JPWO2018042910A1 - Fuel injection device - Google Patents

Abstract

  Provided is a fuel injection device which shortens a spray reach distance. Therefore, among the plurality of injection holes, the injection hole formed so that the injection hole angle formed by the normal direction of the sheet surface and the central axis direction of the injection hole is larger than the injection hole angle of the other injection holes, The valve opening flow velocity at the outlet face of the injection hole is configured to be smaller than the valve opening flow speed at the outlet face of any other injection hole.

Description

  The present invention relates to a fuel injection device used in, for example, an internal combustion engine.

  As shown in Patent Document 1, for example, as a prior art of the present invention, spray is concentrated in the vicinity of a plurality of fuel spray spark plugs to form an air-fuel mixture around the electrodes of the spark plug 7 to form a combustion chamber. 4 discloses a method for appropriately stratifying the inside and improving the ignitability.

  For example, as shown in Document 2, a large-diameter injection hole that has a plurality of injection holes and injects fuel toward an annular shape including a region where the tumble flow is strong, and injects fuel toward a space where the tumble flow is weak There is disclosed a method of reducing the adverse effects of spraying with increased spray penetration by having small-diameter injection holes.

JP-A-2005-54676 International Publication Number WO2013 / 008692

  In a fuel injection device for an internal combustion engine, in order to achieve low exhaust, a method for suppressing unburned gas by increasing system fuel pressure and atomizing injected fuel particles to promote mixing with air, A method of reducing unburned particles by suppressing the adhesion of fuel spray in the engine cylinder has been devised. In particular, when the fuel pressure is increased with the aim of atomization, since the penetration force of the fuel spray increases, the injected fuel spray may adhere to the intake valve and the inner wall surface of the cylinder, and the discharge amount of harmful substances may increase.

  For example, in the fuel injection device having a plurality of injection holes as in the method of Patent Document 1, penetration is increased by reducing the injection holes in the region where the air flow is small and increasing the injection holes in the region where the air flow is large. It is possible to reduce the adverse effects caused by.

  However, even if the hole diameter of the injection hole is reduced with the aim of reducing penetration, if the flow rate of fuel is high due to reasons such as high pressure, the flow of the fuel is separated from the wall surface of the injection hole, and at the outlet of the injection hole In some cases, the fuel flow speed becomes non-uniform so that the spray reach distance becomes long.

  For the above reasons, the method disclosed in the above-mentioned patent document is not necessarily sufficient as a means for reducing the spray reach distance.

  Therefore, the present invention is to provide a fuel injection device that solves the above problems and shortens the spray reach distance.

  In order to solve the above-described problem, the present invention provides an injection hole angle formed by the normal direction of the seat surface and the central axis direction of the injection hole among the plurality of injection holes is larger than the injection hole angles of the other injection holes. The injection hole formed in this way was configured such that the valve opening flow velocity at the outlet face of the injection hole was smaller than the valve opening flow speed at the outlet face of any other injection hole.

  According to the present invention, it is possible to provide a fuel injection device that shortens the spray reach distance. The contents other than the above-described problems, configurations, and effects of the present invention will be described in detail in the following examples.

It is the figure which showed the longitudinal cross-sectional view of the fuel-injection system comprised by the fuel-injection apparatus and ECU of embodiment of this invention, and a fuel-injection apparatus. 1 is a schematic diagram of an in-cylinder direct injection internal combustion engine (direct injection engine) that directly injects fuel into a cylinder according to an embodiment of the present invention. FIG. 3 is a projection view of fuel spray injected from an orifice forming portion when viewed in the direction of the fuel injection device from the A-A ′ cross section of FIG. 2 in the embodiment of the present invention. It is an enlarged view of the orifice formation part seen from the front-end | tip direction of the fuel injection apparatus 204 in embodiment of this invention. It is an enlarged view of the injection hole vicinity of the orifice formation part in FIG. 4 of embodiment of this invention. It is sectional drawing of the orifice formation part in the B-B 'cross section of FIG. 5 of embodiment of this invention, and the valve body 114. FIG. It is the figure which showed the flow velocity distribution of the fuel in the enlarged part of FIG. 6 of embodiment of this invention. It is an enlarged view of the vicinity of the orifice formation part seen from the front-end | tip direction of the fuel injection apparatus in 1st embodiment of this invention. It is the enlarged view which showed the flow velocity vector of the 1st injection hole vicinity of the cross section C-C 'in FIG. 8 of 1st embodiment of this invention. It is the enlarged view which showed the flow velocity vector of the 1st injection hole vicinity of the cross section D-D 'in FIG. 8 of 1st embodiment of this invention. It is a projection figure of the fuel spray injected from the orifice formation part at the time of seeing from the A-A 'cross section of FIG. 2 in 1st embodiment of this invention to the direction of a fuel-injection apparatus. FIG. 3 is a projection view of fuel spray injected from an orifice forming portion when viewed from the A-A ′ cross section of FIG. 2 in the first embodiment of the present invention in the direction of the fuel injection device. It is an enlarged view of the vicinity of the orifice formation part seen from the front-end | tip direction of the fuel injection apparatus in 2nd embodiment of this invention.

  The operation and configuration of the fuel injection device according to the embodiment of the present invention will be described below with reference to FIGS.

  First, the configuration and operation of the fuel injection device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a view showing a fuel injection system including a fuel injection device and an ECU according to the present embodiment, and a longitudinal sectional view of the fuel injection device.

  The fuel injection of the fuel injection device is controlled by the width of the injection pulse sent from the engine control unit (ECU) 154. This injection pulse is input to the drive circuit 153 of the fuel injection device, and the drive circuit 153 determines a drive current waveform based on a command from the ECU 154. The drive circuit 153 supplies the drive current waveform to the fuel injection device for a time based on the injection pulse. In addition, the drive circuit 153 may be mounted as a component or a board integrated with the ECU 154. A device in which the drive circuit 154 and the ECU 154 are integrated is referred to as a drive device 150.

  Next, the configuration and basic operation of the fuel injection device and its driving device will be described. The ECU 154 takes in signals indicating the state of the engine from various sensors, and calculates the injection pulse width and injection timing for controlling the injection amount injected from the fuel injection device in accordance with the operating conditions of the internal combustion engine. The ECU 154 is provided with an A / D converter and an I / O port for taking in signals from various sensors. The injection pulse output from the ECU 154 is input to the drive circuit 103 of the fuel injection device through the signal line 151. The drive circuit 153 controls the voltage applied to the solenoid 105 and supplies a current. The ECU 154 communicates with the drive circuit 153 through the communication line 152 to switch the drive current generated by the drive circuit 153 according to the pressure of the fuel supplied to the fuel injection device and the operation conditions, and to set the current and time. It is possible to change.

  Next, the configuration and operation of the fuel injection device will be described. The fuel injection device in FIG. 1 is a normally valve-closed electromagnetic fuel injection device. When the coil 105 is not energized, the valve body 114 is urged by the spring 110 and is in close contact with the valve seat 118. It has become. In this closed state, the mover 102 is brought into close contact with the valve body 114 by the zero spring 112, and there is a gap between the mover 102 and the magnetic core 107 with the valve body 114 closed. The fuel is supplied from the upper part of the fuel injection device, and the fuel is sealed by the valve seat 118. When the valve is closed, the urging force by the spring 110 and the urging force by the fuel pressure act on the valve body 114 and are pushed in the closing direction.

The fuel injection device includes a magnetic circuit that generates an electromagnetic attractive force for opening and closing the valve body 114.
The magnetic circuit includes a nozzle holder 101, which is a cylindrical member disposed on the outer peripheral side of the magnetic core 107 and the movable element 102, the magnetic core 107, the movable element 102, and the housing 103. When a current is supplied to the coil 105, a magnetic flux is generated in the magnetic circuit, and a magnetic attractive force is generated between the movable element 102, which is a movable part, and the magnetic core 107. When the magnetic attractive force acting on the mover 102 exceeds the sum of the load (biasing force) by the spring 110 and the urging force acting on the valve body 114 due to the fuel pressure, the mover 102 moves upward (upstream direction). At this time, the flange part of the valve body 114 and the valve body support part of the movable element 102 are engaged, so that the valve body 114 moves upward together with the movable element 102. Thereafter, the mover 102 moves until the upper end surface of the mover 102 collides with the lower surface of the magnetic core 107.

  As a result, the valve body 114 is separated from the valve seat 118, and fuel supplied from a common rail (not shown) is injected from the plurality of injection ports 119. Next, after the upper end surface of the movable element 102 collides with the lower surface of the magnetic core 107, the valve body 114 is detached from the movable element 102 and overshoots, but after a certain time, the valve body 114 is moved on the movable element 102. Quiesce. When the supply of current to the coil 105 is cut off, the magnetic flux generated in the magnetic circuit is reduced and the magnetic attractive force is reduced. When the magnetic attractive force becomes smaller than the combined force of the load by the spring 110 and the fluid force received by the valve body 114 and the mover 102 due to the fuel pressure, the mover 102 and the valve body 114 move downward, and the valve body 114 is moved to the valve. At the time of collision with the seat 118, the mover 102 is detached from the valve body 114. On the other hand, the valve body 114 stops after colliding with the valve seat 118, and fuel injection stops.

  In addition, the needle | mover 102 and the valve body 114 may be integrally formed as the same member, or may be comprised by another member, and may be couple | bonded by methods, such as welding or press fit. A cylindrical orifice forming portion 116 having a plurality of injection holes 119 is coupled to the nozzle holder 101, and the orifice forming portion 116 has a guide portion 120 that restricts the movement of the valve body 114 in the radial direction. In FIG. 1, the orifice forming portion 116 and the guide portion 120 are integrally formed, but may be separate members. The valve body 214 is configured such that the movement in the radial direction is restricted by the guide portion 120 and the flange portion 130 of the valve body 114 at two locations on the inner diameter of the magnetic core 107, and the valve body 214 can operate in the opening / closing direction.

  When the movable element 102 and the valve body are the same member, the effect of the present invention does not change even if the zero spring 112 is not structurally configured.

Next, the configuration of this embodiment and the problem of the fuel injection device will be described with reference to FIGS.
FIG. 2 is a schematic view of an in-cylinder direct injection internal combustion engine (direct injection engine) that injects fuel directly into the cylinder of the engine. FIG. 2 shows the state of fuel spray in the engine cylinder immediately after fuel is injected from the tip of the orifice forming portion 116 of the fuel injection device.

FIG. 3 is a projection view of the fuel spray injected from the orifice forming portion 116 of the fuel injection device 204 when the fuel injection device is viewed in the direction of the central axis 201 from the AA ′ cross section of FIG.
FIG. 4 is a view of the orifice forming portion 116 (orifice cup) as viewed from the front end direction of the fuel injection device 204. FIG. 5 is an enlarged view of the vicinity of the injection hole of the orifice forming portion 116 in 401 of FIG. FIG. 6 is a cross-sectional view of the orifice forming portion 116 and the valve body 114 in the BB ′ cross section of FIG. FIG. 7 is a view showing the fuel flow velocity distribution in the enlarged portion 610 of FIG.

  As shown in FIG. 2, the direct injection engine according to the present embodiment includes a fuel injection device 204, an intake valve 205, a spark plug 203, an exhaust valve 211, an intake pipe 207, an exhaust pipe 212, a piston 209, and a cylinder 220 containing the piston 209. Is done. The fuel injection device 204 is attached to the cylindrical surface of the cylinder 204, and two intake valves 205 are attached to the left and right with the fuel injection device 204 as the center. In FIG. 2, for the sake of explanation, the intake valve 205 will be described with reference to the drawing attached to the same cross section as the fuel injection device. FIG. 3 shows the positional relationship between the spray and the two intake valves 205A and 205B.

  First, the operation of the direct injection engine will be described. After the intake valve 205 is opened, the air that has passed through the intake pipe 207 is guided into the engine cylinder 208, and fuel is injected from the fuel injection device 204 in accordance with the flow of the inflowed air. The injected fuel is mixed with air according to the flow of air guided into the engine cylinder 208 to form an air-fuel mixture. Thereafter, when the piston 209 approaches the upper fulcrum, the air-fuel mixture is ignited by the spark plug 203 to burn and obtain a propulsive force.

The fuel injection device 204 of the present embodiment is attached to the engine cylinder inner wall surface 210 close to the intake valve 205 in order to promote the mixing of the incoming air and the fuel. Further, the mounting angle of the fuel injection device 204 is such that the crossing angle 510 of the central axis 201 of the fuel injection device 204 with respect to the horizontal axis 202 in the cylinder of the engine is 5 to 30 degrees in order to prevent interference with the intake valve 205. It is attached to become. When the intake port for taking in air through the intake valve 205 is increased, the pressure loss of the intake pipe increases, so the angle of the intake pipe needs to be reduced. Therefore, the attachment angle of the fuel injection device 204 is determined according to the angle of the intake pipe 207.
Therefore, in order to prevent interference with the intake pipe 207, the central axis of the fuel injection device 204 is preferably arranged so that the angle is small with respect to the horizontal axis 202 in the engine cylinder.

Of the fuel sprays injected from the fuel injection device 204, the first spray D1 is formed so as to be directed most toward the tip 1201 of the spark plug 203 with respect to the other sprays. Further, the second spray D2 and the sixth spray D6 are formed so as to be directed to the tip 1201 side of the spark plug 203 next to the first spray D1, and are formed in the vicinity of the intake valves 205A and 205B. Is done. Second, the third spray D3 and the fifth spray D5 are formed so as to be directed to the front end side of the spark plug 203 after the first spray D1, the second spray D2, and the sixth spray D6. The Further, the third spray D3 and the fifth spray D5 are formed so as to be directed to the piston 209 side rather than the tip side of the spark plug 203. The fourth spray D4 is formed so as to be directed to the piston 209 side further than the third spray D3 and the fifth spray D5, and is directed to the piston 209 side most among all the sprays. It is formed. The central axis 5013 of the first spray D1 that is most directed to the tip 1201 side of the spark plug 203 is related to the position of the fuel injection device 204 in relation to the mounting position of the two fuel injection devices 204 and the mounting position of the spark plug 203. The angle is about 0 to several tens of degrees with respect to the central axis 201.

  Next, the configuration of the orifice forming portion 116 of the fuel injection device 204 will be described with reference to FIGS. FIG. 6 is an enlarged cross-sectional view of a cross section B-B ′ passing through the injection hole 501 that forms the first spray D <b> 1 and the injection hole 504 that forms the fourth spray D <b> 4 in FIG. 5. In FIG. 5, the same symbols are used for the same components as in FIG. FIG. 7 is an enlarged view of 610 in FIG. 6 and shows a fuel flow velocity vector. The region where the flow rate is fast is black, and the region where the flow rate is slow is shown in white. In FIG. 7, the same symbols are used for the same components as in FIGS.

  The seat surfaces (5011, 5041) forming the valve seat 118 that contacts the valve body 114 and seals the fuel have a substantially conical shape, and the fuel is sealed by contacting the spherical surface portion 610 of the valve body 114. . In the orifice forming portion 116, an injection hole is formed on the downstream side with respect to the sheet surfaces (5011, 5041) and the contact surfaces (5015, 5045). The injection holes are composed of injection holes 501, 502, 503, 504, 505 and 506 that form the sprays D <b> 1 to D <b> 6. Counterbore portions 511 to 516 having an inner diameter larger than that of the injection holes are formed at the tip portions of the injection holes 501 to 506. In addition, the spray D1 and the injection hole 501, the spray D2 and the injection hole 502, the spray D3 and the injection hole 503, the spray D4 and the injection hole 504, the spray D5 and the injection hole 505, and the spray D6 and the injection hole 506 are in a corresponding relationship.

  5, an injection hole 504 is formed on the lower side (the piston 209 side in FIG. 2), and an injection hole 501 is formed on the upper side (the side of the spark plug 203 in FIG. 2). Each injection hole is composed of an upstream small diameter portion and a downstream large diameter portion. The injection hole 504 is formed with a counterbore portion 514 having a large diameter portion in order to adjust the length 504L. After the hole of the injection hole 504 having a small diameter portion is formed by a punch, the counterbore portion having a large diameter portion is formed. 514 is similarly formed by punching. Similarly, a counterbore portion 511 having a large diameter portion is formed in the injection hole 501. However, it is not necessarily limited to punching, and it may be formed by laser processing or other methods.

Further, the sheet surfaces (5011, 5041) of the orifice forming portion 116 are formed by lathe processing by applying a drill from the left side to the right side in FIG. Therefore, a recessed portion 605 that is recessed downstream is formed at the tip of the orifice forming portion 116. Since the recess 605 is formed in a spherical shape and has a certain volume, the recess 605 affects the fuel injection characteristics.
In the injection hole 501, an angle θ (hereinafter referred to as an injection hole angle) formed by a normal line 5012 of the sheet surface 5011 and the central axis 5013 of the injection hole 501 is an injection hole angle 5014.

  In addition, the seat surface 5011 is configured in the same plane as the surface 5015 that contacts the spherical surface 610 of the valve body 114 in the valve seat 118, and is formed on a substantially straight line in the sectional view of FIG. The sheet surface 5011 is defined by a plane parallel to the entrance surface of the injection hole 501. Similarly, the seat surface 5041 is flush with the surface 5045 that contacts the spherical surface 610 of the valve body 114 in the valve seat 118, and is formed on a substantially straight line in the sectional view of FIG. The sheet surface 5041 is defined by a plane parallel to the entrance surface of the injection hole 504. Here, the angle of the sheet surfaces (5011, 5041) is, for example, 80 to 160 deg.

  FIG. 6 illustrates a state where the angle of the sheet surface 5041 is 90 degrees. The angle of the sheet surface 5041 is symmetrical to the straight line indicating the sheet surface 5041 from the intersection of the straight line indicating the sheet surface 5041 in FIG. 6 and the central axis of the orifice forming portion 116 (the straight line 201 indicated by the dotted line in FIG. 6). This is an angle formed by drawing a straight line and showing the sheet surface 5041 and the symmetrical line. That is, the angle formed by the straight line indicating the sheet surface 5041 in FIG. 6 and the central axis 201 of the orifice forming portion 116 is 45 degrees.

  The smaller the angle of the sheet surface (5011, 5041), the sharper the angle (5016, 5046) between the sheet surface (5011, 5041) and the central axis (5013, 5043) of the injection hole (501, 504). The injection hole angle (5014, 5044) increases. For example, since the angle of the sheet surface 5011 is smaller than that of the sheet surface 5041, the angle 5016 formed by the sheet surface 5011 and the injection hole 501 is sharper than the angle 5046 formed by the sheet surface 5041 and the injection hole 504. become. Therefore, the injection hole angle 5014 is larger than the injection hole angle 5044.

Here, FIG. 7 is an enlarged view of 501X surrounded by a square in FIG. 6 and shows a fuel flow velocity vector in the injection hole 501. FIG. The speed of the flow rate is shown by the shading so that the region where the flow rate is fast is black and the region where the flow rate is slow is white. When the injection hole angle is large, the fuel flowing from the recess 605 (volume) at the tip of the valve body 114 is easily separated from the downstream injection hole wall surface 5018 at the injection hole inlet (injection hole inlet surface 5017). Therefore, in order to suppress peeling, it is desirable that the angle of the sheet surface is 90 deg or more.
Here, when the fuel injection valve 204 is attached, the injection hole angle 5014 of the injection hole 501 is larger than the other injection holes. The size of the injection hole angle (5014, 5044) between the normal line (5012, 5042) of the sheet surface (5011, 5041) and the central axis (5013, 5043) of each injection hole (501, 504) is large. In this case, the fuel is peeled off at the inlet of the injection hole, and the fuel in the injection hole flows toward the opposite side of the peeled surface.

  Therefore, in the injection hole 501, as compared with the injection hole 504, the fuel that has flowed from the recessed portion 605 (volume) at the tip of the valve body 114 is downstream of the injection hole at the injection hole inlet (injection hole inlet surface 5017). It peels from the wall surface 5018. The fuel flows along the upstream injection hole wall surface 5019 side of the seat surface 5011 on the side of the contact surface 5015 with the valve body 114. Therefore, the flow velocity distribution of the fuel spray at the injection hole outlet surface 5111 becomes non-uniform, and the maximum value of the velocity vector in the injection hole central axis direction at the injection hole outlet surface 5111 becomes large. Here, the injection hole inlet surface 5017 and the injection hole outlet surface 5111 are defined by the inlet surface and the outlet surface of the small diameter portion of the injection hole 501. The central axis 5013 of the injection hole is defined by a straight line connecting the inlet surface center and the outlet surface center of the small diameter portion.

As described above, the center shaft 201 of the fuel injection device 204 shown in FIG. 2 is attached to the horizontal shaft 202 in the cylinder of the engine at 5 to 30 degrees. Further, since the injection hole 501 is most directed toward the tip 1201 side of the spark plug 203, the spray injection angle 5100 with respect to the central shaft 201 is smaller than the injection angles of the other sprays D2, D3, D4, D5, D6. Become.
Then, as shown in FIG. 6, the central axis 5013 of the injection hole 501 is inclined with respect to the normal line 5012 orthogonal to the sheet surface 5011. As a result, the injection hole angle 5014 of the injection hole 501 is increased.

When the inside of the injection hole is not filled with fuel due to fuel peeling, this corresponds to the effect that the inner diameter of the injection hole is substantially reduced. Therefore, Qo flow rate per unit time of the fuel injected from the injection hole, the flow velocity of v _o of the fuel injected from the injection _hole, the cross-sectional area of the injection hole when the D _o, the flow velocity v _o of the formula (1) It is required because of the relationship.

v _o = Qo / Do (1)
From equation (1), when the injection hole diameter D _o decreases, the flow velocity v _o increases. As a result, since the penetration force of the spray becomes large, the reach distance (penetration) of the fuel spray becomes long. As the penetration becomes longer, fuel adhesion to the cylinder inner wall surface 210 of the fuel spray, the piston 209, and the exhaust valve 211 increases. Since the fuel adhering to the cylinder inner wall surface 210 and the piston 209 is difficult to vaporize, PN may increase.

  In particular, as described above, the injection hole 501 has a problem that since the injection hole angle θ (5014) is large, the penetration tends to be long, and the injection hole 501 is likely to adhere to the cylinder inner wall surface 210.

Next, the configuration of this embodiment will be described with reference to FIGS. FIG. 8 is an enlarged view of the vicinity of the injection hole of the orifice forming portion 116 of the present embodiment as viewed from the front end direction of the fuel injection device 204 in FIG. FIG. 9 is an enlarged view showing a flow velocity vector in the vicinity of the injection hole 801 of the section CC ′. FIG. 10 is an enlarged view showing a flow velocity vector in the vicinity of the injection hole 802 of the section DD ′.
9 and 10, the region where the flow velocity is fast is black and the region where the flow velocity is slow is shown in white. 8-10, the same symbols are used for parts similar to those in FIGS. 1 and 6, and detailed description thereof is omitted.

FIG. 11 is a projection view of the fuel spray injected from the orifice forming portion 116 of the fuel injection device 204 in this embodiment when viewed from the AA ′ cross section of FIG. 2 in the direction of the fuel injection device.
FIG. 12 is a schematic view of the direct injection engine in the present embodiment, and shows the state of fuel spray in the engine cylinder immediately after the fuel is injected from the tip of the orifice forming portion 116 of the fuel injection device. 11 and 12, parts similar to those in FIGS. 2 and 3 are denoted by the same symbols, and detailed description thereof is omitted.

  As shown in FIG. 8, a first injection hole 801, a second injection hole 802, and a plurality of other injection holes 803, 804, 805, 806, 807 are formed in the orifice forming portion 116 of the present embodiment. Has been. Each of the injection holes is formed by first to seventh injection holes (801-807) formed by a small diameter portion and first to seventh injection holes (811-817) formed by a large diameter portion. Is done. The injection holes (801-807) form sprays D11-D17 shown in FIG.

  FIG. 9 shows a cross-sectional view of the first injection hole (801, 811) at the injection hole axis, and straight lines connecting the centers of the inlet surface 8017 and the outlet surface 8111 of the first injection hole 801 of the small diameter portion. Defines the injection hole central axis 8013. Further, in order to adjust the length of the first injection hole 801 of the small diameter portion, the first injection hole 8111 of the large diameter portion on the downstream side is formed. The first injection hole 801 of the small diameter portion is composed of a downstream-side downstream injection hole wall surface 8018 and an upstream-side upstream injection hole wall surface 8019.

  The seat surface 8011 is configured in the same plane as a surface 8015 that contacts the spherical surface 610 of the valve body 114 in the valve seat 118, and is formed on a substantially straight line in the cross-sectional view of FIG. The sheet surface 8011 is defined by a plane parallel to the entrance surface 8017 of the injection hole 801. An angle formed by the normal line 8012 of the sheet surface 8011 and the central axis 8013 of the injection hole 801 is defined as an injection hole angle 8014.

  FIG. 10 shows a sectional view of the second injection holes (802, 812) at the injection hole axis, and straight lines connecting the centers of the inlet surface 8027 and the outlet surface 8021 of the first injection hole 802 of the small diameter portion. Defines the injection hole central axis 8023. Further, in order to adjust the length of the second injection hole 802 of the small diameter part, the second injection hole 812 of the large diameter part on the downstream side is formed. The second injection hole 802 in the small-diameter portion includes a downstream-side downstream injection hole wall surface 8028 and an upstream-side upstream injection hole wall surface 8029.

  In the second injection hole (802, 812) as well as the first injection hole (801, 811), the seat surface 8021 is configured in the same plane as the surface 8025 that contacts the spherical surface 610 of the valve body 114 in the valve seat 118. In the cross-sectional view of FIG. 10, it is formed on a substantially straight line. The sheet surface 8021 is defined by a plane parallel to the entrance surface 8027 of the injection hole 802. The angle formed by the normal line 8022 of the sheet surface 8021 and the central axis 8023 of the injection hole 802 is defined by the injection hole angle 8024.

  Although not shown in detail, the third to seventh injection holes (802-807, 812-817) are similarly composed of a small diameter injection hole (803-807) and a large diameter injection hole (813-817). Consists of Further, the central axis (8033-8073) of each small diameter portion injection hole (803-807) is a straight line connecting the center of each outlet face (8031-8071) and the center of the inlet face (8037-8077). Defined. Similarly, the seat surface (8031-8071) is configured in the same plane as the surface (8035-8075) that contacts the spherical surface 610 of the valve body 114 in the valve seat 118, and is formed on a substantially straight line in the sectional view. The sheet surface (8031-8071) is defined by a plane parallel to the entrance surface (8031-8071) of the injection hole (803-807). The angle formed by the normal line (8032-8072) of the sheet surface (8031-8071) and the central axis (8033-8073) of the injection hole (803-807) is the injection hole angle (8034-8074). Defined by

  The fuel injection device 204 of this embodiment is attached to the engine cylinder inner wall surface 210 shown in FIG. 2, and the first injection hole 801 and the second injection hole 802 are on the side of the spark plug 203 in the engine axial direction of FIG. Placed in. A fifth injection hole 805 is disposed on the piston 209 side in the engine axial direction of FIG.

  In this case, as described above, the size of the respective injection hole angles θ of the first injection hole 801 and the second injection hole 802 is equal to the other third to seventh injection holes (803, 804, 805, 806, 807) is configured so that the injection hole angle θ is small. The size of the injection hole angle θ (8034-8074) of the third to seventh injection holes (803, 804, 805, 806, 807) is the injection hole angle θ (5034-5074) in FIGS. It is assumed that each size is the same. In the configuration of FIG. 5, as described with reference to FIG. 7, the penetration of the spray D <b> 1 becomes longer in the injection hole 501. This is because the fuel flow rate is fast and the fuel peels from the downstream injection hole wall surface 5018 at the injection hole inlet. In contrast, in the configuration of the present embodiment, the injection hole 501 having a larger injection hole angle θ than the other injection holes is divided into two. That is, by forming the first injection hole 801 and the second injection hole 802 having a larger injection hole angle θ (8014, 8024) with respect to the other injection holes (803-807) in the orifice forming portion 116, two. As compared with the configuration of FIG. 5, the flow rate per injection hole can be reduced. Therefore, as shown in FIGS. 9 and 10, the flow velocity at the outlet surface 8111 of the injection hole of the injection hole 801 and the outlet surface 8121 of the injection hole 802 can be suppressed.

The fuel injected from the injection hole becomes maximum when the valve element 114 is opened, that is, when the cross-sectional area of the seat opening is increased, and the penetration increases under this condition.
According to the present embodiment, it is possible to reduce the flow velocity in a state where the valve body 114 is opened. As described above, in the present embodiment, in the plurality of injection holes (801-807), the direction of the normal line (8012-8072) of the sheet surface (8011-8071) and the central axis of the injection holes (801-807) ( The angle (8014-8074) formed by the direction of 8013-8073) is defined as the injection hole angle. Of the plurality of injection holes (801-807), the injection holes (801, 802) are in the direction of the normal line (8012, 8022) of the sheet surface 601 and the central axes (8013, 8023) of the injection holes (801, 802). ) Are formed such that the injection hole angle (8014, 8024) formed by the direction of () is larger than the injection hole angle (8034-8074) of any other injection hole (803-807).

  Then, by configuring the injection holes (801, 802) with the two injection holes (801, 802) as described above, valve opening at the outlet surfaces (8111, 8121) of the injection holes (801, 802) is performed. The hourly flow velocity is configured to be smaller than the valve opening velocity at the outlet face (8131-8171) of any other injection hole (803-807).

  When the orifice forming portion 116 is viewed from the downstream side, a plurality of injection holes (801-807) are formed side by side in the circumferential direction with respect to the center 840 of the orifice forming portion 116. In the present embodiment, the area of the exit face (8111, 8121) of the two injection holes (801, 802) is larger than the area of the exit face (8131-8171) of any other injection hole (803-807). Is also configured to be smaller. The total area of the exit surfaces (8111-8121) of the two injection holes (801, 802) is configured to be larger than the area of the exit surface of any other injection hole (8131-8171). It is.

  The two injection holes (801, 802) have their exit surfaces (8111, 8121) with respect to any of the exit surfaces (811, 8171) of the two injection holes (803, 807) positioned so as to sandwich them. Was formed so as to have a small area. That is, the injection hole that has a low flow rate when the valve is opened is composed of two injection holes (801, 802), and the two injection holes (803, 807) positioned so as to sandwich these injection holes (801, 802). The area of the exit face (8111, 8121) of the injection hole (801, 802), which has a low flow velocity when the valve is opened, is made smaller than the area of the exit face (811, 8171).

According to the configuration of the present embodiment described above, since the flow velocity in the state in which the valve body 114 is opened can be reduced, it is possible to suppress penetration even under conditions where the penetration is large in the past, and enhance the PN reduction effect. It is done.
In addition, it is desirable that the areas (cross-sectional areas) of the exit surfaces (8111, 8121) of the two injection holes (801, 802) are substantially the same. Thereby, from Formula (1), the flow volume of the injection hole 801 and the injection hole 802 can be made substantially the same. The injection hole 801 and the injection hole 802 can be formed symmetrically with respect to a plane 820 passing through the center 840 of the orifice forming portion and the injection hole 805 directed to the most piston side. Therefore, sprays D11 and D12 having flow rates symmetrical to the plane 820 can be formed in the injection hole 801 and the injection hole 802. Thereby, the homogeneity of the air-fuel mixture in the engine cylinder can be improved and PN can be suppressed. In addition, the distance 830 between the injection holes 801 and 802 is smaller than the distance 836 between the injection hole 801 and the adjacent injection hole 807 and the distance 831 between the injection hole 802 and the adjacent injection hole 803. It is good to configure.

  Here, as shown in FIG. 8, the length of a straight line connecting the center of the outlet surface 8111 of the injection hole 801 and the center of the outlet surface 8121 of the adjacent injection hole 802 is defined as a distance 830. The exit surface of the injection hole is defined by the exit surface 8111 of the small diameter portion of the injection hole 801 as shown in FIG. Similarly, the distance 831 is defined as the length of a straight line connecting the center of the outlet surface 8121 of the injection hole 802 and the center of the outlet surface 8131 of the adjacent injection hole 803. Hereinafter, similarly, the center of the outlet face (8131-8171) of the injection hole (803-807) and the center of the outlet face (8141-8171, 8111) of the adjacent injection hole (804-807, 801) are connected. The length of the straight line is defined as the distance (832-836).

  A distance 830 between the center of the outlet surface 8111 of the injection hole 801 and the center of the outlet surface 8121 of the injection hole 802 is between the center of the outlet surface 8121 of the injection hole 802 and the center of the outlet surface 8131 of the injection hole 803. The distance 831 is smaller than the distance 831. A distance 830 between the center of the outlet surface 8111 of the injection hole 801 and the center of the outlet surface 8121 of the injection hole 802 is between the center of the outlet surface 8171 of the injection hole 807 and the center of the outlet surface 8111 of the injection hole 801. It is formed to be smaller than the distance 836.

  By increasing the distance 831 and the distance 836 between the injection holes, the fluid resistance between the injection holes is increased, so that the fuel flowing from the upstream of the injection holes is less likely to flow into the injection holes 801 and 802. The flow rate of the first injection hole 801 and the second injection hole 802 can be reduced. As a result, the penetration of the injection hole directed toward the spark plug, which has been a problem in FIG. 5, can be suppressed, and the PN can be reduced.

  Further, the distance 830 between the injection holes of the first injection hole 801 and the second injection hole 802 is the distance 831 between the second injection hole 802 and the third injection hole 803 and the third injection hole 803 and the third injection hole 803. A distance 832 between the fourth injection hole 804, a distance 833 between the fourth injection hole 804 and the fifth injection hole 805, a distance 834 between the fifth injection hole 805 and the sixth injection hole 806, and a sixth injection hole It may be configured to be smaller than any of the distance 835 between the 806 and the seventh injection hole 807 and the distance 836 between the seventh injection hole 807 and the first injection hole 801.

  As a result, the fluid resistance of the first injection hole 801 and the second injection hole 802 can be made larger than that of the other injection holes, so that the fuel flowing from the upstream side of the injection holes is the first injection hole 801 and the second injection hole 802. This makes it difficult to flow into the first injection hole 802, and the flow rates of the first injection hole 801 and the second injection hole 802 can be reduced. As a result, the penetration of the spray D11 of the first injection hole 801 and the spray D12 of the second injection hole 802 can be suppressed, and PN can be reduced.

  In addition, you may comprise these two injection holes (801, 802) by one injection hole. That is, the single injection formed so that the injection hole angle formed by the normal direction of the sheet surface and the central axis direction of the injection hole is larger than the injection hole angles of the other injection holes among the plurality of injection holes. You may comprise so that the area of the exit surface of a hole may become larger than the area of the exit surface of any other injection hole. When these two injection holes (801, 802) are constituted by one injection hole, the shape of the injection hole may be, for example, an elliptical shape so that the cross-sectional area of the injection hole can be easily increased.

  Further, by reducing the flow rate flowing through the first injection hole 801 and the second injection hole 802, the seventh injection hole 807 adjacent to the first injection hole 801 and the second injection hole 802 adjacent to the second injection hole 802 are provided. The flow rate of the three injection holes 803 increases. Accordingly, the flow velocity at the outlet of the third injection hole 803 and the seventh injection hole 807 is increased, the penetration force of the spray D13 and the spray D17 in FIG. 11 is increased, and the penetration of these injection holes can be increased. .

  Since the sprays D13 and D17 formed near the intake valves 205A and 205B are close to the intake valves 205A and 205B, they are easily affected by the flow of the inflowing air. Therefore, by adopting the above-described configuration of the present embodiment, by ensuring the penetration force of the sprays D13 and D17 and lengthening the penetration, the directivity of the sprays D13 and D17 can be secured even when the air flow is strong. The homogeneity of the mixture can be improved. As a result, the effects of improving combustion efficiency and reducing PN can be obtained.

Further, in a transient state where the vehicle accelerates and decelerates compared to the case of steady running where the engine speed is constant, the air flow may be strong and the spray may be affected to lower the homogeneity of the air-fuel mixture.
According to the configuration of the present embodiment, the homogeneity of the air-fuel mixture can be improved and the PN reduction effect can be enhanced by increasing the penetration force of the sprays D13 and D17 even in a transient state.

  In this embodiment, the distance 836 between the first injection hole 801 and the seventh injection hole 807 and the distance 831 between the second injection hole 802 and the third injection hole 803 are set to other adjacent injection holes. Distance 830, distance 832, distance 833, distance 834, and distance 835. Thereby, the penetration of the sprays D13 and D17 directed to the intake valves 301 and 302 can be the longest compared with the other sprays D11, D12, D14, D15, and D16. Therefore, it is possible to shorten the penetration of the sprays D11 and D12 directed in the direction of the spark plug 203 rather than the sprays D13 and D17. By applying this to a direct injection engine constituted by the intake valve 205, the spark plug 203, the piston 209, and the cylinder 229, a PN reduction effect can be obtained.

  In this embodiment, in the state where the fuel injection device is attached, the two injection holes (801, 802) each have a central axis (8013, 8023) with respect to the tip 1201 of the spark plug 203. It arrange | positions so that it may face the 209 side. In addition, when the two injection holes (801, 802) are configured by a single injection hole, the injection hole having a larger exit surface area than any of the other injection holes (803-807) It is good to be comprised so that it may face the spark plug 203 side rather than the other injection hole (803-807).

  Furthermore, in this case, it is desirable that this single injection hole is directed most toward the spark plug with respect to the other injection holes. Further, when the two injection holes (801, 802) are configured, the two injection holes (801, 802) are directed most toward the spark plug 203 with respect to the other injection holes (803-807). It is desirable to configure.

  In other words, the sprays D11 and D12 directed in the spark plug direction are preferably formed so as to be directed toward the piston 209 side with respect to the tip portion 1201 of the spark plug 203. In addition, since the angles of the spray D11 and the spray D12 are determined by the angles of the central axis (injection hole central axis) of the injection hole 801 and the injection hole 802, the central axis of the injection hole of the injection hole 801 and the injection hole 802 is the spark plug 203. It is good to comprise so that it may face the piston 209 side with respect to the front-end | tip part 1201. As a result, the spray D11 and the spray D12 can suppress the fuel fog of the spark plug and can realize stable ignition of the air-fuel mixture, so that the combustion stability can be improved. Further, the smaller the angle 630 formed by the sheet of FIG. 6 is, the larger the injection hole injection angle θ of the injection hole 801 and the injection hole 802 is. Therefore, in this embodiment, for example, the angle 630 is effective within a range of 150 degrees or less.

  As described above, in this embodiment, the flow velocity of the injection hole having a large injection hole angle θ formed by the normal direction of the seat of the valve body and the central axis of each injection hole is made slower than the flow velocity of the other injection holes. Configure. When the amount of fuel flowing from the injection hole with a large injection hole angle θ decreases, the flow rate of the fuel flowing through the injection hole decreases, and the separation of the fuel at the injection hole inlet decreases. As a result, the fuel flows evenly over the entire injection hole with the large injection hole angle θ, so that the substantial injection hole diameter becomes large, and the flow velocity at the outlet of the injection hole with the large injection hole angle θ decreases. Therefore, since the penetration force of the spray injected from the injection hole having the large injection hole angle θ becomes small, the penetration can be shortened and the PN can be suppressed. As a result, the penetration is shortened to prevent the fuel from adhering to the inner wall surface of the cylinder, and the PN can be reduced.

  Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 13 is an enlarged view of the vicinity of the injection hole of the orifice forming portion 116 according to the present embodiment as viewed from the front end direction of the fuel injection device 204 according to the present embodiment. 13, parts similar to those in FIG. 8 are denoted by the same reference numerals and description thereof is omitted.

  The difference between the present embodiment and the first embodiment is that the inner diameters of the injection holes 1303 and 1307 adjacent to the first injection hole 801 and the second injection hole 802 are the same as those of the injection holes 801 and 802. This is the point that made it larger than the inner diameter of the injection hole.

  As in the first embodiment, the injection hole angles (8014, 8024) of the first injection hole 801 and the second injection hole 802 are the injection hole angles of any other injection holes (1303, 804-806, 1307). It is formed so as to be larger. And the internal diameter of the exit surface of two injection holes (1303, 1307) located so that these two injection holes (801, 802) may be pinched | interposed in the circumferential direction is the exit surface of two injection holes (801, 802). It is configured to be larger than the inner diameter of (8111, 8121). In other words, the area of the exit surface of the two injection holes (1303, 1307) positioned so as to sandwich the two injection holes (801, 802) in the circumferential direction is equal to the two injection holes (801, 802). ) Of the exit surface (8111, 8121). In addition, since the definition of the exit surface of two injection holes (1303 and 1307) is the same as that of Example 1, description is abbreviate | omitted.

By configuring in this way, the ratio of the fuel injected from the third injection hole 1303 and the seventh injection hole 1307 can be made larger than that of the first injection hole 801 and the second injection hole 802. Therefore, the amount of fuel injected from the first injection hole 801 and the second injection hole 802 is relatively small. When the fuel flowing through the first injection hole 801 and the second injection hole 802 decreases, the flow rate of the fuel in the injection holes of the first injection hole 801 and the second injection hole 802 decreases.
Therefore, in FIG. 9, the separation of the fuel at the injection hole inlet is reduced, and the fuel is easily injected from the injection hole along the injection hole wall surface 8019. Accordingly, since the separation is small, the fuel flows through the entire first injection hole 801 and the second injection hole 802, so that the substantial injection hole diameter Do becomes larger from the relationship of the equation (1), and the flow velocity Vo. Decreases.

In addition, since the flow velocity distribution at the outlets at the first injection hole 801 and the second injection hole 802 is made uniform, the maximum value of the flow velocity vector decreases. Therefore, since the penetration force of the spray becomes small, the penetration can be shortened. As a result, fuel adhesion to the cylinder inner wall surface 210 can be reduced, and PN can be suppressed.
Further, the inner diameters of the large diameter portion 1313 of the injection hole 1303 and the large diameter portion 1317 of the injection hole 1307 may be configured to be larger than the inner diameters of the large diameter portions 811 and 812. Since it is necessary to provide a certain clearance in the gap between the injection hole diameter and the large diameter part so that the fuel injected from the injection hole does not adhere to the inner diameter of the large diameter part, the inner diameter of the large diameter part is set according to the injection hole diameter. By determining, fuel adhesion to the large diameter portion can be suppressed, and PN generated by the adhered fuel can be suppressed.

DESCRIPTION OF SYMBOLS 101 ... Nozzle holder 102 ... Movable element 103 ... Housing 104 ... Bobbin 105 ... Coil 107 ... Magnetic core 110 ... Spring 112 ... Zero spring 114 ... Valve body 116: Orifice formation part 118 ... Valve seat 119 ... Injection hole 120 ... Guide part 121 ... Seal member 124 ... Adjuster pin 153 ... Drive circuit 154 ... ECU
203 ... Spark plug 204 ... Fuel injection device 205 ... Intake valve 209 ... Piston 211 ... Exhaust valve 220 ... Cylinder

Claims (12)

In a fuel injection device having a plurality of injection holes,
Of the plurality of injection holes, the injection hole formed such that the injection hole angle formed by the normal direction of the sheet surface and the central axis direction of the injection hole is larger than the injection hole angle of any other injection hole, A fuel injection device configured such that a valve opening flow velocity at the outlet surface of the injection hole is smaller than a valve opening flow velocity at the outlet surface of any other injection hole. In a fuel injection device having a plurality of injection holes,
Outlet of the injection hole formed such that the injection hole angle formed by the normal direction of the sheet surface and the central axis direction of the injection hole is larger than the injection hole angle of any other injection hole among the plurality of injection holes A fuel injection device configured such that the surface area is larger than the area of the exit surface of any other injection hole. In a fuel injection device having a plurality of injection holes,
Two injection holes formed so that the injection hole angle formed by the normal direction of the sheet surface and the central axis direction of the injection hole is larger than the injection hole angle of any other injection hole among the plurality of injection holes Each of the exit surface areas of the two injection holes is configured to be smaller than the area of the exit surface of any other injection hole, and the total area of the exit surface areas of the two injection holes is that of any other injection hole. A fuel injection device configured to be larger than the area of the outlet surface. The fuel injection device according to claim 1,
The injection hole, which has a low flow rate when the valve is opened, is composed of two injection holes, and has a low flow rate when the valve is opened with respect to the area of the outlet surface of the two injection holes positioned so as to sandwich the injection holes. A fuel injection device formed so that any area of the exit surface of the injection hole is reduced. The fuel injection device according to claim 3, wherein
The fuel injection device, wherein the two injection holes are formed so that the area of the outlet surface of any two injection holes positioned so as to sandwich them is small. The fuel injection device according to claim 3, wherein
A fuel injection device formed such that the areas of the exit surfaces of the two injection holes have substantially the same size. The fuel injection device according to claim 1,
The injection hole, which has a low flow velocity when the valve is opened, is composed of two injection holes, and the distance between the centers of these outlet surfaces is that of the outlet surface of the injection hole adjacent to the center of the outlet surface of one injection hole. A fuel injection device configured to be smaller than a distance between the center and smaller than a distance between a center of an outlet surface of the other injection hole and a center of an outlet surface of an adjacent injection hole. The fuel injection device according to claim 3, wherein
The distance between the centers of the outlet surfaces of the two injection holes is smaller than the distance between the center of the outlet surface of one injection hole and the center of the outlet surface of the adjacent injection hole, and A fuel injection device configured to be smaller than a distance between a center of an outlet surface and a center of an outlet surface of an adjacent injection hole. The fuel injection device according to claim 2, wherein
A fuel injection device arranged such that an injection hole central axis of the injection hole having a larger exit surface area than any other injection hole is directed to a piston side with respect to a tip portion of a spark plug. The fuel injection device according to claim 3, wherein
The fuel injection device is arranged such that the injection hole central axis of the two injection holes is directed to the piston side with respect to the tip end portion of the spark plug. The fuel injection device according to claim 2, wherein
A fuel injection device configured such that the injection hole having a larger exit surface area than any other injection hole is directed to the spark plug side more than any other injection hole. The fuel injection device according to claim 3, wherein
A fuel injection device configured such that the two injection holes are oriented most toward the spark plug with respect to the other injection holes.

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