Common rail type fuel injection device

Abstract

The invention relates to a common rail type fuel injection device, which belongs to the technical field of power machinery and comprises an oil injector body, a coupling nut, a fixed sleeve and a nozzle which are arranged from top to bottom, a needle valve body is arranged on the inner side of the coupling nut and the inner side of the fixed sleeve, and a needle valve is arranged on the inner side of the needle valve body. A top cap, a cone valve sleeve and a needle valve spring are arranged on the inner side of the oil sprayer body from top to bottom, the needle valve upwards penetrates through the needle valve spring and the cone valve sleeve, the needle valve is connected with a cone valve element on the inner side of the top of the cone valve sleeve, a driving piston and a throttling screw plug are arranged on the inner side of the bottom of the top cap, the driving piston is located above the cone valve element, and the throttling screw plug is located above the driving piston. A sealing conical surface I is arranged on the inner side of the conical valve sleeve. The pressure fluctuation in the working process of the fuel injection device is weakened to a certain extent, and the injection characteristic in a high-pressure common-rail fuel injection system is improved.

Description

Technical Field

[0001] The invention relates to a fuel injection device, which is applied to an engine fuel injection system and belongs to the technical field of power machinery, especially to the application field of high-power medium and low-speed marine engines. Background Art

[0002] For the diesel engine supercharged high-pressure common rail system, in order to achieve more optimized operation of the diesel engine under all working conditions, the fuel pressure in the supercharged common rail system is required to be as large as possible to ensure better injection characteristics in the system and better diesel engine operating conditions. However, due to the compressibility of the fuel and the expansion and deformation of the long fuel pipeline, large pressure fluctuations are bound to occur in the supercharged components, and the large pressure fluctuations affect the injection characteristics of the high-pressure common rail fuel injection system. Summary of the invention

[0003] The purpose of the present invention is to provide a common rail fuel injection device with a pressure stabilizing device to reduce pressure fluctuations and thereby reduce the impact on the injection characteristics of a high pressure common rail fuel injection system.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the present invention provides a common rail fuel injection device, comprising an injector body, a connecting nut, a fixing sleeve, and a nozzle arranged from top to bottom, a needle valve body is arranged on the inner side of the connecting nut and the inner side of the fixing sleeve, a needle valve is arranged on the inner side of the needle valve body, a top cap, a cone valve sleeve, and a needle valve spring are arranged on the inner side of the injector body from top to bottom, the needle valve spring and the cone valve sleeve are passed through the needle valve upward, the needle valve is connected to a cone valve core on the inner side of the top of the cone valve sleeve, a driving piston and a throttling screw are arranged on the inner side of the bottom of the top cap, the driving piston is located above the cone valve core, the throttling screw is located above the driving piston, and a sealing cone surface I is provided on the inner side of the cone valve sleeve.

[0005] Preferably, high-pressure fuel can flow into the oil passage E inside the needle valve through the oil hole 1C on the cone valve sleeve and the oil hole 2D on the needle valve, and after filling the oil passage E and the oil storage groove F of the needle valve body, it will also enter the control chamber 1H through the small hole G on the cone valve core.

[0006] Preferably, when high-pressure fuel enters the control chamber H, the cone valve core is pressed against the sealing cone surface I of the cone valve sleeve by the oil, and the high-pressure fuel cannot flow out of the control chamber H through the oil drain passage J. The sum of the downward force generated by the high-pressure fuel in the control chamber H and the downward force generated by the needle valve spring is greater than the upward force generated by the high-pressure fuel in the oil tank F, the needle valve is seated on the sealing cone surface of the needle valve body, and the fuel injection device does not work.

[0007] Preferably, the servo oil can enter the two-position three-way solenoid valve and flow out through the oil drain path 2M. When the two-position three-way solenoid valve switches its working position, the servo oil enters the control chamber 2Q from the flow channel 3N on the injector body through the hole O on the top cap. The throttling screw between the control chamber 2Q and the hole O is used to stabilize the servo oil pressure of the control chamber 2Q. When the servo oil enters the control chamber 2Q, the driving piston moves downward under the servo oil pressure to push the cone valve core to move downward, and the high-pressure fuel in the control chamber 1H flows out through the oil drain path 1J, and the fuel pressure in the control chamber 1H is reduced.

[0008] Preferably, when the upward force generated by the high-pressure fuel in the oil tank F is greater than the sum of the downward force generated by the high-pressure fuel in the control chamber H and the downward force generated by the needle valve spring, the needle valve is lifted and the fuel injection device works.

[0009] Preferably, after the control signal of the two-position three-way solenoid valve is cut off, the servo oil pressure in the control chamber 2Q decreases, and the downward force of the servo oil on the driving piston is smaller than the upward force of the high-pressure fuel on the cone valve core, and the cone valve core moves upward, and finally the cone valve core is pressed against the sealing cone surface I of the cone valve sleeve, and the high-pressure fuel cannot flow out from the control chamber 1H through the oil drain passage 1J, and the pressure in the control chamber 1H gradually increases, and the sum of the downward force generated by the high-pressure fuel in the chamber and the downward force generated by the needle valve spring is larger than the upward force generated by the high-pressure fuel in the oil tank F, and the needle valve is seated on the sealing cone surface of the needle valve body, and a working cycle ends.

[0010] Preferably, the needle valve body is connected to the nozzle via a nozzle locating pin, and a needle valve body locating pin is provided at the connection between the needle valve body and the injector body.

[0011] Preferably, a retaining ring is provided at the connection between the fixing sleeve and the coupling nut.

[0012] Preferably, a flat oil groove is provided at the top end of the cone valve sleeve, and the top surface except the oil groove is flat.

[0013] Preferably, a sealing ring is provided between the injector body and the top cap, and a fixing bolt and a gasket are connected to the top of the top cap.

[0014] In summary, the present invention includes the following beneficial technical effects:

[0015] The present invention provides a common rail fuel injection device with a pressure stabilizing device, which reduces pressure fluctuations during the operation of the fuel injection device to a certain extent and improves injection characteristics in a high-pressure common rail fuel injection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional schematic diagram of the structure of each component in a common rail fuel injection device of the present invention;

[0017] Figure 2 Another cross-sectional schematic diagram of the structure of each component in a common rail fuel injection device of the present invention;

[0018] Figure 3 It is a cross-sectional schematic diagram of each flow channel in a common rail fuel injection device of the present invention;

[0019] Figure 4 Another cross-sectional schematic diagram of each flow channel in a common rail fuel injection device of the present invention;

[0020] Figure 5 It is a schematic cross-sectional view of the top of a fuel injector body in a common rail fuel injection device of the present invention;

[0021] Figure 6 It is a schematic diagram of the top side view of the injector body in a common rail fuel injection device of the present invention;

[0022] Figure 7 It is a schematic diagram of another side view of the top of the injector body in a common rail fuel injection device of the present invention;

[0023] Figure 8 The present invention is a schematic diagram of the structure of a component in a common rail fuel injection device.

[0024] Figure numerals: 1. nozzle; 2. nozzle locating pin; 3. fixing sleeve; 4. needle valve; 5. needle valve body; 6. retaining ring; 7. connecting nut; 8. needle valve spring; 9. injector body; 10. cone valve sleeve; 11. cone valve core; 12. driving piston; 13. throttle screw plug; 14. top cap; 15. sealing ring; 16. gasket; 17. fixing bolt; 18. needle valve body locating pin. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The embodiment of the present invention discloses a common rail fuel injection device, comprising an injector body 9, a connecting nut 7 arranged at the bottom of the injector body 9, a fixing sleeve 3 arranged at the bottom of the connecting nut 7, and a nozzle 1 arranged at the bottom of the fixing sleeve 3; a needle valve body 5 is connected to the inner side of the connecting nut 7 and the fixing sleeve 3, a needle valve spring 8 is arranged on the inner side of the bottom of the injector body 9, a cone valve sleeve 10 is arranged on the inner side of the middle part of the injector body 9, and a top cap 14 is arranged on the inner side of the top of the injector body 9.

[0027] A needle valve 4 is provided inside the needle valve body 5, and a needle valve spring 8 and a cone valve sleeve 10 are passed upward through the needle valve 4. A cone valve core 11 is provided inside the cone valve sleeve 10 at the top of the needle valve 4; a driving piston 12 is provided on the top of the cone valve sleeve 10 and the cone valve core 11, and a throttle screw 13 is connected to the top of the driving piston 12 on the inside of the top cap 14. The diameters of the cone valve core 11 and the driving piston 12 can be adjusted and designed according to the servo oil pressure and fuel pressure of different fuel injection systems to meet work requirements. A nozzle locating pin 2 is connected between the needle valve body 5 and the nozzle 1, a retaining ring 6 is provided at the connection between the fixing sleeve 3 and the coupling nut 7, a needle valve body locating pin 18 is provided at the connection between the needle valve body 5 and the injector body 9, a sealing ring 15 is provided between the injector body 9 and the top cap 14, and a fixing bolt 17 and a gasket 16 are connected to the top of the top cap 14.

[0028] The top of the injector body 9 is provided with an oil supply port A and an oil supply port K respectively. The bottom of the inner side of the oil supply port A is provided with a flow channel B leading to the cone valve sleeve 10; the outer surface of the middle part of the cone valve sleeve 10 is provided with an oil hole C, the connection between the cone valve sleeve 10 and the needle valve 4 is provided with an oil hole D, the inner side of the needle valve 4 is provided with an oil channel E, the inner side of the needle valve body 5 is provided with an oil storage groove F, the inner side of the cone valve core 11 is provided with a small hole G, and the connection between the top of the needle valve 4 and the cone valve sleeve 10 is provided with a control chamber H A sealing cone surface I is provided on the inner side of the cone valve sleeve 10, an oil drain oil passage 1J is provided on the outer side of the cone valve sleeve 10 of the injector body 9, the oil drain oil passage 1J is connected with a flow passage 4P, a control chamber 2Q is provided at the connection between the throttle screw 13 and the driving piston 12 of the top cap 14, a hole O is provided on the top cap 14 above the throttle screw 13, a flow passage 2L leading to a two-position three-way solenoid valve is provided at the bottom of the oil supply port 2K, and a flow passage 3N and an oil drain oil passage 2M are provided on the side of the injector body 9.

[0029] The throttle screw 13 is installed in front of the servo oil control chamber Q2 to reduce the pressure fluctuation of the servo oil control chamber, reduce the secondary injection phenomenon caused by pressure fluctuation, and stabilize the injection process. The sealing diameter of the sealing cone surface I can be flexibly designed according to the oil drain hole diameter and the return oil flow requirement. A flat oil groove is provided at the top of the cone valve sleeve 10, and the top surface except the oil groove is required to be flat so as to increase the contact area and reduce the collision stress when colliding with the drive piston 12.

[0030] The implementation principle of the present invention is as follows:

[0031] High-pressure fuel is supplied from the fuel supply port A, enters the interior of the fuel injection device through the flow channel B, flows into the oil channel E through the oil hole C on the cone valve sleeve 10 and the oil hole D on the needle valve 4, and after the high-pressure fuel fills the oil channel E and the oil storage groove F of the needle valve body 5, it will also enter the control chamber H through the small hole G on the cone valve core 11. At this time, the cone valve core 11 is pressed against the sealing cone surface I of the cone valve sleeve 10 by the high-pressure fuel, and the high-pressure fuel cannot flow out from the control chamber H through the oil leakage oil channel J. The sum of the downward force generated by the high-pressure fuel in the control chamber H and the downward force generated by the needle valve spring 8 is greater than the upward force generated by the high-pressure fuel in the oil storage groove F, and the needle valve 4 is seated on the sealing cone surface of the needle valve body 5, and the fuel injection device does not work.

[0032] The servo oil is supplied from the oil supply port 2K, enters the two-position three-way solenoid valve (not shown) through the flow channel 2L, and flows out through the oil drain channel 2M. When the fuel injection device control unit collects signals from the sensor and determines that oil injection is required, the two-position three-way solenoid valve receives the control signal and switches the working position, and the servo oil enters the control chamber 2Q from the flow channel 3N on the injector body 9 through the hole O on the top cap 14. A throttling screw 13 is provided between the control chamber 2Q and the hole O to stabilize the servo oil pressure of the control chamber 2Q. When the servo oil enters the control chamber 2Q, the driving piston 12 moves downward under the servo oil pressure. Due to the area difference between the driving piston 12 and the cone valve core 11, the downward force of the servo oil on the driving piston 12 is greater than the upward force of the high-pressure fuel on the cone valve core 11. The driving piston 12 pushes the cone valve core 11 to move downward, and the high-pressure fuel in the control chamber 1H flows out through the oil drain channel 1J, and the fuel pressure in the control chamber 1H is reduced.

[0033] When the upward force generated by the high-pressure fuel in the oil tank F is greater than the sum of the downward force generated by the high-pressure fuel in the control chamber 1H and the downward force generated by the needle valve spring 8, the needle valve 4 is lifted and the fuel injection device works. When the control signal of the two-position three-way solenoid valve is cut off, the servo oil pressure in the control chamber 2Q is reduced, and the downward force of the servo oil on the driving piston 12 is less than the upward force of the high-pressure fuel on the cone valve core 11. The cone valve core 11 moves upward, and finally the cone valve core 11 is pressed against the sealing cone surface I of the cone valve sleeve 10. The high-pressure fuel cannot flow out from the control chamber 1H through the oil leakage oil path 1J. The pressure in the control chamber 1H gradually increases, and the sum of the downward force generated by the high-pressure fuel in the chamber and the downward force generated by the needle valve spring 8 is greater than the upward force generated by the high-pressure fuel in the oil tank F. The needle valve 4 is seated on the sealing cone surface of the needle valve body 5, and a working cycle ends. The high-pressure fuel leaked between the injector body 9 and the cone valve sleeve 10 flows out through the flow channel 4P through the oil leakage oil path 1J.

[0034] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A common rail fuel injection device, characterized in that: The invention comprises an injector body (9), a coupling nut (7), a fixing sleeve (3), and a nozzle (1) arranged from top to bottom. A needle valve body (5) is arranged on the inner side of the coupling nut (7) and the inner side of the fixing sleeve (3). A needle valve (4) is arranged on the inner side of the needle valve body (5). A top cap (14), a cone valve sleeve (10), and a needle valve spring (8) are arranged on the inner side of the injector body (9) from top to bottom. The needle valve spring (8) and the cone valve sleeve (10) are passed through the needle valve (4) upward. The needle valve (4) is connected to a cone valve core (11) on the inner side of the top of the cone valve sleeve (10). A driving piston (12) and a throttling screw (13) are arranged on the inner side of the bottom of the top cap (14). The driving piston (12) is located above the cone valve core (11). The throttling screw (13) is located above the driving piston (12). A sealing cone surface I is arranged on the inner side of the cone valve sleeve (10).

2. A common rail fuel injection device according to claim 1, characterized in that: The high-pressure fuel can flow into the oil passage E inside the needle valve (4) through the oil hole 1C on the cone valve sleeve (10) and the oil hole 2D on the needle valve (4), and after filling the oil passage E and the oil storage groove F of the needle valve body (5), it can also enter the control chamber 1H through the small hole G on the cone valve core (11).

3. A common rail fuel injection device according to claim 2, characterized in that: When high-pressure fuel enters the control chamber H, the cone valve core (11) is pressed against the sealing cone surface I of the cone valve sleeve (10) by the oil, and the high-pressure fuel cannot flow out of the control chamber H through the oil drain passage J. The sum of the downward force generated by the high-pressure fuel in the control chamber H and the downward force generated by the needle valve spring (8) is greater than the upward force generated by the high-pressure fuel in the oil tank F. The needle valve (4) is seated on the sealing cone surface of the needle valve body (5), and the fuel injection device does not work.

4. A common rail fuel injection device according to claim 3, characterized in that: The servo oil can enter the two-position three-way solenoid valve and flow out through the oil drain path 2M. When the two-position three-way solenoid valve switches the working position, the servo oil enters the control chamber 2Q from the flow channel 3N on the injector body (9) through the hole O on the top cap (14). The throttle screw plug (13) between the control chamber 2Q and the hole O is used to stabilize the servo oil pressure of the control chamber 2Q. When the servo oil enters the control chamber 2Q, the driving piston (12) moves downward under the servo oil pressure to push the cone valve core (11) to move downward, and the high-pressure fuel in the control chamber 1H flows out through the oil drain path 1J, and the fuel pressure in the control chamber 1H is reduced.

5. A common rail fuel injection device according to claim 4, characterized in that: When the upward force generated by the high-pressure fuel in the oil tank F is greater than the sum of the downward force generated by the high-pressure fuel in the control chamber H and the downward force generated by the needle valve spring (8), the needle valve (4) is lifted and the fuel injection device works.

6. A common rail fuel injection device according to claim 5, characterized in that: When the control signal of the two-position three-way solenoid valve is cut off, the servo oil pressure in the control chamber 2Q decreases, and the downward force of the servo oil on the driving piston (12) is smaller than the upward force of the high-pressure fuel on the cone valve core (11). The cone valve core (11) moves upward, and finally the cone valve core (11) is pressed against the sealing cone surface I of the cone valve sleeve (10). The high-pressure fuel cannot flow out from the control chamber 1H through the oil drain passage 1J. The pressure in the control chamber 1H gradually increases, and the sum of the downward force generated by the high-pressure fuel in the chamber and the downward force generated by the needle valve spring (8) is larger than the upward force generated by the high-pressure fuel in the oil tank F. The needle valve (4) is seated on the sealing cone surface of the needle valve body (5), and a working cycle ends.

7. A common rail fuel injection device according to claim 6, characterized in that: The needle valve body (5) and the nozzle (1) are connected via a nozzle positioning pin (2), and a needle valve body positioning pin (18) is provided at the connection between the needle valve body (5) and the injector body (9).

8. A common rail fuel injection device according to claim 6, characterized in that: A retaining ring (6) is provided at the connection between the fixing sleeve (3) and the coupling nut (7).

9. A common rail fuel injection device according to claim 6, characterized in that: The top end of the cone valve sleeve (10) is provided with a flat oil groove, and the top surface except the oil groove is flat.

10. A common rail fuel injection device according to claim 6, characterized in that: A sealing ring (15) is provided between the injector body (9) and the top cap (14), and a fixing bolt (17) and a gasket (16) are connected to the top of the top cap (14).

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