JP2010190121A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the valve closing bounce of a control valve element 23 when injection is finished and to achieve the uprightness of the gradient of an initial injection rate when injection is started, in a fuel injection valve. <P>SOLUTION: In an armature 21, the opening surface 33 of a hole 32 storing the control valve element 23 has a larger diameter than a sliding shaft 27, and is exposed to fuel led to flow out of a control chamber 9 when the control chamber 9 is opened. Thereby, when the injection is started, the dynamic pressure of fuel led to flow out of the control chamber 9 is strongly applied to the opening surface 33. Since the control chamber 9 is immediately opened by the control valve element 23, the uprightness of the gradient of the initial injection rate when the injection is started is achieved. When the injection is finished, fuel pressure by a diaphragm effect is strongly applied to the opening surface 33. Since the control chamber 9 is gently closed by the control valve element 23, it is possible to suppress the valve closing bounce of the control valve element 23 when the injection is finished. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection valve that injects and supplies fuel to an internal combustion engine.

  2. Description of the Related Art Conventionally, as shown in FIG. 3, a fuel injection valve 100 that starts or stops fuel injection by increasing or decreasing the fuel pressure in the control chamber 102 by the operation of an electromagnetic solenoid actuator 101 is known. . The fuel injection valve 100 includes an injection valve body (not shown) that opens and closes an injection hole (not shown), and an actuator 101 that drives the injection valve body in a valve opening direction, and is closed with respect to the injection valve body. A control chamber 102 for applying fuel pressure in the direction, an inflow channel 103 for allowing fuel to flow into the control chamber 102, and an outflow channel 104 for allowing fuel to flow out from the control chamber 102 are formed.

  The actuator 101 also has a control valve body 107 that opens and closes the outflow passage 104 with respect to the control chamber 102, an armature 109 that is excited by energization of the solenoid coil 108 and displaced to one side, and an armature 109 that is always attached to the other. And a spring 110 for biasing. Further, the armature 109 has a sliding shaft portion 112 that is slidably supported by a predetermined body 111, and accommodates the control valve body 107 at the other end of the sliding shaft portion 112.

  The fuel injection valve 100 opens and closes the outflow passage 104 with respect to the control chamber 102 according to the operation of the actuator 101, thereby changing the fuel inflow / outflow state to the control chamber 102. Increase or decrease.

  That is, when energization of the solenoid coil 108 starts and the armature 109 and the control valve body 107 are displaced to one side, the outflow channel 104 is opened to the control chamber 102. Here, the outflow side restrictor 115 provided in the outflow passage 104 is set so that the fuel can flow more easily than the inflow side restrictor 116 provided in the inflow passage 103. When the chamber 102 is opened, the fuel outflow rate in the control chamber 102 becomes larger than the fuel inflow rate. As a result, the fuel pressure in the control chamber 102 decreases, the injection valve body is driven in the valve opening direction, and fuel injection starts.

  When the energization of the solenoid coil 108 is stopped and the armature 109 and the control valve body 107 are displaced to the other side, the outflow channel 104 is closed with respect to the control chamber 102. As a result, the inflow of fuel from the inflow channel 103 to the control chamber 102 continues, while the outflow of fuel from the control chamber 102 to the outflow channel 104 stops. As a result, the fuel pressure in the control chamber 102 increases, the injection valve body is driven in the valve closing direction, and fuel injection stops.

  Incidentally, in the fuel injection valve 100, the valve closing bounce of the control valve element 107 at the end of injection is regarded as a problem. That is, when the outflow channel 104 is closed with respect to the control chamber 102 by the control valve element 107, a pressure wave is generated in the fuel flow part such as the outflow channel 104 or the control chamber 102. The pressure wave is reflected and reciprocated at each flow part, resulting in bouncing of the control valve body 107, and the valve closing by the control valve body 107 becomes unstable, and as a result, the end of injection becomes unstable. End up.

In addition, the control valve element 107 at the end of injection is restrained from closing bounce, and the initial injection rate gradient at the start of injection is required to be upright.
That is, in the fuel injection by the fuel injection valve 100, the multi-stage injection is performed before and after the main injection to perform pre-injection, after-injection, and the like. The rate gradient is required to be upright.

  That is, as shown in FIG. 4, with respect to the time transition of the injection rate in one injection (hereinafter referred to as an injection pattern), from the pattern A having a gentle initial injection rate gradient to the pattern B having a more rapid initial injection rate gradient. Conversion is requested. And by making the initial injection rate gradient upright, it becomes possible to inject in a shorter time even with the same injection amount, and as a result, for example, the interval between the main injection and the pre-injection can be shortened. It becomes possible to improve the degree of freedom of multistage.

As described above, the fuel injection valve is required to have a structure that can achieve both the suppression of the valve closing bounce of the control valve element 107 at the end of the injection and the upright initial injection rate gradient at the start of the injection. Yes.
In Patent Document 1, in a fuel injection valve that does not form a control chamber and drives the injection valve body directly by the magnetic attractive force of an electromagnetic solenoid, the pressure wave of the fuel accompanying the closing of the injection valve body is alleviated. The structure to perform is disclosed.

  In the configuration of Patent Document 1, a metal cylinder having a polygonal cross section is arranged in a pressure wave propagation region to suppress the propagation of the pressure wave. However, according to the configuration of Patent Document 1, since the effect of suppressing the propagation of pressure waves is reduced due to deterioration of the metal cylinder, there is a possibility that the bouncing of the injection valve body becomes remarkable as the fuel injection valve is used.

JP 2002-54524 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to form a control chamber and start or stop fuel injection by opening and closing the control chamber by a control valve body of an actuator. In the fuel injection valve, it is to achieve both suppression of the valve closing bounce of the control valve body at the end of injection and erecting the initial injection rate gradient at the start of injection.

[Means of Claim 1]
The fuel injection valve according to claim 1 includes an injection valve body that opens and closes the injection hole and an actuator that drives the injection valve body in a valve opening direction, and applies fuel pressure to the injection valve body in a valve closing direction. A control chamber, an inflow channel for injecting fuel into the control chamber, and an outflow channel for allowing fuel to flow out of the control chamber, and opening and closing the outflow channel with respect to the control chamber according to the operation of the actuator As a result, the state of fuel flow into and out of the control chamber is varied, and the injection valve body is driven in the valve opening direction or the valve closing direction.

  The actuator includes a control valve body that opens and closes the outflow channel with respect to the control chamber, and an armature that is excited and energized by energizing the solenoid coil and is always energized to the other by a predetermined energizing means. And have. Furthermore, the armature has a sliding shaft portion that is slidably supported by a predetermined body, and a housing portion that is provided on the other side of the sliding shaft portion and houses the control valve body. A hole opening toward the other side is provided, and the control valve body is accommodated in the hole. The opening surface of the hole is larger in diameter than the sliding shaft portion, and is exposed to the fuel that has flowed out of the control chamber when the control chamber is opened.

  Thereby, when the outflow channel is opened to the control chamber at the start of injection, the dynamic pressure of the fuel flowing out from the control chamber acts on the opening surface of the hole. For this reason, the armature is strongly biased to one side by the biasing force generated by the dynamic pressure of the fuel in addition to the magnetic attractive force generated by energizing the solenoid coil. As a result, the control valve can be opened more quickly by the control valve body than before, and the movement of the injection valve body in the valve opening direction can be accelerated, so that the initial injection rate at the start of injection is increased. The gradient can be upright.

  In addition, when the control valve body and the armature are about to move toward the other at the end of the injection, the fuel due to the throttle film effect is formed on the opening surface of the hole in the direction opposite to the moving direction of the control valve body and the armature. Pressure acts greatly. For this reason, the rapid movement of the control valve body and the armature is suppressed, and the control chamber is closed more slowly than before by the control valve body. As a result, since the generation of pressure waves can be suppressed, the valve closing bounce of the control valve body at the end of injection can be suppressed.

  As described above, in the fuel injection valve, it is possible to achieve both the suppression of the valve closing bounce of the control valve body at the end of the injection and the erecting of the initial injection rate gradient at the start of the injection.

[Means of claim 2]
According to the fuel injection valve of the second aspect, the sliding shaft portion and the housing portion are provided as separate bodies, and one of the sliding shaft portion and the housing portion is press-fitted into the other and integrated.
Thus, the armature support structure can be formed without dividing the body that slidably supports the slide shaft portion.

  Here, if the sliding shaft portion and the housing portion are provided as an integral part without being separated, the housing portion is larger in diameter than the sliding shaft portion, so the body is divided in the circumferential direction. It is necessary to form the armature support structure so that the armature surrounds the armature. For this reason, since the sliding hole for supporting the sliding shaft portion is formed of different divided bodies in the circumferential direction, the roundness of the sliding hole is lowered.

  On the other hand, if the sliding shaft portion and the accommodating portion are provided separately, a sliding hole is provided in the body, and one of the sliding shaft portion and the accommodating portion is inserted into this sliding hole, and then The armature support structure can be formed by inserting the other and press-fitting. For this reason, the armature support structure can be formed without reducing the roundness of the sliding hole.

It is a block diagram of a fuel injection valve (Example). It is a principal part enlarged view of a fuel injection valve (Example). It is a principal part enlarged view of a fuel injection valve (conventional example). It is a time chart which shows an injection pattern (conventional example).

  The fuel injection valve includes an injection valve body that opens and closes the injection hole, and an actuator that drives the injection valve body in a valve opening direction, and a control chamber for controlling the fuel pressure in the valve closing direction on the injection valve body. An inflow channel for injecting fuel into the chamber and an outflow channel for outflowing fuel from the control chamber are formed, and the outflow channel is opened and closed with respect to the control chamber according to the operation of the actuator. The fuel inflow / outflow state is varied, and the injection valve body is driven in the valve opening direction or the valve closing direction.

  The actuator includes a control valve body that opens and closes the outflow channel with respect to the control chamber, and an armature that is excited and energized by energizing the solenoid coil and is always energized to the other by a predetermined energizing means. And have. Furthermore, the armature has a sliding shaft portion that is slidably supported by a predetermined body, and a housing portion that is provided on the other side of the sliding shaft portion and houses the control valve body. A hole opening toward the other side is provided, and the control valve body is accommodated in the hole. The opening surface of the hole is larger in diameter than the sliding shaft portion, and is exposed to the fuel that has flowed out of the control chamber when the control chamber is opened.

  Furthermore, the sliding shaft portion and the housing portion are provided as separate bodies, and one of the sliding shaft portion and the housing portion is press-fitted into the other and integrated.

[Configuration of Example]
The structure of the fuel injection valve 1 of an Example is demonstrated based on drawing.
For example, the fuel injection valve 1 injects fuel into a cylinder of an internal combustion engine (not shown) and supplies the fuel to each cylinder of the internal combustion engine. The fuel injection valve 1 controls, for example, a common rail that accumulates fuel in a high pressure state, a fuel supply pump (not shown) that supplies high pressure to the common rail, and operations of the fuel injection valve 1 and the fuel supply pump. A fuel injection device is configured together with an electronic control device (not shown: hereinafter referred to as ECU).

  For example, as shown in FIG. 1, the fuel injection valve 1 includes an injection valve body 3 that opens and closes the injection hole 2, a command piston 4 that contacts the injection valve body 3 and moves integrally with the injection valve body 3, A spring 5 for urging the injection valve body 3 in the valve closing direction and an actuator 6 for generating a driving force for driving the injection valve body 3 in the valve opening direction are provided. The fuel injection valve 1 includes a control chamber 9 for applying fuel pressure to the injection valve body 3 in the valve closing direction, an inflow passage 10 for allowing fuel to flow into the control chamber 9, and the control chamber 9. An outflow passage 11 is formed for allowing fuel to flow out.

  Here, the inflow and outflow passages 10 and 11 are respectively provided with an inflow side restrictor 13 for restricting the inflow of fuel into the control chamber 9 and an outflow side restrictor 14 for restricting the outflow of fuel from the control chamber 9. ing. The outflow side throttle 14 is provided so that the fuel passage resistance is smaller than that of the inflow side throttle 13.

  The injection valve body 3 is slidably supported by the valve body 16 and moves in the valve opening direction or the valve closing direction. In addition, the injection valve body 3 forms a nozzle chamber 17 in which high-pressure fuel received from the common rail is accumulated, and opens and closes the nozzle hole 2 with respect to the nozzle chamber 17. The fuel pressure in the nozzle chamber 17 acts on the injection valve body 3 in the valve opening direction.

The command piston 4 is slidably supported by the valve body 16 and seals the control chamber 9. As a result, the volume of the control chamber 9 is varied according to the movement of the command piston 4, and the fuel pressure in the control chamber 9 acts on the injection valve body 3 via the command piston 4.
The fuel leaking from the control chamber 9 and the nozzle chamber 17 through the sliding gap flows into the spring chamber 18 that houses the spring 5. Then, the fuel that has flowed into the spring chamber 18 is returned to the fuel tank together with the fuel accompanying the dynamic leak that has flowed out of the control chamber 9 through the outflow passage 11.

  The actuator 6 includes a solenoid coil 20 that starts or stops energization according to a command from the ECU, an armature 21 that is energized by energization of the solenoid coil 20, a spring 22 that biases the armature 21 to the other, A control valve body 23 is held at the other end of the armature 21 and is displaced together with the armature 21 to open and close the outflow passage 11 with respect to the control chamber 9 (hereinafter, the actuator 6 is referred to as an electromagnetic valve 6).

  And according to the command from ECU, the solenoid valve 6 displaces the control valve body 23 to one side or the other, and opens and closes the outflow passage 11 with respect to the control chamber 9, thereby supplying the fuel to the control chamber 9. The inflow / outflow state is varied to drive the injection valve body 3 in the valve opening direction or the valve closing direction.

  With the above configuration, when energization of the solenoid coil 20 is started, the armature 21 and the control valve body 23 are displaced to one side, and the outflow passage 11 is opened to the control chamber 9. Here, since the outflow side throttle 14 is easier to pass fuel than the inflow side throttle 13, the fuel from the inflow channel 10 to the control chamber 9 is opened when the outflow channel 11 is opened to the control chamber 9. The amount of fuel flowing out from the control chamber 9 to the outflow passage 11 becomes larger than the amount of inflow, and the fuel pressure in the control chamber 9 decreases. For this reason, the resultant force acting on the injection valve body 3 becomes stronger in the valve opening direction, and the injection valve body 3 is driven in the valve opening direction to open the injection hole 2 and fuel injection is started.

  When the energization of the solenoid coil 20 is stopped, the armature 21 and the control valve body 23 are displaced to the other, and the outflow passage 11 is closed with respect to the control chamber 9. Thereby, the outflow of fuel from the control chamber 9 to the outflow passage 11 stops, and the fuel pressure in the control chamber 9 increases due to the inflow of fuel from the inflow passage 10 to the control chamber 9. For this reason, the resultant force acting on the injection valve body 3 becomes stronger in the valve closing direction, the injection valve body 3 is driven in the valve closing direction to close the injection hole 2, and fuel injection is stopped.

[Features of Examples]
The characteristic of the fuel injection valve 1 of an Example is demonstrated based on drawing.
According to the fuel injection valve 1 of the embodiment, as shown in FIG. 2, the armature 21 of the electromagnetic valve 6 includes a sliding shaft portion 27 slidably supported by a predetermined body 26, and a sliding shaft portion 27. A suctioned portion 28 that is provided on one side of the solenoid coil 20 and is attracted to one side by energization of the solenoid coil 20, and an accommodating portion 29 that is provided on the other side of the sliding shaft portion 27 and accommodates the control valve body 23.

  That is, the body 26 is provided with a sliding hole 31, and the sliding shaft portion 27 is slidably accommodated and supported in the sliding hole 31. The sliding shaft portion 27 and the suctioned portion 28 and the housing portion 29 are provided separately, and the housing portion 29 is press-fitted into the sliding shaft portion 27 and integrated as an armature 21. Further, the accommodating portion 29 is provided with a hole 32 that opens toward the other, and the control valve element 23 is accommodated in the hole 32. The opening surface 33 of the hole 32 is larger in diameter than the sliding shaft portion 27 and is exposed to fuel that has flowed out of the control chamber 9 when the control chamber 9 is opened.

[Effects of Examples]
According to the fuel injection valve 1 of the embodiment, the armature 21 of the electromagnetic valve 6 is provided on the other side of the sliding shaft portion 27 slidably supported by the body 26 and the control valve. A housing portion 29 for housing the body 23. The housing portion 29 is provided with a hole 32 that opens toward the other, and the control valve body 23 is housed in the hole 32. The opening surface 33 of the hole 32 is larger in diameter than the sliding shaft portion 27 and is exposed to fuel that has flowed out of the control chamber 9 when the control chamber 9 is opened.

  Thereby, when the outflow passage 11 is opened to the control chamber 9 at the start of injection, the dynamic pressure of the fuel flowing out from the control chamber 9 acts on the opening surface 33 greatly. For this reason, the armature 21 is strongly biased to one side by the biasing force generated by the dynamic pressure of the fuel in addition to the magnetic attractive force generated by energizing the solenoid coil 20. As a result, the control valve body 23 can quickly open the control chamber 9, and the movement of the injection valve body 3 in the valve opening direction can be accelerated. Therefore, the initial injection rate gradient at the start of injection Can be upright.

  In addition, when the control valve body 23 and the armature 21 are about to move toward the other at the end of the injection, the opening film 33 has a throttle film in a direction opposite to the moving direction of the control valve body 23 and the armature 21. The fuel pressure due to the effect acts greatly. For this reason, the rapid movement of the control valve body 23 and the armature 21 is suppressed, and the control valve body 23 is gradually closed by the control valve body 23. As a result, since the generation of pressure waves can be suppressed, the valve closing bounce of the control valve body 23 at the end of injection can be suppressed.

  As described above, in the fuel injection valve 1, it is possible to achieve both the suppression of the valve closing bounce of the control valve body 23 at the end of injection and the upright initial injection rate gradient at the start of injection.

  Further, in connection with the suppression of the valve closing bounce, a throttle film effect is produced between the other surface 35 of the suctioned portion 28 and the one surface 36 of the body 26 at the end of the injection. The fuel pressure due to the throttle film effect acts greatly. As a result, the entire armature 21 is prevented from closing bounce due to both the fuel pressure due to the throttle film effect acting on the suctioned portion 28 and the fuel pressure due to the throttle membrane effect acting on the accommodating portion 29. Robustness against valve bounce is improved.

  Further, the gap to be managed for valve closing bounce suppression is the gap between the other surface 35 and the one surface 36 when the valve is closed, and the other end surface 37 and the opening surface 33 of the control valve body 23 when the valve is closed. There are two steps. Thereby, the management width | variety for obtaining a predetermined valve closing bounce suppression effect can be expanded compared with the case where only the clearance gap between the other surface 35 and the one surface 36 is managed. For this reason, the management man-hour for valve closing bounce suppression can be reduced.

Further, the sliding shaft portion 27 and the sucked portion 28 and the housing portion 29 are provided as separate bodies, and the housing portion 29 is press-fitted into the sliding shaft portion 27 and integrated as the armature 21.
Thereby, the support structure of the armature 21 can be formed without dividing the body 26 that slidably supports the sliding shaft portion 27.

  Here, if the sliding shaft portion 27 and the sucked portion 28 and the housing portion 29 are provided as an integrated body without being separated, the housing portion 29 is larger in diameter than the sliding shaft portion 27. It is necessary to form the support structure of the armature 21 so as to surround the armature 21 with a divided body obtained by dividing the body 26 in the circumferential direction. For this reason, since the sliding hole 31 is formed of different divided bodies in the circumferential direction, the roundness of the sliding hole 31 is reduced.

  On the other hand, if the sliding shaft portion 27 and the sucked portion 28 and the accommodating portion 29 are provided separately, the body 26 is provided with the sliding hole 31, and the sliding shaft 31 is provided in the sliding hole 31. The support structure of the armature 21 can be formed by inserting one of the accommodating portions 29 and then inserting the other and press-fitting. For this reason, the support structure of the armature 21 can be formed without reducing the roundness of the sliding hole 31.

[Modification]
According to the fuel injection valve 1 of the embodiment, the housing portion 29 is press-fitted into the sliding shaft portion 27 and integrated as the armature 21, but the sliding shaft portion 27 is press-fitted into the housing portion 29 and integrated as the armature 21. May be used. Further, the sliding shaft portion 27 and the sucked portion 28 and the accommodating portion 29 are not provided separately, but are provided as an integral armature 21, and the body 26 is divided in the circumferential direction to form a plurality of divided bodies. Alternatively, the support structure of the armature 21 may be formed so as to surround the armature 21 by these divided bodies.

DESCRIPTION OF SYMBOLS 1 Fuel injection valve 2 Injection hole 3 Injection valve body 6 Electromagnetic valve (actuator)
9 Control chamber 10 Inflow passage 11 Outflow passage 20 Solenoid coil 21 Armature 22 Spring (biasing means)
23 Control valve body 26 Body 27 Sliding shaft portion 29 Housing portion 32 Hole 33 Opening surface

Claims (2)

An injection valve body for opening and closing the injection hole, and an actuator for driving the injection valve body in the valve opening direction,
A control chamber for applying fuel pressure to the injection valve body in a valve closing direction, an inflow channel for injecting fuel into the control chamber, and an outflow channel for allowing fuel to flow out from the control chamber are formed. And
By opening and closing the outflow passage with respect to the control chamber according to the operation of the actuator, the state of fuel inflow and outflow into the control chamber is varied, and the injection valve body is opened or closed. In the fuel injection valve to drive,
The actuator is energized by the energization of the solenoid coil and the control valve body that opens and closes the outflow passage with respect to the control chamber, and is displaced to one side, and is always urged to the other by a predetermined urging means. With armature,
This armature has a sliding shaft portion that is slidably supported by a predetermined body, and a housing portion that is provided on the other side of the sliding shaft portion and houses the control valve body,
The accommodation portion is provided with a hole that opens toward the other, and the control valve body is accommodated in the hole,
The opening surface of the hole is larger in diameter than the sliding shaft portion, and is exposed to fuel that has flowed out of the control chamber when the control chamber is opened. The fuel injection valve according to claim 1, wherein
The fuel injection valve, wherein the sliding shaft portion and the housing portion are provided separately, and one of the sliding shaft portion and the housing portion is press-fitted into the other and integrated.

Images