JP2006161678A - Fuel injection nozzle, fuel injection valve and fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress sudden increase of actual injection quantity accompanying open of a second injection hole 8 opened later in a variable injection hole type fuel injection nozzle 1 including a first and the second injection hole 7, 8 opened in front and rear two stage. <P>SOLUTION: When second back pressure fuel applying pressure on a second valve element 11 in a close hole direction is discharged for opening the second injection hole 8, discharge flow rate is regulated by a second orifice 36 formed in a second supply discharge flow passage 35. Consequently, reduction of second close hole energizing force always energizing the second valve element 11 in the close hole direction is suppressed, rising speed of the second valve element 11 can be reduced. Consequently, since sudden increase of a second effective gap area formed between a second seat part 31 and a seat surface 19 is suppressed, increase rate of injection rate can be made loose. As a result, sudden increase of actual injection quantity accompanying open of the second injection hole can be suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention mainly relates to a fuel injection nozzle that injects fuel into a cylinder of an engine.

[Conventional technology]
Conventionally, a variable injection hole type fuel injection nozzle has been used in order to cope with atomization of an engine in a low rotation region and a large amount of short-term injection in a high rotation region. The variable nozzle type fuel injection nozzle has a plurality of nozzle holes that are sequentially opened in at least two stages, and can change the number of nozzle holes to be opened according to the injection amount.

  A conventional variable injection hole type fuel injection nozzle 100 (hereinafter referred to as a nozzle 100) has a body having first and second injection holes 101 and 102 that are opened in two stages, front and rear, as shown in FIG. 103, the first valve body 104 that opens and closes the first nozzle hole 101 that is opened first among the first and second nozzle holes 101 and 102, and moves in the same direction as the first valve body 104, and the first jet The pressure of the high-pressure fuel supplied from a predetermined supply source is in contact with the second valve body 105, the first and second valve bodies 104, 105 that open and close the second injection hole 102 opened after the hole 101. 1. Moves in the same direction as the first piston 106 and the first piston 106 which are transmitted to the second valve bodies 104 and 105 and urged in the direction (closed hole direction) to close the first and second injection holes 101 and 102. And abuts against the second valve body 105 to increase the pressure of the high-pressure fuel. Is transmitted to the valve body 105 and a like second piston 107 for biasing the closed porosity direction (e.g., see Patent Document 1).

  The nozzle 100 constitutes a fuel injection valve 112 together with an electromagnetic two-way valve 111 that repeatedly operates and stops in response to a command from an ECU (not shown). The fuel injection valve 112 is mounted on each cylinder of a direct injection type engine (not shown: hereinafter simply referred to as an engine) such as a multi-cylinder diesel engine, and is used to inject and supply fuel to the combustion chamber. It is done. In addition, the electromagnetic two-way valve 111 opens during operation and closes when operation is stopped.

The fuel injected from the fuel injection valve 112 is high-pressure fuel discharged at a high pressure by a known injection pump (not shown), and is supplied to the nozzle 100 via a known common rail 113. That is, the fuel injection valve 112 constitutes a fuel injection device that injects and supplies fuel to the engine together with the injection pump, the common rail 113, and the like, and the nozzle 100 supplies high pressure fuel using the injection pump, the common rail 113, and the like as a predetermined supply source. Receive.
Hereinafter, the elements constituting the nozzle 100 will be described.

  The body 103 communicates with the common rail 113 via the high-pressure flow path 115, and stores the fuel reservoir 116 to which high-pressure fuel is always supplied, the first and second valve bodies 104 and 105, and the first and second jets. A control chamber 118 to which high pressure fuel is supplied as back pressure fuel that exerts pressure in the closing direction on the guide hole 117 and the first and second valve bodies 104 and 105 that guide the high pressure fuel in the fuel pool 116 to the holes 101 and 102. The first and second pistons 106 and 107 are accommodated, and a leak recovery chamber 119 for recovering fuel leaked from the fuel reservoir 116 and the control chamber 118 is formed. A seat surface 120 on which the first and second valve bodies 104 and 105 are seated is provided below the guide hole 117, and the first and second injection holes 101 and 102 are opened in the seat surface 120.

  The back pressure fuel is supplied from the common rail 113 through the supply flow path 123. An inlet orifice 124 is provided in the supply channel 123 to regulate the supply flow rate. Further, the back pressure fuel is discharged to the fuel tank 126 through the discharge flow path 125 to which the electromagnetic two-way valve 111 is attached. The discharge passage 125 is provided with an outlet orifice 127 having a diameter larger than that of the inlet orifice 124 to restrict the discharge flow rate.

  And when raising the pressure (back pressure) of the back pressure fuel in the control chamber 118, the electromagnetic two-way valve 111 is closed and only the supply to the control chamber 118 through the supply flow path 123 is performed. In order to reduce the back pressure, the electromagnetic two-way valve 111 is opened so that the control chamber 118 is discharged through the discharge flow path 125 and supplied to the control chamber 118 through the supply flow path 123. Make it. Here, since the outlet orifice 127 is larger in diameter than the inlet orifice 124, the discharge flow rate from the control chamber 118 is larger than the supply flow rate to the control chamber 118. Thereby, when the electromagnetic two-way valve 111 opens, the back pressure decreases.

  The fuel in the leak recovery chamber 119 is recovered to the fuel tank 126 through the low pressure channel 130. The leak recovery chamber 119 houses a spring 131 having one end attached to the first piston 106. The spring 131 generates an elastic force that urges the first and second valve bodies 104 and 105 in the closing direction together with the urging force due to the back pressure.

  The first valve body 104 has a cylindrical shape, and the second valve body 105 is slidably accommodated in a cylindrical portion formed on the inner periphery thereof. Further, a first seat part 134 for opening and closing the first nozzle hole 101 is provided at the lower end of the first valve body 104, and a contact surface 135 with which the first piston 106 contacts is provided at the upper end. . The first valve body 104 receives pressure from the high-pressure fuel in the fuel reservoir 116 and is urged in the opening direction, and is also urged by the back pressure and the elastic force of the spring 131 via the first piston 106. It is biased in the closing direction.

  The second valve body 105 has a rod shape, a second seat portion 137 for opening and closing the second injection hole 102 is provided at the lower end, and an abutting surface on which the first and second pistons 106 and 107 abut on the upper end. 138 is provided. The second valve body 105 is urged in the closing direction by the urging force due to the back pressure and the elastic force of the spring via the first and second pistons 106 and 107.

  The first piston 106 has a cylindrical shape, and the second piston 107 is slidably received in a cylindrical portion formed on the inner periphery of the first piston 106, and the first and second valve bodies 104, 105 are in contact with the lower ends. A contact surface 141 that contacts the contact surfaces 135 and 138 is provided. A spring 131 is attached to the first piston 106. The first piston 106 is urged in the closed hole direction by the urging force due to the back pressure and the elastic force of the spring 131 and comes into contact with the first and second valve bodies 104 and 105, and these urging forces in the closed hole direction. Is transmitted to the first and second valve bodies 104 and 105.

  The second piston 107 has a rod shape, and a contact surface 142 that contacts the contact surface 138 of the second valve body 105 is provided at the lower end. The second piston 107 is urged in the closing direction by the back pressure and contacts the second valve body 105, and transmits the urging force in the closing direction to the second valve body 105.

  Thus, the first valve body 104 is urged in the closing direction by the urging force due to the back pressure and the elastic force of the spring 131 via the first piston 106, and the second valve body 105 is The two pistons 106 and 107 are urged in the closing direction by the urging force due to the back pressure and the elastic force of the spring 131.

Next, the operation of the nozzle 100 will be described along with the change with time of the injection rate q shown in FIG.
Here, the injection rate q is an injection rate q1 from the first injection hole 101 (referred to as the first injection rate q1) and an injection rate q2 from the second injection hole 102 (referred to as the second injection rate q2). It is sum. The time-dependent change in the injection rate q shown in FIG. 19 is a time-dependent change when both the first and second nozzle holes 101 and 102 are opened for a sufficiently long period.

  First, when the electromagnetic two-way valve 111 is operated and opened in accordance with a command from the ECU, the back pressure fuel is discharged from the control chamber 118 through the discharge flow path 125, and the back pressure is reduced. As a result, the urging force acting in the opening direction of the first valve body 104 is larger than the urging force acting in the closing direction. As a result, at time t0, as shown in FIG. 17, the first valve body 104 is separated from the seat surface 120 and starts to rise, and the first injection hole 101 is opened. For this reason, the first injection rate q1 starts to increase, and the injection rate q increases. Further, the contact surface 141 of the first piston 106 and the contact surface 138 of the second valve body 105 are separated, and the elastic force of the spring 131 does not act on the second valve body 105.

  After the opening of the first injection hole 101, until the time t1, the effective area (first area) of the gap between the first sheet portion 134 and the sheet surface 120 is larger than the effective cross-sectional area (first effective hole area) of the first injection hole 101. Effective gap area) is smaller. For this reason, the injection rate q between the times t0 and t1 is governed by the first effective gap area. Since the first effective gap area increases with the rise of the first valve body 104, the injection rate q continues to increase during the time t0 to t1.

  When the first effective gap area becomes larger than the first effective hole area at time t1, the injection rate q is governed by the first effective hole area. Since the first effective hole area does not increase even when the first valve element 104 is raised, the injection rate q stops increasing and maintains the maximum value q1max of the first injection rate q1.

  When the urging force acting in the opening direction of the second valve body 105 becomes larger than the urging force acting in the closing direction at time t2, the second valve body 105 is separated from the seat surface 120 as shown in FIG. The second nozzle hole 102 is opened while sitting and starting to rise. For this reason, the second injection rate q2 starts to increase, and the injection rate q increases from q1max.

  After the opening of the second injection hole 102, until the time t3, the effective area (second area) of the gap between the second sheet portion 137 and the sheet surface 120 is larger than the effective cross-sectional area (second effective hole area) of the second injection hole 102. Effective gap area) is smaller. For this reason, the injection rate q between the times t2 and t3 is governed by the second effective gap area. Since the second effective gap area increases as the second valve body 105 rises, the injection rate q continues to increase.

  When the second effective gap area becomes larger than the second effective hole area at time t3, the injection rate q is governed by the second effective hole area. Since the second effective hole area does not increase even when the second valve body 105 is raised, the injection rate q stops increasing, and the maximum value q1max of the first injection rate q1 and the maximum value q2max of the second injection rate q2 are The sum q1max + q2max is maintained.

  During the time t3 to t4, when the electromagnetic two-way valve 111 stops its operation and closes according to a command from the ECU, the discharge of the high-pressure fuel through the discharge passage 125 stops. Then, high-pressure fuel is supplied as back pressure fuel to the control chamber 118 through the supply flow path 123, and the back pressure increases. As a result, first, in the second valve body 105, the urging force acting in the closing direction becomes larger than the urging force acting in the opening direction, and the second valve body 105 starts to descend. Next, in the first valve body 104, the urging force acting in the closing direction becomes larger than the urging force acting in the opening direction, and the first valve body 104 starts to descend. The injection rate q is maintained at q1max + q2max until time t4.

  When the second effective gap area becomes smaller than the second effective hole area at time t4, the injection rate q is controlled by the second effective gap area, and the injection rate q starts to decrease. Since the second effective gap area decreases as the second valve body 105 descends, the injection rate q continues to decrease.

  At time t5, the second valve body 105 is seated on the seat surface 120, and the second injection hole 102 is closed. As a result, the second injection rate q2 becomes 0, and the injection rate q maintains q1max until time t6.

  When the first effective gap area becomes smaller than the first effective hole area at time t6, the injection rate q is controlled by the first effective gap area, and the injection rate q starts to decrease from q1max. And since the 1st effective clearance area reduces with the fall of the 1st valve body 104, the injection rate q continues decreasing.

  At time t7, the first valve body 104 is seated on the seat surface 120, and the first injection hole 101 is closed. Thereby, the first injection rate q1 becomes 0, and the overall injection rate q also becomes 0. When the first valve body 104 is seated on the seat surface 120, the contact surface 141 of the first piston 106 contacts the contact surface 138 of the second valve body 105, and the elasticity of the spring 131 is applied to the second valve body 105. Force comes to work.

  The operation of the electromagnetic two-way valve 111 by the ECU and a command to stop the operation are performed based on the injection timing and the injection period T calculated according to the operating state of the engine. Here, the injection period T corresponds to the opening time of the first and second nozzle holes 101 and 102 and greatly affects the actual injection amount Q.

[Problems with conventional technology]
By the way, according to the nozzle 100, when the second valve body 105 is seated on the seat surface 120, the fuel pressure acting on the second valve body 105 in the opening direction (referred to as the second opening fuel pressure). The pressure receiving surface is a minute donut-shaped surface on the outer peripheral side of the second sheet portion 137. However, when the second valve body 105 is separated from the seat surface 120 and starts to rise, the area of the pressure receiving surface greatly increases from the minute donut-shaped area to the area determined by the effective diameter of the second valve body 105. To do. Thereby, when the second valve body 105 is separated from the seat surface 120, the urging force due to the second opening fuel pressure increases rapidly. For this reason, the ascending speed of the second valve body 105 is extremely high, and the second injection rate q2 reaches the maximum value q2max from 0 in a very short time. Note that the period during which the second injection rate q2 reaches 0 to q2max corresponds to the period from time t2 to t3 in FIG.

  Therefore, as shown in FIG. 20, in the injection period T, there is a threshold value Tct at which the actual injection amount Q increases rapidly. Here, the threshold value Tct is the maximum value of the injection period T in which the injection is performed only from the first injection holes 101. When the injection period T becomes longer than the threshold value Tct, the second valve body 105 is separated from the seat surface 120. Then, the injection from the second injection hole 102 starts.

  That is, when the injection period T is shorter than the threshold value Tct, the injection is performed only from the first injection hole 101, and the actual injection amount Q is gradually increased with the increase of the injection period T with a gradient mainly according to q1max. . However, when the injection period T becomes longer than the threshold value Tct, the second valve body 105 is separated from the seat surface 120, and the second injection rate q2 reaches 0 to q2max in a very short period. For this reason, the actual injection amount Q increases rapidly between the threshold value Tct and Tct + ΔT slightly longer than the threshold value Tct. This Tct + ΔT is the value of the injection period T when the second injection rate q2 reaches q2max and the start of lowering of the second valve body 105 overlaps.

  As a result, it becomes extremely difficult to control the actual injection amount Q between the actual injection amount Qct when the injection period T is the threshold value Tct and the actual injection amount Qct + ΔQ when the injection period T is Tct + ΔT. . Note that when the injection period T is longer than Tct + ΔT, the actual injection amount Q gradually increases as the injection period T increases with a gradient corresponding to q1max + q2max.

Further, according to the nozzle 100, as shown in the period of time t5 to t6 in FIG. 19, when the injection is finished, a step is generated in which the injection rate q maintains a constant value q1max, and the injection is finished sharply. I can't. For this reason, there is a high possibility that surplus fuel is injected and black smoke is generated.
International Publication No. 03/069511 Pamphlet

  The present invention has been made to solve the above-described problems, and suppresses a rapid increase in the actual injection amount associated with the opening of the second injection hole and suppresses a difference in injection rate at the end of injection. Another object is to provide a variable injection hole type fuel injection nozzle.

[Means of Claim 1]
According to a first aspect of the present invention, there is provided a fuel injection nozzle having a body having a plurality of nozzle holes opened at least in two stages, front and rear, and being accommodated in the body and first opened in the plurality of nozzle holes. A cylindrical first valve body that opens and closes one nozzle hole, and a second valve hole that is accommodated in the cylindrical portion of the first valve body and is opened after the first nozzle hole, and the first valve body And a second valve body that moves in the coaxial direction, a second biasing mechanism that generates a second closing biasing force that constantly biases the second valve body in the closing direction, and a second closing hole A second ascending / decelerating mechanism for reducing the ascent speed of the second valve body when the second valve body ascends in the opening direction due to the decrease in the force is provided.
Thus, for example, even if there is a factor that makes the rising speed of the second valve body extremely large, such as a sudden increase in the urging force due to the second opening fuel pressure, the second ascending / decelerating mechanism causes the second The rising speed of the valve body can be reduced. For this reason, the rapid increase of the actual injection amount accompanying opening of a 2nd nozzle hole can be suppressed by reducing the raising speed of a 2nd valve body.

[Means of claim 2]
The second urging mechanism of the fuel injection nozzle according to claim 2 causes the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the second valve body in the direction of closing the second closing hole. The urging force is generated, and the second ascending / decelerating mechanism regulates the discharge flow rate when discharging the second back pressure fuel that exerts pressure in the closing direction with respect to the second valve body, thereby increasing the rising speed of the second valve body. Reduce.
This means is a form of the second urging mechanism and the second ascending / decelerating mechanism.

[Means of claim 3]
In the fuel injection nozzle according to claim 3, a second supply / discharge passage for supplying and discharging the second back pressure fuel is formed, and the restriction of the discharge flow rate is performed by a throttle formed in the second supply / discharge passage. Done.
This means is one means for regulating the discharge flow rate in one form of the second ascending / decelerating mechanism according to claim 2.

[Means of claim 4]
The second urging mechanism of the fuel injection nozzle according to claim 4 causes the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the second valve body in the direction of the hole closing. The second ascending / decelerating mechanism generates an urging force, and when the second back pressure fuel that exerts pressure in the closing direction on the second valve body is discharged, the high pressure fuel is separately supplied at a flow rate smaller than the discharge flow rate. By supplying the valve body so as to exert pressure in the closing direction, the rising speed of the second valve body is reduced.
This means is a form of the second urging mechanism and the second ascending / decelerating mechanism.

[Means of claim 5]
The fuel injection nozzle according to claim 5 is a flow path different from the second supply / discharge flow path for supplying and discharging the second back pressure fuel and the second supply / discharge flow path, A second supply flow path for separately supplying pressurized fuel is formed, and the effective diameter of the throttle formed in the second supply flow path is larger than the effective diameter of the throttle formed in the second supply / discharge flow path. small.
In the form of the second ascending / decelerating mechanism according to the fourth aspect, the means supplies the high-pressure fuel separately at a flow rate smaller than the discharge flow rate so as to apply pressure to the second valve body in the closing direction. Means.

[Means of claim 6]
The second urging mechanism of the fuel injection nozzle according to claim 6 generates an elastic force as a second closing hole urging force in an elastic member mounted inside the body, and the second ascending / decelerating mechanism includes: When the two-valve body rises in the opening direction, the rising speed of the second valve body is reduced by causing the elastic force of the elastic member to act on the second valve body as the second closing hole biasing force.
This means is a form of the second urging mechanism and the second ascending / decelerating mechanism.

[Means of Claim 7]
The first valve body of the fuel injection nozzle according to claim 7 is directly or indirectly through a member different from the first valve body and the second valve body when descending in the closing direction. , Engage with the second valve body.
Thereby, the first and second valve bodies can be lowered at the same speed while being engaged with each other. For this reason, the first and second valve bodies can be seated simultaneously by appropriately adjusting the dimensions of the first and second valve bodies. As a result, it is possible to eliminate a step in the injection rate at the end of injection.

[Means of Claim 8]
The first valve body of the fuel injection nozzle according to claim 8 is lowered in the closing direction by the pressure of the high-pressure fuel supplied from a predetermined supply source acting on the first valve body in the closing direction. When the first valve body rises in the opening direction, the supply of the first back pressure fuel that applies pressure to the first valve body in the closing direction is shut off.
Thereby, when the first nozzle hole is opened, there is no possibility that the pressure of the first back pressure fuel (first back pressure) increases. For this reason, the first nozzle hole can be reliably opened without delay.

[Means of Claim 9]
In the fuel injection nozzle according to the ninth aspect, the supply / discharge of the first back pressure fuel is switched by the three-way valve.
This means is a means for shutting off the supply of the first back pressure fuel when the first valve body rises in the opening direction in the fuel injection nozzle according to claim 8.

[Means of Claim 10]
According to a tenth aspect of the present invention, there is provided a fuel injection nozzle including a body having a plurality of nozzle holes that are opened in at least two stages, a first nozzle that is accommodated in the body and that is first opened in the plurality of nozzle holes. A cylindrical first valve body that opens and closes one nozzle hole, and a second valve hole that is accommodated in the cylindrical portion of the first valve body and is opened after the first nozzle hole, and the first valve body And a second valve body that moves in the coaxial direction, a biasing mechanism that generates a closing biasing force that biases the first and second valve bodies in the closing direction, and an increase in the closing biasing force Due to this, when the first valve body and the second valve body descend in the closing direction, a descending acceleration mechanism is provided that increases the descending speed of the first valve body and the second valve body.
As a result, the time from when the first and second valve bodies start to descend until they are seated on the seat surface, that is, the injection end time is shortened. For this reason, according to this shortening ratio, the time which the level | step difference of an injection rate generate | occur | produces can be shortened.

[Means of Claim 11]
The urging mechanism of the fuel injection nozzle according to claim 11 causes the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the first valve body and the second valve body in the closing direction, The closing acceleration force is generated, and the descending acceleration mechanism applies pressure in the closing direction to the first valve body and the second valve body through the one-way flow path that is closed when the closing biasing force is decreased. By supplying the back pressure fuel, the descending speed of the first valve body and the second valve body is increased.
This means is one form of an urging mechanism and a descending acceleration mechanism. In other words, the effective diameter of the unidirectional channel can be freely set under a predetermined condition. For this reason, the descending speed of the first and second valve bodies can be increased by setting the effective diameter in accordance with the desired descending speed in the settable range of the effective diameter of the one-way flow path.

[Means of Claim 12]
The fuel injection nozzle according to claim 12 includes a control chamber in which the back pressure fuel is supplied and discharged to adjust a closing biasing force and the volume changes, and a control chamber for supplying and discharging back pressure fuel to the control chamber. A supply / exhaust flow path that is open to the control chamber, and includes a closing member that is loosely inserted into the control chamber and is urged by a predetermined urging means to close the opening of the supply / exhaust flow path. A one-way flow path is formed with the inner surface forming the control chamber, and when the back pressure fuel is supplied to the control chamber, the opening is opened by being biased in a direction opposite to the biasing direction by the biasing means. Then, the one-way flow path is opened.
This means is a means for forming a one-way flow path in the fuel injection nozzle according to claim 11.

[Means of Claim 13]
The urging mechanism of the fuel injection nozzle according to claim 13 causes the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the first valve body and the second valve body in the closing direction, A closing acceleration force is generated, and the descending acceleration mechanism receives the pressure of the high-pressure fuel in a predetermined pressure receiving area and closes the first valve body and the second valve body with a pressing area smaller than the pressure receiving area. The descending speed of the first valve body and the second valve body is increased by pressurizing the back pressure fuel that exerts pressure in the direction.
This means is one form of an urging mechanism and a descending acceleration mechanism.

[Means of Claim 14]
A fuel injection nozzle according to a fourteenth aspect has a pressure-receiving surface having a pressure-receiving area according to a thirteenth aspect and a pressure-receiving surface having a pressure-receiving area according to a thirteenth aspect, and the pressure of the high-pressure fuel acting on the pressure-receiving surface. A pressure-increasing piston that increases and transmits to the back-pressure fuel through the pressure surface is provided.
This means is one means for receiving the pressure of the high pressure fuel in a predetermined pressure receiving area and pressurizing the back pressure fuel in a pressure area smaller than the pressure receiving area.

[Means of Claim 15]
In the fuel injection nozzle according to claim 15, when at least one of the first valve body and the second valve body rises in the opening direction, the supply of the back pressure fuel is cut off.
Thereby, when at least one of the first and second nozzle holes is opened, there is no possibility that the pressure of the back pressure fuel (back pressure) increases. For this reason, the first and second nozzle holes can be reliably opened without delay.

[Means of claim 16]
In the fuel injection nozzle according to the sixteenth aspect, switching between supply and discharge of the back pressure fuel is performed by a three-way valve.
This means is a means for shutting off the supply of back pressure fuel when at least one of the first and second valve bodies rises in the opening direction in the fuel injection nozzle according to claim 15.

[Means of Claim 17]
The fuel injection valve according to claim 17 incorporates the fuel injection nozzle according to claim 1 or claim 10.

[Means of Claim 18]
The fuel injection device according to claim 18 uses the fuel injection valve according to claim 17.

  The fuel injection nozzle of the best mode 1 includes a body having a plurality of nozzle holes that are opened at least in two stages, front and rear, and a first that is accommodated inside the body and is opened first among the plurality of nozzle holes. A cylindrical first valve body that opens and closes the nozzle hole, and opens and closes the second nozzle hole that is accommodated in the cylindrical part of the first valve body and is opened after the first nozzle hole, and the first valve body A second valve body that moves in the coaxial direction, and a second biasing mechanism that generates a second closing biasing force that always biases the second valve body in the closing direction, and a second closing biasing force When the second valve body rises in the direction of opening due to the decrease, the second ascending / decelerating mechanism for reducing the ascent speed of the second valve body is provided.

The second urging mechanism generates a second closing force by applying the pressure of the high-pressure fuel supplied from a predetermined supply source to the second valve body in the closing direction. The ascending / decelerating mechanism restricts the discharge flow rate when discharging the second back pressure fuel that exerts pressure in the closing direction with respect to the second valve body, thereby reducing the rising speed of the second valve body.
The fuel injection nozzle is provided with a second supply / discharge passage for supplying and discharging the second back pressure fuel, and the discharge flow rate is regulated by a throttle formed in the second supply / discharge passage.

The first valve body engages with the second valve body directly or indirectly through a member different from the first valve body and the second valve body when descending in the closing direction.
In addition, the pressure of the high-pressure fuel supplied from a predetermined supply source acts on the first valve body in the closing direction with respect to the first valve body, and thus the first valve body is lowered in the closing direction. When the first valve body rises in the opening direction, the supply of the first back pressure fuel that applies pressure to the first valve body in the closing direction is shut off.
Switching between supply and discharge of the first back pressure fuel is performed by a three-way valve.

  The second urging mechanism of the fuel injection nozzle of the best mode 2 has a second closed hole by causing the pressure of the high pressure fuel supplied from a predetermined supply source to act on the second valve body in the closed hole direction. The second ascending / decelerating mechanism generates a force, and when the second back pressure fuel that exerts pressure on the second valve body in the closing direction is discharged, the second valve By supplying the body so as to exert a pressure in the closing direction, the rising speed of the second valve body is reduced.

  In this fuel injection nozzle, a second supply / discharge flow path for supplying and discharging the second back pressure fuel and a flow path different from the second supply / discharge flow path, the second back pressure fuel is separately supplied. A second supply flow path for supplying is formed. The effective diameter of the throttle formed in the second supply channel is smaller than the effective diameter of the throttle formed in the second supply / discharge channel.

  The second urging mechanism of the fuel injection nozzle according to the best mode 3 generates an elastic force as the second closing hole urging force in an elastic member mounted inside the body, When the valve body rises in the opening direction, the rising force of the second valve body is reduced by applying the elastic force of the elastic member to the second valve body as the second closing hole biasing force.

  The fuel injection nozzle according to the best mode 4 includes a body having a plurality of nozzle holes that are opened at least in two stages, front and rear, and a first that is accommodated inside the body and is opened first among the plurality of nozzle holes. A cylindrical first valve body that opens and closes the nozzle hole, and opens and closes the second nozzle hole that is accommodated in the cylindrical part of the first valve body and is opened after the first nozzle hole, and the first valve body A second valve body that moves in the coaxial direction, a biasing mechanism that generates a closing biasing force that biases the first and second valve bodies in the closing direction, and an increase in the closing biasing force. A descending acceleration mechanism is provided that increases the descending speed of the first valve body and the second valve body when the first valve body and the second valve body descend in the closing direction.

  And the urging mechanism generates a closed hole urging force by causing the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the first valve body and the second valve body in the closing direction, The descending acceleration mechanism supplies back pressure fuel that exerts pressure in the closing direction to the first valve body and the second valve body through a one-way flow path that is closed when the closing biasing force is reduced. The descending speed of the first valve body and the second valve body is increased.

  In this fuel injection nozzle, the back pressure fuel is supplied / discharged to adjust the closing biasing force and the volume changes, and the supply / discharge of the back pressure fuel to the control chamber is supplied to the control chamber. A flow path is formed. The fuel injection nozzle is loosely inserted into the control chamber and includes a closing member that is urged by a predetermined urging means to close the opening of the supply / exhaust flow path. A one-way flow path is formed with the inner surface formed, and when back pressure fuel is supplied to the control chamber, the opening is opened by being biased in a direction opposite to the biasing direction by the biasing means. Open the directional flow path.

Further, when at least one of the first valve body and the second valve body rises in the opening direction, the supply of back pressure fuel is shut off.
Switching between back-pressure fuel supply and discharge is performed by a three-way valve.

  The urging mechanism of the fuel injection nozzle of the best mode 5 is closed by applying the pressure of the high-pressure fuel supplied from a predetermined supply source to the first valve body and the second valve body in the closing direction. A hole urging force is generated, and the descending acceleration mechanism receives the pressure of the high-pressure fuel in a predetermined pressure receiving area and closes the first valve body and the second valve body in the closing direction with a pressure area smaller than the pressure receiving area. The lowering speed of the first valve body and the second valve body is increased by pressurizing the back pressure fuel that exerts pressure on the fuel.

  The fuel injection nozzle has a pressure receiving surface having a predetermined pressure receiving area and a pressure surface having a pressure area smaller than the pressure receiving area. The pressure of the high pressure fuel acting on the pressure receiving surface is increased and transmitted to the back pressure fuel through the pressure surface. A pressure-increasing piston.

[Configuration of Example 1]
The configuration of the fuel injection nozzle 1 (hereinafter referred to as nozzle 1) of the first embodiment will be described with reference to FIG. The nozzle 1 injects and supplies fuel to the cylinders of the engine. In order to cope with spray atomization in the low rotation region of the engine and a large amount of short-term injection in the high rotation region, the nozzle 1 is an injection that opens according to the injection amount. It is a variable nozzle type that can change the number of holes.

  And the nozzle 1 comprises the fuel injection valve 3 with the electromagnetic valve 2 which repeats an action | operation and an operation stop according to the command from ECU (not shown). The fuel injection valve 3 is mounted on each cylinder of a direct injection type engine (not shown: hereinafter simply referred to as an engine) such as a multi-cylinder diesel engine, and is used for injecting and supplying fuel to a combustion chamber. .

  The fuel injected from the fuel injection valve 3 is high-pressure fuel discharged at a high pressure by a known injection pump (not shown), and is supplied to the nozzle 1 via a known common rail 4. That is, the fuel injection valve 3 constitutes a fuel injection device that injects and supplies fuel to the engine together with the injection pump, the common rail 4 and the like, and the nozzle 1 supplies high-pressure fuel using the injection pump and the common rail 4 as a predetermined supply source. Receive.

  As shown in FIG. 1, the nozzle 1 is first in the body 9 having the first and second injection holes 7 and 8 that are opened in two stages, front and rear, and first and second injection holes 7 and 8. The first valve body 10 that opens and closes the first injection hole 7 that is opened, the second injection hole 8 that opens after the first injection hole 7 is opened and closed, and the first valve body 10 that moves coaxially with the first valve body 10 is opened. A two-valve body 11.

  Further, the nozzle 1 always abuts at least the first valve body 10 and transmits the pressure of the high-pressure fuel to the first valve body 10 to urge the nozzle 1 in the direction of closing the first injection hole 7 (closed hole direction). A piston 12 is provided. The piston 12 also contacts the second valve body 11 when descending in the closing direction. Thereby, when the 1st valve body 10 descend | falls, it engages with the 2nd valve body 11 indirectly via the piston 12 which is a different member from the 1st valve body 10 and the 2nd valve body 11. FIG.

  The body 9 communicates with the common rail 4 via the high-pressure flow path 15 and accommodates the fuel reservoir 16 to which the high-pressure fuel is constantly supplied, the first and second valve bodies 10 and 11, and the first and second jets. A high pressure fuel is directly supplied from the common rail 4 as a first back pressure fuel that applies pressure in the closing direction to at least the first valve body 10 as a guide hole 17 that guides the high pressure fuel in the fuel reservoir 16 to the holes 7 and 8. A receiving first control chamber 18 is formed. A seat surface 19 on which the first and second valve bodies 10 and 11 are seated is provided below the guide hole 17, and the first and second injection holes 7 and 8 are opened in the seat surface 19. The second nozzle hole 8 is opened to the outer periphery than the first nozzle hole 7.

  The first control chamber 18 is formed by the upper end surface of the piston 12 and the inner surface of the body 9, and the volume changes as the first back pressure fuel is supplied and discharged as the first valve body 10 is raised or lowered. Then, the pressure of the first back pressure fuel (first back pressure) is adjusted by changing the volume of the first control chamber 18. The supply and discharge of the first back pressure fuel is performed through the first supply and discharge flow path 20. In addition, a first orifice 21 is formed in the first supply / discharge flow path 20, and the supply flow rate to the first control chamber 18 and the discharge flow rate from the first control chamber 18 are regulated.

  Switching between supply and discharge of the first back pressure fuel is performed by the electromagnetic valve 2. The electromagnetic valve 2 is a three-way valve, which opens the flow path leading from the first control chamber 18 to the fuel tank 22 during operation, and opens the flow path leading from the common rail 4 to the first control chamber 18 when operation is stopped (hereinafter referred to as electromagnetic). The state in which the valve 2 opens the flow path leading from the first control chamber 18 to the fuel tank 22 is referred to as “open valve”, and the electromagnetic valve 2 opens the flow path leading from the common rail 4 to the first control chamber 18. The state is “closed valve” and the electromagnetic valve 2 is the electromagnetic three-way valve 2).

  The ECU commands the operation and stop of the electromagnetic three-way valve 2 based on the injection timing and the injection period T calculated according to the operating state of the engine. Here, the injection period T corresponds to the opening time of the first and second nozzle holes 7 and 8 and greatly affects the actual injection amount Q.

  And when lowering the 1st valve body 10, the electromagnetic three-way valve 2 is closed, the high pressure fuel of the common rail 4 is supplied to the 1st control chamber 18 as a 1st back pressure fuel, and a 1st back pressure is raised. When the first valve body 10 is raised, the electromagnetic three-way valve 2 is opened, the supply of the first back pressure fuel is shut off, and the first back pressure fuel is discharged from the first control chamber 18 to the fuel tank 22. Then, the first back pressure is reduced.

Further, the first control chamber 18 accommodates a spring 26 that urges the first valve body 10 mainly in the closing direction via the piston 12.
Further, the fuel leaking from the fuel reservoir 16, the first control chamber 18, or the like is recovered to the fuel tank 22 via the low pressure flow path 27.

  The first valve body 10 has a cylindrical shape, and the second valve body 11 is slidably accommodated in a cylindrical portion formed on the inner periphery thereof. A first seat portion 29 for opening and closing the first injection hole 7 is provided at the lower end of the first valve body 10, and the first seat portion 29 is seated when the first valve body 10 is seated on the seat surface 19. It abuts against the surface 19. Further, a contact surface 30 with which the piston 12 contacts is provided at the upper end. The first valve body 10 receives pressure from the high-pressure fuel in the fuel reservoir 16 and is urged in the opening direction, and is also urged by the first back pressure and the elastic force of the spring 26 via the piston 12. It is biased in the closing direction.

  The second valve body 11 has a rod shape, and a lower seat is provided with a second seat portion 31 for opening and closing the second injection hole 8. The second seat portion 31 is seated on the seat surface 19. When it does, it contacts the sheet surface 19. Further, the upper surface of the second valve body 11 forms a second control chamber 32 in which high-pressure fuel is supplied and discharged as a second back pressure fuel that exerts pressure on the second valve body 11 in the closing direction.

  The second control chamber 32 is formed by the upper surface of the second valve body 11, the inner peripheral surface of the first valve body 10, and the lower end surface of the piston 12. The volume changes by supplying and discharging. Then, the pressure of the second back pressure fuel (second back pressure) is adjusted by changing the volume of the second control chamber 32. The supply and discharge of the second back pressure fuel is performed through a second supply and discharge passage 35 formed in the piston 12. The second supply / discharge channel 35 is a channel that connects the first control chamber 18 and the second control chamber 32, and the second back pressure fuel is a high pressure fuel once supplied as the first back pressure fuel. It is supplied through the second supply / discharge channel 35. A second orifice 36 is formed in the second supply / discharge flow path 35, and the supply flow rate to the second control chamber 32 and the discharge flow rate from the second control chamber 32 are regulated.

  Further, a contact portion 37 for contacting the piston 12 projects upward on the upper surface of the second valve body 11. The second valve body 11 is brought into contact with the piston 12 when it is lowered and when it is seated on the seat surface 19 together with the first valve body 10. For this reason, when the second valve body 11 is lowered and seated on the seat surface 19 together with the first valve body 10, the second back body 11 receives the first back via the piston 12 in addition to the biasing force due to the second back pressure. It is urged in the closing direction by the urging force by pressure and the elastic force of the spring. Further, when the second valve body 11 is raised in the opening direction and only the first valve body 10 is raised in the opening direction, the second valve body 11 is not brought into contact with the piston 12 and is attached by the second back pressure. It is urged in the closing direction only by the force.

  With the above configuration, the nozzle 1 has a second urging mechanism for generating a second closing urging force that always urges the second valve body 11 in the closing direction, and a decrease in the second closing urging force. When the 2nd valve body 11 raises, the function as a 2nd raise deceleration mechanism which reduces the raising speed of the 2nd valve body 11 is comprised.

  That is, the second hole closing force of the first embodiment is a biasing force by the second back pressure, and the second biasing mechanism once supplies the high-pressure fuel of the common rail 4 as the first back-pressure fuel, By supplying the second back pressure fuel as the second back pressure fuel to the second control chamber 32 through the second supply / discharge flow path 35, the pressure of the high pressure fuel acts on the second valve body 11 in the closing direction. The urging force by the second back pressure as the urging force is generated.

  In the first embodiment, the electromagnetic three-way valve 2 is opened to discharge the first back pressure fuel to the fuel tank 22, and the second back pressure fuel is discharged to the second control chamber via the second supply / discharge passage 35. By discharging from 32, the biasing force due to the second back pressure as the second hole closing biasing force is reduced. The second ascending / decelerating mechanism restricts the discharge flow rate of the second back pressure fuel at the second orifice 36 when the second valve body 11 rises due to the decrease in the second closing biasing force. The rising speed of the valve body 11 is reduced.

[Operation of Example 1]
The effect | action of the nozzle 1 of Example 1 is demonstrated with the time-dependent change of the injection rate q shown in FIG.
The injection rate q is the sum of the injection rate q1 (first injection rate q1) from the first nozzle hole 7 and the injection rate q2 (second injection rate q2) from the second nozzle hole 8.

  First, as shown in FIG. 1, when the electromagnetic three-way valve 2 is opened with both the first and second nozzle holes 7 and 8 closed, the first control chamber 18 opens the first control chamber 18 through the first supply / discharge channel 20. One back pressure fuel is discharged, and the first back pressure decreases. As a result, the urging force acting in the opening direction of the first valve body 10 becomes larger than the urging force acting in the closing direction. Thereby, at time t0, as shown in FIG. 2, the first valve body 10 is separated from the seat surface 19 and starts to rise, and the first injection hole 7 is opened. For this reason, the first injection rate q1 starts to increase, and the injection rate q increases. Further, the piston 12 and the second valve body 11 are separated, and the urging force due to the first back pressure and the elastic force of the spring 26 do not act on the second valve body 11.

  After the opening of the first injection hole 7, until the time t1, the effective area (first area) of the gap between the first sheet portion 29 and the sheet surface 19 is larger than the effective cross-sectional area (first effective hole area) of the first injection hole 7. Effective gap area) is smaller. For this reason, the injection rate q between the times t0 and t1 is governed by the first effective gap area. Since the first effective gap area increases with the rise of the first valve body 10, the injection rate q continues to increase during the time t0 to t1.

  When the first effective gap area becomes larger than the first effective hole area at time t1, the injection rate q is governed by the first effective hole area. Since the first effective hole area does not increase even when the first valve body 10 is raised, the injection rate q stops increasing and maintains the maximum value q1max of the first injection rate q1.

  When the urging force acting in the opening direction of the second valve body 11 becomes larger than the urging force acting in the closing direction at time t2, the second valve body 11 is separated from the seat surface 19 as shown in FIG. While sitting and starting to rise, the second nozzle hole 8 is opened. For this reason, the second injection rate q2 starts to increase, and the injection rate q increases from q1max.

  Here, the urging force acting in the opening direction of the second valve body 11 is the fuel pressure acting on the second valve body 11 in the opening direction at the lower end of the second valve body 11 (second opening fuel). Pressure). The pressure receiving area of the second open fuel pressure when the second valve body 11 is seated on the seat surface 19 is a minute donut-shaped surface on the outer peripheral side of the second seat portion 31, The pressure receiving area of the second open fuel pressure when the valve body 11 is separated from the seat surface 19 is an area determined by the effective diameter of the second valve body 11. For this reason, when the second valve body 11 is separated from the seat surface 19 and starts to rise, the pressure receiving area of the second open fuel pressure is an area determined by the effective diameter of the second valve body 11 from a minute donut-shaped area. To increase significantly. As a result, as the second valve body 11 starts to rise, the urging force acting on the second valve body 11 in the opening direction is rapidly increased.

  After the opening of the second nozzle hole 8, until the time t3 ', the effective area (the first area) of the gap between the second sheet portion 31 and the sheet surface 19 is larger than the effective cross-sectional area (second effective hole area) of the second nozzle hole 8. 2 effective gap area) is smaller. For this reason, the injection rate q between the times t2 and t3 ′ is governed by the second effective gap area. Since the second effective gap area increases with the rise of the second valve body 11, the injection rate q continues to increase.

  Here, the gradient of the injection rate q at times t2 to t3 ′ in FIG. 4 is gentler than the gradient of the injection rate q at times t2 to t3 in FIG. That is, in Example 1, even if the urging force acting in the opening direction of the second valve body 11 suddenly increases as the second valve body 11 starts to rise, the second ascending / decelerating mechanism functions to The rising speed of the valve body 11 is reduced. For this reason, the increasing speed of the second injection rate q2 at the time t2 to t3 ′ is slower than the increasing speed of the second injection rate q2 at the conventional time t2 to t3. As a result, the injection at the time t2 to t3 ′ is performed. The gradient of the rate q becomes gentle.

  When the second effective gap area becomes larger than the second effective hole area at time t3 ′, the injection rate q is governed by the second effective hole area. Since the second effective hole area does not increase even when the second valve body 11 is raised, the injection rate q stops increasing, and the maximum value q1max of the first injection rate q1 and the maximum value q2max of the second injection rate q2 are The sum q1max + q2max is maintained.

  When the electromagnetic three-way valve 2 is closed during the time t3 ′ to t4 ′, the discharge of the first back pressure fuel stops and the high pressure fuel in the common rail 4 passes through the first supply / discharge passage 20 as the first back pressure fuel. The first back pressure is supplied to the first control chamber 18 and increases. When the first back pressure increases, in the first valve body 10, the urging force acting in the closing direction becomes larger than the urging force acting in the opening direction, and the first valve body 10 starts to descend. Further, the first back pressure fuel is supplied to the second control chamber 32 through the second supply / discharge passage 35 as the second back pressure fuel, and the second back pressure increases. When the second back pressure increases, in the second valve body 11, the urging force acting in the closing direction becomes larger than the urging force acting in the opening direction, and the second valve body 11 starts to descend.

  Here, at time t4 ′, when the first effective gap area is smaller than the first effective hole area when the first valve body 10 is lowered, or when the second valve body 11 is lowered, the second effective gap area is the first time. The time when the second effective gap area is smaller than the second effective hole area, whichever is earlier (in this embodiment, the time t4 ′ is the second effective gap area when the second valve body 11 is lowered). When it becomes smaller than.) The injection rate q maintains q1max + q2max until time t4 ′.

  The second valve body 11 is brought into contact with the piston 12 during the time t2 to t4 ′, and in the closing direction by the urging force due to the first back pressure and the elastic force of the spring 26 in addition to the urging force due to the second back pressure. Be energized. When the second valve body 11 is brought into contact with the piston 12 and when the second valve body 11 starts to descend, the length varies depending on the length of the injection period T. And after time t4 ', the 1st, 2nd valve bodies 10 and 11 engage indirectly through piston 12, and it falls as one.

  When the second effective gap area becomes smaller than the second effective hole area at time t4 ′, the injection rate q is controlled by the second effective gap area, and the injection rate q starts to decrease. And since the 2nd effective clearance area reduces with the fall of the 2nd valve body 11, the injection rate q continues decreasing with the gradient according to the decreasing speed of the 2nd injection rate q2.

  When the first effective gap area becomes smaller than the first effective hole area at time t6 ′, the injection rate q is controlled by the first effective gap area and the second effective gap area. Since the first effective gap area decreases as the first valve body 10 descends, the injection rate q has a gradient corresponding to the sum of the decrease rate of the first injection rate q1 and the decrease rate of the second injection rate q2. Continue to decrease. For this reason, after the time t6 ′, the injection rate q decreases more steeply.

  At time t7 ′, the first and second valve bodies 10 and 11 are seated on the seat surface 19, and the first and second injection holes 7 and 8 are closed. As a result, the injection rate q becomes zero.

[Effect of Example 1]
The nozzle 1 of the first embodiment is a variable injection hole type having first and second injection holes 7 and 8 that are opened in two stages, front and rear, and always urges the second valve body 11 in the closing direction. A second urging mechanism for generating a second closing force for energizing, and a second for reducing the rising speed of the second valve element 11 when the second valve element 11 is raised by a decrease in the second closing force. It has the function of an ascending / decelerating mechanism.

  The second urging mechanism according to the first embodiment supplies the high-pressure fuel in the common rail 4 to the second control chamber 32 through the first supply / discharge passage 20, the first control chamber 18, and the second supply / discharge passage 35. At the same time, by applying the pressure of the high-pressure fuel to the second valve body 11 in the closing direction, a second closing force is generated. The second ascending / decelerating mechanism regulates the discharge flow rate of the second back pressure fuel by the second orifice 36 formed in the second supply / discharge flow path 35 when discharging the first and second back pressure fuels. Thus, the increase in the second valve body 11 is reduced while suppressing the decrease in the second closing force.

  As a result, the second valve body 11 is separated from the seat surface 19 so that the pressure receiving area of the second opening fuel pressure is greatly increased, and the biasing force acting in the opening direction of the second valve body 11 is abruptly increased. Even if it becomes stronger, the ascending speed of the second valve body 11 can be reduced by the second ascending / decelerating mechanism. For this reason, since the time until the second injection rate q2 reaches 0 to the maximum value q2max is longer than the conventional one, the gradient of the injection rate q at the time t2 to t3 ′ is as shown in FIG. It becomes gentler than the gradient of the injection rate q at times t2 to t3 (see FIG. 19).

  As a result, as shown in FIG. 5, it is possible to mitigate the rapid increase in the actual injection amount Q at the threshold value Tct seen from the correlation between the conventional actual injection amount Q and the injection period T. That is, since the value of the injection period T in which the second injection rate q2 reaches q2max and the start of lowering of the second valve body 11 overlaps increases from the conventional Tct + ΔT to Tct + ΔT ′, the actual injection amount Q at the threshold Tct becomes abrupt. The increase is mitigated. The threshold value Tct is the maximum value of the injection period T in which injection is performed only from the first injection holes 7.

  As described above, when the conventional nozzle 100 is used, in the first embodiment, when the actual injection amount Q is controlled between the actual injection amount Qct and Qct + ΔQ, between the actual injection amount Qct and Qct + ΔQ ′. Thus, it becomes easy to control the actual injection amount Q. Note that Qct + ΔQ ′ is a value of the actual injection amount Q when the injection period T is Tct + ΔT ′.

The first valve body 10 of the nozzle 1 of the first embodiment indirectly engages with the second valve body 11 via a piston 12 which is a member different from the first and second valve bodies 10 and 11 when descending. To do. The dimensions of the first and second valve bodies 10 and 11 are designed and manufactured so that they can be seated on the seat surface 19 simultaneously.
Thereby, at the time of completion | finish of injection, the state where only one of the 1st, 2nd injection holes 7 and 8 is opened does not occur. For this reason, as shown at time t4 'to t7' in FIG. 4, only the step of the injection rate q at the end of injection, that is, the first injection hole 7 is opened as seen with the time-dependent change of the conventional injection rate q. Thus, the period during which the injection rate q maintains the maximum value q1max of the first injection rate q1 (time t5 to t6 in FIG. 19) can be eliminated.

The first valve body 10 of the nozzle 1 of the first embodiment is lowered by the pressure of the high-pressure fuel supplied from the common rail 4 acting on the first valve body 10 in the closing direction. And when the 1st valve body 10 raises, the electromagnetic three-way valve 2 opens and the supply of the high pressure fuel as a 1st back pressure fuel is interrupted | blocked.
Thereby, when the 1st nozzle hole 7 is open | released, there is no possibility that a 1st back pressure may increase. For this reason, it is possible to reliably open the first nozzle hole 7 without delay.

  In the nozzle 1 of the second embodiment, as shown in FIG. 6, a flow path 39 that penetrates the first valve body 10 in the radial direction and communicates the fuel reservoir 16 and the second control chamber 32 is formed. The flow path 39 is a second supply flow path for supplying the second back pressure fuel separately from the second supply / discharge flow path 35. The flow path 39 is provided so that the effective diameter is smaller than the effective diameter of the high-pressure flow path 15. Thereby, the flow path 39 functions as a second supply orifice that regulates the supply flow rate of the high-pressure fuel as the second back pressure fuel from the fuel reservoir 16 to the second control chamber 32 (hereinafter, the flow path 39 is referred to as the second flow path 39). Supply orifice 39).

  Further, the second supply orifice 39 is provided such that its effective diameter is smaller than the effective diameter of the second orifice 36. Thus, when the second back pressure fuel is discharged from the second control chamber 32 through the second orifice 36, the high pressure fuel in the fuel reservoir 16 is flowed through the second supply orifice 39 at a flow rate smaller than the discharge flow rate. The second back pressure fuel is supplied to the second control chamber 32.

With the above configuration, when the second back pressure reduction mechanism of the nozzle 1 discharges the second back pressure fuel through the second orifice 36, the second supply orifice 39 is discharged from the fuel reservoir 16 at a flow rate smaller than the discharge flow rate. By supplying the high-pressure fuel as the second back pressure fuel via the, the rising speed of the second valve body 11 is reduced.
The second embodiment shows a second ascending / decelerating mechanism different from the first embodiment. Further, the change with time in the injection rate q is the same as in the first embodiment.

  In the nozzle 1 of the third embodiment, as shown in FIG. 7, a coil spring is provided in the upper space 41 on the inner periphery of the first valve body 10, that is, in the space corresponding to the second control chamber 32 in the first and second embodiments. 42 is accommodated. The coil spring 42 generates an elastic force as the second hole closing biasing force. That is, the coil spring 42 is mounted such that its elastic force always urges the second valve body 11 in the closing direction. The upper space 41 also functions as a leak recovery chamber that recovers fuel that has leaked from the fuel reservoir 16, the first control chamber 18, or the like. Then, the fuel recovered in the upper space 41 is recovered to the fuel tank 22 via the low pressure channel 27.

With the above configuration, the second urging mechanism of the nozzle 1 generates an elastic force as the second closing hole urging force in the coil spring 42, and the second ascending / decelerating mechanism also operates when the second valve body 11 is raised. By causing the elastic force of the coil spring 42 to act on the second valve body 11 in the closing direction, the rising speed of the second valve body 11 is reduced.
The third embodiment shows a second urging mechanism and a second ascending / decelerating mechanism which are different from the first and second embodiments. Further, the change with time in the injection rate q is the same as in the first embodiment.
In addition to the coil spring 42, a plate spring 43 as shown in FIG. 8 can be used as an elastic member that generates an elastic force as the second hole closing biasing force.

[Configuration of Example 4]
The structure of the nozzle 1 of Example 4 is demonstrated using FIG. Note that elements having the same functions as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.
The body 9 of the nozzle 1 according to the fourth embodiment has a control chamber 45 that receives supply of high-pressure fuel directly from the common rail 4 as back pressure fuel that exerts pressure in the closing direction on the first and second valve bodies 10 and 11. Is formed.

  The control chamber 45 is formed by the inner surface of the body 9 and the upper surfaces of the first and second valve bodies 10 and 11, and back pressure fuel is supplied and discharged as the first and second valve bodies 10 and 11 are raised or lowered. The volume changes. Then, the pressure of the back pressure fuel (back pressure) is adjusted by changing the volume of the control chamber 45.

  In the control chamber 45, a supply / discharge flow path 46 formed to supply and discharge back pressure fuel is opened, and a closing member 48 for closing the opening 47 of the supply / discharge flow path 46 is loosely inserted. . The opening 47 is formed by a protrusion 49 protruding downward from the inner surface of the body 9, and the closing member 48 is urged by a spring 50 as a predetermined urging means and abuts against the protrusion 49, thereby opening the opening 47. Close. One end of the spring 50 is connected to the upper surface of the second valve body 11, and the other end is connected to the lower surface of the closing member 48. The closing member 48 is provided with a communication hole 51 that allows the supply / exhaust flow path 46 and the control chamber 45 to communicate with each other even when the opening 47 is closed.

  Further, the control chamber 45 is formed with a one-way flow path 52 that is closed when the back pressure fuel is discharged from the control chamber 45 and opened when the high pressure fuel is supplied to the control chamber 45 as the back pressure fuel. The one-way flow path 52 is formed by a side surface and an upper surface, which are part of the surface of the closing member 48, and an inner surface of the body 9 facing these. The one-way flow path 52 is closed by the protruding portion 49 when the closing member 48 is in contact with the protruding portion 49, and is opened when the closing member 48 is detached from the protruding portion 49 (FIGS. 12 and 13). reference). Further, the effective diameter of the one-way flow path 52 when opened is set to be larger than that of the communication hole 51. For this reason, the supply of back pressure fuel to the control chamber 45 is performed through the one-way flow path 52.

  The back pressure fuel is supplied through the supply / discharge channel 46 and the one-way channel 52 as described above. That is, when high pressure fuel is supplied to the control chamber 45 as back pressure fuel, the closing member 48 is biased in a direction opposite to the biasing direction by the spring 50 by the dynamic pressure of the high pressure fuel flowing into the control chamber 45. . As a result, the closing member 48 is detached from the protrusion 49 and the one-way flow path 52 is opened, so that the back pressure fuel is supplied through the one-way flow path 52.

  The back pressure fuel is discharged through the supply / discharge passage 46 and the communication hole 51. That is, when the back pressure fuel is discharged from the control chamber 45, the supply / discharge flow path 46 has a negative pressure rather than the control chamber 45 due to the flow of fuel from the control chamber 45 toward the supply / discharge flow path 46. Then, the closing member 48 abuts against the protrusion 49 and the one-way flow path 52 is closed by the suction force due to the negative pressure and the biasing force due to the spring, so that the back pressure fuel is discharged only through the communication hole 51. Done. The effective diameter of the communication hole 51 is smaller than the effective diameter of the supply / exhaust flow path 46 and functions as an orifice for the discharge of back pressure fuel.

  Switching between back pressure fuel supply and discharge is performed by the electromagnetic three-way valve 2. When the electromagnetic three-way valve 2 is operated, the flow path leading from the control chamber 45 to the fuel tank 22 is opened, and when the operation is stopped, the flow path leading from the common rail 4 to the control chamber 45 is opened (hereinafter, the electromagnetic three-way valve 2 is connected to the control chamber 45). The state in which the flow path leading from 45 to the fuel tank 22 is opened is referred to as “valve opening”, and the state in which the electromagnetic three-way valve 2 is opened from the common rail 4 to the control chamber 45 is referred to as “valve closing”. ).

  Accordingly, when at least one of the first and second valve bodies 10 and 11 is raised, the supply of high-pressure fuel to the control chamber 45 is shut off. For this reason, when the first and second nozzle holes 7 and 8 are opened, there is no possibility that the back pressure increases, so the first and second nozzle holes 7 and 8 can be reliably opened without delay. it can.

  The first valve body 10 is directly attached with a spring 26 and is urged in the closing direction by the elastic force of the spring 26. The second valve body 11 is urged in the closing direction by the elastic force of the spring 50. The second valve body 11 has a contact portion 53 that contacts the upper end of the first valve body 10 when the second valve body 11 is lifted, and the first and second valve bodies 10 and 11 are engaged with each other and lifted. (See FIGS. 10 and 11).

  With the above configuration, the nozzle 1 includes the urging mechanism that generates the closing urging force that urges the first and second valve bodies 10 and 11 in the closing direction, and the increase in the closing urging force. When the second valve bodies 10 and 11 are lowered in the closing direction, a function as a lowering acceleration mechanism for increasing the lowering speed of the first and second valve bodies 10 and 11 is provided.

  That is, the closing hole biasing force of the fourth embodiment is mainly a biasing force due to the back pressure, and the biasing mechanism supplies the high pressure fuel of the common rail 4 to the control chamber 45 as the back pressure fuel, thereby reducing the pressure of the high pressure fuel. The first and second valve bodies 10 and 11 are caused to act in the closing direction to generate a biasing force due to back pressure as a closing hole biasing force.

  In the fourth embodiment, the high pressure fuel of the common rail 4 is supplied to the control chamber 45 as back pressure fuel, thereby increasing the biasing force due to the back pressure as the closing hole biasing force. The descending acceleration mechanism causes the high-pressure fuel to flow through the one-way flow path 52 that is opened by the dynamic pressure of the high-pressure fuel when the first and second valve bodies 10 and 11 are lowered due to the increase in the closing biasing force. By supplying the control chamber 45, the descending speed of the first and second valve bodies 10 and 11 is increased. That is, the effective diameter of the one-way flow path 52 can be freely set under a predetermined condition. For this reason, in the settable range of the effective diameter of the one-way flow path 52, the descending speed of the first and second valve bodies 10, 11 can be increased by setting the effective diameter according to the desired descending speed. it can.

[Operation of Example 4]
The operation of the fourth embodiment will be described together with the change with time of the injection rate q shown in FIG.
First, as shown in FIG. 9, when the electromagnetic three-way valve 2 is opened with both the first and second injection holes 7 and 8 closed and the opening 47 closed by the closing member 48, the communication hole 51 and The back pressure fuel is discharged from the control chamber 45 through the supply / discharge passage 46 and the back pressure is lowered. As a result, the urging force acting on the first valve body 10 in the opening direction is larger than the urging force acting on the closing direction. Thereby, as shown in FIG. 14, at the time t0, the first valve body 10 is separated from the seat surface 19 and starts to rise, and the first injection hole 7 is opened. For this reason, the first injection rate q1 starts to increase, and the injection rate q increases.

  After the opening of the first nozzle hole 7, until the time t1, the first effective gap area is smaller than the first effective hole area. For this reason, the injection rate q between the times t0 and t1 is governed by the first effective gap area and continues to increase as the first valve body 10 rises.

  When the first effective gap area becomes larger than the first effective hole area at time t1, the injection rate q is controlled by the first effective hole area and stops increasing. The injection rate q maintains the maximum value q1max of the first injection rate q1.

  At time t2, as shown in FIG. 10, when the upper end of the first valve body 10 comes into contact with the contact portion 53 of the second valve body 11 and the first and second valve bodies 10 and 11 are engaged with each other, the first The biasing force acting on the valve body 10 in the opening direction also acts on the second valve body 11 in the opening direction. As a result, the urging force acting in the opening direction on the second valve body 11 is larger than the urging force acting in the closing direction, and the second valve body 11 is separated from the seat surface 19 as shown in FIG. While sitting and starting to rise, the second nozzle hole 8 is opened. For this reason, the second injection rate q2 starts to increase, and the injection rate q increases from q1max.

  After the opening of the second nozzle hole 8, until the time t3, the second effective gap area is smaller than the second effective hole area. For this reason, the injection rate q between the times t <b> 2 and t <b> 3 is governed by the second effective gap area and continues to increase as the second valve body 11 rises.

  When the second effective gap area becomes larger than the second effective hole area at time t3, the injection rate q is controlled by the second effective hole area and stops increasing. The injection rate q maintains the sum q1max + q2max of the maximum value q1max of the first injection rate q1 and the maximum value q2max of the second injection rate q2.

  When the electromagnetic three-way valve 2 is closed during the time t3 to t4, the discharge of the back pressure fuel through the communication hole 51 and the supply / discharge passage 46 is stopped and the high-pressure fuel is supplied from the common rail 4 to the supply / discharge passage 46. Starts. Then, due to the dynamic pressure of the high-pressure fuel toward the control chamber 45, the closing member 48 is urged in the direction opposite to the urging direction by the spring 50, and the opening 47 is opened. As a result, the one-way flow path 52 is opened, and high-pressure fuel is supplied as back pressure fuel to the control chamber 45 through the supply / discharge flow path 46 and the one-way flow path 52 to increase the back pressure (FIGS. 12 and 13). reference).

  As a result, the urging force acting in the closing direction on the first and second valve bodies 10 and 11 is larger than the urging force acting in the opening direction, and the first and second valve bodies 10 and 11 are mutually connected. Starts descending while engaged. The injection rate q is maintained at q1max + q2max until time t4.

  When the second effective gap area becomes smaller than the second effective hole area at time t4, the injection rate q is controlled by the second effective gap area, and the injection rate q starts to decrease.

  At time t5 ″, as shown in FIG. 12, the second valve body 11 is seated on the seat surface 19 and the second injection hole 8 is closed. As a result, the second injection rate q2 becomes 0, and the injection rate q Maintains q1max until time t6 ″.

  When the first effective gap area becomes smaller than the first effective hole area at time t6 ″, the injection rate q is controlled by the first effective gap area, and the injection rate q starts to decrease from q1max.

  At time t7 ″, as shown in FIG. 13, the first valve body 10 is seated on the seat surface 19 and the first injection hole 7 is closed. As a result, the first injection rate q1 becomes 0, and the entire injection is performed. The rate q is also 0. Further, since the high-pressure fuel stops flowing into the control chamber 45, the dynamic pressure of the high-pressure fuel does not act on the closing member 48. Therefore, the closing member 48 is biased by the spring 50. This closes the opening 47. As a result, the one-way flow path 52 is also closed, and the nozzle 1 returns to the state shown in FIG.

  Here, the gradient of the injection rate q at time t4 to t5 ″ and time t6 ″ to t7 ″ in FIG. 14 is steeper than the gradient of injection rate q at time t4 to t5 and time t6 to t7 in FIG. 14 is shorter than the length of time t5 to t6 in Fig. 19. That is, in Example 4, the first and second valve bodies are provided by the function of the descending acceleration mechanism. As a result, the length of the time t4 to t7 ″ is shortened, and the gradient of the injection rate q at the time t4 to t5 ″ and the time t6 ″ to t7 ″ becomes steep. The length of time t5 ″ to t6 ″ is shortened.

[Effect of Example 4]
The nozzle 1 of Example 4 is a variable injection hole type having first and second injection holes 7 and 8 that are opened in two stages, front and rear, and the first and second valve bodies 10 and 11 are closed. An urging mechanism for generating a closing urging force for urging the first and second valve bodies 10 and 11 when the first and second valve bodies 10 and 11 are lowered due to an increase in the closing urging force. It has the function of a descending acceleration mechanism that increases the descending speed.
The urging mechanism of the fourth embodiment supplies the high-pressure fuel of the common rail 4 to the control chamber 45 and applies the pressure of the high-pressure fuel to the first and second valve bodies 10 and 11 in the closing direction. Then, a closing biasing force is generated. The descending acceleration mechanism supplies the high pressure fuel to the control chamber 45 through the one-way flow path 52 opened by the dynamic pressure of the high pressure fuel, thereby reducing the descending speed of the first and second valve bodies 10 and 11. Increase.

  As a result, the time from when the first and second valve bodies 10, 11 start to descend until they are seated on the seat surface 19, that is, the injection end time is shortened. Thereby, the conventional time t4 to t7 can be shortened to the time t4 to t7 ″, and the step of the injection rate q, that is, the injection rate q maintains a constant value q1max at the end of the injection according to the reduction ratio. The time can be shortened from the conventional time t4 to t5 to the time t4 to t5 ″ (see FIGS. 14 and 19).

  As shown in FIG. 15, the nozzle 1 of the fifth embodiment includes a pressure receiving surface 57 and a pressure increasing piston 59 provided with a pressure surface 58 having a pressure area smaller than the pressure receiving area of the pressure receiving surface 57.

  The pressure-increasing piston 59 is accommodated in the upper part of the body 9 so as to be slidable in the axial direction, and the upper end surface forms a pressure receiving surface 57 and the lower end surface forms a pressurizing surface 58. Further, the pressure increasing piston 59 is accommodated so as to close the control chamber 45 from above. That is, the pressurizing surface 58 of the pressure increasing piston 59 forms the control chamber 45 together with the inner surface of the body 9 and the upper end surfaces of the first and second valve bodies 10 and 11. Further, the pressure receiving surface 57 forms a high pressure chamber 60 that receives high pressure fuel from the common rail 4 together with the inner surface of the body 9. As a result, the pressure increasing piston 59 can increase the pressure of the high pressure fuel acting on the pressure receiving surface 57 and transmit it to the back pressure fuel through the pressure surface 58.

  The high pressure chamber 60 is always in communication with the control chamber 45 through a through hole 61 provided so as to penetrate between the pressure receiving surface 57 and the pressure surface 58 in the pressure increasing piston 59. The high pressure fuel in the high pressure chamber 60 is supplied as back pressure fuel to the control chamber 45 through the through hole 61, and the back pressure fuel in the control chamber 45 is discharged to the high pressure chamber 60. Note that an orifice 62 is formed in the through hole 61 to regulate the supply flow rate and the discharge flow rate.

  The back pressure fuel is supplied to and discharged from the control chamber 45 through the high pressure chamber 60 and the through hole 61, and the back pressure fuel supply to the control chamber 45 is switched by the electromagnetic three-way valve 2. That is, when the electromagnetic three-way valve 2 is opened, high-pressure fuel is discharged from the high-pressure chamber 60 to the fuel tank 22, and accordingly, back-pressure fuel is discharged from the control chamber 45 to the high-pressure chamber 60 through the through hole 61. When the electromagnetic three-way valve 2 is closed, high-pressure fuel is supplied from the common rail 4 to the high-pressure chamber 60, and accordingly, high-pressure fuel as back-pressure fuel is supplied from the high-pressure chamber 60 to the control chamber 45 through the through hole 61. .

With the above configuration, the descending acceleration mechanism of the nozzle 1 receives the pressure of the high-pressure fuel supplied to the high-pressure chamber 60 by the pressure-receiving surface 57 having a predetermined pressure-receiving area, and a pressure surface having a pressure area smaller than the pressure-receiving area. By pressurizing the back pressure fuel at 58, the pressure of the high pressure fuel is increased and transmitted to the back pressure fuel. Thus, the descending acceleration mechanism of the nozzle 1 increases the descending speed of the first and second valve bodies 10 and 11.
The fifth embodiment shows a descending acceleration mechanism of a different form from the fourth embodiment. Further, the change with time in the injection rate q is the same as in the fourth embodiment.

[Modification]
The nozzle holes provided in the body 9 of the nozzle 1 of the present embodiment are the first and second nozzle holes 7 and 8 that are opened in two stages, front and rear, but the first and second nozzle holes are further provided. You may make it open in three steps or more by providing the nozzle hole opened before and after 7,8. When the nozzle hole is opened in three or more stages, the number of valve bodies may be increased according to the number of stages.

  In the nozzle 1 of the first to third embodiments, the first and second valve bodies 10 and 11 are indirectly engaged via the piston 12, but the first and second valve bodies 10 and 11 are engaged. May be directly engaged. Further, in the nozzle 1 of Example 4 or Example 5, the first and second valve bodies 10 and 11 are directly engaged, but the first and second valve bodies 10 and 11 are somehow different. You may engage indirectly through a member. Further, the first and second valve bodies 10 and 11 may be engaged when lowered, and may be seated on the seat surface 19 at the same time. In this case, the injection end time can be shortened by the function of the descending acceleration mechanism, and the occurrence of a step can be eliminated.

  Although the switching of the supply and discharge of the first back pressure fuel or the switching of the supply and discharge of the back pressure fuel in the present embodiment was performed using the electromagnetic three-way valve 2, the first valve body 10, or the first and second If the supply of the first back pressure fuel or the back pressure fuel is cut off when the valve bodies 10 and 11 are raised, the present invention is not limited to this mode. For example, the supply path connecting the common rail 4 and the first control chamber 18, or the control chamber 45 or the high pressure chamber 60, and the fuel tank 22, the first control chamber 18, the control chamber 45 or the high pressure chamber 60 are provided. The discharge channel to be connected is formed separately. Then, if an electromagnetic two-way valve is provided in each of the supply flow path and the discharge flow path and these electromagnetic two-way valves are controlled to open and close, the first valve body 10 or the first and second valve bodies 10 and 11 When rising, the supply of the first back pressure fuel or the back pressure fuel can be surely cut off.

(Example 1) which is principal part sectional drawing of a fuel-injection nozzle when the 1st, 2nd injection hole is closed. (Example 1) which is principal part sectional drawing of a fuel-injection nozzle when only a 1st injection hole is open | released. (Example 1) which is principal part sectional drawing of a fuel-injection nozzle when the 1st, 2nd injection hole is open | released. It is a time chart which shows the time-dependent change of an injection rate (Example 1). FIG. 5 is a correlation diagram between an injection period and an actual injection amount (Example 1). (Example 2) which is principal part sectional drawing of a fuel-injection nozzle. (Example 3) which is principal part sectional drawing of a fuel-injection nozzle. (Example 3) which is principal part sectional drawing of a fuel-injection nozzle. (Example 4) which is principal part sectional drawing of a fuel-injection nozzle when the 1st, 2nd injection hole is closed. (Example 4) which is principal part sectional drawing of a fuel-injection nozzle when only a 1st injection hole is open | released. (Example 4) which is principal part sectional drawing of a fuel-injection nozzle when the 1st, 2nd injection hole is open | released. (Example 4) which is the principal part sectional drawing of a fuel-injection nozzle when only the 1st nozzle hole is open | released at the time of completion | finish of injection. (Example 4) which is the principal part sectional drawing of a fuel-injection nozzle when the 1st, 2nd injection hole is closed at the time of completion | finish of injection. (Example 4) which is a time chart which shows the time-dependent change of an injection rate. (Example 5) which is principal part sectional drawing of a fuel-injection nozzle. It is principal part sectional drawing of a fuel-injection nozzle when the 1st, 2nd injection hole is closed (conventional example). It is principal part sectional drawing of a fuel-injection nozzle when only a 1st injection hole is open | released (conventional example). It is principal part sectional drawing of a fuel-injection nozzle when the 1st, 2nd injection hole is open | released (conventional example). It is a time chart which shows a time-dependent change of an injection rate (conventional example). It is a correlation diagram of an injection period and an actual injection amount (conventional example).

Explanation of symbols

1 Nozzle (fuel injection nozzle)
2 Solenoid valve, electromagnetic three-way valve (three-way valve)
3 Fuel injection valve 4 Common rail (predetermined supply source)
7 1st injection hole 8 2nd injection hole 9 Body 10 1st valve body 11 2nd valve body 12 Piston (member different from a 1st valve body and a 2nd valve body)
35 Second supply / discharge flow path 36 Second orifice (throttle formed in the second supply / discharge flow path)
39 channel, second supply orifice (throttle formed in second supply channel, second supply channel)
42 Coil spring (elastic member)
43 Leaf spring (elastic member)
45 Control chamber 46 Supply / exhaust flow path 47 Opening 48 Closing member 50 Spring (predetermined biasing means)
52 one-way flow path 57 pressure receiving surface 58 pressure surface 59 pressure increasing piston

Claims (18)

A body having a plurality of nozzle holes opened at least in two stages, front and rear,
A cylindrical first valve body that is accommodated in the body and opens and closes a first nozzle hole that is first opened in the plurality of nozzle holes;
A second valve body that is accommodated in the cylindrical portion of the first valve body and that opens and closes the second nozzle hole that opens after the first nozzle hole, and that moves in a direction coaxial with the first valve body; In the fuel injection nozzle provided,
A second biasing mechanism for generating a second hole closing biasing force that constantly biases the second valve body in the hole closing direction;
And when the said 2nd valve body raises to the opening direction by the reduction | decrease of the said 2nd hole energizing force, the 2nd raising deceleration mechanism which reduces the raising speed of the said 2nd valve body is provided. Fuel injection nozzle. The fuel injection nozzle according to claim 1,
The second biasing mechanism generates the second closing biasing force by causing the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the second valve body in the closing direction,
The second ascending / decelerating mechanism reduces the ascending speed of the second valve body by regulating the discharge flow rate when discharging the second back pressure fuel that exerts pressure on the second valve body in the closing direction. A fuel injection nozzle characterized by that. The fuel injection nozzle according to claim 2,
A second supply / discharge passage for supplying and discharging the second back pressure fuel is formed;
The discharge flow rate is regulated by a throttle formed in the second supply / discharge flow path. The fuel injection nozzle according to claim 1,
The second biasing mechanism generates the second closing biasing force by causing the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the second valve body in the closing direction,
When the second back pressure fuel that exerts pressure on the second valve body in the closing direction is discharged, the second ascending / decelerating mechanism separately supplies the high-pressure fuel at a flow rate less than the discharge flow rate. A fuel injection nozzle, wherein the rising speed of the second valve body is reduced by supplying pressure so as to exert a pressure in the closing direction. The fuel injection nozzle according to claim 4.
A second supply / discharge flow path for supplying and discharging the second back pressure fuel, and a flow path different from the second supply / discharge flow path, and supplying the second back pressure fuel separately. A second supply channel is formed for
The fuel injection nozzle, wherein an effective diameter of the throttle formed in the second supply channel is smaller than an effective diameter of the throttle formed in the second supply / discharge channel. The fuel injection nozzle according to claim 1,
The second urging mechanism generates an elastic force as the second closing hole urging force in an elastic member mounted inside the body,
The second ascending / decelerating mechanism causes the second valve body to act on the second valve body with the elastic force of the elastic member as the second closing biasing force when the second valve body rises in the opening direction. A fuel injection nozzle that reduces the ascending speed of the two-valve element. The fuel injection nozzle according to any one of claims 1 to 6,
When the first valve body is lowered in the closing direction, the first valve body and the second valve body are directly or indirectly via a member different from the first valve body and the second valve body. A fuel injection nozzle that engages. The fuel injection nozzle according to claim 7,
The first valve body is lowered in the closing direction by the pressure of the high-pressure fuel supplied from a predetermined supply source acting in the closing direction on the first valve body,
The fuel injection nozzle, wherein when the first valve body rises in the opening direction, the supply of the first back pressure fuel that exerts pressure on the first valve body in the closing direction is shut off. The fuel injection nozzle according to claim 8,
The fuel injection nozzle is characterized in that the switching of the supply and discharge of the first back pressure fuel is performed by a three-way valve. A body having a plurality of nozzle holes opened at least in two stages, front and rear,
A cylindrical first valve body that is accommodated in the body and opens and closes a first nozzle hole that is first opened in the plurality of nozzle holes;
A second valve body that is accommodated in the cylindrical portion of the first valve body and that opens and closes the second nozzle hole that opens after the first nozzle hole, and that moves in a direction coaxial with the first valve body; In the fuel injection nozzle provided,
A biasing mechanism for generating a closing biasing force for biasing the first valve body and the second valve body in the closing direction;
And a lowering acceleration mechanism for increasing the lowering speed of the first valve body and the second valve body when the first valve body and the second valve body are lowered in the closing direction due to the increase in the closing biasing force. A fuel injection nozzle is provided. The fuel injection nozzle according to claim 10,
The biasing mechanism generates the closed-hole biasing force by causing the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the first valve body and the second valve body in the closed-hole direction. Let
The descending acceleration mechanism is configured to supply back pressure fuel that exerts pressure on the first valve body and the second valve body in the closing direction via a one-way flow path that is closed when the closing biasing force is decreased. A fuel injection nozzle that increases the descending speed of the first valve body and the second valve body by supplying the fuel. The fuel injection nozzle according to claim 11,
A control chamber in which the back pressure fuel is supplied and discharged to adjust the biasing force of the closed hole to change its volume, and a supply and exhaust flow that opens to the control chamber to supply and discharge the back pressure fuel to and from this control chamber A road is formed,
A closing member that is loosely inserted into the control chamber and is energized by a predetermined energizing means to close the opening of the supply / exhaust flow path;
The closing member forms the one-way flow path with a surface thereof and an inner surface forming the control chamber, and reverses a biasing direction by the biasing means when the back pressure fuel is supplied to the control chamber. The fuel injection nozzle is characterized in that the one-way flow path is opened by being urged in the direction of to open the opening. The fuel injection nozzle according to claim 10,
The biasing mechanism generates the closed-hole biasing force by causing the pressure of the high-pressure fuel supplied from a predetermined supply source to act on the first valve body and the second valve body in the closed-hole direction. Let
The descending acceleration mechanism receives the pressure of the high-pressure fuel in a predetermined pressure receiving area, and applies pressure in a closing direction to the first valve body and the second valve body with a pressurizing area smaller than the pressure receiving area. A fuel injection nozzle that increases the descending speed of the first valve body and the second valve body by pressurizing the back pressure fuel exerted thereon. The fuel injection nozzle according to claim 13,
A pressure-increasing piston having a pressure-receiving surface having the pressure-receiving area and a pressure-receiving surface having the pressure area, and increasing the pressure of the high-pressure fuel acting on the pressure-receiving surface and transmitting the pressure to the back-pressure fuel through the pressure surface. A fuel injection nozzle characterized by. The fuel injection nozzle according to any one of claims 11 to 14,
The fuel injection nozzle, wherein when at least one of the first valve body and the second valve body rises in the opening direction, the supply of the back pressure fuel is cut off. The fuel injection nozzle according to claim 15,
The fuel injection nozzle, wherein the back pressure fuel supply / discharge switching is performed by a three-way valve.   A fuel injection valve in which the fuel injection nozzle according to claim 1 or 10 is incorporated.   A fuel injection device using the fuel injection valve according to claim 17.

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