Three-way valve assembly of oil sprayer

Abstract

The utility model belongs to the technical field of oil sprayers, and particularly discloses a three-way valve assembly of an oil sprayer, which comprises an oil sprayer body, a metering valve and a three-way valve, a switch hole is formed in the end face, close to the switch valve, of the metering valve. The metering valve is provided with a first control cavity communicated with the switch hole. The three-way valve is provided with a third oil hole communicated with the oil sprayer body, and the third oil hole is communicated with the first control cavity through a third buffer groove and the first buffer groove; the third oil hole is communicated with the second control cavity through the third buffer groove, the first buffer groove, the first oil hole and the second buffer groove; the second control cavity is communicated with the first control cavity through the second buffer groove, the first oil hole and the first buffer groove; the second control cavity is communicated with the shell of the oil sprayer through the second oil hole; the first buffer groove, the second buffer groove and the third buffer groove are used for buffering flow stress of fuel oil, delaying fatigue damage of the fuel oil to the three-way valve and prolonging the service life of the three-way valve.

Description

Technical Field

[0001] The utility model belongs to the technical field of fuel injectors, and particularly relates to a three-way valve assembly of a fuel injector. Background Art

[0002] At present, high-pressure common rail fuel injectors adopt three-way valves. The three-way valve can accelerate the pressure release and replenishment speed of the control chamber, and plays a significant role in the working stability and response speed of the fuel injector needle valve. The three-way valve is provided with a low-pressure oil return port, a high-pressure oil inlet port, an auxiliary oil inlet port, each oil passage and a control chamber.

[0003] The working process of the three-way valve is as follows:

[0004] 1) During the fuel injection start process of the fuel injector: the solenoid valve is charged, the low-pressure oil return port is opened, the oil in the control chamber and the oil coming in from the high-pressure oil inlet port flow to the low-pressure oil return port, the pressure in the control chamber drops, resulting in a decrease in the downward acting force on the fuel injector nozzle needle valve, the fuel injector nozzle needle valve lifts, and the fuel injector starts to inject fuel.

[0005] 2) During the fuel injection end process of the fuel injector: the solenoid valve is de-energized, the low-pressure oil return port is closed, the oil coming in from the high-pressure oil inlet port flows into the control chamber, the downward acting force on the fuel injector nozzle needle valve from the control chamber and the needle valve spring is greater than the acting force in the nozzle chamber, the fuel injector nozzle needle valve moves downward, and the fuel injection ends.

[0006] During the fuel injection start and end processes, the following problems exist: in the oil passage, the high-pressure fuel coming in from the oil inlet port flows to various positions. Because the high-pressure fuel flows in the narrow oil passage, the inner walls of the oil passage and the control chamber will be subjected to the impact stress of the high-pressure fuel, causing fatigue damage to the inner walls of the oil passage and the control chamber, and reducing the service life of the three-way valve. Summary of the Utility Model

[0007] The purpose of the utility model is to provide a three-way valve assembly of a fuel injector, which buffers the flow stress of high-pressure fuel, delays the fatigue damage of high-pressure fuel to the three-way valve, and improves the service life of the three-way valve.

[0008] The purpose of the utility model is realized through the following technical solutions:

[0009] A three-way valve assembly of a fuel injector includes:

[0010] A fuel injector body and a metering valve and a three-way valve installed on the fuel injector body;

[0011] The metering valve is provided with a switch hole on the end face close to the switching valve, and the metering valve (1) is provided with a first control chamber communicated with the switch hole;

[0012] The three-way valve is provided with a third oil hole communicating with the injector body. The third oil hole is communicated with the first control cavity through a third buffer groove and a first buffer groove; the third oil hole is communicated with the second control cavity through a third buffer groove, a first buffer groove, a first oil hole and a second buffer groove; the second control cavity is communicated with the first control cavity through a second buffer groove, a first oil hole and a first buffer groove; the second oil hole connects the second control cavity and the injector body; the first buffer groove, the second buffer groove and the third buffer groove are used for buffering the flow stress of the fuel.

[0013] Preferably, a first buffer groove is provided at the top of the three-way valve. The upper end surface of the first buffer groove is communicated with the first control cavity. A connecting portion communicating with the first oil hole is provided on the lower end surface of the first buffer groove. One side of the lower end surface of the first buffer groove is communicated with the top end of the third buffer groove.

[0014] Preferably, the switch hole is provided with a first switch hole section and a second switch hole section. The aperture of the second switch hole section is larger than that of the first switch hole section. The switch valve is used to open or seal the second switch hole.

[0015] Preferably, the sum of the apertures of the first oil hole and the third oil hole is smaller than that of the first switch hole section, and the aperture of the second oil hole is smaller than that of the first oil hole.

[0016] Preferably, the third oil hole is communicated with the injector body through a fourth buffer groove.

[0017] Preferably, the second oil hole is communicated with the injector body through a fifth buffer groove.

[0018] Preferably, it further includes a needle valve and a guide sleeve. The three-way valve and the guide sleeve are separate bodies. A concave cavity cooperating with the upper end surface of the guide sleeve is provided on the lower end surface of the three-way valve. The needle valve is slidably installed in the guide sleeve.

[0019] Due to the adoption of the above technical solutions, the utility model has the following advantages: when the injector returns or feeds oil, the first buffer groove, the second buffer groove and the third buffer groove in the three-way valve slow down the flow stress of the high-pressure fuel, thereby improving the smooth flow of the high-pressure fuel in the three-way valve, delaying the fatigue damage of the inner wall of the three-way valve, and increasing the service life of the three-way valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present utility model, the drawings required for the specific embodiments will be briefly introduced below. In all the drawings, the components or parts are not necessarily drawn according to the actual scale.

[0021] Figure 1 It is a schematic structural diagram of a three-way valve assembly of an injector of the present utility model;

[0022] Figure 2 It is an enlarged schematic view of part A.

[0023] Reference numerals:

[0024] 1 - metering valve, 11 - switching hole, 111 - first switching hole section, 112 - second switching hole section, 12 - first control chamber, 2 - switching valve, 3 - three - way valve, 30 - concave cavity, 31 - second control chamber, 32 - second oil hole, 33 - third oil hole, 34 - first buffer groove, 341 - connecting part, 35 - second buffer groove, 36 - third buffer groove, 37 - first oil hole, 38 - fourth buffer groove, 39 - fifth buffer groove, 4 - injector body, 5 - needle valve, 6 - guide sleeve, 61 - guide cavity. Detailed implementation mode

[0025] Please refer to Figure 1 and Figure 2 , a three - way valve assembly of an injector, comprising:

[0026] An injector body 4 and a metering valve 1 and a three - way valve 3 installed on the injector body 4. The metering valve 1 is provided with a switching hole 11 on the end face close to the switching valve 2, and the metering valve 1 is provided with a first control chamber 12 communicated with the switching hole 11. The three - way valve 3 is provided with a third oil hole 33 communicated with the injector body 4. The third oil hole 33 is communicated with the first control chamber 12 through the third buffer groove 36 and the first buffer groove 34; the third oil hole 33 is communicated with the second control chamber 31 through the third buffer groove 36, the first buffer groove 34, the first oil hole 37 and the second buffer groove 35; the second control chamber 31 is communicated with the first control chamber 12 through the second buffer groove 35, the first oil hole 37 and the first buffer groove 34; the second oil hole 35 connects the second control chamber 31 and the injector body 4; the first buffer groove 34, the second buffer groove 35 and the third buffer groove 36 are used to buffer the flow stress of the fuel. The inner cavity of the injector body 4 is sequentially provided with a metering valve installation cavity and a three - way valve installation cavity from top to bottom; the three - way valve installation cavity is communicated with the oil inlet passage on the injector body 4, and the metering valve installation cavity is communicated with the oil outlet passage on the injector body 4; the metering valve installation cavity and the oil outlet passage are disconnected or communicated through the switching valve 2, so that the switching valve 2 opens or closes the switching hole 11.

[0027] The three-way valve assembly of the fuel injector in the present utility model. When the fuel injector starts to intake fuel, a part of the high-pressure fuel entering from the third fuel hole 33 flows to the first control chamber 12 through the third buffer groove 36 and the first buffer groove 34, and a part flows to the second control chamber 31 through the third buffer groove 36, the first buffer groove 34 and the first fuel hole 37; thereby filling the first control chamber 12 and the second control chamber 31 with high-pressure fuel. Since the volumes and groove diameters of the first buffer groove 34, the second buffer groove 35 and the third buffer groove 36 are much larger than the hole diameters of the first fuel hole 37, the second fuel hole 32 and the third fuel hole 33, after the high-pressure fuel enters the third buffer groove 36 from the third fuel hole 33, the flow rate of the high-pressure fuel will be buffered, the stress of the high-pressure fuel entering the third buffer groove 36 is reduced, and then it is secondarily buffered through the first buffer groove 34. Therefore, the high-pressure fuel smoothly enters the first control chamber 12 or the second control chamber 31, improving the smooth flow of the high-pressure fuel in the above process, and reducing the stress on the inner wall of the three-way valve 3, slowing down the fatigue damage of the three-way valve 3, and increasing the service life of the fuel injector. Similarly, when the fuel injector starts to return fuel, the fuel flows from the second control chamber 31 through the second buffer groove 35, the first fuel hole 37 and the first buffer groove 34 to the first control chamber 12, slowing down the fatigue damage of the three-way valve 3, and when it reaches the switch hole 11, the oil pressure has been reduced, reducing the generation of cavitation in the switch hole 11.

[0028] Please refer to Figure 2 , further, a first buffer groove 34 is provided at the top of the three-way valve 3. The upper end of the first buffer groove 34 is communicated with the first control chamber 12. A connecting portion 341 communicated with the first fuel hole 37 is provided at the lower end of the first buffer groove 34. One side of the lower end surface of the first buffer groove 34 is communicated with the top end of the third buffer groove 36. Specifically, the upper end of the first buffer groove 34 is a groove with a relatively shallow depth, but the bottom area of the first buffer groove 34 is as large as possible, so that the first buffer groove 34 has sufficient buffer space. At the same time, after the switch valve 2 seals the switch hole 11, the second control chamber 31 can be quickly filled with high-pressure fuel, obtaining a faster downward pressure, and the needle valve assembly 5 can be pressed down more quickly. A connecting portion 341 is provided at the lower middle end of the first buffer groove 34, and the connecting portion 341 plays a role of connection and buffering, and the fuel smoothly flows between the first buffer groove 34 and the second control chamber 31.

[0029] Please refer to Figure 2 , further, the switch hole 11 is provided with a first switch hole section 111 and a second switch hole section 112. The hole diameter of the second switch hole section 112 is larger than that of the first switch hole section 111. The switch valve 2 is used to open or seal the second switch hole section 112. With this structure, when returning fuel, the oil flow rate from the first switch hole section 111 is made smaller than the oil outlet rate of the second switch hole section 112, thereby ensuring the smooth outflow of the oil in the first control chamber 12.

[0030] Please refer to Figure 2, Further, the sum of the diameters of the first oil hole 37 and the third oil hole 33 is smaller than the diameter of the first switch hole section 111, and the diameter of the second oil hole 32 is smaller than the diameter of the first oil hole 37. With this structure, when the fuel injector needs to inject fuel, the switching valve 2 opens the switch hole 11. The fuel inlet rate of the first control chamber 12 is less than the fuel outlet rate. The oil in the second control chamber 31 needs to be replenished to the first control chamber 12. Since the diameter of the second oil hole 32 is smaller than that of the first oil hole 37, the fuel inlet rate of the second control chamber 31 is less than the fuel outlet rate, the pressure in the second control chamber 31 decreases, the needle valve 5 moves upward, and the fuel injector starts to inject fuel.

[0031] Please refer to Figure 2 , Further, the third oil hole 33 is connected to the fuel injector body 4 through a fourth buffer groove 38. With this structure, the fourth buffer groove 38 effectively buffers the flow stress of the high-pressure fuel entering the third oil hole 33.

[0032] Please refer to Figure 2 , Further, the second oil hole 32 is connected to the fuel injector body 4 through a fifth buffer groove 39. With this structure, the fifth buffer groove 39 effectively buffers the flow stress of the high-pressure fuel entering the second oil hole 32.

[0033] Please refer to Figure 2 , Further, the three-way valve assembly of the fuel injector further includes a needle valve 5 and a guide sleeve 6. The three-way valve 3 and the guide sleeve 6 are separate. A concave cavity 30 is provided on the lower end surface of the three-way valve 3 to cooperate with the upper end surface of the guide sleeve 6. The needle valve 5 is slidably installed in the guide sleeve 6. Specifically, an installation groove is provided on the lower end surface of the second control chamber 31, and the installation groove and the guide sleeve 6 form a guide cavity 61. The needle valve 5 slides in the guide cavity 61 under an external force.

[0034] Due to the adoption of the above technical solutions, the present utility model has the following advantages: When the fuel injector returns or inlet fuel, the first buffer groove 34, the second buffer groove 35 and the third buffer groove 36 in the three-way valve slow down the flow stress of the high-pressure fuel, thereby improving the smooth flow of the high-pressure fuel in the three-way valve 3; the flow stress of the high-pressure fuel is reduced, the fatigue damage of the inner wall of the three-way valve 3 is delayed, and the service life of the fuel injector is improved. The three-way valve 3 improves the stable operation of the fuel injector by reasonably designing the flow rate ratio and position of the first oil hole 37, the second oil hole 32, the third oil hole 33, the first switch hole section 111 and the second switch hole section 112.

Claims

1. A three-way valve assembly for a fuel injector, characterized in that: include: A fuel injector body (4) and a metering valve (1) and a three-way valve (3) mounted on the fuel injector body (4); The metering valve (1) is provided with a switch hole (11) on the end surface close to the switch valve (2), and the metering valve (1) is provided with a first control chamber (12) which is in communication with the switch hole (11); The three-way valve (3) is provided with a third oil hole (33) connected to the fuel injector body (4); the third oil hole (33) is connected to the first control chamber (12) through the third slow groove (36) and the first slow groove (34); the third oil hole (33) is connected to the second control chamber (31) through the third slow groove (36), the first slow groove (34), the first oil hole (37) and the second slow groove (35); the second control chamber (31) is connected to the first control chamber (12) through the second slow groove (35), the first oil hole (37) and the first slow groove (34); the second oil hole (32) connects the second control chamber (31) and the fuel injector body (4); the first slow groove (34), the second slow groove (35) and the third slow groove (36) are used to buffer the flow stress of the fuel.

2. The three-way valve assembly of the fuel injector according to claim 1, characterized in that: A first slow groove (34) is provided at the top of the three-way valve (3); the upper end surface of the first slow groove (34) is communicated with the first control chamber (12); the lower end surface of the first slow groove (34) is provided with a connecting portion (341) communicated with the first oil hole (37); and one side of the lower end surface of the first slow groove (34) is communicated with the top end of the third slow groove (36).

3. The three-way valve assembly of the fuel injector according to claim 1 or 2, characterized in that: The switch hole (11) is provided with a first switch hole section (111) and a second switch hole section (112); the aperture of the second switch hole section (112) is larger than the aperture of the first switch hole section (111); and the switch valve (2) is used to open or seal the second switch hole section (112).

4. The three-way valve assembly of the fuel injector according to claim 3, characterized in that: The sum of the apertures of the first oil hole (37) and the third oil hole (33) is smaller than the aperture of the first switch hole section (111), and the aperture of the second oil hole (32) is smaller than the aperture of the first oil hole (37).

5. The three-way valve assembly of the fuel injector according to claim 1, 2 or 4, characterized in that: The third oil hole (33) is connected to the fuel injector body (4) through the fourth slow groove (38).

6. The three-way valve assembly of the fuel injector according to claim 1, 2 or 4, characterized in that: The second oil hole (32) is connected to the fuel injector body (4) through the fifth slow groove (39).

7. The three-way valve assembly of the fuel injector according to claim 5, characterized in that: The second oil hole (32) is connected to the fuel injector body (4) through the fifth slow groove (39).

8. The three-way valve assembly of the fuel injector according to claim 1, 2, 4 or 7, characterized in that: It also comprises a needle valve (5) and a guide sleeve (6); the three-way valve (3) and the guide sleeve (6) are of a split type; the lower end surface of the three-way valve (3) is provided with a concave cavity (30) matching with the upper end surface of the guide sleeve (6); the needle valve (5) is slidably installed in the guide sleeve (6).

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