JP2005155418A - Fuel injection valve device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve device capable of stably opening and closing a valve element and performing smooth fuel injection with minimum cost increase. <P>SOLUTION: This device is provided with a nozzle part 3 provided with the valve element 5 opening and closing an injection port 4 injecting fuel into a combustion chamber of an internal combustion engine, a drive means 8 opening and closing the valve element 5 and a housing part 2 having a fuel flow passage built in. The drive means 8 is provided with an electromagnet 12 attracting a movable member 15 connected to the valve element by electricity carry, and a spring 14 energizing the movable member 15 in a direction separating from the electromagnet 12. The fuel flow passage in the housing part2 consists of a fuel supply part 22, a spring storage chamber 13, and a straight line communication hole 23 from the fuel supply part to the spring storage chamber 13. The communication hole 23 is provided with a restriction part 25 of inner diameter 0.5-1.5 mm over a predetermined length. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel injection valve device that injects fuel into a combustion chamber of an internal combustion engine.

  Conventionally, this type of fuel injection valve device includes a nozzle portion having an injection port at the tip for injecting fuel toward the combustion chamber of the engine, a valve body for opening and closing the injection port, a drive unit for driving the valve body to open and close, And a housing portion containing a flow path through which fuel is conducted. A valve body is accommodated in the nozzle part, and opens and closes the injection port by driving an electromagnet accommodated in the housing part. The fuel flow path contacts the fuel supply part provided at the rear end of the housing part, the communication hole formed along the axis of the inner collar provided in the core of the electromagnet, and the inner collar. The nozzle portion is reached through a spring accommodating chamber for accommodating the spring that has been caused to move.

  By the way, in this type of fuel injection valve device, the flow state of the fuel in the flow path inside the housing portion affects the fuel injection from the nozzle portion. Therefore, for example, as can be seen in Patent Document 1 below, there is known one that stabilizes the engine speed at the time of hot restart early by reducing the volume of the spring accommodating chamber. That is, in the following Patent Document 1, the lower protrusion of the inner collar protrudes into the spring storage chamber, thereby reducing the volume of the spring storage chamber and reducing the fuel remaining in the flow path. Yes.

  However, even if the amount of fuel staying inside is reduced by projecting the lower protrusion of the inner collar into the spring housing chamber to reduce the volume of the spring housing chamber, the pulsation (pressure) of the fuel flowing inside the fuel during fuel injection Fluctuations) cannot be sufficiently suppressed, and there is a disadvantage that a stable opening / closing operation of the valve body cannot be obtained.

In addition, by projecting the lower protrusion of the inner collar into the spring storage chamber, the communication hole extending in the axial direction in the inner collar is bent at a right angle at the boundary with the protrusion, and on the outer periphery of the protrusion. Not only does the structure of the inner collar have to be opened and the manufacturing cost increases, but the flow of fuel increases due to an increase in the bent portion of the fuel flow path formed from the fuel supply section to the nozzle section. Is unnecessarily disturbed, which has the disadvantage of adversely affecting smooth fuel injection.
JP-A-8-312492 (FIGS. 1 and 2)

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection valve device that can eliminate such inconveniences, obtain a stable opening / closing operation of a valve body with a small increase in cost, and perform a smooth fuel injection. To do.

  In order to achieve such an object, the present invention comprises a nozzle portion provided with a valve body that opens and closes the injection port, and has an injection port for injecting fuel into the combustion chamber facing the combustion chamber of the internal combustion engine, A movable member including a drive unit that opens and closes the valve body of the nozzle unit and a housing unit that incorporates a fuel flow path for conducting fuel to the nozzle unit, and the drive unit is integrally connected to the valve body. And an electromagnet that adsorbs the movable member by energization, and a spring that urges the movable member released from the electromagnet in a direction away from the electromagnet. A fuel supply portion formed at a rear end portion of the housing portion located on the opposite side of the nozzle portion; a spring storage chamber for storing the spring; and the fuel supply portion to the spring storage chamber. In the fuel injection valve device constituted by a communication hole that communicates linearly, the communication hole includes a throttle portion having an inner diameter of 0.5 to 1.5 mm over a predetermined length. To do.

  In the present invention, the communication hole constituting the fuel flow path communicates linearly from the fuel supply portion to the spring storage chamber, so that the fuel in the flow passage in the housing portion can flow smoothly, and the fuel is not stagnated. It can feed toward the nozzle part. And, by providing a throttle part with an inner diameter of 0.5 to 1.5 mm in the communication hole, it is possible to stabilize the opening / closing operation of the valve body, and to accurately supply the power to the electromagnet of the driving means. Valve opening time can be obtained. The range of the inner diameter dimension of the throttle portion has been clarified by various tests by the present inventors.If the inner diameter dimension of the throttle portion is less than 0.5 mm, the flow of fuel is inhibited, and if it exceeds 1.5 mm, In particular, fuel pulsation (change in pressure) occurs when the valve body opens when the power supply time is short, and the valve opening time is affected by pressure fluctuations even if the power supply time is kept constant. Variation occurs. Therefore, by setting the inner diameter dimension of the throttle portion to 0.5 to 1.5 mm, fuel pulsation when the valve element is opened can be suppressed, and a stable valve opening operation can be obtained.

  Furthermore, it is preferable that the length dimension of the said throttle part shall be 5-30 mm. As a result of various tests by the present inventor, when the length of the throttle portion is less than 5 mm and exceeds 30 mm, especially when the power feeding time is short, the variation in the valve opening time is large, It became clear that stable valve body opening / closing operation could not be obtained due to the pressure change. Therefore, by setting the length dimension of the throttle portion to 5 mm to 30 mm, it is possible to suppress the variation in the valve opening time corresponding to the power feeding time and to obtain a stable opening / closing operation of the valve body.

  In the present invention, it is preferable that when the cylindrical inner collar that contacts one end of the spring is inserted into the communication hole, the throttle portion is formed inside the inner collar. As a result, only by processing the inner diameter of the inner collar as a throttle part, the throttle part can be provided without adding parts, and an increase in cost can be prevented for easy manufacture.

  At this time, it is preferable that the downstream end of the throttle portion opens in the axial direction toward the spring storage chamber. As a result, the fuel can smoothly flow from the throttle portion toward the spring storage chamber, and the fuel can flow smoothly without any stagnation within the throttle portion.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional explanatory view showing the configuration of the fuel injection valve device of this embodiment, FIG. 2 is a diagram showing the relationship between the power feeding time and the opening / closing operation of the valve body, and FIG. 3 is the fuel in the flow path after the valve is opened. 4 is a diagram showing the valve closing operation of the valve body during the valve closing response, FIG. 5 is a diagram showing the valve opening time with respect to the power feeding time, and FIG. 6 is a good inner diameter of the throttle portion. FIG. 7 is a diagram showing a range of a good length dimension of the throttle portion.

  As shown in FIG. 1, the fuel injection valve device 1 of the present embodiment includes a substantially cylindrical housing portion 2 and a cylindrical nozzle portion 3 that is connected to the distal end portion of the housing portion 2. . The nozzle unit 3 includes an injection port 4 that faces the combustion chamber of the internal combustion engine and injects fuel into the combustion chamber at the tip, and a valve body 5 that opens and closes the injection port 4 is housed therein. In the nozzle portion 3, reference numeral 6 is a vortex forming member that forms a vortex in the fuel when the valve is opened, and reference numeral 7 is an annular sealing member having heat shielding properties.

  A drive means 8 for driving opening and closing of the valve body 5 is accommodated in the housing portion 2. The driving means 8 includes an electromagnet 12 including a coil 10 wound and supported on a cylindrical bobbin 9, a cylindrical core 11 inserted into the coil 10, and a spring storage chamber 13 formed in the core 11. And a stored spring 14. Further, the driving means 8 includes a movable member 15 made of a magnetic material or a soft magnetic material attracted to the end face of the core 11 of the electromagnet 12. The movable member 15 includes a plurality of radially formed fuel flow grooves 16, and is provided inside the housing portion 2 so as to be movable in a direction that attracts and separates from the electromagnet 12. Further, the movable member 15 is coupled to the valve body 5 via a rod 17 and is urged in a direction away from the core 11 by a spring 14 housed in the spring housing chamber 13 of the core 11.

  An annular restricting member 18 is fixed at a boundary position with the nozzle portion 3 inside the housing portion 2, and the rod 17 is provided so as to be movable in the axial direction through the restricting member 18. Yes. The rod 17 is integrally formed with a flange portion 19 in which movement of the rod 17 is restricted by contact with the restriction member 18. When the movable member 15 is attracted to the core 11 by energizing the electromagnet 12 (the state shown in FIG. 1), the flange portion 19 comes into contact with the regulating member 18 and the movement of the rod 17 is regulated. A predetermined valve opening state is reached (in this embodiment, the moving distance of the valve body when the valve is opened is 0.5 mm).

  A fuel supply unit 22 including a filter 21 is provided at the rear end of the extending portion 20 that continuously extends rearward from the core 11. A communication hole 23 communicating linearly is formed from the fuel supply portion 22 to the spring storage chamber 13. An inner collar 24 that is in contact with one end of the spring 14 is fitted into the communication hole 23 on the spring housing chamber 13 side. The inner collar 24 can adjust the urging force of the movable member 15 in the spring 14 depending on the degree of insertion. The inner collar 24 is formed in a cylindrical shape and constitutes a part of the communication hole 23. As described above, the fuel supply portion 22, the communication hole 23, the inside of the inner collar 24, and the spring storage chamber 13 form a fuel flow path inside the housing portion 2. Furthermore, the inside of the inner collar 24 is the throttle portion 25 of the present invention over its entire length. The inner diameter of the throttle portion 25 is 1.0 mm, and the length is 20 mm. The downstream end of the throttle portion 25 opens in the axial direction of the inner collar 24 toward the spring storage chamber 13.

  Reference numeral 26 in the figure denotes a power supply connector for supplying power to the coil 10. A power supply means (not shown) is connected to the power supply connector 26 via a lead wire 27.

  Next, the operation of the fuel injection valve device 1 will be described with reference to FIG. When power is supplied to the coil 10 via the power supply connector 26, the movable member 15 moves toward the core 11 and is attracted by the attraction of the electromagnet 12. Accordingly, the valve body 5 is separated from the injection port 4, and the fuel in the nozzle portion 3 is injected from the injection port 4 to a high pressure. When the power supply to the coil 10 from the power supply connector 26 is stopped, the movable member 15 is separated from the core 11 by the bias of the spring 14. Along with this, the valve body 5 closes the fuel injection port 4. Thereby, the fuel injection from the injection port 4 is stopped. In this way, the valve body 5 is driven by energization and de-energization of the electromagnet 12 to open and close the injection port 4, and fuel is injected from the injection port 4 according to the time during which the electromagnet 12 is energized. Control the flow rate.

  Here, the relationship between the energization of the electromagnet 12 and the operation of the valve body 5 will be described. As shown in FIG. 2, the valve body 5 is fully opened through the valve opening response range in response to the start of energization, and the energization is canceled. Accordingly, the valve body 5 is completely closed through the valve closing response range. When the time from the start of energization to the release of energization is defined as the power supply time, and the time from when the valve body 5 is fully opened until it is completely closed is defined as the valve opening time, the valve opening time corresponds to the power supply time.

  However, when the valve body 5 is opened, fuel pulsation (change in pressure) occurs in the housing portion 2 due to movement of the movable member 15 and expansion and contraction of the spring 14. When pressure fluctuations occur in the internal fuel, even if the power supply time is kept constant, the valve opening time is affected by the pressure fluctuations and cannot be stably opened and closed. Therefore, in the present embodiment, the throttle portion 25 is provided inside the inner collar 24, and the inner diameter of the throttle portion 25 is set to 1.0 mm. Can be opened and closed stably. If it demonstrates in detail, as shown in FIG. 3, the fluctuation | variation of a pressure will arise in an internal fuel by opening the valve body 5. FIG. In FIG. 3, the solid line a is that of the fuel injection valve device 1 of the present embodiment (the inner diameter dimension of the throttle portion 25 is 1.0 mm), and the broken line b shown for comparison is the inner diameter dimension of the throttle portion 25 being 2 .2mm. When the inner diameter of the throttle portion 25 is 2.2 mm, the pressure fluctuates greatly and continues to fluctuate for a long time. Regarding the valve closing operation of the valve body 5 at this time, the valve body 5 is completely removed from the time when the energization is stopped at each of the power feeding times of 0.65 msec, 0.7 msec, 0.8 msec, 0.9 msec, and 1.0 msec. When the time until closing is measured, as shown in FIG. 4A, the variation width of the time when the valve body 5 is completely closed is large. On the other hand, in the fuel injection valve device 1 of the present embodiment in which the inner diameter dimension of the throttle portion 25 is 1.0 mm, as shown by the solid line a in FIG. 3, the pressure fluctuation is gradual and the fluctuation decreases at an early stage. Yes. Regarding the valve closing operation of the valve body 5 at this time, when the time until the valve body 5 is completely closed is measured for each power feeding time, the valve body 5 is completely closed as shown in FIG. The time variation width is small. Then, as shown in FIG. 5, when a straight line c serving as a reference of the valve opening time with respect to the power supply time is shown and compared, when the diameter of the throttle portion 25 is 2.2 mm, the power supply time is as shown by the broken line d. In contrast, the fuel injection valve device 1 according to the present embodiment has a large variation with respect to the reference straight line c. Thus, there is almost no variation for every power feeding time along the reference straight line c, and an extremely stable valve closing operation can be obtained.

  In the present embodiment, the inner diameter dimension of the throttle section 24 is 1.0 mm, but the inner diameter dimension of the throttle section 24 may be 0.5 mm to 1.5 mm. That is, when the variation in the valve opening time with respect to each of a plurality of power feeding times was measured by changing the inner diameter dimension of the throttle section 24, when the inner diameter dimension of the throttle section 24 exceeded 1.5 mm, the feeding time was 0.7 msec or less. It has been clarified that when the variation in the valve opening time is large and the power feeding time is short, a stable opening / closing operation of the valve body 5 may not be obtained due to the influence of the pressure change in the flow path. Further, when the inner diameter of the throttle portion 24 is less than 0.5 mm, the fuel cannot be smoothly circulated inside the throttle portion 24. Therefore, by setting the inner diameter dimension of the throttle portion 24 to 0.5 mm to 1.5 mm, variation in the valve opening time corresponding to the power feeding time is small, and a stable opening / closing operation of the valve body 5 can be obtained.

  Similarly, the length dimension of the throttle portion 24 is set to 20 mm in the present embodiment, but when the length dimension of the throttle portion 24 is changed, the variation in the valve opening time for each of a plurality of power feeding times is measured. When the inner diameter of the throttle portion 24 is in the range of 0.5 mm to 1.5 mm, it has become clear that the length of the throttle portion 24 is preferably 5 to 30 mm. That is, as shown in FIG. 7, when the length dimension of the throttle portion 24 is less than 5 mm and exceeds 30 mm, the valve opening time varies greatly when the power feeding time is 0.7 msec or less. It has become clear that when the is short, there is a possibility that a stable opening / closing operation of the valve body 5 may not be obtained due to the influence of the pressure change in the flow path. Therefore, when the length of the throttle portion 24 is set to 5 mm to 30 mm, variation in the valve opening time corresponding to the power feeding time is small, and a stable opening / closing operation of the valve body 5 can be obtained.

  Further, as shown in FIG. 1, by opening the downstream end of the throttle portion 25 toward the spring storage chamber 13 in the axial direction of the inner collar 24, fuel is supplied from the throttle portion 25 toward the spring storage chamber 13. The fuel can flow smoothly, and the fuel can flow smoothly without any stagnation in the throttle portion 25. Further, by providing the narrowed portion 25 over the entire length of the inner collar 24, the narrowed portion 25 can be provided with a very simple structure and without increasing the manufacturing cost.

  The diaphragm portion 25 is not limited to be provided over the entire inner length of the inner collar 24. Although not shown, the diaphragm portion 25 is provided in a part of the inner collar 24 within a range where the length dimension is 5 to 30 mm. May be formed. Even when the inner collar 24 is not provided, it can be opened by providing a throttle part having an inner diameter of 0.5 mm to 1.5 mm and a length of 5 to 30 mm at any position of the communication hole 23. The pressure fluctuation in the flow path accompanying the valve can be suppressed. At this time, the position of the throttle portion is preferably in the vicinity of the spring housing chamber 13, whereby the fuel pressure fluctuation accompanying the movement of the movable member 15 and the expansion and contraction of the spring 14 can be suppressed at an early stage.

Cross-sectional explanatory drawing which shows the structure of the fuel injection valve apparatus of one Embodiment of this invention. The diagram which shows the relationship between electric power feeding time and the opening / closing operation | movement of a valve body. The diagram which shows the pressure fluctuation of the fuel in the flow path after valve opening. The diagram which shows valve closing operation | movement of the valve body at the time of valve closing response. The diagram which shows the valve opening time with respect to electric power feeding time. The diagram which shows the range of the favorable internal-diameter dimension of an aperture part. The diagram which shows the range of the favorable length dimension of an aperture part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel injection valve apparatus, 2 ... Housing part, 3 ... Nozzle part, 4 ... Injection port, 5 ... Valve body, 8 ... Drive means, 12 ... Electromagnet, 13 ... Spring storage chamber, 14 ... Spring, 15 ... Movable member , 22 ... Fuel supply part, 23 ... Communication hole, 24 ... Inner collar, 25 ... Restriction part.

Claims (4)

A nozzle part provided with a nozzle that faces the combustion chamber of the internal combustion engine and injects fuel into the combustion chamber at the tip, and a valve body that opens and closes the injection port, and driving means that opens and closes the valve body of the nozzle part And a housing part containing a fuel flow path for conducting fuel to the nozzle part, wherein the driving means is integrally connected to the valve body, and an electromagnet for attracting the movable member by energization. And a spring for biasing the movable member released from the adsorption by the electromagnet in a direction away from the electromagnet, and the fuel flow path in the housing portion is located on the opposite side of the nozzle portion. A fuel supply portion formed at the rear end of the housing portion, a spring storage chamber for storing the spring, and a communication hole communicating linearly from the fuel supply portion to the spring storage chamber. The fuel injection valve device which is,
The communication hole includes a throttle portion having an inner diameter of 0.5 to 1.5 mm over a predetermined length.   2. The fuel injection valve device according to claim 1, wherein the length of the throttle portion is 5 to 30 mm. A cylindrical inner collar that comes into contact with one end of the spring is inserted into the communication hole,
The fuel injection valve device according to claim 1 or 2, wherein the throttle portion is formed inside the inner collar.   4. The fuel injection valve device according to claim 1, wherein a downstream end of the throttle portion opens in an axial direction toward the spring storage chamber. 5.

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