JP4214970B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve.

  Conventionally, there is known a so-called boot-type injection fuel injection valve that includes two nozzle needles and switches from small injection to large injection during one fuel injection period (Patent Document 1). The fuel injection valve described in Patent Document 1 includes a hollow cylindrical first nozzle needle and a second nozzle needle accommodated in the hollow portion, and an independent first, A second pressure control chamber is provided. When the first and second pressure control chambers release the pressure in the first pressure control chamber, the first nozzle needle moves to the counter-injection hole side to close the first injection hole, and the pressure in the second pressure control chamber The second nozzle needle is formed so as to move to the injection hole side and open the second injection hole.

  This fuel injection valve operates as follows. When energization of the control valve is started, the return passage is opened, and the pressure in the first and second pressure control chambers begins to gradually decrease. When the pressure in the first pressure control chamber becomes the valve opening pressure of the first nozzle needle, the first nozzle needle is detached from the end face of the valve body, and fuel is injected from the first injection hole. At this time, the second nozzle needle is conversely seated on the end face of the valve body and closes the second injection hole. Therefore, at this stage, fuel is injected only from the first injection holes (small injection).

  Next, when energization to the control valve is stopped, the return passage is blocked, and the pressure in the first and second pressure control chambers begins to rise. Since the second pressure control chamber has a smaller volume than the first pressure control chamber, the pressure in the second pressure control chamber rises faster. Then, the second nozzle needle opens the second injection hole faster than the first nozzle needle closes the first injection hole. At this time, both the injection holes of the first injection hole and the second injection hole are opened, and fuel is injected from both of the injection holes (large injection).

Thereafter, when the pressure in the first and second pressure control chambers further increases, the first nozzle needle is seated on the valve body, and fuel injection from the first injection hole is stopped. At this time, the second nozzle needle remains separated from the valve body, and the second injection hole remains open.
JP 2003-254188 A

  In recent years, exhaust gas regulations for diesel engines have become more stringent. In order to reduce emissions in the exhaust gas, it is necessary to improve the accuracy of fuel injection.

  In the conventional fuel injection valve, a space is formed between the end of the second nozzle needle and the end face of the valve body when the second injection hole is opened. Even after energization of the control valve is stopped and the first injection hole is closed, the second nozzle needle is in a state of being separated from the valve body, so that the fuel remaining in the space is injected from the second injection hole. There is a possibility. As a result, excess fuel is injected from the second injection holes, and a large amount of carbon monoxide (CO) may be generated in the exhaust gas.

  The present invention has been made in view of the above problems, and in a fuel injection valve provided with two nozzle needles, when the fuel injection is finished, the nozzle needles are seated simultaneously to stop the fuel from the injection holes. For the purpose.

  In order to achieve the above object, a fuel injection valve according to claim 1 is configured so that a nozzle needle is reciprocated by the pressure of fuel introduced into the valve body, and the fuel injection valve is formed from an injection hole formed in the valve body. A fuel injection valve that blocks fuel injection and allows fuel injection, and is accommodated in the valve body so as to be reciprocally movable, and a first nozzle needle that opens and closes a first injection hole as an injection hole formed in the valve body. And a second nozzle needle that is reciprocally accommodated in the first nozzle needle and opens and closes the second injection hole formed in the valve body, and the first injection hole and the second injection hole are simultaneously closed. An urging force adjusting means for adjusting the urging force applied to the first nozzle needle and the second nozzle needle is provided.

  According to this, the 1st injection hole and the 2nd injection hole which were formed in the valve body are opened and closed by the 1st nozzle needle and the 2nd nozzle needle, and it is attached to the 1st nozzle needle and the 2nd nozzle needle. The opening / closing timing of the first and second injection holes can be adjusted by adjusting the force. Since the urging force is adjusted by the urging force adjusting means so that the valve closing timings of the first and second injection holes are coincident, excess fuel is not injected when the fuel injection is stopped. For example, the amount of carbon monoxide generated in the exhaust gas can be suppressed as compared with the above-described conventional fuel injection valve.

In the fuel injection valve according to claim 1 , a first upper end surface and a second upper end surface are formed on the opposite injection hole sides of the first nozzle needle and the second nozzle needle, and the first upper end surface and the second upper end surface are formed. A first pressure control chamber and a second pressure control chamber are independently formed between the inner wall of the valve body facing each upper end surface, and the urging force adjusting means is a fuel pressure in the first pressure control chamber. The first pressure control chamber adjusting means for adjusting the pressure and the second pressure control chamber adjusting means for adjusting the fuel pressure in the second pressure control chamber.

  According to this, as the means for adjusting the urging force, the fuel pressure in the first pressure control chamber and the second pressure control chamber is adjusted by the first pressure control chamber adjusting means and the second pressure control chamber adjusting means. The urging force can be easily adjusted.

The fuel injection valve according to claim 2 is provided with a first inlet throttle and a first outlet throttle, and a second inlet throttle and a second outlet throttle at the entrance and exit of the first pressure control chamber and the second pressure control chamber, The first pressure adjusting means adjusts the pressure in the first pressure control chamber by adjusting the flow passage cross-sectional area ratio between the first inlet throttle and the first outlet throttle, and the second pressure adjusting means The pressure in the second pressure control chamber is adjusted by adjusting the flow passage cross-sectional area ratio of the second outlet throttle.

  According to this, the first pressure control chamber is provided with the first inlet throttle and the first outlet throttle, and the second pressure control chamber is provided with the second inlet throttle and the second outlet throttle. By adjusting the area ratio of the flow passage cross section of the outlet throttle, the rising speed and the falling speed of the fuel pressure in the pressure control chamber can also be adjusted. This increases the degree of freedom in adjusting the fuel pressure in the first and second pressure control chambers.

In the fuel injection valve according to claim 3 , the first lower end surface and the second lower end surface are formed on the injection hole side of the first upper end surface and the second upper end surface, respectively, and the biasing force adjusting means includes the first upper end surface. The area ratio between the first lower end surface and the area ratio between the second upper end surface and the second lower end surface is adjusted.

  According to this, the first and second nozzles are adjusted by adjusting the area ratio of the first upper end surface to the first lower end surface and the second upper end surface to the second lower end surface formed on the first and second nozzle needles. The biasing force applied to the needle can be adjusted. Thereby, the opening and closing timing of the first and second nozzle needles can be adjusted.

According to a fourth aspect of the present invention, there is provided a fuel injection valve for supplying fuel introduced into a valve body to a first pressure control chamber and a second pressure control chamber, a fuel inflow passage, a first pressure control chamber, and a second pressure control chamber. And a return passage for discharging surplus fuel from.

  According to this, since the first pressure control chamber and the second pressure control chamber are arranged in parallel to the fuel flow from the fuel inflow passage to the return passage, the fuel in the first and second pressure control chambers It becomes easy to adjust the pressure independently.

In the fuel injection valve according to the fifth aspect , a communication passage that connects the first pressure control chamber and the second pressure control chamber to the second nozzle needle is formed, and the fuel inflow passage is connected to the first pressure control chamber. The return passage is connected to the second pressure control chamber.

  According to this, the communication path which connects the 1st pressure control room and the 2nd pressure control room to the 2nd nozzle needle is formed. The fuel inflow passage is connected to the first pressure control chamber, and the return passage is connected to the second pressure control chamber. In other words, the first pressure control chamber and the second pressure control chamber are arranged in series with respect to the fuel flow from the fuel inflow passage to the return passage. This reduces the control flow rate of the fuel used during the injection control in the first and second pressure control chambers.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a main part of the fuel injection valve 10. FIG. 1 shows when fuel injection is stopped.

  A fuel injection valve 10 shown in FIG. 1 is inserted and mounted in a cylinder head of an engine (not shown), and is configured to directly inject fuel into each cylinder of the engine. High pressure fuel supplied from a fuel injection pump (not shown) through a fuel pipe to a common rail (not shown) is accumulated at a constant high pressure in the common rail, and is introduced into a fuel injection valve 10 disposed in each cylinder through the fuel pipe. The Of the introduced fuel, surplus fuel is returned to a fuel tank (not shown). A fuel injection pump (not shown) is provided to adjust the fuel discharge pressure in accordance with the engine speed, load, intake fuel pressure, intake air amount, cooling water temperature, and the like.

  The fuel injection valve 10 includes a valve body 20, a first nozzle needle 50 and a second nozzle needle 60 accommodated therein, and an electromagnetic valve 90.

  The valve body 20 has a valve body end face 21 at the bottom. Inside the valve body 20, there are a fuel inflow passage 22 for introducing high pressure fuel in a common rail (not shown), a return passage 23 for returning surplus fuel to a fuel tank (not shown), and an oil reservoir chamber 24 for storing high pressure fuel. Is formed. A first injection hole 30 and a second injection hole 40 are formed in the valve body end surface 21. The first injection hole 30 is formed upstream of the second injection hole 40 with respect to the flow of high-pressure fuel from the common rail.

  The first nozzle needle 50 is formed in a hollow cylindrical shape, and is accommodated in a space formed in the valve body 20 so as to be reciprocally movable. A first upper end surface 53 is formed on the side of the first nozzle needle 50 opposite to the injection hole, and a first lower end surface 54 is formed on the injection hole side. The first lower end surface 54 includes a first lower end surface portion 54a and a first lower end surface portion 54b. The first lower end surface portion 54a is formed on the outer peripheral side of the first nozzle needle 50 with respect to the first lower end surface portion 54b. Between the first lower end surface portion 54a and the first lower end surface portion 54b, a first seat portion 52 that can be seated and separated from the valve body end surface 21 is formed. When the first seat portion 52 is seated on the valve body end surface 21, fuel injection is stopped from the first injection hole 30.

  A first pressure control chamber 70 is formed between the first upper end surface 53 and the inner wall of the valve body 20 facing the upper end surface 53. A first spring 51 that urges the first upper end surface 53 toward the first lower end surface 54 is provided in the first pressure control chamber 70. The first nozzle needle 50 can be reciprocated by adjusting the pressure in the first pressure control chamber 70. A fuel passage 25 is formed between the side wall portion of the first nozzle needle 50 and the inner wall of the valve body 20 facing the side wall portion. The fuel passage 25 is a passage for guiding high-pressure fuel to the first and second injection holes 30 and 40.

  A fuel inflow passage 22 and a return passage 23 are connected to the first pressure control chamber 70. A first inlet throttle 71 is provided at the inlet, and a first outlet throttle 72 is provided at the outlet. By adjusting the area ratio of the flow path cross-sectional areas of the first inlet throttle 71 and the first outlet throttle 72, the balance between the inflow amount and the outflow amount of fuel into the first pressure control chamber 70 can be adjusted. Therefore, the fuel pressure increase / decrease speed in the first pressure control chamber 70 can be adjusted.

  The second nozzle needle 60 is formed in a cylindrical shape, and is accommodated in a hollow portion in the first nozzle needle 50 so as to be able to reciprocate. A second upper end surface 63 is formed on the side opposite to the injection hole of the second nozzle needle 60, and a second lower end surface 64 is formed on the injection hole side. The 2nd lower end surface 64 is comprised from the 2nd lower end surface part 64a and the 2nd lower end surface part 64b. The second lower end surface portion 64a is formed on the outer peripheral side of the second nozzle needle 60 with respect to the second lower end surface portion 64b. A second seat portion 62 that can be seated and separated from the valve body end surface 21 is formed between the second lower end surface portion 64a and the second lower end surface portion 64b. When the second seat portion 62 is seated on the valve body end surface 21, fuel injection is stopped from the second injection hole 40.

  A second pressure control chamber 80 is formed between the second upper end face 63 and the inner wall of the valve body 20 facing the upper end face 63. A second spring 61 is provided in the second pressure control chamber 80 to urge the second upper end surface 63 toward the second lower end surface 64. The second nozzle needle 60 can be reciprocated by adjusting the pressure in the second pressure control chamber 80. A space surrounded by the second lower end surface portion 64a, the first lower end surface portion 54b, and the valve body end surface 21 is formed. This space becomes the nozzle needle chamber 26.

  A fuel inflow passage 22 and a return passage 23 are connected to the second pressure control chamber 80. A second inlet throttle 81 is provided at the inlet, and a second outlet throttle 82 is provided at the outlet. By adjusting the area ratio of the flow path cross-sectional areas of the second inlet throttle 81 and the second outlet throttle 82, the balance between the inflow amount and the outflow amount of fuel into the second pressure control chamber 80 can be adjusted. Therefore, the fuel pressure increase / decrease speed in the second pressure control chamber 80 can be adjusted.

  The fuel inflow passage 22 branches off in order to supply fuel to the first pressure control chamber 70, the second pressure control chamber 80, and the fuel passage 25. In the return passage 23, pipes for returning the surplus fuel from the first pressure control chamber 70 and the second pressure control chamber 80 to the fuel tank are joined on the way, and the return passage 23 is downstream from the joining point. And a solenoid valve 90 for switching between communication and shut-off between the fuel tank and the low pressure passage on the fuel tank side.

  The electromagnetic valve 90 includes a control valve 91, and a solenoid 92 and a third spring 93 are provided above the control valve 91. When the drive current is not supplied to the solenoid 92, the control valve 91 is seated on a valve seat (not shown) by the urging force of the third spring 93 and the return passage 23 is blocked. When the drive current is supplied, the control valve 91 is separated from the valve seat by the exciting suction force generated in the solenoid 92 and opens the return passage 23. The drive current of the control valve 91 is supplied to the solenoid 92 at a timing determined according to the operating state of the engine by an engine control unit (ECU) (not shown).

(Regarding the conditions for opening and closing the nozzle needle)
Next, the conditions for opening and closing the first and second nozzle needles 50 and 60 will be described. Since the first and second nozzle needles 50 and 60 have basically the same configuration, the first nozzle needle 50 will be described as an example here. A force in the direction of the first lower end surface 54 and a force in the direction of the first upper end surface 53 are applied to the first nozzle needle 50 by the pressure of the fuel introduced into the valve body 20 and the first spring 51 (hereinafter referred to as this). Called energizing force).

  Specifically, the urging force obtained by the product of the area of the first upper end surface 53 and the fuel pressure in the first pressure control chamber 70 and the urging force of the first spring 51 act on the first upper end surface 53, and these urging forces are applied. Tries to press the first nozzle needle 50 against the end face 21 of the valve body. The fuel pressure in the first pressure control chamber 70 can be adjusted by opening and closing a control valve 91 provided in the return passage 23. When the return passage 23 is opened and the fuel in the first pressure control chamber 70 is discharged, the fuel pressure in the first pressure control chamber 70 decreases. Then, the urging force that presses the first nozzle needle 50 against the valve body end surface 21 is weakened.

  In a state where the first nozzle needle 50 is pressed against the valve body end surface 21, the first lower end surface portion 54a is determined by the product of the axial projected area of the first lower end surface portion 54a and the fuel pressure in the fuel passage 25. A force acts, and the biasing force tries to lift the first nozzle needle 50.

  If the urging force for pressing the first nozzle needle 50 against the valve body end surface 21 is larger than the urging force for lifting the first nozzle needle 50, the first nozzle needle 50 closes the first injection hole 30. To do. On the contrary, if the urging force to be pressed against the valve body end surface 21 is smaller than the urging force to be lifted, the first nozzle needle 50 opens the first injection hole 30. The opening and closing of the first injection hole 30 is performed by reducing the fuel pressure in the first pressure control chamber 70 by opening the return passage 23 to weaken the urging force applied to the first upper end surface 53. .

  The fuel pressure in the first pressure control chamber 70 when the first injection hole 30 is opened is referred to as the valve opening pressure. Conversely, the fuel pressure in the first pressure control chamber 70 when the first injection hole 30 is closed is referred to as the valve closing pressure. The valve closing pressure is higher than the valve opening pressure (see FIG. 2B). This is because the fuel pressure is applied to the first lower end surface portions 54a and 54b when the valve is opened, and the urging force for lifting the first nozzle needle 50 is larger than when the valve is closed.

  The timing of opening and closing the first injection hole 30 can be arbitrarily changed by adjusting the urging force applied to the first nozzle needle 50 (first urging force adjusting means). In order to adjust the urging force, the fuel pressure in the first pressure control chamber 70, the area of the first upper end surface 53, and the area of the first lower end surface 54 may be adjusted. By adjusting the opening / closing timing of the control valve 91 and the flow passage area ratio of the first inlet throttle 71 and the first outlet throttle 72, the fuel pressure in the first pressure control chamber 70 becomes the valve opening pressure and the valve closing pressure. You can adjust the time.

  As a result, the first and second injection holes 30 and 40 can be closed simultaneously. Further, the valve opening pressure and the valve closing pressure can also be adjusted by adjusting the area ratio of the area of the first upper end surface 53 and the axial projected area of the first lower end surface 54, and the first and second injection holes can be adjusted. It becomes possible to close 30 and 40 simultaneously. Moreover, the valve opening timing of the 1st, 2nd injection holes 30 and 40 can also be adjusted separately.

  Next, the operation of the fuel injection valve 10 of the present embodiment will be described based on FIGS. 1 and 2. FIG. 2A shows a change in the lift amount of the control valve 91 when the solenoid 92 is energized. FIG. 2B shows the pressure state of the first pressure control chamber 70 when the control valve 91 is operated. FIG. 2C shows the pressure state of the second pressure control chamber 80 when the control valve 91 is operated. FIG. 2D shows the pressure state of the nozzle-needle chamber 26. FIG. 2 (e) shows a change in the lift amount of the first nozzle needle 50. FIG. 2 (f) shows a change in the lift amount of the second nozzle needle 60. FIG. 2G shows the change in the injection rate of fuel injected from the fuel injection valve 10.

(When injection stops)
The relatively high-pressure fuel accumulated in the common rail passes through the fuel inflow passage 22 and is supplied to the first and second pressure control chambers 70 and 80 and the fuel passage 25 as shown in FIG. At this time, the fuel pressures in the first and second pressure control chambers 70 and 80 and the fuel passage 25 are substantially equal.

  Until the time t1 in FIG. 2, the drive current is not supplied to the solenoid 92, and the control valve 91 is seated on the valve seat by the urging force of the third spring 93 to block the return passage 23 (FIG. 2). 2 (a)). Since the return passage 23 is blocked, the supplied fuel remains in the first and second pressure control chambers 70 and 80. As shown in FIGS. 2B and 2C, the pressure in the first and second pressure control chambers 70 and 80 is maintained at a relatively high pressure.

  Since the urging force for pressing the first nozzle needle 50 against the valve body end surface 21 is larger than the urging force for lifting, the first seat portion 52 is seated on the valve body end surface 21, The fuel is not injected from the first injection hole 30.

  At this time, since the first seat portion 52 is seated on the valve body end surface 21 at the second lower end surface portion 64b of the second nozzle needle, the fuel does not flow into the inter-nozzle needle chamber 26, and the second nozzle needle 60 The second seat portion 62 is also seated on the valve body end surface 21 without generating an urging force for lifting the valve.

(Operation when opening the first injection hole)
When a drive current is supplied to the control valve 91 at time t1 in FIG. 2A, the control valve 91 is lifted by the exciting suction force generated by the solenoid 92, and the return passage 23 is opened. .

  When the return passage 23 is opened, as shown in FIGS. 2B and 2C, the fuel in the first and second pressure control chambers 70 and 80 flows into the first and second outlet throttles 72 and 82, And it is discharged to the fuel tank through the control valve 91. The pressure in the first and second pressure control chambers 70 and 80 decreases at a predetermined lowering speed.

  As shown in FIG. 2B, when the pressure in the first pressure control chamber 70 decreases to the valve opening pressure of the first nozzle needle 50, the first nozzle needle 50 is lifted and the first seat portion 52 is moved to the valve body. It is separated from the end face 21 (time t2 in FIG. 2). When the first seat portion 52 is separated from the valve body end face 21, the fuel in the fuel passage 25 flows into the first injection hole 30 and the fuel is injected from the first injection hole 30. Thereafter, as shown in FIG. 2E, the first nozzle needle 50 is lifted to a predetermined lift amount, and the lift is stopped by a stopper or the like (not shown).

  When the first nozzle needle 50 is lifted, the fuel in the fuel passage 25 flows into the nozzle needle chamber 26 as shown in FIG. 2D, and the pressure in the nozzle needle chamber 26 begins to rise.

  At this time, since the second seat portion 62 is seated on the valve body end face 21, fuel is not injected from the second injection holes 40. As shown in FIG. 2G, since the fuel is injected only from the first injection hole 30, the injection rate is in a relatively low state.

(Operation when the first and second injection holes are open)
As shown in FIG. 2C, when the pressure in the second pressure control chamber 80 decreases to the valve opening pressure of the second nozzle needle 60, the second nozzle needle 60 is lifted and the second seat portion 62 is moved to the valve body. It is separated from the end face 21 (time t3 in FIG. 2). When the second seat portion 62 is separated from the valve body end face 21, the fuel in the fuel passage 25 and the nozzle-needle chamber 26 flows into the second injection hole 40, and the fuel is injected from the second injection hole 40. Thereafter, as shown in FIG. 2 (f), the second nozzle needle 60 is lifted to a predetermined lift amount, and the lift is stopped by a stopper or the like (not shown).

  At this time, as shown in FIG. 2 (g), fuel is injected from both the first and second injection holes 30, 40. Get higher.

(Operation when injection stops)
When a predetermined time corresponding to the operating state elapses, the supply of drive current to the solenoid 92 is stopped at time t4, and the control valve 91 blocks the return passage 23 (see FIG. 1). Then, since the outflow of fuel downstream from the first and second outlet throttles 72 and 82 is stopped, the pressure in the first and second pressure control chambers 70 and 80 starts to rise again.

  At time t5, as shown in FIG. 2 (c), the pressure in the second pressure control chamber 80 rises to the valve closing pressure of the second nozzle needle 60, and the second nozzle needle 60 moves in the direction of the valve body end face 21. Move to. At time t6, as shown in FIG. 2 (b), the pressure in the first pressure control chamber 70 increases to the valve closing pressure of the first nozzle needle 50, and the first nozzle needle 50 is moved toward the valve body end face 21. Moving.

  In the case of this embodiment, the area ratio of the first and second upper end surfaces 53 and 63 and the first and second lower end surfaces 54 and 64 of the first and second nozzle needles 50 and 60 is adjusted, and the first and second The valve closing timing of the first and second nozzle needles 50, 60 is arbitrarily determined by adjusting the area ratio of the flow path cross sections of the inlets and outlet throttles 71, 72, 81, 82 of the pressure control chambers 70, 80. Therefore, the first and second seat portions 52 and 62 can be seated on the valve body end surface 21 at the same time. If the first and second seat portions 52 and 62 are simultaneously seated on the valve body end face 21, excess fuel will not be injected after stopping fuel injection as in the prior art fuel injection valve. Generation of carbon monoxide can be suppressed.

Next, the operation and effect of the fuel injection valve 10 of this embodiment will be described.
(1) By adjusting the urging force acting on the first and second nozzle needles 50 and 60, the first and second seat portions 52 and 62 can be seated on the valve body end face 21 simultaneously. When the fuel injection is stopped, excess fuel is not injected, and generation of carbon monoxide in the exhaust gas can be suppressed.

  (2) Since the fuel pressure in the first and second pressure control chambers 70 and 80 is adjusted as means for adjusting the biasing force, the biasing force can be easily adjusted.

  (3) As means for adjusting the fuel pressure in the first and second pressure control chambers 70, 80, the first and second inlet throttles 71, 81 and the first and second inlet throttles 71, 81 are provided at the entrances of the first and second pressure control chambers 70, 80. Since the first and second outlet throttles 72 and 82 are provided and the area ratio of the flow passage cross section of the inlet / outlet throttle is adjusted, the pressure increase rate when fuel is supplied to the first and second pressure control chambers 70 and 80 , And the pressure drop speed when discharging can be arbitrarily adjusted. This increases the degree of freedom in adjusting the fuel pressure in the first and second pressure control chambers 70 and 80. As a result, the time until the fuel pressure reaches the valve opening pressure and the valve closing pressure can be adjusted, and as a result, the fuel pressure in the first and second pressure control chambers 70 and 80 can be made independent even with one control valve 91. Can be adjusted. Further, an open / close valve can be used as the control valve 91.

  (4) The valve opening pressure and the valve closing pressure can be adjusted by adjusting the area ratio of the first upper end surface 53, the first lower end surface 54, the second upper end surface 63, and the second lower end surface 64. Thereby, the timing of closing the first and second injection holes 30 and 40 can be made simultaneously.

  (5) Since the first and second pressure control chambers 70 and 80 are provided in parallel with the fuel flow from the fuel inflow passage 22 to the return passage 23, the inlet / outlet throttles and the like are provided in the pressure control chambers 70 and 80, respectively. Many elements for adjusting the pressure in the pressure control chamber can be provided. As a result, it becomes easy to simultaneously close the first and second injection holes 30 and 40.

(Other embodiments)
Another embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of a main part of the fuel injection valve 10 according to another embodiment. In addition, the same function thing as 1st Embodiment attaches | subjects the same code | symbol.

  A recess is formed in the second upper end surface 63 of the second nozzle needle 60. A communication passage 65 having a predetermined flow path cross-sectional area that connects the first pressure control chamber 70 and the second pressure control chamber 80 is formed in the recess.

  The fuel inflow passage 22 is branched in the middle, and is connected to the first pressure control chamber 70 and the fuel passage 25 via the first inlet throttle 71. The return passage 23 is connected to the second pressure control chamber 80 via the second outlet throttle 82.

  The biasing force of the first and second nozzle needles 70 and 80 is determined by the cross-sectional area of the first inlet throttle 71, the second outlet throttle 82, and the communication passage 65, and the area ratio of the first and second upper end faces 53 and 63. , And the first and second lower end surfaces 54 and 64 are adjusted by changing the area ratio.

  Accordingly, the first and second injection holes 30 and 40 can be closed simultaneously by adjusting the urging forces of the first and second nozzle needles.

Next, the operational effects in other embodiments will be described.
(1) The second nozzle needle 60 is formed with a communication passage 65 having a predetermined flow path cross-sectional area that allows the first pressure control chamber 70 and the second pressure control chamber 80 to communicate with each other. The fuel inflow passage 22 is connected to the first pressure control chamber 70, and the return passage 23 is connected to the second pressure control chamber 80. In other words, the first and second pressure control chambers 70 and 80 are arranged in series with respect to the fuel flow from the fuel inflow passage 22 to the return passage 23. As a result, the control flow rate of the fuel used during the injection control in the first and second pressure control chambers 70 and 80 is reduced. If the control flow rate of the fuel is reduced, it becomes possible to reduce the drive loss of the fuel injection pump, and the engine efficiency is improved.

It is principal part sectional drawing of the fuel injection valve 10 of 1st Embodiment. It is a characteristic view which shows increase / decrease in the injection rate accompanying the change of the pressure of the pressure control chamber of 1st Embodiment. It is principal part sectional drawing of the fuel injection valve 10 of other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel injection valve 20 Valve body 21 Valve body end surface 22 Fuel inflow path 23 Return path 25 Fuel path 26 Nozzle needle inter-chamber 30 1st injection hole 40 2nd injection hole 50 1st nozzle needle 52 1st sheet | seat part 53 1st top End surface 54 First lower end surface 60 Second nozzle needle 62 Second sheet portion 63 Second upper end surface 64 Second lower end surface 65 Communication path 70 First pressure control chamber 71 First inlet throttle 72 First outlet throttle 80 Second pressure control Chamber 81 Second inlet throttle 82 Second outlet throttle 90 Solenoid valve 91 Control valve

Claims (5)

A fuel injection valve that reciprocates the nozzle needle by the pressure of fuel introduced into the valve body to cut off fuel injection from an injection hole formed in the valve body, and allows injection.
A first nozzle needle that is accommodated in the valve body so as to be reciprocally movable, and that opens and closes a first injection hole as the injection hole formed in the valve body;
A second nozzle needle which is accommodated in the first nozzle needle so as to be reciprocally movable and opens and closes a second injection hole formed in the valve body;
An urging force adjusting means in which an urging force applied to the first nozzle needle and the second nozzle needle is adjusted so as to simultaneously block the first injection hole and the second injection hole ;
A first upper end surface and a second upper end surface are formed on the side opposite to the injection holes of the first nozzle needle and the second nozzle needle,
A first pressure control chamber and a second pressure control chamber are independently formed between the first upper end surface and the second upper end surface and the inner wall of the valve body facing the respective upper end surfaces. ,
The biasing force adjusting means includes first pressure control chamber adjusting means for adjusting fuel pressure in the first pressure control chamber, and second pressure control chamber adjusting means for adjusting fuel pressure in the second pressure control chamber. A fuel injection valve characterized by. The entrance and exit of the first pressure control chamber and the second pressure control chamber are provided with a first inlet throttle and a first outlet throttle, and a second inlet throttle and a second outlet throttle,
The first pressure adjusting means adjusts the pressure in the first pressure control chamber by adjusting a flow passage cross-sectional area ratio between the first inlet throttle and the first outlet throttle;
The said 2nd pressure adjustment means adjusts the pressure in the said 2nd pressure control chamber by adjusting the flow-path cross-sectional area ratio of the said 2nd inlet throttle and the said 2nd outlet throttle. The fuel injection valve as described. A first lower end surface and a second lower end surface are formed on the injection hole side of the first upper end surface and the second upper end surface, respectively.
The biasing force adjusting means is characterized in that an area ratio between the first upper end face and the first lower end face and an area ratio between the second upper end face and the second lower end face are adjusted. Item 4. The fuel injection valve according to Item 1 . In the valve body, surplus fuel is supplied from the fuel inflow passage for supplying the introduced fuel to the first pressure control chamber and the second pressure control chamber, and from the first pressure control chamber and the second pressure control chamber. The fuel injection valve according to any one of claims 1 to 3, wherein a return passage for discharging is formed . The second nozzle needle is formed with a communication path that communicates the first pressure control chamber and the second pressure control chamber.
The fuel inflow passage is connected to the first pressure control chamber;
The return passage, a fuel injection valve according to any one of claims 1 to 3, characterized in that connected to the second pressure control chamber.

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