CN212508615U - Electric control fuel injection valve - Google Patents

Abstract

The utility model discloses an electric control fuel injection valve, which comprises a shell, a first fuel channel and a second fuel channel, wherein the first fuel channel is arranged on the shell; the sleeve is provided with a second fuel oil channel communicated with the first fuel oil channel, and the end part of the sleeve is provided with a pressure chamber; the needle valve is provided with a third fuel oil channel communicated with the second fuel oil channel, and the third fuel oil channel is communicated with the pressure chamber; the nozzle is provided with a spray hole communicated with the pressure chamber, and when the pressure of the fuel in the pressure chamber is greater than a preset value, the fuel in the pressure chamber can drive the needle valve to be far away from the nozzle; the resetting mechanism resets the needle valve when the fuel pressure in the pressure chamber is smaller than a preset value; the valve rod can enable the first fuel oil channel to be communicated with or disconnected from the second fuel oil channel; and the servo driving mechanism can drive the valve rod to move so as to enable the first fuel passage to be communicated with the second fuel passage, and the fuel driving valve rod cuts off the communication between the first fuel passage and the second fuel passage. The utility model discloses an automatically controlled fuel injection valve can be applicable to high-power engine, and the degree of integrating is high.

Description

Electric control fuel injection valve

Technical Field

The utility model relates to the technical field of engines, concretely relates to automatically controlled fuel injection valve.

Background

In order to reduce emissions and improve fuel economy, there is increasing interest in having more flexible and adjustable electronically controlled fuel injection systems in various load regions of engine operation. At present, most of common electronic control fuel injection systems are built on the basis of mechanical, hydraulic and electronic control technologies, and the flexible control of fuel injection quantity, fuel injection pressure, fuel injection timing and fuel injection rule is realized by closed-loop control of common rail pressure by adopting a pressure-time type fuel metering principle. The injection system is not limited by the rotating speed of the diesel engine, the injection pressure and the injection duration can be optimized according to the load and the rotating speed, and the performance and the emission of the diesel engine at low speed can be obviously improved. For a high-power engine, especially for a high-power marine engine, due to poor quality of used fuel, large fuel injection amount, high injection temperature and the like, the common electronic control fuel injection system in the market is difficult to popularize and apply on the high-power engine.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an automatically controlled fuel injection valve, its simple structure integrates the degree height to it is lower to the requirement for fuel quality, can satisfy the injection demand of high-power engine to quick, high-efficient, large-traffic fuel injection.

To achieve the purpose, the utility model adopts the following technical proposal:

an electronically controlled fuel injection valve comprising: the fuel injection device comprises a shell, a fuel injection valve and a fuel injection valve, wherein the shell is provided with a first fuel oil channel; the sleeve is arranged in the shell, a second fuel oil channel which can be communicated with the first fuel oil channel is arranged on the sleeve, and a pressure chamber is arranged at the end part of the sleeve; the needle valve is movably arranged in the sleeve and is provided with a third fuel oil channel communicated with the second fuel oil channel, and the third fuel oil channel is communicated with the pressure chamber; the nozzle is arranged at one end of the shell and fixedly connected with the sleeve, the nozzle is provided with a spray hole communicated with the pressure chamber, and when the pressure of fuel oil in the pressure chamber is greater than a preset value, high-pressure fuel oil in the pressure chamber can drive the needle valve to be far away from the nozzle so as to open the spray hole; the resetting mechanism is arranged between the sleeve and the needle valve, and when the fuel pressure in the pressure chamber is smaller than a preset value, the resetting mechanism resets the needle valve so that the needle valve blocks the spray hole; a valve stem movably disposed within the housing, wherein movement of the valve stem enables the first fuel passage to be communicated with or disconnected from the second fuel passage; and the servo driving mechanism comprises an electromagnetic valve and a servo oil supply system, when the servo oil supply system supplies servo oil to the electromagnetic valve, the servo oil can drive the valve rod to move so as to enable the first fuel oil channel and the second fuel oil channel to be communicated, and when the servo oil supply system does not supply servo oil to the electromagnetic valve, the high-pressure fuel oil in the second fuel oil channel drives the valve rod to move so as to disconnect the first fuel oil channel and the second fuel oil channel from being communicated.

Preferably, the servo driving mechanism further comprises a servo oil transfer block, the servo oil transfer block is provided with a servo oil channel, the servo oil channel is communicated with the electromagnetic valve, the electromagnetic valve is provided with a servo oil inlet throttling hole and a servo oil return throttling hole, the servo oil inlet throttling hole is communicated with the servo oil supply system, and the servo oil return throttling hole is communicated with an oil return tank.

Preferably, a drive piston is further provided in the housing, one end of the drive piston abuts against one end of the valve rod, and the drive piston is driven to move by the servo oil in the servo oil passage.

Preferably, a pressure regulator is provided in the servo oil supply system, and the pressure regulator is configured to regulate a pressure of the servo oil supplied from the servo oil supply system.

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

Preferably, a guide post is arranged in the sleeve, a guide hole is formed in one end of the needle valve, and one end of the guide post is arranged in the guide hole; the second fuel oil channel penetrates through the guide post, and the third fuel oil channel is communicated with the guide hole.

Preferably, the valve rod is provided with an annular groove configured to communicate the first fuel passage with the second fuel passage when the valve rod is moved toward the second fuel passage.

Preferably, a round hole is formed in the end of the sleeve, and the end of the valve rod can be arranged in the round hole and limited by the bottom surface of the round hole.

Preferably, a plurality of radial holes are uniformly distributed in the circumferential direction at one end of the needle valve, which is located in the pressure chamber, and the radial holes are communicated with the third fuel oil channel and the pressure chamber.

Preferably, one end of the needle valve is provided with a first conical surface, the pressure chamber is provided with a second conical surface which can be attached to the first conical surface, and the first conical surface is provided with a through hole which is communicated with the third fuel oil channel and the pressure chamber.

The utility model has the advantages that:

1. the utility model provides an automatically controlled fuel injection valve, the servo drive mechanism that structural adoption has the solenoid valve can be applicable to the fuel quality difference that uses, the injection quantity is big, the high-power engine of injection temperature, and integrates the degree height, simple structure.

2. The utility model provides an automatically controlled fuel injection valve through set up servo oil feed orifice and servo oil return orifice at the solenoid valve, has realized the regulation to servo oil feed and the servo oil flow of oil return in-process to realized the nimble control to automatically controlled fuel injection valve fuel injection.

Drawings

Fig. 1 is a cross-sectional view of an electronically controlled fuel injection valve according to an embodiment of the present invention;

fig. 2 is an enlarged schematic view of fig. 1 at a according to the present invention;

fig. 3 is an enlarged schematic view of fig. 1 at B according to the present invention;

FIG. 4 is a schematic view of the assembly of a needle valve with a pressure chamber provided by the present invention;

fig. 5 is a schematic view of another needle valve and pressure chamber assembly provided by the present invention.

In the figure:

1. a housing; 11. a drive housing; 111. a first fuel passage; 12. installing a sleeve; 2. a sleeve; 21. a guide sleeve; 211. a second fuel passage; 212. a circular hole; 213. a first limit step; 214. a guide post; 2141. a second limit step; 22. a needle valve body; 221. a pressure chamber; 222. a second conical surface; 3. a needle valve; 31. a radial bore; 32. a third fuel passage; 33. a guide hole; 34. a first-stage cylindrical surface; 35. a first conical surface; 36. a through hole; 4. a nozzle; 41. spraying a hole; 5. a reset mechanism; 6. a valve stem; 61. a ring groove; 62. grooving; 7. a servo drive mechanism; 71. a servo oil supply system; 72. an oil return tank; 73. an electromagnetic valve; 731. the servo oil enters the oil throttle hole; 732. a servo oil return orifice; 74. a servo oil transfer block; 741. a servo oil channel; 8. a drive piston; 9. a high pressure fuel rail.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used in the orientation or positional relationship shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

The embodiment provides an automatically controlled fuel injection valve, and its simple structure integrates the degree height to the requirement for the quality of fuel is lower, can satisfy the injection demand of high-power engine to quick, high-efficient, large-traffic fuel injection, especially is applicable to marine high-power diesel engine, double fuel machine and even fuel machine at most.

Example one

As shown in fig. 1, the present embodiment provides an electrically controlled fuel injection valve, which includes a housing 1, a sleeve 2, a needle valve 3, a nozzle 4, a reset mechanism 5, a valve rod 6, and a servo driving mechanism 7, wherein the housing 1 is provided with a first fuel passage 111, the sleeve 2 is disposed in the housing 1, the sleeve 2 is provided with a second fuel passage 211 capable of communicating with the first fuel passage 111, an end of the sleeve 2 is provided with a pressure chamber 221, the needle valve 3 is movably disposed in the sleeve 2, the needle valve 3 is provided with a third fuel passage 32 communicating with the second fuel passage 211, the third fuel passage 32 is communicated with the pressure chamber 221, the nozzle 4 is mounted at one end of the housing 1 and fixedly connected with the sleeve 2, the nozzle 4 is provided with an orifice 41 communicating with the pressure chamber 221, when a fuel pressure in the pressure chamber 221 is greater than a predetermined value, a high-pressure fuel in the pressure chamber 221 can drive the needle, when the fuel pressure in the pressure chamber 221 is smaller than a preset value, the reset mechanism 5 resets the needle valve 3 so that the needle valve 3 blocks the nozzle 41, the valve rod 6 is movably disposed in the housing 1, and the movement of the valve rod 6 can connect or disconnect the first fuel passage 111 with or from the second fuel passage 211, the servo driving mechanism 7 includes an electromagnetic valve 73 and a servo oil supply system 71, when the servo oil supply system 71 supplies servo oil to the electromagnetic valve 73, the servo oil can drive the valve rod 6 to move so that the first fuel passage 111 is communicated with the second fuel passage 211, and when the servo oil supply system 71 does not supply servo oil to the electromagnetic valve 73, the high-pressure fuel rod 6 in the second fuel passage 211 moves so that the first fuel passage 111 is disconnected with the second fuel passage 211. Further, the servo driving mechanism 7 further includes a servo oil transfer block 74, the servo oil transfer block 74 is disposed on the housing 1 and is fixedly connected to the housing 1, the servo oil transfer block 74 is provided with a servo oil channel 741, the servo oil channel 741 is communicated with the electromagnetic valve 73, and the servo oil flowing through the electromagnetic valve 73 can flow into the housing 1 through the servo oil channel 741.

The electric control fuel injection valve provided by the embodiment controls the supply and the disconnection of the servo oil through the servo driving mechanism 7, when the servo oil is supplied, the servo oil drives the valve rod 6 to move, so that the first fuel passage 111 is communicated with the second fuel passage 211, the high-pressure fuel sequentially passes through the first fuel passage 111 and the second fuel passage 211, then enters the third fuel passage 32 communicated with the second fuel passage 211 and enters the pressure chamber 221 communicated with the third fuel passage 32, when the pressure of the high-pressure fuel in the pressure chamber 221 is greater than a preset value, the high-pressure fuel in the pressure chamber 221 drives the needle valve 3 to be away from the nozzle 4, and the high-pressure fuel in the third fuel passage 32 enters the nozzle 4, so that the fuel injection of a high-power engine is realized.

Optionally, the housing 1 may include a mounting sleeve 12 and a driving housing 11, the mounting sleeve 12 is fixedly connected to the driving housing 11, the driving housing 11 is provided with an upper passage, a side passage and a lower passage, and the upper passage of the driving housing 11 and the servo oil transfer block 74 together form a servo oil driving oil chamber; the side passage is the first fuel passage 111 of this embodiment, and the first fuel passage 111 is directly connected to the high-pressure fuel common rail 9 through a high-pressure fuel pipe, and is used for feeding high-pressure fuel; the valve rod 6 is disposed in a lower passage thereof, and the valve rod 6 is movable in the lower passage.

Further, a driving piston 8 may be disposed in the driving housing 11, the driving piston 8 is movably disposed in the servo oil driving oil cavity, and one end of the driving piston 8 abuts against one end of the valve rod 6, the servo oil enters the servo oil driving oil cavity through a servo oil passage 741 of the servo oil transfer block 74, so that the servo oil driving oil cavity generates pressure, the pressure pushes the driving piston 8 and the valve rod 6 to move downward at the same time, and further the first fuel passage 111 and the second fuel passage 211 are communicated, and the high-pressure fuel can enter the second fuel passage 211 through the first fuel passage 111; when the pressure of the servo oil in the servo oil driving oil cavity is released, the high-pressure fuel oil in the second fuel oil channel 211 pushes the valve rod 6 and the driving piston 8 to move upwards simultaneously, and the valve rod 6 cuts off the communication between the first fuel oil channel 111 and the second fuel oil channel 211.

Alternatively, the sleeve 2 may be composed of a needle valve body 22 and a guide sleeve 21, the needle valve body 22 is fixedly connected with the guide sleeve 21, the nozzle 4 is fixedly connected with the end surface of the needle valve body 22, the pressure chamber 221 may be disposed at the end of the needle valve body 22, and the third fuel passage 32 may communicate with the nozzle hole 41 disposed on the nozzle 4 through the pressure chamber 221. A circular hole 212 and a second fuel passage 211 are arranged in the middle of the guide sleeve 21, wherein an annular area is formed between the circular hole 212 and the valve rod 6, the annular area can be used for communicating the first fuel passage 111 and the second fuel passage 211 after the valve rod 6 moves downwards, the bottom surface of the circular hole 212 can be used for mechanical limiting when the valve rod 6 moves downwards, and the second fuel passage 211 is communicated with the circular hole 212; the guide sleeve 21 is provided with a guide post 214 inside, the guide post 214 can play a role of guiding when the needle valve 3 moves, an annular deep groove is formed between the guide post 214 and the wall of the guide sleeve 21, and the resetting mechanism 5 can be arranged in the annular deep groove of the guide sleeve 21. Further, the guide post 214 may be a two-step structure, the lower end of the guide post 214 may form a clearance fit with the needle 3 to seal the high-pressure fuel between the guide sleeve 21 and the needle 3, and the step of the guide post 214 may be used for mechanical limitation when the needle 3 moves upward. Preferably, the return mechanism 5 may be an elastic element, preferably a spring.

Optionally, as shown in fig. 2, the needle valve 3 further has a guide hole 33 inside, the guide hole 33 and the guide post 214 of the guide sleeve 21 may form a clearance seal, and the second limiting step 2141 of the guide post 214 may abut against an end surface of the needle valve 3 where the guide hole 33 is located, so as to limit the upward movement of the needle valve 3, and the guide hole 33 is communicated with the third fuel passage 32; a radial hole 31 is formed below the needle valve 3, the third fuel channel 32 is communicated with the radial hole 31 below the needle valve 3, and the radial hole 31 below the needle valve 3 is arranged in a pressure chamber 221 so that high-pressure fuel can smoothly enter the pressure chamber 221 formed by the needle valve 3 and the needle valve body 22; the upper end of the needle valve 3 is arranged in the annular deep groove of the guide sleeve 21 and can be used as a base of the resetting mechanism 5, the lower end of the needle valve 3 can be abutted to form clearance fit with the spray holes 41 to ensure high-pressure fuel sealing in the pressure chamber 221, 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 to be away from the nozzle 4 to open the spray holes 41, at the moment, the third fuel channel 32 is communicated with the spray holes 41 of the nozzle 4 through the pressure chamber 221, and when the fuel pressure in the pressure chamber 221 is less than the preset value, the resetting mechanism 5 resets the needle valve 3 to enable the needle valve 3 to block the spray holes 41. Optionally, the guide sleeve 21 is further provided with a first limiting step 213, the needle valve 3 is further provided with a first-stage cylindrical surface 34, and the first-stage cylindrical surface 34 can abut against the first limiting step 213, so that the needle valve 3 is mechanically limited when moving upwards.

Alternatively, as shown in fig. 3, the valve rod 6 may be divided into an upper section and a lower section, wherein the upper section is a cylindrical surface and forms a sealing gap with the driving housing 11 for preventing the high-pressure fuel at the fuel inlet from leaking; the lower section is a cylindrical surface, but the diameter of the lower section is larger than that of the upper section, and an annular area is formed by the lower section and the circular hole 212 of the guide sleeve 21, the upper end surface of the lower section cylindrical surface can be abutted against the end surface of a lower passage of the driving shell 11 to realize mechanical limit when the valve rod 6 moves upwards, the bottom of the lower section cylindrical surface can be provided with a cutting groove 62, and the cutting groove 62 can be cylindrical or rectangular; an annular groove 61 is cut on the upper section cylindrical surface close to the lower section cylindrical surface, an annular flow passage is formed between the annular groove 61 and the driving shell 11, so that high-pressure fuel in the first fuel passage 111 can conveniently flow into the second fuel passage 211, wherein the annular groove 61 can be in any shape, and can be a rectangular annular groove or a circular annular groove; when the valve rod 6 moves downward, the annular groove 61 can communicate the first fuel passage 111 and the annular region, and the high-pressure fuel in the first fuel passage 111 can flow into the annular region through the annular groove 61 of the valve rod 6, and then the high-pressure fuel flows from the annular region into the second fuel passage 211 through the cut groove 62. Preferably, the plurality of cutting grooves 62 are provided, and the plurality of cutting grooves 62 are circumferentially and uniformly distributed on the lower cylindrical surface of the valve rod 6, so that the high-pressure fuel can uniformly flow into the second fuel passage 211 through the cutting grooves 62.

Alternatively, a servo oil inlet orifice 731 and a servo oil return orifice 732 are respectively arranged in a servo oil inlet oil path and a servo oil return oil path of the solenoid valve 73 in the servo drive mechanism 7, wherein the servo oil inlet orifice 731 is communicated with the servo oil supply system 71, and servo oil supplied by the servo oil supply system 71 can flow through the solenoid valve 73 through the servo oil inlet orifice 731, and the flow rate of the servo oil can be adjusted by the servo oil inlet orifice 731; the servo oil return orifice 732 communicates with the oil return tank 72, and the returned servo oil can flow through the solenoid valve 73 via the servo oil return orifice 732, and the flow rate thereof is regulated by the servo oil return orifice 732. The servo oil inlet orifice 731 and the servo oil return orifice 732 are arranged, so that the flow of servo oil in the electromagnetic valve 73 in the oil inlet and return processes can be adjusted. Preferably, the electromagnetic valve 73 can be a high-response three-position two-way switch, or a three-position two-way reversing valve, or a proportional electromagnetic valve, and on-off control of supplying the servo oil to the servo oil supply system 71 can be realized by powering on and off the electromagnetic valve 73, so that injection control of subsequent fuel oil is realized. Preferably, a pressure regulator is provided in the servo oil supply system 71, and the pressure regulator is used for realizing flexible regulation of the pressure of the servo oil supplied by the servo oil supply system 71.

As shown in fig. 4, in the structure of the needle valve 3 and the pressure chamber 221 provided in this embodiment, the radial holes 31 of the needle valve 3 are uniformly distributed, and the pressure chamber 221 of the needle valve body 22 may be a cylindrical chamber with a diameter larger than that of the lower cylindrical surface of the needle valve 3; it will be appreciated that the pressure chamber 221 may also be a hexahedral chamber, such as a rectangular parallelepiped chamber, with a side length greater than the diameter of the lower cylindrical surface of the needle valve 3. The lower end part of the needle valve 3 is abutted to the spray hole 41, so that the pressure chamber 221 and the spray hole 41 are disconnected on one hand, and the downward movement of the needle valve 3 can be mechanically limited 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 3 is moved upward by the upward force of the pressure chamber 221, the nozzle holes 41 are opened, and the high-pressure fuel in the pressure chamber 221 enters the nozzle holes 41.

The utility model discloses a concrete theory of operation as follows:

initial wait for injection state: when the engine is in a state where fuel injection is not required, as shown in fig. 1, the solenoid valve 73 is in a closed state, the servo oil passage 741 communicates with the return tank 72 through the servo oil return orifice 732 in the solenoid valve 73, and the relative pressure of the servo oil in the servo oil drive oil chamber is zero. High-pressure fuel oil from the high-pressure fuel oil common rail 9 enters the first fuel oil channel 111 through a high-pressure fuel oil inlet on the driving shell 11 and then enters an annular flow channel formed by the annular groove 61 of the valve rod 6 and the driving shell 11, when the fuel oil pressure of the second fuel oil channel 211 in the guide sleeve 21 below the valve rod 6 is very low or zero, the valve rod 6 moves downwards under the driving force of the annular flow channel high-pressure fuel oil and is communicated with the first fuel oil channel 111 and the annular area through the annular groove 61, the high-pressure fuel oil is rapidly supplemented into the second fuel oil channel 211 of the guide sleeve 21 through the cutting groove 62 through the annular area, the internal pressure of the second fuel oil channel 211 is increased, when the internal pressure of the second fuel oil channel 211 of the guide sleeve 21 is far lower than the starting pressure of an oil injector, the valve rod 6 can be driven to move upwards, and meanwhile, a small amount of fuel, after several up-and-down movements, the valve rod 6 will be in a close equilibrium state (i.e. the valve rod 6 disconnects the first fuel passage 111 and the second fuel passage 211), and at the same time, the fuel in the annular flow passage of the valve rod 6 and the second fuel passage 211 of the guide sleeve 21 will be stabilized at a certain pressure value, and waits for an injection command of the engine.

And (3) injection opening process: when the engine needs to inject fuel, the control system sends out a control signal, the electromagnetic valve 73 is energized, the servo oil output by the servo oil supply system 71 enters the servo oil inlet orifice 731, then enters the servo oil driving oil cavity composed of the driving shell 11 and the servo oil transfer block 74 through the servo oil channel 741, further pushes the driving piston 8 and the valve rod 6 to move downwards against the fuel resistance in the second fuel oil channel 211 of the guide sleeve 21 until the valve rod 6 reaches the mechanical limit position of the guide sleeve 21, meanwhile, high-pressure fuel oil waiting in an annular flow channel composed of the annular groove 61 of the valve rod 6 and the driving shell 11 rapidly passes through an annular area formed by the valve rod 6 and a round hole 212 on the upper part of the guide sleeve 21, then sequentially enters the second fuel oil channel 211 and the third fuel oil channel 32 through the cutting groove 62 on the bottom of the valve rod 6, and then enters the pressure chamber 221 composed of the needle valve 3 and the needle valve body 22, the pressure of the fuel in the pressure chamber 221 rises, the needle valve 3 moves upward against the resistance of the return mechanism 5 under the action of the high-pressure fuel in the pressure chamber 221, at this time, the nozzle hole 41 opens, and the high-pressure fuel in the pressure chamber 221 enters the nozzle hole 41 of the nozzle 4, thereby realizing fuel injection. The servo oil inlet orifice 731 in the servo oil inlet oil path can be used for adjusting the servo oil inlet flow, changing the opening speed of the driving piston 8 and the valve rod 6, and further achieving the purpose of inhibiting fuel pressure fluctuation in the lifting process of the needle valve 3; further, the fuel injection pressure at the initial injection time can be adjusted by adjusting the servo oil inlet pressure in the servo oil supply system 71, so that trapezoidal and boot-shaped injection is realized.

And (3) injection closing process: after the injection is completed, the control system sends out a control signal, the electromagnetic valve 73 is powered off, the servo oil driving oil cavity between the driving shell 11 and the servo oil switching block 74 is communicated with the oil return tank 72 through the servo oil return orifice 732, the pressure of the servo oil in the servo oil driving oil cavity is reduced, at the moment, the valve rod 6 moves upwards under the action of high-pressure fuel oil below until the mechanical limit on the driving shell 11 is reached and then is completely closed, the pressure of the fuel oil in the second fuel oil channel 211 of the guide sleeve 21 is reduced, the needle valve 3 moves downwards under the action of the driving force of the reset mechanism 5 so as to plug the spray hole 41, and the injection is completed. The servo oil return orifice 732 in the servo oil return oil path can adjust the closing speed of the valve rod 6 and the driving piston 8 by changing the return oil flow of the servo oil, and plays a role in suppressing fuel pressure fluctuation in the seating process of the needle valve 3 and reducing impact force when the valve rod 6 is closed.

Example two

The present embodiment provides an electronically controlled fuel injection valve which differs from the first embodiment in the structure of the pressure chamber 221 formed between the needle valve 3 and the needle valve body 22.

Alternatively, as shown in fig. 5, in another structure of the needle valve 3, one end of the needle valve 3 is provided with a first conical surface 35, the needle valve body 22 is provided with a second conical surface 222 which can be attached to the first conical surface 35, the first conical surface 35 is provided with through holes 36 which communicate with the third fuel passage 32, the through holes 36 are obliquely arranged and can be uniformly arranged in the circumferential direction, high-pressure fuel passing through the through holes 36 can provide uniform upward force to the needle valve 3, when the fuel pressure in the third fuel passage 32 is smaller than a preset value, the first conical surface 35 is attached to the second conical surface 222, at this time, the third fuel passage 32 is disconnected from the spray hole 41, and the spray hole 41 is blocked; when the fuel pressure of the third fuel passage 32 is greater than a preset value, the needle valve 3 moves upward, and the third fuel passage 32 communicates with the nozzle hole 41 through the through hole 36, thereby performing fuel injection.

The rest of the structure of this embodiment is the same as that of the first embodiment, and is not described again.

It is obvious that the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, rearrangements and substitutions will now occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. An electronically controlled fuel injection valve, comprising:

a housing (1), the housing (1) being provided with a first fuel passage (111);

the sleeve (2) is arranged in the shell (1), the sleeve (2) is provided with a second fuel passage (211) which can be communicated with the first fuel passage (111), and the end part of the sleeve (2) is provided with a pressure chamber (221);

the needle valve (3) is movably arranged in the sleeve (2), the needle valve (3) is provided with a third fuel oil channel (32) communicated with the second fuel oil channel (211), and the third fuel oil channel (32) is communicated with the pressure chamber (221);

the nozzle (4) is mounted at one end of the shell (1) and fixedly connected with the sleeve (2), the nozzle (4) is provided with a spray hole (41) communicated with the pressure chamber (221), and when the pressure of fuel in the pressure chamber (221) is larger than a preset value, high-pressure fuel in the pressure chamber (221) can drive the needle valve (3) to be far away from the nozzle (4) so as to open the spray hole (41);

the resetting mechanism (5) is arranged between the sleeve (2) and the needle valve (3), and when the fuel pressure in the pressure chamber (221) is smaller than a preset value, the resetting mechanism (5) resets the needle valve (3) so that the needle valve (3) blocks the spray hole (41);

a valve rod (6), wherein the valve rod (6) is movably arranged in the shell (1), and the first fuel channel (111) can be communicated with or disconnected from the second fuel channel (211) through the movement of the valve rod (6);

the servo driving mechanism (7) comprises an electromagnetic valve (73) and a servo oil supply system (71), when the servo oil supply system (71) supplies servo oil to the electromagnetic valve (73), the servo oil can drive the valve rod (6) to move so as to enable the first fuel oil channel (111) and the second fuel oil channel (211) to be communicated, when the servo oil supply system (71) does not supply the servo oil to the electromagnetic valve (73), high-pressure fuel oil in the second fuel oil channel (211) drives the valve rod (6) to move so as to disconnect the communication of the first fuel oil channel (111) and the second fuel oil channel (211).

2. An electric control fuel injection valve according to claim 1, characterized in that the servo drive mechanism (7) further comprises a servo oil transfer block (74), the servo oil transfer block (74) is provided with a servo oil passage (741), the servo oil passage (741) is communicated with the solenoid valve (73), the solenoid valve (73) is provided with a servo oil inlet orifice (731) and a servo oil return orifice (732), the servo oil inlet orifice (731) is communicated with the servo oil supply system (71), and the servo oil return orifice (732) is communicated with a return tank (72).

3. An electrically controlled fuel injection valve according to claim 2, characterized in that a drive piston (8) is further arranged in the housing (1), one end of the drive piston (8) abuts against one end of the valve stem (6), and the drive piston (8) is driven to move by the servo oil in the servo oil channel (741).

4. An electrically controlled fuel injection valve according to claim 2 or 3, characterized in that a pressure regulator is arranged in the servo oil supply system (71) for regulating the pressure of the servo oil supplied by the servo oil supply system (71).

5. An electrically controlled fuel injection valve according to claim 1, characterized in that the sleeve (2) is provided with a first limit step (213) and the needle valve (3) is provided with a first cylindrical surface (34), the first cylindrical surface (34) being able to abut against the first limit step (213).

6. An electric control fuel injection valve according to claim 1, characterized in that a guide post (214) is provided in said sleeve (2), a guide hole (33) is provided at one end of said needle valve (3), and one end of said guide post (214) is disposed in said guide hole (33); the second fuel passage (211) is disposed to penetrate the guide post (214), and the third fuel passage (32) is communicated with the guide hole (33).

7. The electrically controlled fuel injection valve according to claim 1, characterized in that the valve stem (6) is provided with an annular groove (61), the annular groove (61) being configured to communicate the first fuel passage (111) with the second fuel passage (211) when the valve stem (6) is moved toward the second fuel passage (211).

8. An electrically controlled fuel injection valve according to claim 1 or 7, characterized in that the end of the sleeve (2) is provided with a circular hole (212), and the end of the valve stem (6) can be placed in the circular hole (212) and is limited by the bottom surface of the circular hole (212).

9. An electric control fuel injection valve according to claim 1, characterized in that one end of the needle valve (3) in the pressure chamber (221) is circumferentially and evenly provided with a plurality of radial holes (31), and the plurality of radial holes (31) are communicated with the third fuel channel (32) and the pressure chamber (221).

10. An electric control fuel injection valve according to claim 1, characterized in that one end of the needle valve (3) is provided with a first conical surface (35), the pressure chamber (221) is provided with a second conical surface (222) which can be attached to the first conical surface (35), and the first conical surface (35) is provided with a through hole (36) which communicates the third fuel passage (32) and the pressure chamber (221).

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