CN111075626B - A variable nozzle injector - Google Patents

Abstract

The present invention provides a variable injection hole fuel injector, comprising a fuel injection nozzle and a fuel injector body, the fuel injection nozzle is installed at the lower end of the fuel injector body, and the fuel injection nozzle includes a needle valve base , Inner shaft needle and outer shaft needle, the lower end of the needle valve base is circumferentially evenly distributed with a plurality of oil injection holes, the inner shaft needle and the outer shaft needle are installed in the inner cavity of the needle valve base, and are connected with the needle valve base. The valve base forms a first oil holding tank, the inner pin and the outer pin are distributed in a cross shape, the lower ends of the inner pin and the outer pin are provided with spherical protrusions, and the spherical protrusions are connected to the The fuel injection holes are in one-to-one correspondence, and when the inner shaft needle and the outer shaft needle rise or fall respectively, a part of the fuel injection holes are controlled to open or close respectively. The fuel injector with variable nozzle holes provided by the present invention achieves the purpose of energy saving and emission reduction by changing the number of nozzle holes to meet the demand for fuel supply under different loads of the engine.

Description

A variable nozzle injector

technical field

The invention belongs to the technical field of fuel injection, and in particular relates to a fuel injector with variable injection holes.

Background technique

Since the 1990s, the application of electronic control technology in diesel engines has gradually increased. The use of electronically controlled fuel injectors can not only achieve higher combustion efficiency, but also reduce the emission of harmful substances.

The electronically controlled injector determines whether to inject fuel through the opening and closing of the solenoid valve, and the length of the power-on time determines the amount of fuel injection, which can reasonably control the fuel injection timing. However, the continuous development of engine combustion methods has put forward higher requirements for electronically controlled injectors: 1. In the case of small oil volume, the solenoid valve opening time is short and the control accuracy is poor. 2. The fuel injection pressure is fixed, and the fuel injection quantity can only be controlled by adjusting the fuel injection duration. It cannot meet the requirements of slow fuel injection at low speed and small load and rapid fuel injection at high speed and large load.

In view of the above problems, Chinese patent CN 203248299 U discloses a small-bore swirl chamber diesel fuel injection nozzle. The fuel injection nozzle includes a needle valve and a needle valve body, and the two are used for grinding and matching. By designing the size of the needle valve and the needle valve body , control the flow area of the fuel injection nozzle, and then achieve the purpose of controlling the fuel injection pressure and fuel injection quantity. After the needle valve and the needle valve body are assembled, the maximum lift of the needle valve in the needle valve body is 0.18-0.4mm. Where the needle valve lift is the largest, the flow area is not more than 0.18mm ² . Although this type of fuel injector can change the flow area, the flow area is determined by the upper and lower positions of the needle valve, and the accuracy of the needle valve's upper and lower displacement is very high.

Chinese patent CN 106762303 A also discloses an orifice nozzle for controlling the injection stability of a commercial vehicle diesel engine with a small amount of oil. The fuel injection nozzle includes a needle valve and a needle valve body. The needle valve head is composed of two steps. The height of the step is 0.2-0.8 times the maximum lift of the needle valve, and the diameter of the first step is slightly larger than the diameter of the second step. When the small needle valve lifts, reduce the amount of fuel in the pressure chamber between the needle valve head and the needle. The annular flow cross-sectional area between the valve bodies makes it smaller than the nozzle hole area to achieve precise control of fuel injection when the fuel volume is small; the inner diameter of the upper part of the needle valve body is the same as the outer diameter of the needle valve and is a clearance fit to form a high-pressure fuel. The axial sealing surface, the lower cone of the needle valve body and the boss of the needle valve head form the sealing cone surface of the fuel injection nozzle that controls the injection of high pressure fuel; the outer diameter of the lower part of the needle valve body of the fuel injection nozzle is between 11-13mm. This invention ensures the injection reliability and power performance of the large circulating fuel supply, and at the same time improves the fuel flow performance of the fuel injector when the fuel volume is small, and improves the injection stability of the small fuel volume. It is difficult to control the accuracy of the needle valve up and down displacement.

The above two patents are aimed at the annular flow area between the needle valve and the needle valve body, so as to control the fuel injection rate and fuel injection quantity. Chinese patent CN 103362710 A also discloses a variable nozzle type electronically controlled fuel injector, the purpose of this invention is to provide a variable nozzle type electronically controlled fuel injector, including an electronically controlled actuator part, a fuel injection nozzle, The fuel injector body, the electric control actuator part and the fuel injection nozzle are respectively installed on the upper and lower ends of the fuel injector body. The fuel injection nozzle includes a needle valve and a needle valve base. The needle valve is installed in the needle valve base and is connected with the needle valve. The base forms an oil holding tank. The lower end of the needle valve base is provided with a main fuel injection hole and a secondary fuel injection hole from bottom to top. The lower end of the needle valve has a double sealing surface structure. The cylindrical sealing surface seals the main oil injection hole, and the conical sealing surface seals the auxiliary oil injection hole. When the needle valve rises, the auxiliary oil injection hole is connected to the oil tank before the main oil injection hole. This invention is not only conducive to the control of small fuel injection in the multiple injection process, but also can combine the main injection and shoe injection, thereby improving the fuel injection effect, improving the economy and power of the engine, and meeting stricter emission requirements. Compared with the previous two patents, this patent takes changing the fuel injection hole as the starting point to achieve the effect of controlling the fuel injection amount, but also has the problem of precise control of the up and down movement position of the needle valve.

SUMMARY OF THE INVENTION

Aiming at the problems of the current control accuracy of small fuel quantity of diesel engines and the requirements for fuel injection quantity and fuel injection rate of low-speed small-load and high-speed high-load diesel engines, the present invention proposes a variable nozzle number injector.

In order to achieve the above purpose, the technical solution adopted in the present invention is: a variable nozzle fuel injector, comprising a fuel injection nozzle, a fuel injector main body and an electric control device, the fuel injection nozzle includes a needle valve base, an inner Axle needle and an outer axis needle, the needle valve base is installed on the lower end of the main body of the fuel injector, the lower end of the needle valve base is circumferentially evenly distributed with a plurality of fuel injection holes, and the inner and outer axis needles are installed at the The inner cavity of the needle valve base and the needle valve base form a first oil holding groove, the inner shaft needle and the outer shaft needle are distributed crosswise, and the lower ends of the inner shaft needle and the outer shaft needle are both. There are spherical protrusions, and the spherical protrusions correspond to the oil injection holes one-to-one. The electronic control device includes a first electronic control device and a second electronic control device, and the first electronic control device controls the external The rise or fall of the shaft needle to open or close the oil injection hole corresponding to the outer shaft, the second electronic control device controls the rise or fall of the inner shaft to open or close the corresponding to the inner shaft injection hole.

The beneficial effects of the present invention are as follows: the injector with variable nozzle holes provided by the present invention adapts to the demand for oil supply under different loads of the engine by changing the number of nozzle holes, and when a small amount of oil is injected, the multi-hole injector Opening part of the nozzle holes extends the injection time and makes it easier to control the injection precision compared to the full opening of the nozzle holes. The mist is fully evaporated and mixed evenly to achieve the purpose of energy saving and emission reduction. Specifically, the inner axis needles and the outer axis needles are distributed in a cross shape.

On the basis of the above technical solutions, the present invention can also have the following further specific options or optimized options.

Specifically, the fuel injection nozzle further includes a needle valve top seat, the lower end of the needle valve top seat is in contact with the upper end of the needle valve base, and the needle valve top seat is cylindrical and has a second inner cavity , the second inner cavity and the top end of the outer pin are surrounded to form a second oil holding groove, the upper end of the inner pin is higher than the upper end of the outer pin, and the injector main body includes a guide column, a housing, a pressure relief ring and an armature, the lower end of the pressure relief ring is in contact with the upper end of the guide column, the guide column is provided with a first inner cavity, and the upper end of the inner pin passes through the first inner cavity, and form a third oil holding groove with the upper end of the guide column and the lower end of the pressure relief ring, the casing is circumferentially sleeved on the upper end of the fuel injection nozzle, the outer circumference of the guide column, the outer circumference of the pressure relief ring and the outer circumference of the armature, and A fourth oil tank is formed with the upper end of the pressure relief ring. The injector body is also provided with a high-pressure oil passage and a low-pressure oil passage. The oil inlet of the high-pressure oil passage is communicated with the high-pressure oil pump, and the oil outlet is The fuel injection holes are communicated with each other, the high-pressure oil passage is communicated with the first, second, and third oil-containing grooves, respectively, the oil outlet of the low-pressure oil passage is communicated with the low-pressure fuel tank, and the low-pressure oil The passages are respectively communicated with the second oil holding tank, the third oil holding tank and the fourth oil holding tank.

Specifically, it also includes an electric control device, the electric control device includes a first electric control device and a second electric control device, the first electric control device controls the rise or fall of the outer shaft needle, the second electric control device The control device controls the rising or falling of the inner pin. Specifically, the first electronic control device controls the opening and closing of the low-pressure oil passage toward the second oil holding tank; the second electronic control device controls the opening and closing of the low-pressure oil passage toward the third oil holding tank and closed.

The beneficial effect of adopting the above-mentioned further scheme is that the present invention simultaneously designs the electromagnetic control structure of the inner and outer shaft needles. The opening and closing of the outer shaft needle is determined by the solenoid valve of the first electronic control device. The initial state of the solenoid valve is the energized state. At this time, the spool of the solenoid valve blocks the low-pressure oil passage, and the second oil tank contains high-pressure oil; if the solenoid valve When the power is cut off, the low-pressure oil passage is connected. At this time, there is low-pressure oil in the second oil tank. The opening and closing of the inner shaft needle and the outer shaft needle is determined by the solenoid valve of the second electronic control device. The initial state of the solenoid valve is the energized state. At this time, the spool of the solenoid valve blocks the low-pressure oil passage, and the third oil tank contains high-pressure oil; If the solenoid valve is powered off, the low-pressure oil passage is connected, and the third oil tank is filled with low-pressure oil. When the first oil holding tank, the second oil holding tank, the third oil holding tank and the fourth oil holding tank hold high-pressure oil or low-pressure oil respectively, the pressure difference between the bottom and the top of the inner pin and the outer pin is used to control the oil. rise or fall, so as to further control the opening or closing of the fuel injection holes. Specifically, when the first electric control device and the second electric control device control and close the low-pressure oil passage, the first, second, and third oil holding tanks hold the high-pressure oil respectively, and the fourth oil holding tank The low-pressure oil contained in the oil tank, the inner pin and the outer pin are pressed on the needle valve base, and no oil is injected at this time; when the first electric control device is turned on and the second electric control device is closed, the The second oil holding tank is communicated with the low-pressure oil passage, and the pressure in its inner cavity becomes smaller. Due to the pressure difference between the first oil holding tank and the second oil holding tank, the outer shaft needle moves upward, and the corresponding four oil injection holes spray oil; When both the first electric control device and the second electric control device are turned on, the second oil holding tank is communicated with the low-pressure oil passage, and the pressure in its inner cavity becomes smaller. Due to the pressure difference between the first oil holding tank and the second oil holding tank, As a result, the outer shaft needle moves upward, the third oil holding tank communicates with the low-pressure oil passage, and the pressure in its inner cavity becomes smaller. Due to the pressure difference between the first oil holding groove and the third oil holding groove, the inner shaft needle moves upward. At this time All eight of the fuel injection holes are open. The double-shaft needle structure effectively avoids the problem of the control accuracy of the needle valve's up and down displacement.

Specifically, the lower end of the needle valve base is evenly distributed with 8 of the oil injection holes in the circumferential direction, and the lower ends of the inner shaft needle and the outer shaft needle are evenly distributed with 4 of the spherical protrusions. When the needle and the outer shaft needle descend, the spherical protrusion closes the injection hole.

The beneficial effect of adopting the above-mentioned further scheme is that the fuel injection holes of the fuel injector can be set to any number, and the inner and outer shaft needles respectively control a part of the fuel injection holes, and the optimal number is 8, and the control is the easiest at this time. The needle valve base is provided with 8 oil injection holes, and a double-shaft needle structure is specially designed, wherein the outer shaft needle is nested outside the inner shaft needle, and the inner and outer shaft needles are distributed in a * shape. There are 4 spherical protrusions on the head of each pin, corresponding to the 4 holes of the injector respectively. When the pin is seated, the spherical protrusions linearly seal the nozzle holes.

Specifically, a second spring is arranged in the second oil holding tank, the lower end of the second spring is in contact with the top end of the outer pin, and the upper end of the second spring is in contact with the lower end of the guide post . A fourth spring is arranged in the fourth oil holding tank, the lower end of the fourth spring is in contact with the top end of the pressure relief ring, and the upper end of the fourth spring is in contact with the lower end of the armature.

The beneficial effect of adopting the above-mentioned further solution is that the second spring can assist the up and down movement of the outer pin and play a buffering role. The fourth spring can cooperate with the second electronic control device to assist the armature to move up and down, so as to open or close the low-pressure oil passage and play a buffering role.

Specifically, the outer periphery of the guide column is provided with a convex ridge along its axial direction, the inner wall of the casing is provided with a limiting groove along its axial direction, and the convex ridge is embedded in the limiting groove.

The beneficial effect of adopting the above-mentioned further solution is that the convex ridge cooperates with the limiting groove, so that the circumferential rotation of the guide column around its axis can be restricted, thereby ensuring the smooth flow of the high-pressure oil passage and the low-pressure oil passage.

Specifically, the outer wall of the pressure relief ring and the inner wall of the casing are threadedly connected.

The beneficial effect of adopting the above further solution is that the threaded connection can not only prevent oil leakage and pressure relief between the pressure relief ring and the casing, but also relatively fix the connection between the pressure relief ring and the casing. Location.

Specifically, a sealing ring is provided where the needle valve base and the housing abut each other.

The beneficial effect of adopting the above-mentioned further solution is that the sealing ring is used to avoid oil leakage and pressure relief between the needle valve base and the housing.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, and implement it according to the content of the description, the preferred embodiments of the present invention are described in detail below with the accompanying drawings. Specific embodiments of the present invention are given in detail by the following examples and the accompanying drawings.

Description of drawings

Fig. 1 is a front view of a fuel injector with a variable nozzle hole provided by the present invention;

2 is a schematic structural diagram of a fuel injector with variable nozzle holes provided by the present invention;

3 is a detailed view of a fuel injector of a variable nozzle fuel injector provided by the present invention;

Fig. 4 is the A-A cross-sectional schematic diagram of Fig. 2 provided by the present invention;

5 is a schematic diagram of the connection structure between the inner pin and the outer pin of a variable nozzle fuel injector provided by the present invention;

6 is a schematic diagram of filling of high-pressure oil and low-pressure oil when a variable nozzle injector provided by the present invention does not inject oil;

7 is a schematic diagram of filling of high-pressure oil and low-pressure oil when part of the injection holes of a variable injection hole injector provided by the present invention is injected;

FIG. 8 is a schematic diagram showing the filling of high-pressure oil and low-pressure oil when all the injection holes of a variable injection orifice injector according to the present invention are injected.

In the figure: 1-high pressure oil; 2-low pressure oil; 3-fuel injection nozzle; 4-injector body; 5-second electric control device; 6-first electric control device; 7-high pressure oil passage; 8- Low pressure oil passage; 31- needle valve base; 32- inner shaft needle; 33- outer shaft needle; 34- fuel injection hole; 35- spherical protrusion; 36- needle valve top seat; 11- first oil tank; 12- The second oil tank; 13- the third oil tank; 14- the fourth oil tank; 41- guide column; 42- shell; 43- pressure relief ring; 44- armature; ; 411-limit groove; 422-seal ring.

Detailed ways

In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the accompanying drawings and specific embodiments, but the content of the present invention is not limited to the following embodiments.

The present invention provides a fuel injector with variable injection holes, comprising a fuel injection nozzle 3 and a fuel injector body 4, the fuel injection nozzle 3 is installed at the lower end of the fuel injector body 4, and the fuel injection nozzle 3. It includes a needle valve base 31, an inner shaft needle 32 and an outer shaft needle 33. The lower end of the needle valve base 31 is circumferentially evenly distributed with a plurality of oil injection holes 34. The inner shaft needle 32 and the outer shaft needle 33 are installed on the The inner cavity of the needle valve base 31 and the needle valve base 31 form the first oil-reserving groove 11, the inner shaft needle 32 and the outer shaft needle 33 are distributed in a cross shape, and the inner shaft needle 32 and the outer shaft needle The lower ends of the 33 are provided with spherical protrusions 35, which correspond to the oil injection holes 34 one-to-one. The fuel injection holes 34 are opened or closed.

The fuel injector with variable nozzle holes provided by the present invention adapts to the demand for fuel supply under different loads of the engine by changing the number of nozzle holes. Compared with the full opening of the nozzle hole, the injection time is prolonged, and it is easier to control the injection accuracy. At the same time, when a large amount of oil is required, the nozzle hole of the injector is fully opened, which saves the injection time and makes the oil mist fully evaporate and mix evenly. The purpose of energy saving and emission reduction.

Specifically, the fuel injector 3 further includes a needle valve top seat 36 , the lower end of the needle valve top seat 36 is in contact with the upper end of the needle valve base 31 , and the needle valve top seat 36 is connected to the outer shaft. The top end of the needle 33 forms a second oil holding groove 12, the upper end of the inner pin 32 is higher than the upper end of the outer pin 33, the injector body 4 includes a guide post 41, a housing 42, a pressure relief The ring 43 and the armature 44, the guide post 41 is circumferentially arranged on the outer circumference of the inner pin 32, the lower end of the pressure relief ring 43 abuts the upper end of the guide pin 41, and is in contact with the upper end of the outer pin 33 A third oil holding groove 13 is formed with the upper end of the guide post 41 and the lower end of the pressure relief ring 43 , and the casing 42 is circumferentially arranged around the upper end of the fuel injection nozzle 3 , the outer periphery of the guide post 41 , and the pressure relief ring 43 The outer circumference and the outer circumference of the armature 44 and the upper end of the pressure relief ring 43 form a fourth oil receiving groove 14. The injector body 4 is also provided with a high-pressure oil passage 7 and a low-pressure oil passage 8. The oil inlet is communicated with the high pressure oil pump, the high pressure oil passage 7 is communicated with the first oil holding tank 11, the second oil holding tank 12 and the third oil holding tank 13 respectively, and the oil outlet of the low pressure oil passage 8 is connected with the low pressure oil tank The low-pressure oil passage 8 communicates with the second oil holding tank 12 , the third oil holding tank 13 and the fourth oil holding tank 14 respectively.

When the high-pressure oil 1 or the low-pressure oil 2 contained in the first oil tank 11 , the second oil tank 12 , the third oil tank 13 and the fourth oil tank 14 respectively, pass through the bottom of the inner pin 32 and the outer pin 33 The pressure difference between the top and the top can be controlled to rise or fall, so as to further control the opening or closing of the fuel injection hole 34 . Specifically, when the first electric control device 6 and the second electric control device 5 control and close the low-pressure oil passage 8, the first oil holding tank 11, the second oil holding tank 12 and the third oil holding tank 13 respectively hold the high-pressure oil Oil, the low-pressure oil contained in the fourth oil tank 14, the inner pin 32 and the outer pin 33 are pressed on the needle valve base 31 at this time, and no oil is injected at this time; when the first electronic control device 6 is turned on , when the second electronic control device 5 is closed, the second oil holding tank 12 is communicated with the low-pressure oil passage 8, and the pressure in its inner cavity becomes smaller. Due to the pressure difference between the first oil holding tank 11 and the second oil holding tank 12, the external The shaft needle 33 moves upward, and the corresponding four oil injection holes 34 inject oil; when the first electronic control device 6 and the second electronic control device 5 are both turned on, the second oil holding tank 12 and the low-pressure oil passage 8 The inner cavity pressure becomes smaller. Due to the pressure difference between the first oil holding tank 11 and the second oil holding tank 12, the outer pin 33 moves upward. The third oil holding tank 13 is communicated with the low-pressure oil passage 8. The cavity pressure becomes smaller. Due to the pressure difference between the first oil tank 11 and the third oil tank 13, the inner pin 32 moves upward, and the eight injection holes 34 are all opened. The double-shaft needle structure effectively avoids the problem of the control accuracy of the needle valve's up and down displacement.

Specifically, it also includes an electric control device, the electric control device includes a first electric control device 6 and a second electric control device 5, the first electric control device 6 controls the rise or fall of the outer shaft needle 33, so The second electronic control device 5 controls the rise or fall of the inner shaft needle 32 . Specifically, the first electronic control device 6 controls the opening and closing of the low-pressure oil passage 8 toward the second oil holding tank 12 ; the second electronic control device 5 controls all the oil paths toward the third oil holding tank 13 The low-pressure oil passage 8 is opened and closed.

The present invention designs the electromagnetic control structure of the inner and outer shaft needles 33 at the same time. The opening and closing of the outer shaft needle 33 is determined by the solenoid valve of the first electronic control device 6, and the initial state of the solenoid valve is the energized state. At this time, the spool of the solenoid valve blocks the low-pressure oil passage, and the second oil tank 12 contains high-pressure oil; If the solenoid valve is powered off and the low pressure oil passage is connected, the second oil holding tank 12 is filled with low pressure oil at this time. The opening and closing of the inner shaft needle 32 and the outer shaft needle 33 is determined by the solenoid valve of the second electronic control device 5. The initial state of the solenoid valve is the energized state. It is high-pressure oil; if the solenoid valve is powered off, the low-pressure oil passage is connected, and at this time, there is low-pressure oil in the third oil tank 13 .

Specifically, the lower end of the needle valve base 31 has 8 oil injection holes 34 evenly distributed in the circumferential direction, and the lower ends of the inner pin 32 and the outer pin 33 are evenly distributed with 4 spherical protrusions 35 . The fuel injection holes 34 of the fuel injector can be set to any number, and the inner and outer shaft needles 33 respectively control a part of the fuel injection holes 34, and the optimal number is 8, and the control is the easiest at this time. The needle valve base 31 is provided with 8 oil injection holes 34, and a double-shaft needle structure is specially designed, wherein the outer shaft needle is nested outside the inner shaft needle 32, and the inner and outer shaft needles are *-shaped There are 4 spherical protrusions 35 on the head of each pintle, corresponding to 4 holes of the injector respectively. When the pintle is seated, the spherical protrusions 35 linearly seal the nozzle holes.

Specifically, a second spring 122 is arranged in the second oil holding tank 12 , the lower end of the second spring 122 is in contact with the top end of the outer pin 33 , and the upper end of the second spring 122 is in contact with the guide The lower end of the column 41 abuts. A fourth spring 144 is arranged in the fourth oil holding tank 14 , the lower end of the fourth spring 144 is in contact with the top end of the pressure relief ring 43 , and the upper end of the fourth spring 144 is in contact with the armature 44 the lower end of the contact. The second spring 122 can assist the up and down movement of the outer pin 33 and play a buffering role. The fourth spring 144 can cooperate with the second electronic control device 5 to assist the armature 44 to move up and down, so as to open or close the low-pressure oil passage and play a buffering role.

Specifically, the outer circumference of the guide post 41 is provided with a convex ridge along its axial direction, and the inner wall of the housing 42 is provided with a limiting groove 411 along its axial direction, and the convex ridge is embedded in the limiting groove 411 . The protruding ridges cooperate with the limiting grooves 411 to limit the circumferential rotation of the guide post 41 around its axis, thereby ensuring the smooth flow of the high-pressure oil passage 7 and the low-pressure oil passage 8 .

Specifically, the pressure relief ring 43 and the housing 42 are connected by screw threads. The threaded connection can not only prevent oil leakage between the pressure relief ring 43 and the casing 42 and pressure relief, but also relatively fix the position between the pressure relief ring 43 and the casing 42 .

Specifically, a sealing ring 422 is provided where the needle valve base 31 and the housing 42 abut each other. The sealing ring is used to prevent oil leakage and pressure relief between the needle valve base 31 and the housing 42 .

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. within the range.

Claims (8)

1. The fuel injector with the variable spray holes is characterized by comprising a fuel injector (3), a fuel injector main body (4) and an electric control device, wherein the fuel injector (3) comprises a needle valve base (31), an inner shaft needle (32) and an outer shaft needle (33), the needle valve base (31) is installed at the lower end of the fuel injector main body (4), a plurality of fuel spray holes (34) are evenly distributed in the circumferential direction of the lower end of the needle valve base (31), the inner shaft needle (32) and the outer shaft needle (33) are installed in an inner cavity of the needle valve base (31), a first oil containing groove (11) is formed between the needle valve base (31), the inner shaft needle (32) and the outer shaft needle (33) are distributed in a cross mode, spherical protrusions (35) are arranged at the lower end portions of the inner shaft needle (32) and the outer shaft needle (33), the spherical protrusions (35) correspond to the fuel spray holes (34) one by one, the electric control device comprises a first electric control device (6) and a second electric control device (5), the first electric control device (6) controls the rising or falling of the outer pintle (33) to open or close the oil injection hole (34) corresponding to the outer pintle (33), the second electric control device (5) controls the rising or falling of the inner pintle (32) to open or close the oil injection hole (34) corresponding to the inner pintle (32), the oil nozzle (3) further comprises a needle valve top seat (36), the lower end of the needle valve top seat (36) is abutted to the upper end of the needle valve base (31), the needle valve top seat (36) is cylindrical and is provided with a second inner cavity, the second inner cavity and the top end of the outer pintle (33) are surrounded to form a second oil containing groove (12), the upper end of the inner pintle (32) is higher than the upper end of the outer pintle (33), the oil injector main body (4) comprises a guide column (41), a shell (42), a pressure relief ring (43) and an armature (44), let out clamping ring (43) lower extreme with guide post (41) upper end butt, guide post (41) are equipped with first inner chamber, interior pintle (32) upper end is passed first inner chamber, and with guide post (41) upper end and the lower extreme of letting out clamping ring (43) form third and contain oil groove (13), casing (42) circumference cover is established fuel sprayer (3) upper end guide post (41) periphery, let out clamping ring (43) periphery and armature (44) periphery, and with let out clamping ring (43) upper end and form fourth and contain oil groove (14), sprayer main part (4) still are equipped with high-pressure oil passageway (7) and low pressure oil passageway (8), the oil inlet and the high-pressure oil pump intercommunication of high-pressure oil passageway (7), and its with nozzle hole (34) intercommunication, high-pressure oil passageway (7) respectively with first flourishing oil groove (11), The second oil containing groove (12) is communicated with the third oil containing groove (13), the oil outlet of the low-pressure oil passage (8) is communicated with the low-pressure oil tank, and the low-pressure oil passage (8) is communicated with the second oil containing groove (12), the third oil containing groove (13) and the fourth oil containing groove (14) respectively.

2. The variable orifice fuel injector of claim 1, characterized in that: the first electric control device (6) controls the low-pressure oil passage (8) facing the second oil containing groove (12) to be opened and closed; the second electric control device (5) controls the low-pressure oil passage (8) facing the third oil containing groove (13) to be opened and closed, when the first electric control device (6) and the second electric control device (5) control the low-pressure oil passage (8) to be closed, the first oil containing groove (11), the second oil containing groove (12) and the third oil containing groove (13) respectively contain high-pressure oil, the fourth oil containing groove (14) contains low-pressure oil, and at the moment, the inner shaft needle (32) and the outer shaft needle (33) are pressed on the needle valve base (31), and oil is not injected; when the first electric control device (6) is opened and the second electric control device (5) is closed, the second oil containing groove (12) is communicated with the low-pressure oil passage (8), the pressure of the inner cavity of the second oil containing groove becomes small, the outer pintle (33) moves upwards due to the pressure difference between the first oil containing groove (11) and the second oil containing groove (12), and oil is injected from the corresponding oil injection hole (34); when the first electric control device (6) and the second electric control device (5) are both started, the second oil containing groove (12) is communicated with the low-pressure oil passage (8), the pressure of the inner cavity of the second oil containing groove becomes small, the outer pintle (33) is caused to move upwards due to the pressure difference between the first oil containing groove (11) and the second oil containing groove (12), the third oil containing groove (13) is communicated with the low-pressure oil passage (8), the pressure of the inner cavity of the third oil containing groove becomes small, the inner pintle (32) is caused to move upwards due to the pressure difference between the first oil containing groove (11) and the third oil containing groove, and the oil injection holes (34) are both started at the moment.

3. The variable orifice fuel injector according to claim 1 or 2, characterized in that: even cloth of tip circumference has 8 under needle valve base (31) nozzle opening (34), the lower extreme tip equipartition of interior pintle (32) and outer pintle (33) has 4 spherical bulge (35), works as when interior pintle (32) and outer pintle (33) descend, spherical bulge (35) are sealed nozzle opening (34).

4. The variable orifice fuel injector according to claim 1 or 2, characterized in that: and a second spring (122) is arranged in the second oil containing groove (12), the lower end of the second spring (122) is abutted against the top end of the outer shaft needle (33), and the upper end of the second spring (122) is abutted against the lower end of the guide column (41).

5. The variable orifice fuel injector according to claim 1 or 2, characterized in that: and a fourth spring (144) is arranged in the fourth oil containing groove (14), the lower end of the fourth spring (144) is abutted to the top end of the pressure relief ring (43), and the upper end of the fourth spring (144) is abutted to the lower end of the armature (44).

6. The variable orifice fuel injector according to claim 1 or 2, characterized in that: the guide post (41) periphery is equipped with protruding stupefied along its axial, casing (42) inner wall is equipped with spacing groove (411) along its axial, protruding stupefied embedding in spacing groove (411).

7. The variable orifice fuel injector according to claim 1 or 2, characterized in that: the outer wall of the pressure relief ring (43) is in threaded connection with the inner wall of the shell (42).

8. The variable orifice fuel injector according to claim 1 or 2, characterized in that: the needle valve base (31) and the shell (42) are provided with sealing rings (422) at the mutual abutting positions.

Images