valve 7. The injection body 1 is provided with a first fuel passage 101 and a second fuel passage 102. The needle valve assembly 2 includes a valve body 21 and a needle valve 22. The valve body 21 is fixedly connected to the injection body 1 and is located downstream in the fuel flow direction. The valve body 21 is provided with a mixing chamber 3 and a fuel injection hole 4 communicating with the mixing chamber 3. The mixing chamber 3 communicates with the first fuel passage 101. The needle valve 22 is slidably disposed in the valve body 21, and a fuel chamber 5 and an oil inlet passage 6 are provided in the needle valve 22. The oil inlet passage 6 communicates the fuel chamber 5 with the second fuel passage 102. The fuel chamber 5 communicates with the mixing chamber 3. The check valve is disposed in the fuel chamber 5 and is configured to be able to open or close the oil inlet passage 6. The control valve 7 is configured to be able to drive the needle valve 22 to move so as to open or close the fuel injection hole 4. With such a setting, the control valve 7 is used to drive the needle valve 22 to move to open the fuel injection hole 4, and the mixed fuel at the bottom of the mixing chamber 3 enters the engine combustion chamber from the fuel injection hole 4. At this time, the oil pressure at the bottom of the mixing chamber 3 drops rapidly, and the pressure difference between the mixing chamber 3 and the oil inlet passage 6 increases. The check valve automatically opens, and the second fuel sequentially overflows into the mixing chamber 3 through the oil inlet passage 6 and the fuel chamber 5, forms a mixed fuel with the first fuel from the upper part of the mixing chamber 3, and is jointly injected into the engine combustion chamber with the first fuel. It can realize the mixed injection of two different fuels in the same fuel injector, reduce the complexity of the injection system, and effectively improve the economy, power performance, and emission performance of the engine.

[0035] It should be noted that the first fuel is the main fuel of the engine that is not easy to be compression-ignited, such as natural gas, methanol, ammonia, gasoline, etc. It is the main body of the engine fuel, accounting for more than 80%. The second fuel is mainly diesel, and can also be other auxiliary fuels that can be used for compression ignition. The second fuel is used to generate high temperature by combustion self-ignition to ignite the first fuel. There is a pressure difference between the first fuel inlet corresponding to the first fuel passage 101 and the second fuel inlet corresponding to the second fuel passage 102. The pressure of the second fuel inlet is greater than the pressure of the first fuel inlet. Specifically, the characteristic value of the pressure difference between the two is between 5 bar and 50 bar. And, according to the actual requirements of the engine, the number and diameter of the first fuel passage 101 and the second fuel passage 102 can be reasonably set.

[0036] In this embodiment, the injection body 1 is provided with a control chamber 103 and a pressure regulating passage 104. The control chamber 103 is connected to the control valve 7 through the pressure regulating passage 104. One end of the needle valve 22 is disposed in the control chamber 103, and the control valve 7 can regulate the fuel pressure in the control chamber 103 to drive the needle valve 22 to move, so that the other end of the needle valve 22 opens or closes the fuel injection hole 4.

[0037] Optionally, to ensure that the needle valve 22 can be reset in time to close the fuel injection hole 4 after the injection stops, the fuel injector further includes a first elastic member 8 disposed in the control chamber 103. The first elastic member 8 is configured to always have a tendency to drive the needle valve 22 to move towards the position closing the fuel injection hole 4. Further, the first elastic member 8 is a compression spring.

[0038] Optionally, to ensure the stable direction of the elastic force of the first elastic member 8 and to prevent the first elastic member 8 from skewing to a certain extent during the elastic deformation process, one end of the first elastic member 8 abuts against the inner wall of the control chamber 103. A convex portion is provided on the end face of one end of the needle valve 22. The other end of the first elastic member 8 is sleeved on the convex portion and abuts against the needle valve 22.

[0039] Optionally, to limit the maximum displacement of the needle valve 22, the needle valve 22 is provided with a stepped portion, and the stepped portion can abut against the injection body 1 to limit the needle valve 22 from continuing to move away from the fuel injection hole 4.

[0040] Specifically, the following technical solution is exemplarily given in this embodiment: The needle valve 22 includes a main body portion and a blocking portion. One end of the main body portion is placed in the control chamber 103, and the other end of the main body portion is connected to the blocking portion. The fuel chamber 5 and the oil inlet passage 6 are provided in the main body portion. The blocking portion is provided with an oil outlet passage 9 and a fuel hole 10. The oil outlet passage 9 communicates with the fuel chamber 5, and the fuel hole 10 communicates with the mixing chamber 3 and the oil outlet passage 9. The blocking portion is used to open or close the fuel injection hole 4.

[0041] Further, the blocking portion and the inner wall of the mixing chamber 3 are sealed in a contact seal band manner to close the fuel injection hole 4. The main body portion and the blocking portion can be connected by hard connection methods such as threaded connection, interference connection or welding, etc., which can be specifically set according to actual requirements and will not be further limited here.

[0042] Optionally, the one-way valve includes a second elastic member 11 and a sealing member 12. The two ends of the second elastic member 11 respectively abut against the blocking portion and the sealing member 12, and the second elastic member 11 is configured to always have a tendency to drive the sealing member 12 to move towards the position closing the oil inlet passage 6. Further, the second elastic member 11 is a compression spring.

[0043] In this embodiment, the sealing member 12 is spherical. In other embodiments, other structural forms for realizing the sealing function can also be adopted, such as conical surface sealing, plane sealing, etc., to realize the one-way valve function, which will not be further limited here.

[0044] Optionally, the valve body 21 is provided with a first oil inlet passage 13 and a second oil inlet passage 14. The first oil inlet passage 13 communicates the first fuel passage 101 with the mixing chamber 3, and the second oil inlet passage 14 communicates the second fuel passage 102 with the oil inlet passage 6.

[0045] Optionally, to better achieve fluid control of the second fuel and reduce the friction coefficient during the relative movement of both the needle valve 22 and the valve body 21, a fuel groove 15 is provided on the inner side wall of the valve body 21. The fuel groove 15 communicates with the fuel inlet passage 6 and the second fuel inlet passage 14, and the oil pressure in the fuel groove 15 is greater than the oil pressure in the mixing chamber 3. It should be noted that the pressure difference between the mixing chamber 3 and the fuel groove 15 is set between 5 bar and 50 bar to ensure that the first fuel in the mixing chamber 3 does not enter the fuel groove 15 through the conjugate seal. A small amount of the second fuel in the fuel groove 15 can leak into the mixing chamber 3, and the flow rate of the second fuel entering the mixing chamber 3 is controlled by the gap of the conjugate seal, making its flow rate lower than the demand for the second fuel under the full operating conditions of the engine.

[0046] In this embodiment, conjugate seal is adopted between the needle valve 22 and the valve body 21. When there is a pressure difference between the control chamber 103 and the fuel groove 15, there will be a small amount of leakage in the conjugate seal, but this leakage is small enough not to affect the pressure maintaining function of the control chamber 103.

[0047] Optionally, to further improve the connection stability and reliability between the valve body 21 and the injection body 1 and achieve good sealing performance, the fuel injector further includes a fastener 16, and the fastener 16 is fixedly connected between the valve body 21 and the injection body 1.

[0048] This embodiment also provides an engine, including a combustion chamber and the fuel injector in the above solution, and the fuel injection hole 4 communicates with the combustion chamber.

[0049] Taking the fuel injector of this embodiment as an example, the working principle is described in detail as follows:

[0050] When the control valve 7 is in the closed and stable state, the control chamber 103, the mixing chamber 3, and the fuel groove 15 are all in a high-pressure state, so that the seal 12 closes the fuel inlet passage 6 and the blocking part closes the fuel injection hole 4.

[0051] When the control valve 7 is opened, the oil pressure in the control chamber 103 drops. At this time, the mixing chamber 3 is in a high-pressure state, and the high pressure in the mixing chamber 3 pushes the needle valve 22, so that the needle valve 22 moves against the elastic force of the first elastic member 8 until the stepped portion of the needle valve 22 collides and abuts against the injection body 1, and the blocking part disengages from the inner wall of the mixing chamber 3. The mixed fuel at the bottom of the mixing chamber 3 is sprayed into the engine combustion chamber from the fuel injection hole 4.

[0052] At this time, the pressure at the bottom of the mixing chamber 3 drops rapidly, and the pressure difference between the oil inlet passage 6 and the bottom of the mixing chamber 3 gradually increases until the oil pressure in the oil inlet passage 6 overcomes the elastic force of the second elastic member 11 to move the seal member 12 and open the oil inlet passage 6. The second fuel sequentially passes through the oil inlet passage 6, the fuel chamber 5 and the oil outlet passage 9, and finally is injected into the bottom of the mixing chamber 3 through the fuel hole 10, forms a mixed fuel with the first fuel from the upper part of the mixing chamber 3, and the two are jointly injected into the engine combustion chamber.

[0053] When the control valve 7 is closed again, the oil pressure in the control chamber 103 rises again to a stable pressure, and the generated oil pressure and the first elastic member 8 jointly push the needle valve 22 to move until the blocking portion of the needle valve 22 contacts and seals the inner wall of the mixing chamber 3 to close the fuel injection hole 4 and stop the injector from injecting. At this time, the pressure at the bottom of the mixing chamber 3 rises rapidly, the pressure difference between the oil inlet passage 6 and the bottom of the mixing chamber 3 returns to normal, the second elastic member 11 resets and pushes the seal member 12 to continue to seal the oil inlet passage 6, and the second fuel stops injecting.

[0054] It should be noted that the sources of the second fuel at the bottom of the mixing chamber 3 are as follows: a part is from the last time the injector stops injecting and enters the bottom of the mixing chamber 3 during the process of the pressure difference between the oil inlet passage 6 and the bottom of the mixing chamber 3 recovering; a part is when the injector is in the injection state and enters the bottom of the mixing chamber 3; a part leaks into the top of the mixing chamber 3 through the coupling seal from the fuel tank 15 due to the pressure difference and finally converges into the bottom of the mixing chamber 3.

[0055] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A fuel injector, characterized in that, Comprising: An injection body (1), the injection body (1) being provided with a first fuel passage (101) and a second fuel passage (102); A needle valve assembly (2), the needle valve assembly (2) including a valve body (21) and a needle valve (22), the valve body (21) being fixedly connected to the injection body (1) and located downstream in the fuel flow direction, the valve body (21) being provided with a mixing chamber (3) and a fuel injection hole (4) communicating with the mixing chamber (3), the mixing chamber (3) communicating with the first fuel passage (101), the needle valve (22) being slidably disposed within the valve body (21), and a fuel chamber (5) and an oil inlet passage (6) being provided within the needle valve (22), the oil inlet passage (6) communicating the fuel chamber (5) with the second fuel passage (102), the fuel chamber (5) communicating with the mixing chamber (3); A check valve, the check valve being disposed within the fuel chamber (5) and configured to be able to open or close the oil inlet passage (6); A control valve (7), the control valve (7) being configured to be able to drive the needle valve (22) to move so that the needle valve (22) opens or closes the fuel injection hole (4).

2. The fuel injector according to claim 1, characterized in that, The injection body (1) is provided with a control chamber (103), one end of the needle valve (22) being disposed within the control chamber (103), the control valve (7) being able to regulate the fuel pressure within the control chamber (103) to drive the needle valve (22) to move, such that the other end of the needle valve (22) opens or closes the fuel injection hole (4).

3. The fuel injector according to claim 2, characterized in that, The fuel injector further includes a first elastic member (8), the first elastic member (8) being configured to always have a tendency to drive the needle valve (22) to move towards the position of closing the fuel injection hole (4).

4. The fuel injector according to claim 3, characterized in that, The first elastic member (8) is a compression spring.

5. The fuel injector according to claim 2, characterized in that, The needle valve (22) includes a main body portion and a blocking portion, one end of the main body portion being disposed within the control chamber (103), the other end of the main body portion being connected to the blocking portion, the fuel chamber (5) and the oil inlet passage (6) being provided in the main body portion, the blocking portion being provided with an oil outlet passage (9) and a fuel hole (10), the oil outlet passage (9) communicating with the fuel chamber (5), the fuel hole (10) communicating the mixing chamber (3) with the oil outlet passage (9), the blocking portion being used to open or close the fuel injection hole (4).

6. The fuel injector according to claim 5, characterized in that, The check valve includes a second elastic member (11) and a sealing member (12), both ends of the second elastic member (11) respectively abutting against the blocking portion and the sealing member (12), and the second elastic member (11) being configured to always have a tendency to drive the sealing member (12) to move towards the position of closing the oil inlet passage (6).

7. The fuel injector according to any one of claims 1-6, characterized in that, The valve body (21) is provided with a first oil inlet passage (13) and a second oil inlet passage (14), the first oil inlet passage (13) communicating the first fuel passage (101) with the mixing chamber (3), the second oil inlet passage (14) communicating the second fuel passage (102) with the oil inlet passage (6).

8. The fuel injector according to claim 7, characterized in that, An inner side wall of the valve body (21) is provided with a fuel tank (15), the fuel tank (15) communicates with the fuel inlet passage (6) and the second fuel inlet passage (14), and an oil pressure in the fuel tank (15) is greater than an oil pressure in the mixing chamber (3).

9. The fuel injector according to any one of claims 1-6, characterized in that, The fuel injector further includes a fastener (16), and the fastener (16) is fixedly connected between the valve body (21) and the injection body (1).

10. An engine, characterized in that, A combustion chamber and the fuel injector according to any one of claims 1-9 are included, and the fuel injection hole (4) communicates with the combustion chamber.

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