CN106704065A - Resonant type electronic control fuel injector with engraved groove - Google Patents

Abstract

The object of the present invention is to provide a resonant electronically controlled fuel injector with grooves, which includes a fuel injector head, a fuel injector body, a restrictor valve assembly, a solenoid valve assembly, a tight cap, a needle valve limit sleeve, Nozzle, needle valve body, needle valve seat and other components. There is a pressure storage chamber in the fuel injector body, which is connected with the main oil inlet hole and the flow limiting valve assembly, which can ensure the stability of the fuel injection process of each cylinder during large pulse width fuel injection. The restrictor valve assembly is installed under the pressure accumulator chamber to avoid abnormal continuous fuel injection. The bottom of the restrictor valve assembly is processed with a resonant through hole and a resonant orifice, which effectively reduces the fluctuation of fuel passing through the restrictor valve assembly by using the wave superposition principle. Micron-level grooves are set on the surface of the needle valve body, which can effectively improve the stability of the cavitation flow and reduce the degree of cavitation of the injector. The internal hydraulic pressure of the injector is balanced and there is no static pressure difference, which realizes the function of no static leakage of the injector.

Description

A Resonant Electronically Controlled Fuel Injector with Groove

technical field

The invention relates to an engine fuel injection device, in particular to a high-pressure common rail fuel injection device.

Background technique

At present, in order to improve fuel economy, higher requirements are put forward for the injection pressure of common rail fuel system. The increase of the rail pressure will lead to the problem of static fuel leakage between common rail injector parts, especially when the rail pressure exceeds 200MPa, the static leakage problem is obvious, not only loses most of the energy, but also greatly increases the heat generated, making the whole There are potential dangers in the system, which limits the further improvement of fuel injection pressure. As the work of the injector increases gradually and the flow rate increases, the degree of cavitation and cavitation in the injector increases significantly, and the reliability of the injector decreases.

In addition, the precise control of multiple injection injection patterns is the biggest advantage and key technology of the high-pressure common rail electronically controlled fuel injection system for diesel engines. In the multiple injection of the high pressure common rail system, the water hammer pressure fluctuation caused by the injection directly affects the realization of the ideal fuel injection law of the multiple injection, and then affects the performance of the diesel engine.

Contents of the invention

The object of the present invention is to provide a resonant electronically controlled fuel injector with grooves that can ensure small fuel pressure fluctuations, fast response, no static leakage function and reduce cavitation during multiple injections.

The purpose of the present invention is achieved like this:

The present invention is a resonant electronically controlled fuel injector with grooves, which is characterized in that it includes a fuel injector head, a fuel injector body, a flow limiting valve assembly, a solenoid valve assembly, a needle valve assembly, a nozzle, a downward high pressure oil The fuel injector head is installed above the fuel injector body, the main oil inlet hole is set inside the fuel injector head, the pressure storage chamber is set inside the fuel injector body, the main oil inlet hole communicates with the pressure storage chamber, and the flow limiting valve assembly is set In the pressure accumulator chamber, the lower end of the fuel injector body is installed with a solenoid valve assembly and a needle valve assembly in turn. The tight cap is located outside the solenoid valve assembly and the needle valve assembly. The upper end of the tight cap is connected to the lower end of the fuel injector body through a threaded connection. ;

The flow-limiting valve assembly includes a limit spring seat, a flow-limiting piston, a ball valve reset spring seat, and a support control slider. The limit spring seat, the flow-limiting piston, and the ball valve return spring seat are arranged from top to bottom. A damping spring is installed between the flow-limiting pistons, and the support control slider is installed in the ball valve reset spring seat. A ball valve is arranged between the upper end of the support control slider and the flow-limiting piston. The ball valve reset spring is installed between them, the piston blind hole and the flow limiting hole are set in the flow limiting piston, the axial center through hole is set in the support control slider, the resonant through hole and the resonant orifice are set in the ball valve return spring seat, and the ball valve return spring seat A transition oil chamber is set between the fuel injector body below it, and the blind hole of the piston is connected to the pressure accumulator chamber and the restrictor hole. The throttle holes are all connected to the axial center through hole and the transition oil chamber;

The solenoid valve assembly includes an electromagnet, a coil, an armature, a balance valve stem, a valve seat, and an intermediate block. The coil is wound on the electromagnet. The solenoid valve reset spring seat is arranged above the electromagnet, and the armature is arranged below the electromagnet. The armature and the solenoid valve reset The return spring of the solenoid valve is set between the spring seats, the balance valve stem is located in the valve seat, the upper end of the balance valve stem is fixedly connected with the armature, the middle block is set under the valve seat, and the oil return hole, the middle oil circuit, and the lower shape are set in the middle block. The oil inlet hole and the oil return hole are connected or disconnected with the intermediate oil circuit and the oil tank under the control of the balance valve stem;

The needle valve assembly includes a needle valve stop sleeve, a needle valve seat, and a needle valve body. Part is located in the needle valve seat, and a control cavity is formed between the top of the needle valve body and the needle valve limit sleeve. A protrusion is set on the needle valve limit sleeve, and the protrusion is located at the control cavity. A needle is set between the needle valve body and the protrusion. The valve return spring, the control chamber communicates with the middle oil circuit and the lower oil inlet hole respectively, and an oil tank is formed between the needle valve body and the needle valve seat;

The nozzle includes a spray hole and an engraved groove, the spray hole is processed on the needle valve seat, and the engraved groove is arranged on the surface of the lower end of the long needle valve;

The upper end of the downward high-pressure oil circuit is connected to the transition oil chamber, and is connected to the oil tank through the injector body, the valve seat, the middle block, and the needle valve seat, and the downward oil inlet hole is connected to the downward high-pressure oil circuit.

The present invention may also include:

1. The engraved grooves are specifically located between the sealing cone surface formed when the long needle valve is seated and the lower end of the needle valve body. The number of engraved grooves is an integral multiple of the number of nozzle holes, and the depth of the engraved grooves is on the order of microns.

2. When injecting fuel from the injection hole, the fuel pressure in the transition oil chamber drops, and the flow-limiting piston, ball valve, and support control slider move downward as a whole, and the ball valve is not seated on the return spring seat of the ball valve. When the quality of fuel flowing out of the nozzle hole exceeds the threshold value, the flow limiting piston presses the ball valve and makes it seat on the ball valve return spring seat, and the flow limiting hole is disconnected from the axial center through hole; Under the action of the ball valve return spring, the flow limiting piston, the ball valve and the support control slider return to the initial position as a whole.

3. When the coil is energized, the balance valve stem moves upwards, the oil return hole is connected to the fuel tank, the fuel in the control chamber is returned to the fuel tank through the middle oil circuit and the oil return hole, the needle valve body is lifted upwards, and the injection hole is opened to spray. After the coil is powered off, the balance valve stem moves downward under the action of the return spring of the solenoid valve and is pressed on the upper end surface of the middle block, and the oil return hole is disconnected from the oil tank.

4. The diameter of the middle part of the resonant orifice is smaller than the diameter of both ends thereof, and smaller than the diameter of the resonant through hole, and the total axial length of the resonant orifice and the resonant through hole is consistent.

The advantage of the present invention is that: the present invention adopts the structure of the accumulator chamber, which can greatly improve the pressure fluctuation of the entire fuel injection system, and especially can reduce the mutual interference of each fuel injector when injecting fuel. The structure of the present invention adopts the restrictor valve assembly, which effectively avoids the occurrence of abnormal situations such as abnormal fuel injection, and adds a resonance structure to reduce fuel pressure fluctuations, ensure normal and stable fuel injection process and improve fuel economy at the same time performance and reliability of injector work. The invention uses a solenoid valve to control the balance valve rod to adjust the switch of the oil return circuit, which is beneficial to improve the response speed and control accuracy of the needle valve, provides flexible fuel injection rules, and effectively improves the emission stability and economical efficiency of the diesel engine. sex. The invention adopts groove structure, and matches the diameter, depth and number of grooves according to the requirements of actual working conditions, so as to improve the stability of cavitation flow and reduce the cavitation degree of the fuel injector with the best effect. The internal hydraulic balance of the needle valve assembly has no static pressure difference, which realizes the function of no static leakage of the injector.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic diagram of a restrictor valve assembly;

Fig. 3 is a schematic diagram of a solenoid valve assembly;

Fig. 4 is A-A schematic diagram;

Fig. 5 is a schematic diagram of the structure of the nozzle part of the present invention.

detailed description

The present invention is described in more detail below in conjunction with accompanying drawing example:

Referring to Figures 1-5, a resonant electronically controlled fuel injector with grooves according to the present invention includes a fuel injector head 1, a flow limiting valve assembly 3, a solenoid valve assembly 5, a needle valve seat 7, a needle valve body 8, Nozzle 9, needle valve stop sleeve 11, tight cap 14, injector body 15. The fuel injector head 1 is mounted on the fuel injector body 15 through threaded fitting connection, and is sealed by the sealing ring 2 placed on the fuel injector body 15 . A main oil inlet hole 17 is arranged in the injector head 1 and communicates with the pressure accumulator chamber 16 in the injector body 15 . A restrictor valve assembly 3 is arranged below the accumulator chamber 16 . The limiting valve assembly 3 is installed inside the fuel injector body 15, and its main structure includes a retaining ring 18, a damping spring 19, a ball valve 21, a support control slider 22, a ball valve return spring 27, a ball valve return spring seat 28, and a flow limiting piston 29, limit spring seat 31. Wherein, the flow limiting hole 20 and the piston blind hole 30 are processed on the flow limiting piston 29, and the axial center through hole 23 is processed on the supporting control slider 22, so as to ensure that the fuel can flow smoothly to the lower oil passage. Wherein the bottom of the ball valve return spring seat 27 is processed with two resonant holes, which are the resonant through hole 24 and the resonant throttling hole 26 respectively. A solenoid valve assembly 5 , a needle valve seat 7 and a needle valve body 8 are arranged in sequence below the injector body 15 , and the three are assembled and connected through a tight cap 14 . The main structure of the solenoid valve assembly 5 includes a solenoid valve return spring seat 32, a coil 33, an armature 34, a valve seat 35, an intermediate block 39, a balance valve stem 40, an electromagnet 41, and a solenoid valve return spring 42. The armature 34 and the balance valve stem 40 are assembled inside the valve seat 35 . The oil return hole 36 , the downward oil inlet hole 37 , the middle oil passage 38 , etc. are processed inside the middle block 39 , and the middle block 39 forms the control chamber 13 with the needle valve stop sleeve 11 and the needle valve body 8 . A needle valve cavity 12 is formed between the needle valve limiting sleeve 11 and the needle valve seat 7 . The needle valve body 8 is installed in the needle valve seat 7, the upper end of the needle valve body 8 covered with the needle valve return spring 6 is arranged in the needle valve chamber 12, and an oil tank 10 is arranged between the needle valve body 8 and the needle valve seat 7. The injection hole 43 is processed on the needle valve seat 7, and the surface of the needle valve body 8 is provided with a groove 44 with a depth of micron level.

Figure 1 is a schematic diagram of the overall structure of a resonant electronically controlled fuel injector with grooves in the present invention, which consists of a fuel injector head 1, a sealing ring 2, a flow limiting valve assembly 3, a solenoid valve assembly 5, and a needle valve seat 7. The needle valve body 8, the needle valve limit sleeve 11, the tight cap 14, the fuel injector body 15, and the pressure accumulator chamber 16 are composed. The fuel injector body 15 is provided with a pressure accumulator chamber 16 , and the pressure accumulator chamber 16 communicates with the main oil inlet hole 17 on the injector head 1 . The oil chamber in the flow limiting piston 29 communicates with the accumulator chamber 16 through the piston blind hole 30 and the flow limiting hole 20 opened therein in sequence. The fuel injector head 1 and the fuel injector body 15 are assembled through threads, and the sealing ring 2 seals them. When the delivered high-pressure fuel enters the injector through the main oil inlet hole 17 , the fuel passing through the accumulator chamber 16 will pass through the restrictor valve assembly 3 downward. After the fuel flows out from the restrictor valve assembly 3 , it flows through the downward high-pressure oil circuit 4 and enters the control chamber 13 and the oil tank 10 . A solenoid valve assembly 5 is installed between the lower part of the restrictor valve assembly 3 and the upper part of the needle valve seat 7 . In the solenoid valve assembly 5, the lifting and seating of the armature 34 and the balance valve stem 40 are controlled by electromagnetic force. When the coil 33 is energized, the balance valve stem 40 is lifted upwards, the oil return hole 36 is opened, and the fuel in the control chamber 13 flows through the middle oil circuit 38 and drains through the oil return hole 36 . Therefore, the fuel pressure in the control chamber 13 drops, forming a fuel pressure difference with the oil tank 10, so that the needle valve body 8 lifts up, and fuel injection starts. During this process, the needle valve stop sleeve 11 acts to limit the displacement of the needle valve body 8 . When the coil 33 is powered off and the balance valve rod 40 is seated downward, the oil return hole 36 is closed, and the fuel directly enters the control chamber 13 through the downward oil inlet hole 37 . The needle valve body 8 is installed inside the needle valve seat 7 and is compressed by the needle valve return spring 6 . Both the needle valve seat 7 and the solenoid valve assembly 5 are installed inside the tight cap 14, and are fastened by the injector body 15 and the threaded wire. The internal hydraulic pressure of the injector is balanced and there is no static pressure difference, which realizes the function of no static leakage of the injector.

Fig. 2 is a partial structural diagram of the flow limiting valve assembly of the present invention. It is made up of retaining ring 18, damping spring 19, ball valve 21, support control slider 22, ball valve reset spring seat 28, flow limiting piston 29, limit spring seat 31, etc. The restrictor valve assembly 3 is arranged inside the fuel injector body 15 through the accumulator chamber 16 . The retaining ring 18 not only acts as a limiter for the overall restrictor valve assembly 3, but also cooperates with the limit spring seat 31, on the one hand as a spring seat for the damping spring 19, and on the other hand to limit the maximum displacement of the restrictor piston 29. Under the spring pre-tightening force of the damping spring 19 and the ball valve return spring 27 , the ball valve 21 cooperates with the lower end surface of the flow limiting piston 29 and the upper end surface of the supporting control slider 22 . The ball valve return spring seat 28 is pressed against the bottom under the spring force of the ball valve return spring 27, and the seat surface of the ball valve 21 is formed at its top variable section. The high-pressure fuel enters the piston blind hole 30 in the flow-limiting piston 29 through the pressure accumulator chamber 16 , flows through the flow-limiting hole 20 and enters the axial center through hole 23 supporting the control slider 22 . The fuel flowing out from the axial center through hole 23 enters the transition oil chamber 25 through the resonance through hole 24 and the resonance throttle hole 26 . By setting and processing the resonance through hole 24 and the resonance throttle hole 26, the amplitude of the fuel pressure wave passing through the two holes is reduced. In addition, one section of the processed resonant throttle hole 26 has a smaller hole diameter than the resonant through hole 24, so the throttling effect is stronger, resulting in a difference in the flow rate of the fuel flowing through the two holes, so that the fuel pressure wave originally in the same phase produces a Phase difference, the two fuel pressure waves are superimposed and cancel each other out, so the pressure fluctuation is greatly reduced. The fuel flowing out from the transition oil chamber 25 leads to the lower oil circuit through the downward high-pressure oil circuit 4 . When the fuel injector works normally, fuel is sprayed out from the nozzle hole 43, so that the fuel pressure in the transition oil chamber 25 drops. Due to the throttling effect of the restrictor hole 20 on the fuel, the fuel pressure in the piston blind hole 30 in the restrictor piston 29 and the pressure accumulator chamber 16 rises, forming a pressure difference with the fuel pressure in the transition oil chamber 25, so the restrictor Piston 29, ball valve 21 and support control slider 22 are displaced downward as a whole, which compensates the fuel injected by the injector to a certain extent, but ball valve 21 cannot be seated on ball valve reset spring seat 27. When the fuel injection stops working, as the fuel flows through the restrictor hole 20, the pressure difference between the upper and lower surfaces of the restrictor piston 29 will gradually decrease. Under the action of the ball valve return spring 27, the restrictor piston 29, ball valve 21 and support control Slide block 22 three return to initial position again. When the injection hole 43 continuously injects fuel, and the quality of the outflowing fuel exceeds the threshold value, causing the injector to appear in an abnormal working state, the oil pressure in the transition oil chamber 25 below the flow limiting piston 29 drops rapidly, forming a pressure difference between the upper and lower sides, resulting in a limit The flow piston 29 compresses the ball valve 21 and is seated on the ball valve reset spring seat 28, preventing the fuel oil from continuing to flow. Because the fuel supply is cut off, the fuel injector stops working, which reduces the occurrence of abnormal fuel injection to a certain extent, improves fuel economy and the stability of the fuel injector.

Fig. 3 is a partial structural diagram of the solenoid valve assembly of the present invention. It consists of solenoid valve return spring seat 32, coil 33, armature 34, valve seat 35, middle block 39, balance valve stem 40, electromagnet 41, solenoid valve return spring 42 and the like. The solenoid valve return spring seat 32, the coil 33, the electromagnet 41 and the solenoid valve return spring 42 are built in the injector body 15, wherein the solenoid valve return spring seat 32 is fastened to the top of the solenoid valve by threads. The solenoid valve return spring 42 is between the solenoid valve return spring seat 32 and the armature 34 , and the armature 34 and the balance valve rod 40 are arranged inside the valve seat 35 below the injector body 15 . The intermediate block 39 is located below the valve seat 35 . When the fuel injector starts to inject fuel, the coil 33 is energized, forms a magnetic circuit with the armature 34 and the electromagnet 41, generates electromagnetic force, attracts the balance valve stem 40 to move upward, and the oil return hole 36 in the middle block 39 is opened. At this time, the fuel in the control chamber 13 is returned to the fuel tank through the middle oil passage 38 and the oil return hole 36 in sequence, the fuel pressure in the control chamber 13 drops, and the pressure on the upper surface of the needle valve body 8 decreases, which is consistent with the oil in the oil tank 10. The fuel pressure creates a differential pressure. Under the action of the pressure difference, the needle valve body 8 is lifted upwards, and the injection hole 43 is opened for fuel injection. When the injector stops injecting fuel, the coil 31 is powered off, and since the armature 34 and the balance valve stem 40 are tightly integrated, they are jointly moved downward by the spring preload force of the return spring 42 of the solenoid valve, and are compressed. On the upper end face of the intermediate block 39, the oil return hole 36 is blocked. At the same time, oil enters the downward oil inlet hole 37 inside the middle block, the control chamber 13 builds up pressure, and the needle valve body 8 takes a seat.

FIG. 4 is an enlarged view of section A-A of the needle valve body 8 . Its curved surface can play a good guiding role.

Figure 5 is a schematic diagram of the structure of the nozzle part. It consists of nozzle holes 43 and grooves 44 . During the movement of the needle valve body 8 , the sealing cone surface is opened, and the fuel flows from the oil tank 10 through the sealing cone surface and the engraved groove 44 to the injection hole 43 . The engraved groove 44 changes the flow direction and velocity of the fuel, and then adjusts the flow direction and velocity at the entrance of the injection hole, increases the effective flow area of the injection hole 43, reduces the degree of cavitation, and stabilizes the internal cavity of the injection hole 7 The flow slows down the fluctuation of the fuel injection quantity and reduces the degree of cavitation in the hole.

It can be seen from the above working process that during the fuel injection process of a resonant electronically controlled fuel injector with grooves in the present invention, the flow limiting valve assembly 3 installed in the fuel injector body 15 effectively avoids the abnormal fuel injection state. of the continuation. The groove 44 provided on the surface of the needle valve body 8 effectively improves the stability of the cavitation flow and reduces the degree of cavitation of the injector. In addition, the addition of the resonant structure effectively reduces fuel pressure fluctuations, ensuring the stability of the working process and fuel economy. When the present invention is applied to the common rail system, under the state of large fuel injection, the structure of the pressure accumulator 16 can effectively reduce the pressure fluctuation of the common rail, thereby reducing the phenomenon of uniformity and stability degradation of the fuel injection process of each cylinder. occur.

Claims (9)

1. A resonant electronically controlled fuel injector with grooves, characterized by: including injector head, injector body, flow limiting valve assembly, solenoid valve assembly, needle valve assembly, nozzle, downward high pressure oil The fuel injector head is installed above the fuel injector body, the main oil inlet hole is set inside the fuel injector head, the pressure storage chamber is set inside the fuel injector body, the main oil inlet hole communicates with the pressure storage chamber, and the flow limiting valve assembly is set In the pressure accumulator chamber, the lower end of the fuel injector body is installed with a solenoid valve assembly and a needle valve assembly in turn. The tight cap is located outside the solenoid valve assembly and the needle valve assembly. The upper end of the tight cap is connected to the lower end of the fuel injector body through a threaded connection. ; The flow-limiting valve assembly includes a limit spring seat, a flow-limiting piston, a ball valve reset spring seat, and a support control slider. The limit spring seat, the flow-limiting piston, and the ball valve return spring seat are arranged from top to bottom. A damping spring is installed between the flow-limiting pistons, and the support control slider is installed in the ball valve reset spring seat. A ball valve is arranged between the upper end of the support control slider and the flow-limiting piston. The ball valve reset spring is installed between them, the piston blind hole and the flow limiting hole are set in the flow limiting piston, the axial center through hole is set in the support control slider, the resonant through hole and the resonant orifice are set in the ball valve return spring seat, and the ball valve return spring seat A transition oil chamber is set between the fuel injector body below it, and the blind hole of the piston is connected to the pressure accumulator chamber and the restrictor hole. The throttle holes are all connected to the axial center through hole and the transition oil chamber; The solenoid valve assembly includes an electromagnet, a coil, an armature, a balance valve stem, a valve seat, and an intermediate block. The coil is wound on the electromagnet. The solenoid valve reset spring seat is arranged above the electromagnet, and the armature is arranged below the electromagnet. The armature and the solenoid valve reset The return spring of the solenoid valve is set between the spring seats, the balance valve stem is located in the valve seat, the upper end of the balance valve stem is fixedly connected with the armature, the middle block is set under the valve seat, and the oil return hole, the middle oil circuit, and the lower shape are set in the middle block. The oil inlet hole and the oil return hole are connected or disconnected with the intermediate oil circuit and the oil tank under the control of the balance valve stem; The needle valve assembly includes a needle valve stop sleeve, a needle valve seat, and a needle valve body. Part is located in the needle valve seat, and a control cavity is formed between the top of the needle valve body and the needle valve limit sleeve. A protrusion is set on the needle valve limit sleeve, and the protrusion is located at the control cavity. A needle is set between the needle valve body and the protrusion. The valve return spring, the control chamber communicates with the middle oil circuit and the lower oil inlet hole respectively, and an oil tank is formed between the needle valve body and the needle valve seat; The nozzle includes a spray hole and an engraved groove, the spray hole is processed on the needle valve seat, and the engraved groove is arranged on the surface of the lower end of the long needle valve; The upper end of the downward high-pressure oil circuit is connected to the transition oil chamber, and is connected to the oil tank through the injector body, the valve seat, the middle block, and the needle valve seat, and the downward oil inlet hole is connected to the downward high-pressure oil circuit. 2. A resonant electronically controlled fuel injector with a groove according to claim 1, characterized in that: the groove is located at the sealing cone formed when the long needle valve is seated Between the surface and the lower end of the needle valve body, the number of engraved grooves is an integral multiple of the number of spray holes, and the depth of the engraved grooves is on the order of microns. 3. A resonant electronically controlled fuel injector with a groove according to claim 1 or 2, wherein the fuel pressure in the transition oil chamber drops when the injection hole injects fuel , the flow-limiting piston, ball valve, and support control slider move downward as a whole, and the ball valve is not seated on the return spring seat of the ball valve, and the flow-limiting hole communicates with the axial center through hole; The flow piston presses the ball valve and makes it seat on the return spring seat of the ball valve, and the flow limiting hole is disconnected from the axial center through hole; The slider returns to its original position as a whole. 4. A resonant electronically controlled fuel injector with grooves according to claim 1 or 2, characterized in that: when the coil is energized, the balance valve stem moves upwards, the oil return hole is connected to the fuel tank, and the control The fuel in the cavity is returned to the fuel tank through the intermediate oil circuit and the oil return hole, the needle valve body is lifted upwards, and the nozzle hole is opened to inject fuel; after the coil is powered off, the balance valve stem moves downward under the action of the return spring of the solenoid valve, and is Press on the upper end surface of the middle block, and the oil return hole is disconnected from the oil tank. 5. A resonant electronically controlled fuel injector with grooves according to claim 3, characterized in that: when the coil is energized, the balance valve stem moves upwards, the oil return hole is connected to the fuel tank, and the control chamber The fuel is returned to the fuel tank through the intermediate oil circuit and the oil return hole, the needle valve body is lifted upwards, and the injection hole is opened for fuel injection; after the coil is powered off, the balance valve stem moves downward under the action of the return spring of the solenoid valve and is pressed on the On the upper end face of the middle block, the oil return hole is disconnected from the oil tank. 6. A resonant electronically controlled fuel injector with grooves according to claim 1 or 2, characterized in that: the diameter of the middle part of the resonant orifice is smaller than the diameters of its two ends, and smaller than the diameter of the resonant through hole , the total axial length of the resonant orifice and the resonant through hole is consistent. 7. A resonant electronically controlled fuel injector with grooves according to claim 3, characterized in that: the diameter of the middle part of the resonant orifice is smaller than the diameter of both ends of the resonant orifice, and smaller than the diameter of the resonant through hole, and the resonance The total axial length of the throttling hole and the resonant through hole is consistent. 8. A resonant electronically controlled fuel injector with grooves according to claim 4, characterized in that: the diameter of the middle part of the resonant orifice is smaller than the diameter of both ends of the resonant orifice, and smaller than the diameter of the resonant through hole, and the resonance The total axial length of the throttling hole and the resonant through hole is consistent. 9. A resonant electronically controlled fuel injector with grooves according to claim 5, characterized in that: the diameter of the middle part of the resonant orifice is smaller than the diameter of both ends of the resonant orifice, and smaller than the diameter of the resonant through hole, and the resonance The total axial length of the throttling hole and the resonant through hole is consistent.