An electronically controlled fuel injection valve

Abstract

The present invention discloses an electronically controlled fuel injection valve, comprising a housing provided with a first fuel channel; a sleeve provided with a second fuel channel that can communicate with the first fuel channel, and a pressure chamber provided at the end of the sleeve; a needle valve provided with a third fuel channel that communicates with the second fuel channel, and the third fuel channel communicates with the pressure chamber; a nozzle provided with a spray hole that communicates with the pressure chamber, and when the fuel pressure in the pressure chamber is greater than a preset value, the high-pressure fuel in the pressure chamber can drive the needle valve away from the nozzle; a reset mechanism, when the fuel pressure in the pressure chamber is less than a preset value, the reset mechanism resets the needle valve; a valve stem that can connect or disconnect the first fuel channel with the second fuel channel; a servo drive mechanism that can drive the valve stem to move so that the first fuel channel and the second fuel channel are connected, and the high-pressure fuel drives the valve stem to disconnect the connection between the first fuel channel and the second fuel channel. The electronically controlled fuel injection valve of the present invention can be applied to high-power engines, and has a high degree of integration.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to an electronically controlled fuel injection valve. Background Art

[0002] In order to reduce emissions and improve fuel economy, more and more people are paying attention to electronic fuel injection systems that are more flexible and adjustable in various load areas of engine operation. At present, most common electronic fuel injection systems are based on mechanical, hydraulic and electronic control technologies. They adopt the principle of pressure-time fuel metering and realize flexible control of injection quantity, injection pressure, injection timing and injection rules through closed-loop control of common rail pressure. This injection system is not limited by the speed of the diesel engine. The injection pressure and injection duration can be optimized according to the load and speed, which can significantly improve the performance and emissions of the diesel engine at low speed. However, the current electronic fuel injection system is usually used for small power engines with small fuel injection volume, low injection temperature and high fuel quality requirements. For high-power engines, especially high-power marine engines, due to the poor quality of the fuel used, large fuel injection volume, high injection temperature and other reasons, the common electronic fuel injection system on the market is difficult to be promoted and applied on high-power engines. Summary of the invention

[0003] The purpose of the present invention is to provide an electronically controlled fuel injection valve which has a simple structure, a high degree of integration, and low requirements on the quality of the fuel, and can meet the injection requirements of high-power engines for fast, efficient, and large-flow fuel injection.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] An electronically controlled fuel injection valve comprises: a housing, the housing being provided with a first fuel passage; a sleeve, the sleeve being arranged in the housing, the sleeve being provided with a second fuel passage which can communicate with the first fuel passage, and a pressure chamber being arranged at an end of the sleeve; a needle valve, the needle valve being movably arranged in the sleeve, the needle valve being provided with a third fuel passage which communicates with the second fuel passage, and the third fuel passage being connected with the pressure chamber; a nozzle, the nozzle being mounted at one end of the housing and fixedly connected to the sleeve, the nozzle being provided with a spray hole which communicates with the pressure chamber, and when the fuel pressure in the pressure chamber is greater than a preset value, the high-pressure fuel in the pressure chamber can drive the needle valve away from the nozzle to open the spray hole; a reset mechanism, the reset mechanism being provided with between the sleeve and the needle valve, when the fuel pressure in the pressure chamber is less than a preset value, the reset mechanism resets the needle valve so that the needle valve blocks the spray hole; a valve stem, the valve stem is movably arranged in the housing, and the movement of the valve stem can connect or disconnect the first fuel channel with the second fuel channel; a servo drive mechanism, including a solenoid valve and a servo oil supply system, when the servo oil supply system supplies servo oil to the solenoid valve, the servo oil can drive the valve stem to move so that the first fuel channel and the second fuel channel are connected, and when the servo oil supply system does not supply servo oil to the solenoid valve, the high-pressure fuel in the second fuel channel drives the valve stem to move to disconnect the connection between the first fuel channel and the second fuel channel.

[0006] Preferably, the servo drive mechanism also includes a servo oil adapter block, the servo oil adapter block is provided with a servo oil channel, the servo oil channel is connected to the solenoid valve, the solenoid valve is provided with a servo oil inlet throttling hole and a servo oil return throttling hole, the servo oil inlet throttling hole is connected to the servo oil supply system, and the servo oil return throttling hole is connected to a return oil tank.

[0007] Preferably, a driving piston is further provided in the housing, one end of the driving piston abuts against one end of the valve stem, and the driving piston can be driven to move by the servo oil in the servo oil channel.

[0008] Preferably, a pressure regulator is provided in the servo oil supply system, and the pressure regulator is used to adjust the pressure of the servo oil supplied by the servo oil supply system.

[0009] Preferably, the sleeve is provided with a first limiting step, and the needle valve is provided with a first-stage cylindrical surface, and the first-stage cylindrical surface can abut against the first limiting step.

[0010] Preferably, a guide column is provided in the sleeve, a guide hole is provided at one end of the needle valve, and one end of the guide column is placed in the guide hole; the second fuel channel passes through the guide column, and the third fuel channel is connected to the guide hole.

[0011] Preferably, the valve stem is provided with an annular groove, and the annular groove is configured to connect the first fuel channel with the second fuel channel when the valve stem moves toward the second fuel channel.

[0012] Preferably, a circular hole is provided at the end of the sleeve, and the end of the valve stem can be placed in the circular hole and limited by the bottom surface of the circular hole.

[0013] Preferably, one end of the needle valve located in the pressure chamber is provided with a plurality of radial holes evenly distributed in the circumferential direction, and the plurality of radial holes communicate with the third fuel channel and the pressure chamber.

[0014] Preferably, a first conical surface is provided at one end of the needle valve, the pressure chamber is provided with a second conical surface that can fit with the first conical surface, and a through hole connecting the third fuel channel and the pressure chamber is opened on the first conical surface.

[0015] Beneficial effects of the present invention:

[0016] 1. The electronically controlled fuel injection valve provided by the present invention adopts a servo drive mechanism with a solenoid valve in structure, which can be applied to high-power engines with poor fuel quality, large injection volume and high injection temperature, and has a high degree of integration and a simple structure.

[0017] 2. The electronically controlled fuel injection valve provided by the present invention realizes the regulation of the servo oil flow rate during the servo oil inlet and oil return processes by setting a servo oil inlet throttle hole and a servo oil return throttle hole in the solenoid valve, thereby realizing flexible control of fuel injection of the electronically controlled fuel injection valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a cross-sectional view of an electronically controlled fuel injection valve provided by an embodiment of the present invention;

[0019] Figure 2 The present invention Figure 1 A magnified schematic diagram of point A;

[0020] Figure 3 The present invention Figure 1 An enlarged schematic diagram of point B;

[0021] Figure 4 It is a schematic diagram of the assembly of a needle valve and a pressure chamber provided by the present invention;

[0022] Figure 5It is a schematic diagram of assembly of another needle valve and pressure chamber provided by the present invention.

[0023] In the figure:

[0024] 1. Housing; 11. Drive housing; 111. First fuel channel; 12. Mounting sleeve; 2. Sleeve; 21. Guide sleeve; 211. Second fuel channel; 212. Circular hole; 213. First limiting step; 214. Guide column; 2141. Second limiting step; 22. Needle valve body; 221. Pressure chamber; 222. Second conical surface; 3. Needle valve; 31. Radial hole; 32. Third fuel channel; 33. Guide hole; 34. First-stage cylindrical surface; 35, first conical surface; 36, through hole; 4, nozzle; 41, spray hole; 5, reset mechanism; 6, valve stem; 61, ring groove; 62, cut groove; 7, servo drive mechanism; 71, servo oil supply system; 72, return oil tank; 73, solenoid valve; 731, servo oil inlet throttle hole; 732, servo oil return throttle hole; 74, servo oil adapter block; 741, servo oil channel; 8, drive piston; 9, high-pressure fuel common rail. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0026] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0028] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0029] The present embodiment provides an electronically controlled fuel injection valve, which has a simple structure, a high degree of integration, and low requirements for fuel quality. It can meet the injection needs of high-power engines for fast, efficient, and large-flow fuel injection, and is particularly suitable for high-power marine diesel engines, dual-fuel engines, and even multi-fuel engines.

[0030] Embodiment 1

[0031] like Figure 1As shown, an electronically controlled fuel injection valve provided in this embodiment includes a housing 1, a sleeve 2, a needle valve 3, a nozzle 4, a reset mechanism 5, a valve stem 6, and a servo drive mechanism 7, wherein the housing 1 is provided with a first fuel channel 111, the sleeve 2 is arranged in the housing 1, the sleeve 2 is provided with a second fuel channel 211 which can be communicated with the first fuel channel 111, and a pressure chamber 221 is provided at the end of the sleeve 2, the needle valve 3 is movably arranged in the sleeve 2, the needle valve 3 is provided with a third fuel channel 32 which is communicated with the second fuel channel 211, and the third fuel channel 32 is communicated with the pressure chamber 221, the nozzle 4 is installed at one end of the housing 1 and is fixedly connected to the sleeve 2, the nozzle 4 is provided with a spray hole 41 which is communicated with the pressure chamber 221, and when the fuel pressure in the pressure chamber 221 is greater than a preset value, the high-pressure fuel in the pressure chamber 221 can drive the needle valve 3 away from the spray hole 41. Nozzle 4 is provided between sleeve 2 and needle valve 3 to open the spray hole 41. Reset mechanism 5 is provided between sleeve 2 and needle valve 3. When the fuel pressure in pressure chamber 221 is less than a preset value, reset mechanism 5 resets needle valve 3 to make needle valve 3 block spray hole 41. Valve stem 6 is movably provided in housing 1. Movement of valve stem 6 can connect or disconnect first fuel channel 111 with second fuel channel 211. Servo drive mechanism 7 includes solenoid valve 73 and servo oil supply system 71. When servo oil supply system 71 supplies servo oil to solenoid valve 73, servo oil can drive valve stem 6 to move to connect first fuel channel 111 with second fuel channel 211. When servo oil supply system 71 does not supply servo oil to solenoid valve 73, high pressure fuel in second fuel channel 211 drives valve stem 6 to move to disconnect connection between first fuel channel 111 and second fuel channel 211. Furthermore, the servo drive mechanism 7 also includes a servo oil adapter block 74, which is arranged on the shell 1 and fixedly connected to the shell 1, and the servo oil adapter block 74 is provided with a servo oil channel 741, and the servo oil channel 741 is connected to the solenoid valve 73. The servo oil flowing through the solenoid valve 73 can flow into the shell 1 through the servo oil channel 741.

[0032] The electronically controlled fuel injection valve provided in this embodiment controls the supply and disconnection of servo oil through the servo drive mechanism 7. When the servo oil is supplied, the servo oil drives the valve stem 6 to move, thereby connecting the first fuel channel 111 with the second fuel channel 211. The high-pressure fuel passes through the first fuel channel 111 and the second fuel channel 211 in sequence, and then enters the third fuel channel 32 connected to the second fuel channel 211, and enters the pressure chamber 221 connected to the third fuel channel 32. When the pressure of the high-pressure fuel in the pressure chamber 221 is greater than the preset value, the high-pressure fuel in the pressure chamber 221 drives the needle valve 3 away from the nozzle 4, and the high-pressure fuel in the third fuel channel 32 enters the nozzle 4, thereby realizing fuel injection of a high-power engine.

[0033] Optionally, the housing 1 may include a mounting sleeve 12 and a drive housing 11, the mounting sleeve 12 is fixedly connected to the drive housing 11, the drive housing 11 is provided with an upper passage, a side passage and a lower passage, the upper passage of the drive housing 11 and the servo oil adapter block 74 together constitute a servo oil drive oil chamber; the side passage is the first fuel channel 111 of the present embodiment, and the first fuel channel 111 is directly connected to the high-pressure fuel common rail 9 through a high-pressure oil pipe for high-pressure fuel inlet; the above-mentioned valve stem 6 is arranged in the lower passage, and the valve stem 6 can move in the lower passage.

[0034] Furthermore, a driving piston 8 may be provided in the driving housing 11. The driving piston 8 may be movably placed in the servo oil driving oil chamber, and one end of the driving piston 8 abuts against one end of the valve stem 6. The servo oil enters the servo oil driving oil chamber through the servo oil channel 741 of the servo oil adapter block 74, so that the servo oil driving oil chamber generates pressure. The pressure pushes the driving piston 8 and the valve stem 6 to move downward at the same time, thereby connecting the first fuel channel 111 and the second fuel channel 211, and the high-pressure fuel can enter the second fuel channel 211 through the first fuel channel 111; when the servo oil pressure in the servo oil driving oil chamber is released, the high-pressure fuel in the second fuel channel 211 will push the valve stem 6 and the driving piston 8 to move upward at the same time, and the valve stem 6 cuts off the connection between the first fuel channel 111 and the second fuel channel 211.

[0035] Optionally, the sleeve 2 may be composed of a needle valve body 22 and a guide sleeve 21, wherein the needle valve body 22 and the guide sleeve 21 are fixedly connected, the nozzle 4 is fixedly connected to the end surface of the needle valve body 22, the pressure chamber 221 may be arranged at the end of the needle valve body 22, and the third fuel channel 32 may be connected to the spray hole 41 arranged on the nozzle 4 through the pressure chamber 221. A circular hole 212 and a second fuel channel 211 are arranged in the middle of the guide sleeve 21, wherein an annular area formed between the circular hole 212 and the valve stem 6 can be used to connect the first fuel channel 111 and the second fuel channel 211 after the valve stem 6 moves downward, and the bottom surface of the circular hole 212 can be used for mechanical limit when the valve stem 6 moves downward, and the second fuel channel 211 is connected to the circular hole 212; a guide column 214 is arranged inside the guide sleeve 21, and the guide column 214 can play a guiding role when the needle valve 3 moves, and an annular deep groove is formed between the guide column 214 and the barrel wall of the guide sleeve 21, and the reset mechanism 5 can be arranged in the annular deep groove of the guide sleeve 21. Furthermore, the guide column 214 may be a two-stage stepped structure, and the lower end of the guide column 214 may form a clearance fit with the needle valve 3, thereby sealing the high-pressure fuel between the guide sleeve 21 and the needle valve 3, and the step of the guide column 214 may be used for mechanical limiting when the needle valve 3 moves upward. Preferably, the reset mechanism 5 may be an elastic element, preferably a spring.

[0036] Alternatively, if Figure 2As shown, the needle valve 3 is further provided with a guide hole 33 inside, and the guide hole 33 and the guide column 214 of the guide sleeve 21 can form a gap seal, and the second limiting step 2141 of the guide column 214 can abut against the end surface of the needle valve 3 provided with the guide hole 33, so as to limit the upward movement of the needle valve 3, and the guide hole 33 is connected with the third fuel channel 32; the needle valve 3 is provided with a radial hole 31 below, and the third fuel channel 32 is connected with the radial hole 31 below the needle valve 3, and the radial hole 31 below the needle valve 3 is placed in the pressure chamber 221 so that the high-pressure fuel can smoothly enter the pressure chamber 221 composed of the needle valve 3 and the needle valve body 22; the needle valve 3 is provided with a radial hole 31 below, and the third fuel channel 32 is connected with the radial hole 31 below the needle valve 3, and the radial hole 31 below the needle valve 3 is placed in the pressure chamber 221 so that the high-pressure fuel can smoothly enter the pressure chamber 221 composed of the needle valve 3 and the needle valve body 22; The upper end of the valve 3 is placed in the annular deep groove of the guide sleeve 21 and can be used as the base of the reset mechanism 5. The lower end of the needle valve 3 can abut against the spray hole 41 to form a clearance fit to ensure the sealing of the high-pressure fuel in the pressure chamber 221. When the fuel pressure in the pressure chamber 221 is greater than the preset value, the high-pressure fuel in the pressure chamber 221 can drive the needle valve 3 away from the nozzle 4 to open the spray hole 41. At this time, the third fuel channel 32 is connected with the spray hole 41 of the nozzle 4 through the pressure chamber 221. When the fuel pressure in the pressure chamber 221 is less than the preset value, the reset mechanism 5 resets the needle valve 3 so that the needle valve 3 blocks the spray hole 41. Optionally, the guide sleeve 21 is further provided with a first limiting step 213, and the needle valve 3 is further provided with a first-stage cylindrical surface 34. The first-stage cylindrical surface 34 can abut against the first limiting step 213, thereby realizing mechanical limiting of the needle valve 3 when it moves upward.

[0037] Alternatively, if Figure 3 As shown, the valve stem 6 can be divided into an upper section and a lower section, wherein the upper section is a cylindrical surface, and a sealing gap is formed between the upper section and the drive housing 11 to prevent leakage of high-pressure fuel at the oil inlet; the lower section is also a cylindrical surface, but the diameter needs to be larger than the upper cylindrical surface, and forms an annular area with the circular hole 212 of the guide sleeve 21, and the upper end surface of the lower cylindrical surface can abut against the lower passage end surface of the drive housing 11 to achieve mechanical limitation of the valve stem 6 when it moves upward, and the bottom of the lower cylindrical surface can have a groove 62, which can be cylindrical or rectangular; the upper cylindrical surface is close to the lower cylindrical surface. An annular groove 61 is cut at the position of the cylindrical surface of the first section, and an annular flow channel is formed between the annular groove 61 and the drive housing 11, so that the high-pressure fuel in the first fuel channel 111 can flow into the second fuel channel 211, wherein the annular groove 61 can be of any shape, and can be a rectangular annular groove or a circular annular groove; when the valve stem 6 moves downward, the annular groove 61 can connect the first fuel channel 111 and the annular area, and the high-pressure fuel in the first fuel channel 111 can flow into the annular area through the annular groove 61 of the valve stem 6, and then the high-pressure fuel flows from the annular area through the groove 62 into the second fuel channel 211. Preferably, a plurality of grooves 62 are provided, and the plurality of grooves 62 are evenly distributed circumferentially on the lower cylindrical surface of the valve stem 6, so that the high-pressure fuel can flow into the second fuel channel 211 evenly through the groove 62.

[0038] Optionally, a servo oil inlet throttling hole 731 and a servo oil return throttling hole 732 are respectively provided in the servo oil inlet oil circuit and the return oil circuit of the solenoid valve 73 in the servo drive mechanism 7, wherein the servo oil inlet throttling hole 731 is connected with the servo oil supply system 71, and the servo oil supplied by the servo oil supply system 71 can flow through the solenoid valve 73 through the servo oil inlet throttling hole 731, and the flow rate is regulated by the servo oil inlet throttling hole 731; the servo oil return throttling hole 732 is connected with the return oil tank 72, and the return servo oil can flow through the solenoid valve 73 through the servo oil return throttling hole 732, and the flow rate is regulated by the servo oil return throttling hole 732. The provision of the servo oil inlet throttling hole 731 and the servo oil return throttling hole 732 can realize the regulation of the servo oil flow rate during the servo oil inlet and return processes in the solenoid valve 73. Preferably, the solenoid valve 73 can be a high-response three-position two-way switch, or a three-position two-way reversing valve, or a proportional solenoid valve. By energizing and de-energizing the solenoid valve 73, the on-off control of the servo oil supply system 71 can be realized, thereby realizing the subsequent fuel injection control. Preferably, a pressure regulator is provided in the servo oil supply system 71, and the pressure regulator is used to realize the flexible adjustment of the servo oil pressure supplied by the servo oil supply system 71.

[0039] like Figure 4 As shown, the needle valve 3 and the pressure chamber 221 structure provided in this embodiment, the radial holes 31 of the needle valve 3 are evenly distributed, and the pressure chamber 221 of the needle valve body 22 can be a cylindrical chamber, whose diameter is greater than the diameter of the lower cylindrical surface of the needle valve 3; it can be understood that the pressure chamber 221 can also be a hexahedral chamber, such as a rectangular chamber, whose side length is greater than the diameter of the lower cylindrical surface of the needle valve 3. The lower end of the needle valve 3 abuts against the spray hole 41, which is used to disconnect the pressure chamber 221 and the spray hole 41 on the one hand, and can realize the mechanical limit of the downward movement of the needle valve 3 on the other hand; when the pressure of the high-pressure fuel in the pressure chamber 221 is greater than the preset value, the needle valve 3 moves upward due to the upward force of the pressure chamber 221, the spray hole 41 opens, and the high-pressure fuel in the pressure chamber 221 enters the spray hole 41.

[0040] The specific working principle of the present invention is as follows:

[0041] Initial waiting injection state: The state when the engine does not need fuel injection. Figure 1As shown, the solenoid valve 73 is in a closed state, and the servo oil channel 741 is connected to the return oil tank 72 through the servo oil return throttle hole 732 on the solenoid valve 73, and the relative pressure of the servo oil in the servo oil driving oil chamber is zero. The high-pressure fuel from the high-pressure fuel common rail 9 enters the first fuel channel 111 through the high-pressure fuel inlet on the drive housing 11, and then enters the annular flow channel formed by the annular groove 61 of the valve stem 6 and the drive housing 11. When the fuel pressure in the second fuel channel 211 in the guide sleeve 21 below the valve stem 6 is very low or zero, the valve stem 6 will move downward under the driving force of the high-pressure fuel in the annular flow channel, and connect the first fuel channel 111 and the annular area through the annular groove 61. The high-pressure fuel passes through the annular area and is quickly replenished into the second fuel channel 211 of the guide sleeve 21 through the cut groove 62. The second fuel channel The pressure in 211 increases. When the pressure in the second fuel channel 211 of the guide sleeve 21 is much lower than the start-up pressure of the injector, the valve stem 6 can be driven to move upward. At the same time, due to a small amount of fuel leakage between the gap formed by the guide sleeve 21 and the needle valve 3, the valve stem 6 will be in a nearly closed equilibrium state after several up and down movements (that is, the valve stem 6 disconnects the connection between the first fuel channel 111 and the second fuel channel 211). At the same time, the annular flow channel of the valve stem 6 and the fuel in the second fuel channel 211 of the guide sleeve 21 will also be stabilized at a certain pressure value, waiting for the injection command of the engine.

[0042] Injection start process: When the engine needs to perform fuel injection, the control system sends a control signal, the solenoid valve 73 is energized, and the servo oil output by the servo oil supply system 71 passes through the servo oil oil inlet throttle hole 731, and then passes through the servo oil channel 741 into the servo oil drive oil chamber composed of the drive housing 11 and the servo oil adapter block 74, thereby pushing the drive piston 8 and the valve stem 6 to overcome the fuel resistance in the second fuel channel 211 of the guide sleeve 21 and move downward until the valve stem 6 reaches the mechanical limit of the guide sleeve 21, and waits for the annular groove 61 of the valve stem 6 and the drive housing 11 to form a The high-pressure fuel in the annular flow channel quickly passes through the annular area formed by the valve stem 6 and the circular hole 212 on the upper part of the guide sleeve 21, and then enters the second fuel channel 211 and the third fuel channel 32 in sequence through the groove 62 at the bottom of the valve stem 6, and then enters the pressure chamber 221 composed of the needle valve 3 and the needle valve body 22. The fuel pressure in the pressure chamber 221 increases, and the needle valve 3 overcomes the resistance of the reset mechanism 5 under the action of the high-pressure fuel in the pressure chamber 221 and moves upward. At this time, the spray hole 41 is opened, and the high-pressure fuel in the pressure chamber 221 enters the spray hole 41 of the nozzle 4, thereby realizing fuel injection. Among them, the servo oil inlet throttle hole 731 in the servo oil inlet oil circuit can be used to adjust the servo oil inlet flow rate, change the opening speed of the driving piston 8 and the valve stem 6, and thereby achieve the purpose of suppressing the fuel pressure fluctuation during the lifting process of the needle valve 3; further, by adjusting the servo oil inlet pressure in the servo oil supply system 71, the fuel injection pressure at the initial injection moment can also be adjusted, thereby realizing trapezoidal and boot-shaped injection.

[0043] Injection closing process: After the injection is completed, the control system sends a control signal, the solenoid valve 73 is powered off, the servo oil driving oil chamber between the drive housing 11 and the servo oil adapter block 74 is connected to the return oil tank 72 through the servo oil return oil throttle hole 732, and the servo oil pressure in the servo oil driving oil chamber is reduced. At this time, the valve stem 6 moves upward under the action of the high-pressure fuel below until it reaches the mechanical limit on the drive housing 11 and is completely closed. The fuel pressure in the second fuel channel 211 of the guide sleeve 21 is reduced, and the needle valve 3 moves downward under the driving force of the reset mechanism 5 to block the spray hole 41, and the injection is completed. Among them, the servo oil return oil throttle hole 732 in the servo oil return oil circuit can adjust the closing speed of the valve stem 6 and the drive piston 8 by changing the return oil flow of the servo oil, which plays a role in suppressing the fuel pressure fluctuation during the seating of the needle valve 3 and reducing the impact force when the valve stem 6 is closed.

[0044] Embodiment 2

[0045] This embodiment provides an electronically controlled fuel injection valve, which is different from the first embodiment in that the structure of the pressure chamber 221 formed between the needle valve 3 and the needle valve body 22 is different.

[0046] Alternatively, if Figure 5As shown, another structure of the needle valve 3 is provided, a first conical surface 35 is provided at one end of the needle valve 3, the needle valve body 22 is provided with a second conical surface 222 which can fit with the first conical surface 35, a through hole 36 connected to the third fuel channel 32 is opened on the first conical surface 35, the through hole 36 is arranged obliquely, and can be arranged uniformly in the circumferential direction, the high-pressure fuel passing through the through hole 36 can provide a uniform upward force to the needle valve 3, when the fuel pressure in the third fuel channel 32 is less than a preset value, the first conical surface 35 fits with the second conical surface 222, at this time, the third fuel channel 32 is disconnected from the spray hole 41, and the spray hole 41 is blocked; when the fuel pressure in the third fuel channel 32 is greater than the preset value, the needle valve 3 moves upward, at this time, the third fuel channel 32 is connected with the spray hole 41 through the through hole 36, and fuel injection is realized.

[0047] The remaining structures of this embodiment are the same as those of the first embodiment and will not be described in detail.

[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An electronically controlled fuel injection valve, characterized in that: include: A housing (1), wherein the housing (1) is provided with a first fuel passage (111); A sleeve (2), the sleeve (2) being arranged in the housing (1), the sleeve (2) being provided with a second fuel passage (211) capable of communicating with the first fuel passage (111), and a pressure chamber (221) being provided at an end of the sleeve (2); a needle valve (3), the needle valve (3) being movably disposed in the sleeve (2), the needle valve (3) being provided with a third fuel passage (32) communicating with the second fuel passage (211), the third fuel passage (32) being connected with the pressure chamber (221); A nozzle (4), the nozzle (4) being mounted on one end of the housing (1) and fixedly connected to the sleeve (2), the nozzle (4) being provided with a spray hole (41) communicating with the pressure chamber (221), and when the fuel pressure in the pressure chamber (221) is greater than a preset value, the high-pressure fuel in the pressure chamber (221) can drive the needle valve (3) away from the nozzle (4) to open the spray hole (41); a reset mechanism (5), the reset mechanism (5) being arranged between the sleeve (2) and the needle valve (3), and when the fuel pressure in the pressure chamber (221) is less than a preset value, the reset mechanism (5) resets the needle valve (3) so that the needle valve (3) blocks the spray hole (41); a valve stem (6), the valve stem (6) being movably disposed in the housing (1), and the movement of the valve stem (6) being able to connect or disconnect the first fuel channel (111) and the second fuel channel (211); A servo drive mechanism (7) comprising a solenoid valve (73) and a servo oil supply system (71); when the servo oil supply system (71) supplies servo oil to the solenoid valve (73), the servo oil can drive the valve stem (6) to move so that the first fuel channel (111) and the second fuel channel (211) are connected; when the servo oil supply system (71) does not supply servo oil to the solenoid valve (73), the high-pressure fuel in the second fuel channel (211) drives the valve stem (6) to move so as to disconnect the connection between the first fuel channel (111) and the second fuel channel (211); A high-pressure fuel common rail (9), wherein high-pressure fuel from the high-pressure fuel common rail (9) enters the first fuel channel (111) through a high-pressure fuel inlet of the housing (1); The servo drive mechanism (7) further comprises a servo oil adapter block (74), the servo oil adapter block (74) being provided with a servo oil channel (741), the servo oil channel (741) being in communication with the solenoid valve (73), the solenoid valve (73) being provided with a servo oil inlet throttling hole (731) and a servo oil return throttling hole (732), the servo oil inlet throttling hole (731) being in communication with the servo oil supply system (71), and the servo oil return throttling hole (732) being in communication with an oil return tank (72).

2. The electronically controlled fuel injection valve according to claim 1, characterized in that: A driving piston (8) is also provided in the housing (1), one end of the driving piston (8) abuts against one end of the valve stem (6), and the driving piston (8) can be driven to move by the servo oil in the servo oil channel (741).

3. The electronically controlled fuel injection valve according to claim 1 or 2, characterized in that: A pressure regulator is provided in the servo oil supply system (71), and the pressure regulator is used to adjust the pressure of the servo oil supplied by the servo oil supply system (71).

4. The electronically controlled fuel injection valve according to claim 1, characterized in that: The sleeve (2) is provided with a first limiting step (213), and the needle valve (3) is provided with a first-stage cylindrical surface (34), and the first-stage cylindrical surface (34) can abut against the first limiting step (213).

5. The electronically controlled fuel injection valve according to claim 1, characterized in that: A guide column (214) is arranged in the sleeve (2); a guide hole (33) is arranged at one end of the needle valve (3); one end of the guide column (214) is placed in the guide hole (33); the second fuel channel (211) is arranged to pass through the guide column (214); and the third fuel channel (32) is connected to the guide hole (33).

6. The electronically controlled fuel injection valve according to claim 1, characterized in that: The valve stem (6) is provided with an annular groove (61), and the annular groove (61) is configured to connect the first fuel channel (111) and the second fuel channel (211) when the valve stem (6) moves toward the second fuel channel (211).

7. The electronically controlled fuel injection valve according to claim 1 or 6, characterized in that: A circular hole (212) is provided at the end of the sleeve (2), and the end of the valve stem (6) can be placed in the circular hole (212) and limited by the bottom surface of the circular hole (212).

8. The electronically controlled fuel injection valve according to claim 7, characterized in that: One end of the needle valve (3) located in the pressure chamber (221) is provided with a plurality of radial holes (31) evenly distributed in the circumferential direction, and the plurality of radial holes (31) are connected to the third fuel channel (32) and the pressure chamber (221).

9. The electronically controlled fuel injection valve according to claim 1, characterized in that: A first conical surface (35) is provided at one end of the needle valve (3), the pressure chamber (221) is provided with a second conical surface (222) that can fit with the first conical surface (35), and a through hole (36) that connects the third fuel channel (32) and the pressure chamber (221) is provided on the first conical surface (35).

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