A fuel injector with an improved force transmission assembly

Abstract

The present invention discloses a fuel injector with an improved force transmission component, comprising an injector housing, a nozzle pair installed at the lower part of the injector housing, and a ball valve installed at the upper part, wherein the ball valve is opened by a driving electromagnet installed at the upper part of the injector housing and an improved force transmission component located between the ball valve component and the driving electromagnet. The improved force transmission component of the present invention reduces jitter and improves the consistency of ball valve opening due to the uniform oil film buffering generated by the guide vane when the armature component is upward, thereby making the injection opening stable; when the armature component is downward, due to the optimization of mass and shape and the reduction of inertia, the impact of the armature component on the ball valve is greatly reduced, making the ball valve closing more stable, thereby making the injection closing more rapid; the consistent opening and rapid and stable closing of the entire ball valve make the overall performance of the injector more stable, especially the injection stability and consistency between samples at high rail pressure and small flow are stably improved.

Description

Technical Field

[0001] The present invention relates to a fuel injector with an improved force transmission assembly. Background Art

[0002] A fuel injector used for fuel injection in an internal combustion engine generally includes an injector housing, a fuel injection nozzle assembly installed at the lower part of the injector housing, and a ball valve assembly installed at the upper part. The ball valve assembly is opened by a driving solenoid valve installed at the upper part of the injector housing. The core component for controlling the stability of the ball valve is the armature assembly. The transmission of force is achieved by the interaction between the solenoid valve assembly and the armature assembly.

[0003] Usually, the high-pressure fuel from the common rail pipe is introduced into the injector housing through the fuel inlet joint and then divided into two paths. One path goes directly to the end of the injector nozzle in the injector nozzle pair through the middle hole cavity in the injector housing to be sprayed; the other path enters the high-pressure control chamber at the top of the injector. When the fuel injector is not working, through precise calculation, the hydraulic pressure generated by the high-pressure control chamber is transmitted to the needle valve stem in the injector nozzle pair through the control rod, so that the cone part at the lower end of the needle valve stem is pressed against the inner cone surface of the needle valve body for sealing, and the fuel injector does not spray fuel.

[0004] At this time, if the electromagnet in the driving solenoid valve is energized, the ball valve is opened by driving the armature assembly in the solenoid valve, so that the pressure in the high-pressure control chamber drops, and the needle valve stem in the injector nozzle pair moves upward under the upward hydraulic force, so that the conical part at the lower end of the needle valve stem is separated from the inner conical surface in the needle valve body, opening the injector nozzle channel at the lower end of the needle valve body, and spraying atomized fuel into the engine combustion chamber.

[0005] To achieve the above functions, when the armature component is moved by the electromagnetic force, the ball valve opens and closes accordingly. The control rod and the needle valve stem in the nozzle assembly must achieve a balance between the axial spring force and the hydraulic force through precise calculation, most of which is hydraulic pressure. In the entire actuator assembly: the electromagnet is fixed and has no effect, the ball valve is light in weight and has little effect, and the remaining largest factor is the armature component. Therefore, it is particularly important to reduce the impact of the armature component's motion inertia on the opening and closing of the ball valve.

[0006] As the engine combustion requires the fuel injector to spray more and more times, up to 9 times, and the requirements for the stability of the injection amount are getting higher and higher, the consistency of high rail pressure and small flow is also getting higher and higher, which requires the opening and closing actions (up and down) of the needle valve stem in the control rod and the injector pair to be stable and fast, and the entire stability is determined by the pressure decay in the high-pressure control chamber. The pressure stability in the high-pressure chamber depends on the stability of the ball valve switch, and the movement trajectory of the ball valve is consistent with the movement of the armature component.

[0007] To achieve the above purpose, the prior art is to set a buffer spring to reduce the inertial impact on the ball valve when closing when controlling the armature component to move downward, and to increase the buffer spring lift pad to control the consistency of the armature component's descending position each time. When the armature component moves upward, the specially made straight guide groove on the top of the armature forms an oil film between the fuel armature and the electromagnet, and the oil film reduces the upward impact vibration of the armature component. The above prior art has the technical problems of being not economical and difficult to process the injector. Summary of the invention

[0008] The purpose of the present invention is to provide a fuel injector with an improved force transmission component to solve the above technical problems existing in the existing fuel injectors for internal combustion engine fuel injection. The fuel injector equipped with the improved force transmission component solves the above problems in a simpler and more economical way, and at the same time cancels the buffer stroke selection, reducing the difficulty in the injection process.

[0009] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0010] A fuel injector with an improved force transmission component, comprising an injector housing, a fuel injection nozzle assembly mounted at the lower part of the injector housing, and a ball valve mounted at the upper part of the injector housing, characterized in that the ball valve is opened by a driving electromagnet mounted at the upper part of the injector housing and an improved force transmission component located between the ball valve component and the driving electromagnet; the improved force transmission component comprises at least one guide vane, an armature rod and an armature, the armature rod vertically passes through the armature and is fixedly connected to the armature, and the upper part of the armature rod is inserted into the driving electromagnet The top of the armature rod is connected to the lower end of the electromagnet spring installed in the electromagnet spring mounting hole; the lower part of the armature rod passes through the clamping screw and the bottom end of the armature rod acts on the ball in the ball valve; the armature is located between the clamping screw and the driving electromagnet, and the guide plate is arranged in a superimposed form between the top surface of the armature and the bottom surface of the driving electromagnet, and oil film contact is formed between the top surface of the uppermost guide plate and the bottom surface of the driving electromagnet, and between the bottom surface of the smallest guide plate and the top surface of the armature.

[0011] In a preferred embodiment of the present invention, the guide plate is made of magnetic conductive material and is in the shape of a thin disc.

[0012] In a preferred embodiment of the present invention, at least one guide hole is provided on the guide plate.

[0013] In a preferred embodiment of the present invention, a circumferential groove is provided on the upper portion of the armature rod.

[0014] In a preferred embodiment of the present invention, the bottom surface of the armature is composed of a circular surface and a guide surface located outside the circular surface, and the guide surface is inclined.

[0015] In a preferred embodiment of the present invention, a center hole is opened in the center of the armature, and the armature rod passes through the center hole of the armature; a guide groove for welding is opened at the bottom edge of the center hole of the armature, and solder accumulates in the guide groove to weld the armature and the armature rod together.

[0016] In a preferred embodiment of the present invention, a notch penetrating the guide surface and the top surface of the armature is provided at the position where the armature is located on the guide surface.

[0017] Due to the adoption of the above technical solution, the present invention adopts a reduced-mass armature rod, an armature, and a guide vane installed between the armature and the driving electromagnet, eliminating the traditional buffer spring and buffer spring pad. When the force transmission component moves upward, the fuel is more evenly and effectively introduced between the armature and the guide vane through the special guide vane to form a buffer oil film, thereby reducing the jitter of the force transmission component when it moves upward. When the force transmission component moves downward, the armature rod and the armature, which have been optimized in quality, reduce the impact energy of the force transmission component when it moves downward due to the reasonable reduction of inertia. The optimization of the entire force transmission component makes the ball valve more stable and consistent when switching.

[0018] The armature and the armature rod of the present invention are continuously welded by a specific method, thereby reducing welding deformation, improving the connection strength between the two parts, and offsetting the pre-support problem caused by removing the buffer spring.

[0019] In the fuel injector equipped with the improved force transmission assembly of the present invention, due to the uniform oil film buffering generated by the guide vane when the armature component moves upward, the jitter is reduced and the consistency of the ball valve opening is improved, so that the injection opening is stable; when the armature component moves downward, due to the optimization of mass and shape, the reduction of inertia greatly reduces the impact of the armature component on the ball valve, so that the ball valve closing is more stable, and the injection closing is faster; the consistent opening and rapid and stable closing of the entire ball valve stably improves the stability and consistency of the injector at high rail pressure and small flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic structural diagram of a fuel injector equipped with an improved force transmission component.

[0021] Figure 2 for Figure 1 An enlarged schematic diagram of point I.

[0022] Figure 3 It is a schematic diagram of the guide plate structure of the present invention.

[0023] Figure 4 It is a schematic diagram of the armature structure of the present invention. DETAILED DESCRIPTION

[0024] See also Figure 1 and Figure 2 The fuel injector with improved force transmission assembly shown in the figure comprises an injector housing 2, a high-pressure fuel inlet passage 3 is provided on one side of the upper part of the injector housing 2, and a return passage 24 is provided on the other side; an external volume 5 of the metering servo valve is provided in the injector housing 2. The lower end of the high-pressure fuel inlet passage 3 is connected to an oil inlet chamber 30.

[0025] A control valve sleeve 14 and a control valve stem 6 are installed in the fuel injector housing 2. The control valve sleeve 14 is positioned at a position corresponding to the fuel injector housing 2 through a step 16 and a cylindrical section 17. The control valve sleeve 14 is fastened to the fuel injector housing by a compression screw plug 18.

[0026] The control chamber volume 15 defined by the top surface of the upper end of the control valve stem 6 and a part of the circumferential surface of the oil leakage hole 13 is pressure-independent from the metering valve external volume 5. The control chamber volume 15 communicates with the high-pressure fuel inlet passage 3 in the injector housing 2 through the oil inlet metering hole 8 provided on the control valve sleeve 14, and the control chamber volume 15 also communicates with the oil return passage 24 through the oil leakage metering hole 11 provided on the control valve sleeve 14.

[0027] A group of ball valves 12 are arranged on the top of the control valve sleeve 14. The ball valve 12 is composed of a ball 12a and a valve seat 12b. An improved force transmission component 1 is arranged above the ball valve 12. The improved force transmission component 1 includes a guide plate 1a, an armature rod 1b2, and an armature 1b1, wherein the armature rod 1b2 and the armature 1b1 are welded into a whole.

[0028] A driving electromagnet 31 is installed on the upper part of the improved force transmission component 1. When the driving electromagnet 31 is energized, a magnetic force is generated to attract the improved force transmission component 1, overcoming the preload force of the electromagnetic valve spring 32, unloading the initial pressure loaded on the ball valve 12, and the ball valve 12 leaves the control valve sleeve 14, opening the oil leakage metering hole 11, so that the oil leakage metering hole 11 is connected to the oil return channel 24. If the driving electromagnet 31 is powered off, the improved force transmission component 1 loses its magnetic attraction, and under the push of the electromagnetic spring 32, the ball 12a in the ball valve 12 is pushed down, thereby closing the oil leakage metering hole 11, so that the oil leakage metering hole 11 is not connected to the oil return channel 24.

[0029] The axial lower end of the fuel injector housing 2 is connected with a fuel injector pair 23 through a fuel injector cap 20. The fuel injector pair 23 is composed of a needle valve body 4 and a needle valve stem 9. The end face 22 and the outer cylinder 21 of the needle valve body 4 are positioned and fixed by the fuel injector cap 20 and the bottom surface of the fuel injector housing 2.

[0030] There is a cylindrical matching section 23a between the needle valve stem 9 and the needle valve body 4. The cylindrical matching section 23a enables the needle valve stem 9 to move axially relative to the needle valve body 4, while ensuring the gap sealing of the cylindrical matching section 23a. The cone part 25 at the lower end of the needle valve stem 9 is sealed with the inner cone surface 26 in the needle valve body 4, and the sealing diameter is d in the figure. Therefore, the needle valve stem 9 can move axially up and down in the needle valve body 4, and move downward until the cone part 25 at the lower end of the needle valve stem 9 coincides with the inner cone surface 26 in the needle valve body 4. The bottom of the needle valve body 4 is provided with an oil injection hole 33.

[0031] The nozzle pair 23 sprays or stops according to the working needs of the fuel injector, which is achieved by moving the needle valve stem 9 upward or downward to press the sealing line d. As the engine emission requirements become higher and higher, each injection requires precision, requiring the needle valve to move accurately and have good repeatability during the entire working process. The source of the entire power is the stability and consistency of the ball valve 12 switch, and the decisive factor is the stability and consistency of the force transmission component.

[0032] In order to reduce manufacturing costs and improve the working stability and consistency of the force transmission component, the present invention optimizes the traditional force transmission component (consisting of a split armature rod, an armature component composed of an armature, and a buffer spring and a buffer spring pad) into an improved force transmission component (including an armature rod 1b2 with a reduced mass and changed shape, an integral armature component composed of an armature 1b1 and a guide plate 1a).

[0033] The improved force transmission assembly consists of a guide vane 1a, an armature rod 1b2, and an armature 1b1, wherein the armature rod 1b2 vertically passes through the armature 1b1 and is fixedly connected to the armature 1b1 to form an armature component 1b, the upper part of the armature rod 1b2 is inserted into the electromagnet spring mounting hole 31a at the center of the driving electromagnet 31, and the top of the armature rod 1b2 is connected to the lower end of the electromagnet spring 32 installed in the electromagnet spring mounting hole 31a; the lower part of the armature rod 1b2 passes through the clamping screw 18 and the bottom end of the armature rod 1b2 acts on the ball 12a in the ball valve 12; the armature 1b1 is located between the clamping screw 18 and the driving electromagnet 31, and the guide vane 1a is arranged in a superimposed form between the top surface of the armature 1b1 and the bottom surface of the driving electromagnet 31, and oil film contact is formed between the top surface of the uppermost guide vane 1a and the bottom surface of the driving electromagnet 31, and between the bottom surface of the smallest guide vane 1a and the top surface of the armature 1b2.

[0034] When the armature component 1b moves upward, the guide vane 1a generates a uniform oil film buffer, which reduces the jitter and improves the opening consistency of the ball valve 12, thereby making the injection opening stable; when the armature component 1b moves downward, due to the optimization of mass and shape, the reduction of inertia greatly reduces the impact of the armature component 1b on the ball valve 12, making the closing of the ball valve 12 more stable, thereby making the injection closing faster; the consistent opening and rapid and stable closing of the entire ball valve 12 steadily improves the stability and consistency of the injector at high rail pressure and small flow.

[0035] See also Figure 3 and Figure 4 In order to play the above role, a circumferential groove 35 is provided on the upper part of the armature rod 1b2 to reduce the weight.

[0036] The bottom surface of the armature 1b1 is composed of a circular surface 37 and a guide surface 38 located outside the circular surface 37, and the guide surface 38 is inclined. A center hole 39 is provided at the center of the armature 1b2, and the armature rod 1b2 passes through the center hole 39 of the armature 1b1; a welding guide groove 36 is provided at the bottom edge of the center hole 39 of the armature 1b1, and solder is accumulated in the guide groove 36 to weld the armature 1b1 and the armature rod 1b2 together, so that the armature rod 1b2 and the armature 1b1 are welded into a whole armature component 1b more firmly.

[0037] In addition, a notch 40 penetrating the guide surface 38 and the top surface of the armature 1b1 is provided at the position of the armature 1b1 on the guide surface 38 to reduce the weight.

[0038] The guide plate 1a is made of magnetic conductive material and is in the shape of a thin disc, with a plurality of guide holes 37 opened in the middle.

Claims

1. A fuel injector with an improved force transmission assembly, comprising an injector housing, a nozzle assembly mounted at the lower part of the injector housing, and a ball valve mounted at the upper part of the injector housing, characterized in that: The ball valve is opened by a driving electromagnet installed on the upper part of the injector housing and an improved force transmission component located between the ball valve and the driving electromagnet; the improved force transmission component includes at least one guide vane, an armature rod and an armature, the armature rod vertically passes through the armature and is fixedly connected to the armature, the upper part of the armature rod is inserted into the electromagnet spring mounting hole at the center of the driving electromagnet, and the top of the armature rod is connected to the lower end of the electromagnet spring installed in the electromagnet spring mounting hole; the lower part of the armature rod passes through the clamping screw and the bottom end of the armature rod acts on the ball in the ball valve; the armature is located between the clamping screw and the driving electromagnet, and the guide vane is arranged on the armature in a superimposed form Oil film contact is formed between the top surface and the bottom surface of the driving electromagnet, between the top surface of the guide vane and the bottom surface of the driving electromagnet, and between the bottom surface of the smallest guide vane and the top surface of the armature; a circle of circumferential grooves is provided on the upper part of the armature rod, and the bottom surface of the armature is composed of a circular surface and a circle of guide surfaces located outside the circular surface, and the guide surface is inclined. A center hole is provided at the center of the armature, and the armature rod passes through the center hole of the armature; a guide groove for welding is provided at the bottom edge of the center hole of the armature, and solder is accumulated in the guide groove to weld the armature to the armature rod; a notch is provided at the position where the armature is located on the guide surface, which passes through the guide surface and the top surface of the armature.

2. A fuel injector with an improved force transmission assembly as claimed in claim 1, characterized in that: The guide plate is made of magnetic conductive material and is in the shape of a thin disc.

3. A fuel injector with an improved force transmission assembly as claimed in claim 2, characterized in that: At least one guide hole is provided on the guide plate.

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