FUEL INJECTION VALVE

Abstract

The fuel injection valve includes a valve body having an injection hole at an end of the valve body facing in a first direction, and a needle valve provided inside the valve body and movable in an axial direction which includes both the first direction and a second direction opposite to the first direction. The needle valve is driven in the axial direction by a change in internal pressure of a back pressure chamber in the valve body. The fuel injection valve includes a control valve that controls the internal pressure of the back pressure chamber, and an actuator that drives the control valve. The control valve is longer than the needle valve in the axial direction. An end of the control valve facing in the second direction and the actuator are arranged away in the second direction from a center of the valve body in the axial direction.

Description

TECHNICAL FIELD

The present disclosure relates to a fuel injection valve that injects fuel.

BACKGROUND

There is a fuel injection valve including a valve body and a needle valve. The valve body has an injection hole formed at a lower end of the valve body. The needle valve is provided to be displaceable in an up-down direction inside the valve body, and moves downward to close the injection hole and moves upward to open the injection hole.

SUMMARY

A fuel injection valve according to at least one embodiment includes a valve body having an injection hole at an end of the valve body facing in a first direction, a needle valve provided inside the valve body and movable in an axial direction which includes both the first direction and a second direction opposite to the first direction. The needle valve closes the injection hole according to a movement of the needle valve in the first direction, and the needle valve opens the injection hole according to a movement of the needle valve in the second direction. A back pressure chamber is provided inside the valve body such that the needle valve faces the back pressure chamber in the second direction. An increase in internal pressure of the back pressure chamber causes the movement of the needle valve in the first direction, and a decrease in internal pressure of the back pressure chamber causes the movement of the needle valve in the second direction. The fuel injection valve includes a control valve provided inside the valve body and configured to control the internal pressure of the back pressure chamber, and an actuator configured to drive the control valve. The control valve is longer than the needle valve in the axial direction. An end of the control valve facing in the second direction and the actuator are located away in the second direction from a center of the valve body in the axial direction.

BRIEF DESCRIPTION OF DRAWINGS

The features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a front sectional view showing a fuel injection valve according to a first embodiment;

FIG. 2 is a front sectional view showing a fuel injection valve according to a second embodiment;

FIG. 3 is a front sectional view showing a fuel injection valve according to a third embodiment;

FIG. 4 is an enlarged front sectional view of a part of the fuel injection valve of FIG. 3;

FIG. 5 is a plan sectional view of the fuel injection valve of FIG. 4;

FIG. 6 is a sectional view of the fuel injection valve of FIG. 5 taken at an angle different from that of FIG. 4;

FIG. 7 is a plan view and a front view showing an arrangement of a control valve and an actuator of a first comparative example;

FIG. 8 is a plan view and a front view showing an arrangement of a control valve and an actuator of a second comparative example; and

FIG. 9 is a plan view and a front view showing an arrangement of a control valve and an actuator of the third embodiment.

DETAILED DESCRIPTION

Comparative examples will be described below. A fuel injection valve of a first comparative example includes a valve body and a needle valve. The valve body has an injection hole formed at a lower end of the valve body. The needle valve is provided to be displaceable in an up-down direction inside the valve body, and moves downward to close the injection hole and moves upward to open the injection hole. A back pressure chamber is formed above the needle valve inside the valve body. The needle valve moves downward by an internal pressure increase of the back pressure chamber, and moves upward by an internal pressure decrease of the back pressure chamber. Provided above the back pressure chamber are a control valve for controlling the pressure in the back pressure chamber and an actuator for driving the control valve.

In the fuel injection valve of the first comparative example, the control valve and the actuator are generally arranged in a lower part of the valve body. Therefore, the needle valve can be shortened and the mass can be reduced. Therefore, the needle valve can be driven with high response even by a relatively small driving force. However, since it is generally difficult to secure a large installation space for the actuator below the valve body, it is difficult to mount a large-sized and high-power actuator. Therefore, application to a high pressure fuel system becomes difficult.

On the other hand, in a second comparative example, an needle valve is elongated and the needle valve is extended from a lower end of a valve body to an upper part of the valve body. Accordingly, a back pressure chamber, a control valve, and an actuator are arranged in the upper part of the valve body. According to this configuration, it is easier to secure a large installation space for the actuator in the upper part of the valve body than in its lower part. Thus, a large-sized actuator can be easily mounted. However, since the needle valve becomes long and the mass thereof becomes large, the responsiveness of the needle valve deteriorates.

In contrast, the present disclosure can facilitate mounting of a large-sized actuator while ensuring a responsiveness of a needle valve.

A fuel injection valve according to a first aspect includes a valve body having an injection hole at an end of the valve body facing in a first direction, a needle valve provided inside the valve body and movable in an axial direction which includes both the first direction and a second direction opposite to the first direction. The needle valve closes the injection hole according to a movement of the needle valve in the first direction, and the needle valve opens the injection hole according to a movement of the needle valve in the second direction. A back pressure chamber is provided inside the valve body such that the needle valve faces the back pressure chamber in the second direction. An increase in internal pressure of the back pressure chamber causes the movement of the needle valve in the first direction, and a decrease in internal pressure of the back pressure chamber causes the movement of the needle valve in the second direction. The fuel injection valve includes a control valve provided inside the valve body and configured to control the internal pressure of the back pressure chamber, and an actuator configured to drive the control valve.

The control valve is longer than the needle valve in the axial direction. An end of the control valve facing in the second direction and the actuator are located away in the second direction from a center of the valve body in the axial direction.

According to the first aspect, since the control valve is longer in the axial direction than the needle valve, the actuator that drives the control valve is arranged away in the second direction from the center of the valve body in the axial direction. It is easier to secure a large installation space for the actuator in an area away in the second direction from the center than an area away in the first direction from the center. Thus, a large-sized actuator can be easily mounted. In addition, the actuator is disposed away in the second direction from the valve body by increasing the length of the control valve, not by increasing the length of the needle valve. Hence, increase in mass of the needle valve and deterioration in responsiveness of the needle valve can be avoided. Therefore, installation of the large-sized actuator can be facilitated while ensuring the responsiveness of the needle valve.

A fuel injection valve according to a second aspect includes a valve body including a first body having an injection hole at an end of the first body facing in a first direction, and a second body provided such that the first body faces the second body in a second direction that is opposite to the first direction. The fuel injection valve includes a needle valve provided inside the first body and movable in an axial direction which includes both the first direction and the second direction. The needle valve closes the injection hole according to a movement of the needle valve in the first direction, and the needle valve opens the injection hole according to a movement of the needle valve in the second direction. A back pressure chamber is provided inside the valve body such that the needle valve faces the back pressure chamber in the second direction. An increase in internal pressure of the back pressure chamber causes the movement of the needle valve in the first direction, and a decrease in internal pressure of the back pressure chamber causes the movement of the needle valve in the second direction. The fuel injection valve includes a control valve provided inside the second body and configured to control the internal pressure of the back pressure chamber, and an actuator configured to drive the control valve.

An end of the control valve facing in the first direction is located away in the first direction from a center of the second body in the axial direction. An end of the control valve facing in the second direction and the actuator are located away in the second direction from the center of the second body in the axial direction.

According to the second aspect, the two ends of the control valve are located on different sides of the center of the second body in the axial direction. Thus, the actuator that drives the control valve is arranged away in the second direction from the center. It is easier to secure a large installation space for the actuator in an area away in the second direction from the center than an area away in the first direction from the center. Thus, a large-sized actuator can be easily mounted. In addition, the actuator is disposed away in the second direction from the center by placing the two ends of the control valve on the different sides of the center, not by increasing the length of the needle valve. Hence, increase in mass of the needle valve and deterioration in responsiveness of the needle valve can be avoided. Therefore, installation of the large-sized actuator can be facilitated while ensuring the responsiveness of the needle valve.

Embodiments of the present disclosure will be described with reference to drawings. It is noted that, the present disclosure is not limited to the embodiments and may be implemented with appropriate modification without departing from the gist of the disclosure.

First Embodiment

FIG. 1 is a front sectional view showing a fuel injection valve 93 according to a first embodiment. The fuel injection valve 93 is provided in a fuel injection system 90 which is applied to an engine of an automobile. A liquid fuel, such as diesel fuel, gasoline, an ethanol or a mixture of them can be used as a fuel for the engine.

The fuel injection system 90 includes a pressure accumulator 91, a high pressure pipe 92, the fuel injection valve 93, and an ECU 94. The pressure accumulator 91 is supplied with high-pressure fuel from a high-pressure pump (not shown). The pressure accumulator 91 retains therein a high-pressure fuel in a high-pressure state. Each fuel injection valve 93 (only one is shown in FIG. 1) is connected to the pressure accumulator 91 via a corresponding high pressure pipe 92.

The fuel injection valve 93 includes a valve body 20, a needle valve 31, a control valve 52, and an actuator 54. In the following description, one of longitudinal directions (axial direction) of the needle valve 31 is referred to as a down direction and the other of the longitudinal directions is referred to as an up direction in accordance with the drawings. However, the fuel injection valve 93 may be arranged in any direction. For example, the longitudinal directions may be oblique to the up-down direction, or the longitudinal directions may be parallel to the horizontal direction. The down direction in the present embodiment corresponds to a first direction in the present disclosure, and the up direction in the present embodiment corresponds to a second direction in the present disclosure. Moreover, hereinafter, a direction orthogonal to the longitudinal directions (up-down direction) of the needle valve 31 is referred to as a lateral direction.

The valve body 20 includes a nozzle body 24, an orifice plate 22, and an injector body 21 in order from the bottom. The nozzle body 24 and the orifice plate 22 are fastened to a lower part of the injector body 21 by a retaining nut 29. In the present embodiment, the nozzle body 24 corresponds to a first body according to the present disclosure, and the injector body 21 corresponds to a second body according to the present disclosure.

The nozzle body 24 is a tubular member that opens upward, and has an injection hole 34 at a lower end thereof. The needle valve 31 is inserted into the nozzle body 24 so as to be displaceable in the up-down direction. A part of an inner peripheral surface of the nozzle body 24 forms a guide 38 that slidably contacts an outer peripheral surface of the needle valve 31 and thereby guides the needle valve 31 in the up-down direction. The needle valve 31 moves downward to close the injection hole 34 and moves upward to open the injection hole 34. The valve body 20 has therein a high pressure passage 13, a back pressure chamber 36, and a low pressure passage 58.

The pressure accumulator 91 supplies a high pressure fuel to the injector body 21 through the high pressure pipe 92, and then the high pressure fuel is sent to the injection hole 34 through the high pressure passage 13. The high pressure passage 13 extends to the injection hole 34 through the injector body 21, the orifice plate 22, and the nozzle body 24. Specifically, the injector body 21 and the orifice plate 22 are each provided with a hole that forms a part of the high pressure passage 13. Further, a gap between the inner peripheral surface of the nozzle body 24 and the needle valve 31 also forms a part of the high pressure passage 13. A cut portion 37 for securing the high-pressure passage 13 is provided between a part of the needle valve 31 and a part of the guide 38 that are in slidably contact with each other.

The back pressure chamber 36 is provided upward of the needle valve 31 inside the nozzle body 24. Specifically, a cylinder 35 is fitted on an upper part of the needle valve 31, and a needle valve spring 32 is provided between the cylinder 35 and the needle valve 31. The needle valve spring 32 presses downward the needle valve 31, and accordingly a reaction force is generated to press upward the cylinder 35. This pressing force causes the cylinder 35 to be pressed against the orifice plate 22. A space surrounded by the orifice plate 22, the cylinder 35, and the needle valve 31 forms the back pressure chamber 36. The needle valve 31 moves downward by an internal pressure increase of the back pressure chamber 36, and the needle valve 31 moves upward by an internal pressure decrease of the back pressure chamber 36.

The low pressure passage 58 is a passage for releasing the pressure in the back pressure chamber 36, and is provided in the injector body 21. The orifice plate 22 is provided with an inflow passage 14 through which the high pressure fuel in the high pressure passage 13 flows into the back pressure chamber 36, and an outflow passage 27 through which the high pressure fuel in the back pressure chamber 36 flows into the low pressure passage 58. The inflow passage 14 is a groove-shaped passage that is recessed from a lower end surface of the orifice plate 22, and extends above the cylinder 35 in the lateral direction. An end portion of the inflow passage 14 facing the back pressure chamber 36 forms an inflow passage orifice 14a. The outflow passage 27 penetrates the orifice plate 22 in the up-down direction, and an outflow passage orifice 27a is provided at an upper end portion of the outflow passage 27.

The upper part of the injector body 21 has a housing recess 48 that opens upward. Further, the injector body 21 is provided with a valve attachment hole 49 that penetrates from a bottom surface of the housing recess 48 to the lower end surface of the injector body 21. The valve attachment hole 49 is arranged right above the upper opening of the outflow passage 27, and extends in the up-down direction in parallel with a hole that forms the low pressure passage 58.

The control valve 52 is a valve for opening and closing the upper opening of the outflow passage 27. The control valve 52 moves upward to open the upper opening of the outflow passage 27 and moves downward to close the opening. The control valve 52 includes a rod portion 52b having a rod shape extending in the up-down direction, an umbrella portion 52a having an umbrella shape provided at an upper end of the rod portion 52b, and a valve portion 52c attached to a lower end of the rod portion 52b. In the present embodiment, in the control valve 52, the umbrella portion 52a and a rod portion 52b are integrally formed, and the valve portion 52c is formed separately from them. The umbrella portion 52a and the rod portion 52b may be formed as separate bodies, and then they may be joined together. Further, the rod portion 52b may be divided into multiple members in the up-down direction and then joined together.

The rod portion 52b and the valve portion 52c are inserted into the valve attachment hole 49, and the umbrella portion 52a is housed in the housing recess 48. Therefore, the control valve 52 is slidable in the up-down direction in the injector body 21. The control valve 52 is longer than the needle valve 31 in the up-down direction. A stroke length of the control valve 52 in the up-down direction is shorter than a stroke length of the needle valve 31 in the up-down direction. A support member 62 is disposed inside the housing recess 48 and supports the upper part of the rod portion 52b to be slidable in the up-down direction. Specifically, the support member 62 is a tubular member, and the upper part of the rod portion 52b is slidably inserted inside the support member 62. A part of the housing recess 48 below the support member 62 forms a part of the low pressure passage 58.

An upper part of the valve portion 52c has a hemispherical shape, and the hemispherical upper part is housed in a hemispherical concave part provided in a lower end surface of the rod portion 52b. Thereby, the valve portion 52c is rotatably engaged with the lower end part of the rod portion 52b. Therefore, for example, even when the rod portion 52b is slightly inclined from a desired position due to an error in dimensional accuracy, thermal expansion, disturbance, etc., this inclination can be absorbed between the rod portion 52b and the valve portion 52c. Therefore, the valve portion 52c can reliably close the upper opening of the outflow passage 27. The rod portion 52b and the valve portion 52c are displaced together in the up-down direction.

The lower end of the control valve 52 is located below a center C1 of the valve body 20 in the up-down direction, and the upper end of the control valve 52 is located above the center C1 of the valve body 20 in the up-down direction. The center C1 of the valve body 20 in the up-down direction is a bisector of a line segment that extends in the up-down direction from the height of the lower end of the nozzle body 24 to the height of the upper end of the injector body 21. More specifically, the lower end of the control valve 52 is located below a center C2 of the injector body 21 in the up-down direction, and the upper end of the control valve 52 is located above the center C2 of the injector body 21 in the up-down direction. The center C2 of the injector body 21 in the up-down direction is a bisector of a line segment that extends in the up-down direction from the height of the lower end of the injector body 21 to the height of the upper end of the injector body 21. Further specifically, in the present embodiment, the lower end of the control valve 52 is located at the lower end part of the injector body 21, and the upper end of the control valve 52 is located at the upper end part of the injector body 21.

The control valve 52 moves upward to open the upper opening of the outflow passage 27, thereby reducing the pressure in the back pressure chamber 36. As a result, the needle valve 31 is lifted up by hydraulic pressure and the injection hole 34 is opened. On the other hand, the control valve 52 moves downward to close the upper opening of the outflow passage 27, thereby increasing the pressure in the back pressure chamber 36. As a result, the needle valve 31 is lifted down by hydraulic pressure and the injection hole 34 is opened.

The actuator 54 drives the control valve 52 in the up-down direction by acting on the upper end portion (i.e. the umbrella portion 52a) of the control valve 52. More specifically, a control valve spring 56 is provided above the control valve 52 and presses the control valve 52 downward. The actuator 54 having a tubular shape is provided around the control valve spring 56. In the present embodiment, the actuator 54 is a solenoid and, when energized, attracts the upper end part of the control valve 52 by magnetic force, thereby lifting up the control valve 52. As a result, the upper opening of the outflow passage 27 is opened. On the other hand, when the energization is terminated, the attraction is stopped and the control valve 52 moves down by pressing force of the control valve spring 56. As a result, the upper opening of the outflow passage 27 is closed. The actuator 54 is attached to the upper part of the injector body 21 by a fastening member 57. The energization of the second actuator 54 is controlled by the ECU 94.

According to the present embodiment, the following effects can be obtained. The control valve 52 is longer than the needle valve 31, and thus the control valve 52 extends to the upper part of the injector body 21. Thus, the actuator 54 that drives the control valve 52 can be easily arranged above or at the upper part of the injector body 21. It is easier to secure a large installation space for the actuator 54 at or above the upper part of the injector body 21 than at the lower part thereof. Thus, a large-sized actuator 54 can be easily mounted. Therefore, it becomes easy to be used for a high pressure fuel system.

In addition, the actuator 54 is disposed at the upper part of the injector body 21 by increasing the length of the control valve 52, not by increasing the length of the needle valve 31. Hence, increase in mass of the needle valve 31 and deterioration in responsiveness of the needle valve can be avoided. Therefore, installation of the large-sized actuator 54 can be facilitated while ensuring the responsiveness of the needle valve 31.

In the present embodiment, by lengthening the control valve 52, the mass of the control valve 52 increases, and the responsiveness of the control valve 52 deteriorates accordingly. However, as compared with the case where the needle valve 31 becomes long and its responsiveness deteriorates, the adverse effect on the injection control can be suppressed. The reason is that, first, as described above, the stroke length of the control valve 52 in the up-down direction is smaller than the stroke length of the needle valve 31 in the up-down direction.

Secondly, a decrease in upward speed and a decrease in downward speed due to the mass increase of the needle valve 31 directly leads to a decrease in valve opening speed and a decrease in valve closing speed of the injection hole 34. On the other hand, a decrease in upward speed or a decrease in downward speed of the control valve 52 leads to a delay in start timing of the pressure decrease or a delay in start timing of the pressure increase in the back pressure chamber 36. That is, it only leads to a delay in lifting-up start timing of the needle valve 31 or a delay in lifting-down start timing of the needle valve 31, but does not lead to the decrease in upward speed or downward speed of the needle valve 31. The delay in start timing of the pressure decrease and the delay in start timing of the pressure increase in the back pressure chamber 36 can be dealt with by advancing the ON/OFF timing of the actuator 54 accordingly. From the above points, in the present embodiment in which the control valve 52 is lengthened, the adverse effect on the injection control can be reduced as compared with the case where the needle valve 31 is lengthened.

Second Embodiment

Next, a second embodiment of the present disclosure will be described. In the present embodiment, the same or corresponding members as those in the first embodiment are assigned the same reference numerals, and only the points different from the first embodiment will be described.

FIG. 2 is a front sectional view showing a fuel injection valve 93 according to the present embodiment. In the present embodiment, a hole that forms a part of a low pressure passage 58 parallel with the valve attachment hole 49 is not provided. A gap between the inner peripheral surface of the valve attachment hole 49 and a control valve 52 forms the part of the low pressure passage 58. Specifically, in this embodiment, an inner diameter of the valve attachment hole 49 is slightly larger than an outer diameter of the control valve 52. A ring 52d is fitted on a lower end portion (valve portion 52c) of the control valve 52 for preventing the lower end portion of the control valve 52 from sliding on the inner peripheral surface of the valve attachment hole 49 in the lateral direction.

According to the present embodiment, the gap between the inner peripheral surface of the valve attachment hole 49 and the control valve 52 serves as the part of the low pressure passage 58, so that the structure of a valve body 20 can be simplified.

Third Embodiment

Next, a third embodiment of the present disclosure will be described. In the present embodiment, the same or corresponding members as those in the first and second embodiments are assigned the same reference numerals, and only the points different from the second embodiment will be described.

FIG. 3 is a front sectional view showing a fuel injection valve 93 and its periphery according to the present embodiment. The housing recess 48, the control valve 52, the actuator 54, the control valve spring 56, and the support member 62 referred to in the first and second embodiments correspond to, respectively, a second housing recess 48, a second control valve 52, a second actuator 54, a second control valve spring 56, and a second support member 62 in the present embodiment.

FIG. 4 is a diagram in which a part of FIG. 3 is enlarged. More specifically, a sectional view taken along the line V-V of FIG. 4 is FIG. 5, and a sectional view taken along the line IV-IV of FIG. 5 is FIG. 4. The outflow passage 27 and the outflow passage orifice 27a in the first and second embodiments correspond to, respectively, a second outflow passage 27 and a second outflow passage orifice 27a in the present embodiment. A valve body 20 includes a control chamber plate 23 between an orifice plate 22 and a nozzle body 24. A control chamber 46 is provided in the control chamber plate 23.

A recess is provided on the control chamber plate 23 and opens upward, and the opening of the recess is closed by the orifice plate 22. Accordingly, the control chamber 46 is formed. The control chamber 46 communicates with the back pressure chamber 36 via a connection path 47 provided in the control chamber plate 23. A recess is provided at the lower end part of the orifice plate 22, and the recess opens downward and forms an intermediate chamber 26. A first outflow passage 25 is provided so as to penetrate from a ceiling surface of the recess (i.e. intermediate chamber 26) to an upper end surface of the orifice plate 22. The intermediate chamber 26 and the low pressure passage 58 communicate with each other through the first outflow passage 25. The recess forming the intermediate chamber 26 functions as a pressure chamber by closing its opening. Further, an annular groove 16 is provided around the intermediate chamber 26 on the lower end surface of the orifice plate 22. The annular groove 16 has an annular shape and faces downward. Moreover, the orifice plate 22 is provided with the second outflow passage 27 that extends therethrough in the up-down direction. The second outflow passage 27 connects the control chamber 46 to the low pressure passage 58, and the second outflow passage 27 is provided with the outflow passage orifice 27a.

The control chamber 46 houses a driven valve 41 to be displaceable in the up-down direction, and a driven valve spring 45 that presses the driven valve 41 upward. When the driven valve 41 contacts a ceiling surface of the control chamber 46, the driven valve 41 closes the opening of the intermediate chamber 26 and the opening of the annular groove 16. The driven valve 41 has a communication passage 42 through which the control chamber 46 communicates with the intermediate chamber 26. The communication passage 42 is provided with a communication passage orifice 42a. On the other hand, the first outflow passage 25 is not provided with an orifice. Therefore, when the driven valve 41 is in contact with a ceiling surface of the control chamber 46 and the upper opening of the first outflow passage 25 is open, a high-pressure fuel flowing into the intermediate chamber 26 through the communication passage orifice 42a is quickly discharged into the low pressure passage 58 from the first outflow passage 25 having no orifice. On the other hand, when the driven valve 41 is in contact with the ceiling surface of the control chamber 46 and the upper opening of the first outflow passage 25 is closed, a high-pressure fuel flowing into the intermediate chamber 26 through the communication passage orifice 42a is accumulated in the intermediate chamber 26, and thereby the pressure in the intermediate chamber 26 increases.

FIG. 6 is a cross-sectional view taken along a line VI-VI of FIG. 5. An injector body 21, the orifice plate 22 and the control chamber plate 23 are each provided with a hole that forms a part of a high pressure passage 13. These holes are provided behind the low pressure passage 58 in a front view.

The orifice plate 22 has an inflow passage 14 for allowing the high pressure fuel in the high pressure passage 13 to flow into the control chamber 46. The inflow passage 14 communicates with the annular groove 16. The inflow passage 14 is provided with an inflow passage orifice 14a.

As shown in FIG. 4, a lower end part of the injector body 21 has a first housing recess 44 that has a cylindrical shape and opens downward. The first housing recess 44 houses a first control valve 51 and a first actuator 53. In a plan view, the center line of the first housing recess 44 and the center line of the second housing recess 48 are eccentric.

The first control valve 51 is a valve for opening and closing the upper opening of the first outflow passage 25. The first control valve 51 moves upward to open the upper opening of the first outflow passage 25 and moves downward to close the opening. The first control valve 51 includes a rod portion 51b having a rod shape extending in the up-down direction, an umbrella portion 51a having an umbrella shape provided at an upper end of the rod portion 51b, and a valve portion 51c attached to a lower end of the rod portion 51b. The first control valve 51 is shorter than the needle valve 31 in the up-down direction. A first support member 61 is disposed inside the first housing recess 44 and supports the rod portion 51b to be slidable in the up-down direction. Specifically, the first support member 61 is a tubular member, and the rod portion 51b is inserted inside the support member 62 and slidable in the up-down direction. A gap between the respective members inside the first housing recess 44 constitutes a part of the low pressure passage 58.

The valve portion 51c has the same shape and function as the valve portion 52c of the second control valve 52. A stroke length of the first control valve 51 in the up-down direction is shorter than a stroke length of the needle valve 31 in the up-down direction.

The first actuator 53 drives the first control valve 51 in the up-down direction by acting on an upper end portion (i.e. the umbrella portion 51a) of the control valve 51. More specifically, a first control valve spring 55 is provided above the first control valve 51 and urges the first control valve 51 downward. The first actuator 53 having a tubular shape is provided around the first control valve spring 55. In the present embodiment, the first actuator 53 is a solenoid and, when energized, attracts the upper end part of the first control valve 51 by magnetic force, thereby lifting up the first control valve 51. As a result, the upper opening of the first outflow passage 25 is opened. On the other hand, when the energization is terminated, the attraction is stopped and the first control valve 51 moves down by pressing force of the first control valve spring 55. As a result, the upper opening of the first outflow passage 25 is closed. The energization of the first actuator 53 is controlled by the ECU 94.

Next, the functions of the fuel injection valve 93 of the present embodiment will be described. Basically, when the first control valve 51 is opened, regardless of whether the second control valve 52 is opened or closed, the pressures inside the control chamber 46 and the back pressure chamber 36 become low, and the needle valve 31 moves upward. However, when the first control valve 51 is opened while the second control valve 52 is open, the pressures inside the control chamber 46 and the back pressure chamber 36 become low relatively quickly. When the first control valve 51 is opened while the second control valve 52 is closed, the pressures in the control chamber 46 and the back pressure chamber 36 become low relatively slowly. Further, basically, when the first control valve 51 is closed, regardless of whether the second control valve 52 is opened or closed, the pressures inside the control chamber 46 and the back pressure chamber 36 become high, and the needle valve 31 moves downward. However, when the first control valve 51 is closed while the second control valve 52 is closed, the pressures inside the control chamber 46 and the back pressure chamber 36 become high relatively quickly. When the first control valve 51 is closed and at the same time the second control valve 52 is opened, the pressures in the control chamber 46 and the back pressure chamber 36 become high relatively slowly. The details are described as follows.

When at least the first control valve 51 is closed, the pressures in the control chamber 46 and the back pressure chamber 36 are high and the needle valve 31 is at the lowest. In this state, when both the first control valve 51 and the second control valve 52 become open, the pressure in the control chamber 46 releases to the low pressure passage 58 through the communication passage 42, the intermediate chamber 26 and the first outflow passage 25, and also releases to the low pressure passage 58 from the second outflow passage 27. Therefore, the pressures inside the control chamber 46 and the back pressure chamber 36 relatively quickly become low, and the needle valve 31 moves upward relatively quickly.

On the other hand, in the state where the needle valve 31 is at the lowest, when the first control valve 51 is opened and while the second control valve 52 is closed, the pressure in the control chamber 46 releases to the low pressure passage 58 through the communication passage 42, the intermediate chamber 26 and the first outflow passage 25, but does not release to the low pressure passage 58 from the second outflow passage 27. Therefore, the pressures inside the control chamber 46 and the back pressure chamber 36 relatively slowly become low, and the needle valve 31 moves upward relatively slowly.

When at least the first control valve 51 is open, the pressures in the control chamber 46 and the back pressure chamber 36 are low and the needle valve 31 is at the highest. In this state, when both the first control valve 51 and the second control valve 52 become closed, the pressure between the control chamber 46 and the intermediate chamber 26 through the communication passage orifice 42a does not release to the low pressure passage 58 from the first outflow passage 25. As a result, the pressure in the intermediate chamber 26 increases. Due to the pressure increase in the intermediate chamber 26, the driven valve 41 is pushed downward, and the driven valve 41 is separated from the ceiling surface of the control chamber 46. Therefore, the annular groove 16 is opened, and the high-pressure fuel in the high pressure passage 13 flows into the control chamber 46 through the inflow passage 14 and the annular groove 16. At this time, since both control valves 51 and 52 are closed, the inflow high pressure fuel accumulates in the control chamber 46 and the back pressure chamber 36 as it is. Accordingly, the pressures inside the control chamber 46 and the back pressure chamber 36 relatively quickly become high, and the needle valve 31 moves downward relatively quickly.

On the other hand, in the state where the needle valve 31 is at the highest, also when the first control valve 51 becomes closed while the second control valve 52 is open, the driven valve 41 is separated from the ceiling surface of the control chamber 46 by the same mechanism as above. Thus, the high pressure fuel in the high pressure passage 13 flows into the control chamber 46. Therefore, the pressure in the control chamber 46 increases. However, at this time, since the second control valve 52 is open, a part of the inflow high pressure fuel flows out to the low pressure passage 58 through the second outflow passage 27. Therefore, the pressures inside the control chamber 46 and the back pressure chamber 36 relatively slowly become high, and the needle valve 31 moves downward relatively slowly.

FIG. 7(a) is a plan view showing a positional relationship between the two actuators 53 and 54 of a first comparative example. FIG. 7(b) is a sectional view taken along a line VIIb-VIIb of FIG. 7(a). The first comparative example is an example in which the second control valve 52 and the second actuator 54 are of the same sizes as the first control valve 51 and the first actuator 53 and are arranged side by side in the lateral direction with the first control valve 51 and the first actuator 53. In this first comparative example, the sum of the outer diameters of the two actuators 53, 54 need to be smaller than the inner diameter of the valve body 20.

FIG. 8(a) is a plan view showing a positional relationship between the two actuators 53 and 54 of a second comparative example. FIG. 7(b) is a sectional view taken along a line VIIIb-VIIIb of FIG. 8(a). The second comparative example is an example in which the first control valve 51 is disposed inside the second control valve 52, and the first actuator 53 is disposed inside the second actuator 54. In the second comparative example, outward expansion of the first actuator 53 is limited by the second actuator 54, and inward expansion of the second actuator 54 is limited by the first actuator 53.

FIG. 9(a) is a plan view showing a positional relationship between the two actuators 53 and 54 of the present embodiment. FIG. 9(b) is a sectional view taken along a line IXb-IXb of FIG. 9(a). As described above, in a plan view, the center line of the first housing recess 44 and the center line of the second housing recess 48 are eccentric. Therefore, the center lines of the first control valve 51 and the first actuator 53 which are housed in the first housing recess 44 are eccentric from the center lines of the second control valve 52 and the second actuator 54 which are housed in the second housing recess 48.

Since the second control valve 52 is longer than the first control valve 51, the second actuator 54 that drives the second control valve 52 is arranged above the first actuator 53 that drives the first control valve 51 while the lower part of the second control valve 52 is arranged side by side in the lateral direction with the first control valve 51. Accordingly, the first actuator 53 and the second actuator 54 are prevented from interfering with each other, and a part of the second actuator 54 is overlapped with the first actuator 53 in the plan view.

According to the present embodiment, the following effects can be obtained. The upward moving speed and the downward moving speed of needle valve 31 can be controlled because the first outflow passage 25, the second outflow passage 27, the first control valve 51, the second control valve 52, the first actuator 53 and the second actuator 54 are provided, for example.

Further, since the second actuator 54 is partially overlapped with the first actuator 53 in the plan view, an area of the first actuator 53 or an area of the second actuator 54 can be easily increased. Particularly, the area of the second actuator 54 can be easily increased. Therefore, while saving the spaces of the first actuator 53 and the second actuator 54, it is easy to increase a magnetic pole surface area of the first actuator 53 or the second actuator 54 and increase a driving force. Therefore, for example, even if the fuel injection valve has the same size as a fuel injection valve including only one actuator, the fuel injection valve becomes easy to be used for the a high-pressure fuel system.

Further, the first control valve 51 is shorter than the needle valve 31 and therefore has a small mass. Therefore, the first actuator 53 is relatively small but can be controlled with a sufficiently high response.

OTHER EMBODIMENTS

The present embodiment may also be implemented with the following modifications. For example, the actuator 54 may be an actuator other than a solenoid such as a piezo actuator. Further, for example, the actuator 54 may be provided at an arbitrary position above the center C1 of the valve body 20 in the up-down direction instead of being provided at the upper end portion or above the injector body 21.

Further, for example, instead of forming each of the orifices 14a, 27a, 42a, the diameters of the flow paths 14, 27, 42 themselves including them may be reduced so that the flow paths 14, 27, 42 themselves can function as orifices.

Further, for example, instead of the arrangement in which the longitudinal direction of the control valve 52 is parallel to the longitudinal direction (up-down direction) of the needle valve 31, the longitudinal direction of the control valve 52 may be set slightly oblique to the longitudinal direction of the needle valve 31. Further, for example, in the third embodiment, instead of the configuration in which the second control valve 52 opens and closes the second outflow passage 27, the second control valve 52 may open and close the inflow passage 14.

Further, for example, instead of making the inner diameter of the valve attachment hole 49 larger than the outer diameter of the second control valve 52, a groove extending in the up-down direction may be provided in the valve attachment hole 49 or the second control valve 52, and the groove may secure the low pressure passage 58.

Further, for example, In the third embodiment, the driven valve 41 may be omitted. In that case, when both the first control valve 51 and the second control valve 52 are closed, the pressures in the control chamber 46 and the back pressure chamber 36 becomes high. In this state, when both the first control valve 51 and the second control valve 52 are opened, the pressures relatively quickly become low. When only one is opened, the pressures relatively slowly become low.

Further, for example, in FIG. 9(a), a part of the second actuator 54 overlaps with a part of the first actuator 53 in the plan view. However, a whole part of the first actuator 53 may overlap with a part of the second actuator 54 in the plan view. Further, for example, in FIG. 9(b), the lower portion of the second control valve 52 is arranged side by side in the lateral direction with the entire first control valve 51, but the lower portion of the second control valve 52 may be arranged side by side in the lateral direction only with the upper portion of the first control valve 51.

While the present disclosure has been described with reference to embodiments thereof, it is to be understood that the disclosure is not limited to the embodiments and constructions. To the contrary, the present disclosure is intended to cover various modification and equivalent arrangements. In addition, while the various elements are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure.

Claims

1. A fuel injection valve comprising: a valve body having an injection hole at an end of the valve body facing in a first direction;a needle valve which is an entire of a movable body provided inside the valve body and movable in an axial direction which includes both the first direction and a second direction opposite to the first direction, the needle valve closing the injection hole according to a movement of the needle valve in the first direction, the needle valve opening the injection hole according to a movement of the needle valve in the second direction;a back pressure chamber provided inside the valve body such that the needle valve faces the back pressure chamber in the second direction, an increase in internal pressure of the back pressure chamber causes the movement of the needle valve in the first direction, and a decrease in internal pressure of the back pressure chamber causes the movement of the needle valve in the second direction;a control valve provided inside the valve body and configured to control the internal pressure of the back pressure chamber; andan actuator configured to drive the control valve, whereinthe control valve is longer than the needle valve in the axial direction, andan end of the control valve facing in the second direction and the actuator are located away in the second direction from a center of the valve body in the axial direction.

2. The fuel injection valve according to claim 1, wherein the valve body includes a first body and a second body such that the first body faces the second body in the second direction,the injection hole is formed at an end of the first body facing in the first direction,the needle valve and the back pressure chamber are provided inside the first body,the control valve is provided inside the second body,an end of the control valve facing in the first direction is located away in the first direction from a center of the second body in the axial direction,the end of the control valve facing in the second direction is located away in the second direction from the center of the second body in the axial direction, andthe actuator is located away in the second direction from the center of the second body in the axial direction and attached to the second body.

3. A fuel injection valve comprising: a valve body including a first body having an injection hole at an end of the first body facing in a first direction, and a second body provided such that the first body faces the second body in a second direction that is opposite to the first direction;a needle valve provided inside the first body and movable in an axial direction which includes both the first direction and the second direction, the needle valve closing the injection hole according to a movement of the needle valve in the first direction, the needle valve opening the injection hole according to a movement of the needle valve in the second direction;a back pressure chamber provided inside the valve body such that the needle valve faces the back pressure chamber in the second direction, an increase in internal pressure of the back pressure chamber causes the movement of the needle valve in the first direction, and a decrease in internal pressure of the back pressure chamber causes the movement of the needle valve in the second direction;a control valve provided inside the second body and configured to control the internal pressure of the back pressure chamber; andan actuator configured to drive the control valve, whereinan end of the control valve facing in the first direction is located away in the first direction from a center of the second body in the axial direction,an end of the control valve facing in the second direction is located away in the second direction from the center of the second body in the axial direction, andthe actuator is located away in the second direction from the center of the second body in the axial direction and attached to the second body.

4. The fuel injection valve according to claim 1, wherein the control valve is inserted into a valve attachment hole provided in the valve body, anda gap between an inner peripheral surface of the valve attachment hole and the control valve forms a part of a low pressure passage through which the internal pressure of the back pressure chamber is released.

5. The fuel injection valve according to claim 1, wherein a stroke length of the control valve in the axial direction is shorter than a stroke length of the needle valve in the axial direction.

6. The fuel injection valve according to claim 1, further comprising: a first control valve provided inside the valve body and configured to control the internal pressure of the back pressure chamber;a second control valve as the control valve;a first actuator configured to control the first control valve; anda second actuator as the actuator, whereinthe second control valve is longer than the first control valve in the axial direction,a direction orthogonal to the axial direction is defined as a lateral direction,a part of the second control valve is arranged side by side in the lateral direction with at least a part of the first control valve,an end of the second control valve facing in the second direction is located away in the second direction from an end of the first control valve facing in the second direction,the second actuator is located away in the second direction from the first actuator, anda part of the second actuator overlaps at least a part of the first actuator when viewed in a plan view along the axial direction.

7. The fuel injection valve according to claim 6, wherein the first control valve is shorter than the needle valve in the axial direction.