Common rail fuel injection device

Abstract

The utility model relates to a common rail type fuel injection device, which belongs to the technical field of power machinery, and comprises a fuel 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. According to the utility model, 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 utility model relates to a fuel injection device, which is applied to an engine fuel injection system and belongs to the technical field of power machinery, particularly 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 high as possible to ensure better injection characteristics and better diesel engine operating conditions in the system. 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. Utility Model Content

[0003] The purpose of the utility model 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 utility model provides a common rail fuel injection device, including an injector body, a connecting nut, a fixing sleeve, and a nozzle arranged from top to bottom, a needle valve body is provided on the inner side of the connecting nut and the inner side of the fixing sleeve, a needle valve is provided on the inner side of the needle valve body, a top cap, a cone valve sleeve, and a needle valve spring are provided 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 throttle screw are provided on the inner side of the bottom of the top cap, the driving piston is located above the cone valve core, the throttle 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 channel E inside the needle valve through the oil hole 1C on the cone valve sleeve and the oil hole 2D on the needle valve. After filling the oil channel 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 line -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 line 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 throttle screw plug between the control chamber 2Q and the hole O is used to stabilize the servo oil pressure in the control chamber 2Q. When the servo oil enters the control chamber 2Q, the drive piston moves downward under the servo oil pressure, pushing the cone valve core to move downward. The high-pressure fuel in the control chamber 1H flows out through the oil drain line 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, 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, 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, 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, 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, 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 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 a working cycle is completed.

[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 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 has the following beneficial technical effects:

[0015] The utility model provides a common rail fuel injection device with a pressure stabilizing device, which reduces pressure fluctuations during the working process 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 This is a schematic cross-sectional view of the components of the common rail fuel injection device of the present invention;

[0017] Figure 2 This is another cross-sectional schematic diagram of the structure of the components in the common rail fuel injection device of the present invention;

[0018] Figure 3 Schematic cross-sectional view of each flow channel in the common rail fuel injection device of the present utility model;

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

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

[0021] Figure 6 This is a schematic side view of the top of the injector body in the common rail fuel injection device of the present utility model;

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

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

[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; 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.

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

[0027] A needle valve 4 is installed inside the needle valve body 5. A needle valve spring 8 and a cone valve sleeve 10 are inserted upward through the needle valve 4. A cone valve core 11 is installed inside the cone valve sleeve 10, atop the needle valve 4. A driving piston 12 is installed atop the cone valve sleeve 10 and cone valve core 11. A throttle screw 13 is connected to the top of the driving piston 12, inside the top cap 14. The diameters of the cone valve core 11 and driving piston 12 can be adjusted to meet the servo oil pressure and fuel pressure of different fuel injection systems to meet operational requirements. A nozzle locating pin 2 connects the needle valve body 5 to the nozzle 1. A retaining ring 6 is installed at the connection between the fixing sleeve 3 and the coupling nut 7. A needle valve body locating pin 18 is installed at the connection between the needle valve body 5 and the injector body 9. A sealing ring 15 is installed between the injector body 9 and the top cap 14. 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 cone valve sleeve 10 is provided with an oil hole C in the middle. 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 tank F. The inner side of the cone valve core 11 is provided with a small hole G. The top of the needle valve 4 is provided with a control chamber H at the connection between the cone valve sleeve 10 and the needle valve sleeve 10. A sealing cone surface I is provided on the inner side of the cone valve sleeve 10, and an oil drain passage J is provided on the outer side of the cone valve sleeve 10 of the injector body 9. The oil drain passage J is connected to a flow channel 4P. A control chamber 2Q is provided at the connection between the throttle screw 13 and the drive piston 12 of the top cap 14. A hole O is provided above the throttle screw 13. A flow channel 2L leading to a two-position three-way solenoid valve is opened at the bottom of the oil supply port 2K. A flow channel 3N and an oil drain passage 2M are opened 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 pressure fluctuations in the servo oil control chamber, mitigate secondary injection caused by pressure fluctuations, and stabilize the injection process. The sealing diameter of the sealing cone I can be flexibly designed based on the oil drain hole diameter and return oil flow requirements. A flat oil groove is provided at the top of the cone valve sleeve 10. The top surface outside the groove is required to be flat to maximize the contact area and reduce collision stress when it collides with the drive piston 12.

[0030] The implementation principle of this utility model is as follows:

[0031] High-pressure fuel is supplied from fuel supply port A, enters the fuel injection device through flow channel B, and flows into oil channel E through oil hole C in cone valve sleeve 10 and oil hole D in needle valve 4. After filling oil channel E and oil reservoir F in needle valve body 5, the high-pressure fuel enters control chamber H through small hole G in cone valve core 11. At this point, the high-pressure fuel presses cone valve core 11 against the sealing conical surface I of cone valve sleeve 10, preventing the high-pressure fuel from escaping from control chamber H through drain line J. The combined downward force of the high-pressure fuel in control chamber H and the downward force of needle valve spring 8 is greater than the upward force of the high-pressure fuel in oil reservoir F. Needle valve 4 seats on the sealing conical surface of needle valve body 5, and the fuel injection device stops operating.

[0032] Servo oil is supplied from supply port 2K, flows through flow channel 2L, enters a two-position, three-way solenoid valve (not shown), and flows out through drain line 2M. When the fuel injection control unit detects a need for injection based on a signal from a sensor, the two-position, three-way solenoid valve receives the control signal and switches to its operating position. Servo oil flows from flow channel 3N in the injector body 9 through hole O in the top cap 14 and enters control chamber 2Q. A throttle screw 13 is located between control chamber 2Q and hole O to stabilize the servo oil pressure in control chamber 2Q. When servo oil enters control chamber 2Q, the driving piston 12 moves downward under the servo oil pressure. Due to the area difference between driving piston 12 and poppet 11, the downward force exerted by the servo oil on driving piston 12 is greater than the upward force exerted by the high-pressure fuel on poppet 11. As a result, driving piston 12 pushes poppet 11 downward, causing the high-pressure fuel in control chamber 1H to flow out through drain line 1J, reducing the fuel pressure in control chamber 1H.

[0033] When the upward force exerted by the high-pressure fuel in reservoir F exceeds the combined downward force exerted by the high-pressure fuel in control chamber 1H and the downward force exerted by needle spring 8, needle valve 4 lifts, and the fuel injection device operates. When the control signal to the two-position, three-way solenoid valve is cut off, the servo oil pressure in control chamber 2Q decreases. The downward force exerted by the servo oil on the drive piston 12 is less than the upward force exerted by the high-pressure fuel on the poppet 11, causing the poppet 11 to move upward. Eventually, the poppet 11 presses against the sealing surface I of the poppet sleeve 10, preventing the high-pressure fuel from flowing out of control chamber 1H through drain line 1J. The pressure in control chamber 1H gradually increases, and the combined downward force exerted by the high-pressure fuel in the chamber and the downward force exerted by needle spring 8 exceeds the upward force exerted by the high-pressure fuel in reservoir F. Needle valve 4 then seats on the sealing surface of needle valve body 5, completing a single operating cycle. High-pressure fuel leaking between injector body 9 and poppet sleeve 10 flows through flow passage 4P and drain line 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, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. 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 provided on the inner side of the coupling nut (7) and the inner side of the fixing sleeve (3). A needle valve (4) is provided 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 provided 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 throttle screw (13) are provided 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 throttle screw (13) is located above the driving piston (12). A sealing cone surface I is provided on the inner side of the cone valve sleeve (10).

2. The common rail fuel injection device according to claim 1, characterized in that: 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). After filling the oil passage E and the oil tank F of the needle valve body (5), the fuel can also enter the control chamber 1H through the small hole G on the cone valve core (11).

3. The common rail fuel injection device according to claim 2, characterized in that: When high-pressure fuel enters the control chamber 1H, 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 1H through the oil drain passage 1J. 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) 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. The 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 line 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 (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) downward. The high-pressure fuel in the control chamber 1H flows out through the oil drain line 1J, and the fuel pressure in the control chamber 1H is reduced.

5. The 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. The 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 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.

7. The common rail fuel injection device according to claim 6, characterized in that: The needle valve body (5) is connected to the nozzle (1) 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. The 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. The common rail fuel injection device according to claim 6, characterized in that: A flat oil groove is provided on the top of the cone valve sleeve (10), and the top surface except the oil groove is flat.

10. The 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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