JP2013181454A - Fuel injection system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress interference of a fuel spray on the top surface or the intake vale of a piston when performing fuel injection during its intake stroke, in an internal combustion engine equipped with a fuel injection valve for injecting fuel directly into a cylinder.SOLUTION: In a fuel injection valve for injecting fuel directly into the cylinder of an internal combustion engine, a plurality of injection holes are arranged side by side on the circumference at the tip of an injection valve body confronting rear the top surface in the cylinder, and respective injection holes are formed while being inclined to the tip direction of the fuel injection valve from the inside to the outside relative to the axis of the injection valve body. When injecting the fuel from the fuel injection valve during the intake stroke, the lift amount from the valve seat of the valve body is controlled to an optional intermediate lift amount less than the maximum lift amount at the fuel injection in an initial intake stroke (a), while the lift amount from the seat of the valve body is controlled to the maximum lift amount at the fuel injection later than the initial intake stroke (b).

Description

  The present invention relates to a fuel injection system for an internal combustion engine.

  As a fuel injection valve for an internal combustion engine, a valve body that can be displaced in the axial direction is provided in the injection valve body, and the valve body is formed at the tip of the injection valve body by being displaced in the axial direction. The thing of the structure which opens and closes a nozzle hole is known. In such a fuel injection valve, fuel is supplied to the injection hole when the valve element is separated from the valve seat portion formed inside the injection valve main body. Thereby, fuel is injected from the nozzle hole. On the other hand, when the valve body is seated on the valve seat portion, the supply of fuel to the nozzle hole is shut off. Thereby, fuel injection is stopped.

  Patent Document 1 discloses a technique related to an internal combustion engine including a fuel injection valve that directly injects fuel into a cylinder. In the internal combustion engine described in Patent Document 1, the fuel injection valve injects fuel from the end of one side of the cylinder head toward the intake passage toward the inside of the cylinder. In this internal combustion engine, the spray injected from the fuel injection valve has an eight-letter shape sandwiching the ignition plug in a top view and a fan shape in a side view. In the technique described in Patent Literature 1, the spread angle of the spray fan shape is reduced or the lift amount of the intake valve is reduced so that the fuel and the intake valve do not interfere with each other.

  Patent Document 2 discloses a technique for varying the lift amount of a valve body in a fuel injection valve that opens and closes an injection hole by displacing a valve body provided inside the injection valve body in the axial direction by electromagnetic force. Has been.

JP 2006-258008 A JP 2009-150270 A JP 2010-255444 A JP 2009-138639 A

  In an internal combustion engine provided with a fuel injection valve that directly injects fuel into a cylinder, fuel may be injected from the fuel injection valve during an intake stroke in order to form a more homogeneous mixture. However, if fuel is injected into the cylinder during the intake stroke, the spray of fuel injected on the top surface of the piston located above the cylinder or the intake valve that is open may interfere. When fuel spray interferes with the top surface of the piston or the intake valve and the fuel adheres to these, the discharge amount of unburned fuel components and particulate matter increases, and the exhaust characteristics may deteriorate.

  The present invention has been made in view of such problems, and in an internal combustion engine having a fuel injection valve that directly injects fuel into a cylinder, the top of the piston is used when fuel injection is performed during an intake stroke. It aims at suppressing that the spray of fuel interferes with a surface or an intake valve.

  In the present invention, when fuel is injected from the fuel injection valve during the intake stroke, the lift amount of the valve body is controlled to an arbitrary intermediate lift amount smaller than the maximum lift amount during the fuel injection in the initial stage of the intake stroke, and the intake stroke At a time after the initial stage, the lift amount of the valve body is controlled to the maximum lift amount.

More specifically, the fuel injection system for an internal combustion engine according to the present invention is:
A fuel injection valve for directly injecting fuel into a cylinder of an internal combustion engine,
A valve body that can be displaced in the axial direction is provided in the injection valve body,
A plurality of nozzle holes are arranged circumferentially at the tip of the injection valve body facing the top surface in the cylinder, and each nozzle hole faces from the inner side to the outer side with respect to the axis of the injection valve body. And inclined toward the tip of the fuel injection valve,
When the valve element is separated from the valve seat formed inside the injection valve body, the fuel is supplied to the nozzle hole, and when the valve element is seated on the valve seat, the fuel supply to the nozzle hole is shut off. A fuel injection valve that is closed; and
When fuel is injected from the fuel injection valve during the intake stroke, the lift amount from the valve seat portion of the valve body is controlled to an arbitrary intermediate lift amount smaller than the maximum lift amount at the time of fuel injection at the initial stage of the intake stroke, At the time of fuel injection at a time after the initial stage of the intake stroke, a lift control unit that controls the lift amount from the valve seat portion of the valve body to the maximum lift amount;
Is provided.

  In the fuel injection valve according to the present invention, each injection hole is formed so as to incline toward the tip of the fuel injection valve from the inner side toward the outer side with respect to the axis of the injection valve main body. That is, the plurality of injection holes are formed so as to spread from the inner side to the outer side toward the tip of the fuel injection valve. Therefore, the fuel spray spreads in a conical or fan shape from the tip of the fuel injection valve.

  Here, when the lift amount from the valve seat portion of the valve body at the time of fuel injection becomes small, the fuel that has flowed into the nozzle hole easily flows in the axial direction of the nozzle hole. For this reason, the central angle (spreading angle) of the fuel spray increases and the penetration force decreases.

  In the initial stage of the intake stroke, the piston is positioned above the cylinder. In the present invention, during fuel injection at such a time, the lift amount from the valve seat portion of the valve element is controlled to an arbitrary intermediate lift amount smaller than the maximum lift amount. Thereby, since the penetration force of the fuel spray can be reduced, it is possible to suppress the fuel spray from interfering with the top surface of the piston. As a result, adhesion of fuel to the top surface of the piston can be suppressed.

  Further, in the present invention, the amount of lift from the valve seat portion of the valve body is controlled to the maximum lift amount at the time of fuel injection at a time after the initial stage of the intake stroke. Accordingly, since the central angle of the fuel spray can be reduced, it is possible to suppress the fuel spray from interfering with the opened intake valve. As a result, the adhesion of fuel to the intake valve can be suppressed.

  In the present invention, each nozzle hole of the injection valve main body has an axis of the nozzle hole that is directed from the inner side to the outer side than the direction perpendicular to the plane formed by the inlet side opening of the nozzle hole. You may form so that it may incline outside.

  According to this, the plurality of injection holes are formed so as to expand further from the inner side toward the outer side toward the distal end direction of the fuel injection valve. Therefore, the spread angle of the fuel spray becomes larger, and the penetration force of the fuel spray becomes smaller. Therefore, it is possible to further suppress the interference of fuel spray on the top surface of the piston.

  According to the present invention, in an internal combustion engine equipped with a fuel injection valve that directly injects fuel into a cylinder, fuel injection interferes with the top surface of the piston or the intake valve when fuel injection is performed during the intake stroke. Can be suppressed.

It is a figure which shows the structure of the fuel injection valve vicinity of the internal combustion engine which concerns on an Example. It is a figure which shows the structure of the fuel injection valve which concerns on an Example. It is a figure which shows the structure of the nozzle hole of the fuel injection valve which concerns on an Example. It is a figure which shows the structure of the nozzle hole of the fuel injection valve which concerns on an Example. It is a figure which shows the lift position of the needle valve at the time of the fuel injection based on an Example. It is a figure which shows the mode of spraying of the fuel injected from the fuel injection valve based on an Example. It is a figure which shows the positional relationship of the spray of the fuel injected from the fuel injection valve in the intake stroke, and an intake valve based on an Example. It is a figure which shows the execution time of intermediate | middle lift injection and the execution time of full lift injection in an intake stroke based on an Example. It is a figure which shows the lift amount of a needle valve based on an Example, the spread angle of fuel spray, a metering ratio, and the particle size of fuel spray. It is a flowchart which shows the flow of the fuel-injection control which concerns on an Example.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

<Example>
[Schematic configuration of the system]
A schematic configuration of a fuel injection system for an internal combustion engine according to the present embodiment will be described based on FIGS. 1, 2, 3A, and 3B. FIG. 1 is a diagram showing a configuration in the vicinity of a fuel injection valve of an internal combustion engine according to this embodiment. FIG. 2 is a diagram illustrating a configuration of the fuel injection valve according to the present embodiment. 3A and 3B are diagrams showing the configuration of the injection hole of the fuel injection valve according to the present embodiment. FIG. 3A is a cross-sectional view of a portion where a nozzle hole is formed at the tip of the fuel injection valve. FIG. 3B is a view of the tip portion of the fuel injection valve as viewed from below in FIG. 3A.

  The internal combustion engine 1 according to the present embodiment is a multi-cylinder internal combustion engine for driving a vehicle, and is a direct-injection type spark ignition internal combustion engine. However, the internal combustion engine according to the present invention is not limited to a spark ignition type internal combustion engine, and may be a compression ignition type internal combustion engine. In the internal combustion engine 1, two intake ports 2 and two exhaust ports 3 are connected to each cylinder 8. The intake port 2 sends intake air into the cylinder 8 through opening and closing of the intake valve 4, and the exhaust port 3 sends combustion gas and the like as exhaust to the exhaust system of the internal combustion engine 1 through opening and closing of the exhaust valve 5. A piston 9 is slidably provided in the cylinder 8.

  The internal combustion engine 1 is provided with a spark plug 6 and a fuel injection valve 7. The spark plug 6 is provided on a substantially central axis of the cylinder 8 and has a discharge portion that faces the cylinder 8 from a substantial center of the top surface in the cylinder 8. The spark plug 6 ignites the air-fuel mixture in the cylinder 8.

  The fuel injection valve 7 is a fuel injection valve that directly injects fuel into the cylinder 8. The fuel injection valve 7 is provided on the intake port 2 side of the cylinder 8, and the tip thereof faces the position between the openings of the two intake ports 2 on the side of the top surface in the cylinder 8. A plurality of injection holes are formed at the tip of the fuel injection valve 7. Fuel is injected obliquely downward in FIG. 1 from the injection hole toward the central axis of the cylinder 8. In FIG. 1, 10 represents the spray of fuel injected from the fuel injection valve 7. The detailed configuration of the fuel injection valve 7 will be described later.

  The internal combustion engine 1 is provided with an ECU 30 that is an electronic control unit. Various devices such as the fuel injection valve 7 are electrically connected to the ECU 30. Various sensors such as an accelerator opening sensor 31, a crank angle sensor 32, a water temperature sensor 33, and an oil temperature sensor 34 are electrically connected to the ECU 30. The accelerator opening sensor 31 detects the accelerator opening of a vehicle on which the internal combustion engine 1 is mounted. The crank angle sensor 32 detects the crank angle of the internal combustion engine 1. The water temperature sensor 33 detects the temperature of the cooling water of the internal combustion engine 1. The oil temperature sensor 34 detects the temperature of the lubricating oil of the internal combustion engine 1. Then, detection values of various sensors are input to the ECU 30.

  In this embodiment, the ECU 30 executes various controls in the internal combustion engine 1. For example, by changing the fuel injection timing from the fuel injection valve 7 by the ECU 30, combustion control for switching the combustion mode in the internal combustion engine 1 between stratified combustion and homogeneous combustion is executed. Stratified combustion is realized by executing fuel injection at a time near the top dead center of the compression stroke. On the other hand, homogeneous combustion is realized by executing fuel injection a plurality of times during the intake stroke. In this embodiment, an operation region in which stratified combustion is performed and an operation region in which homogeneous combustion is performed are determined in advance, and the ECU 30 selects one of the combustion forms according to the operation state of the internal combustion engine 1 and selects the selected combustion. The fuel injection timing is controlled to realize the form.

[Configuration of fuel injection valve]
The fuel injection valve 7 is a solenoid-driven fuel injection valve. A passage 71 through which fuel flows is formed in an injection valve body (body) 78 of the fuel injection valve 7. The passage 71 is supplied with fuel from a delivery pipe (not shown) through an introduction port 77. The supplied fuel is injected from an injection hole 76 formed at the tip in accordance with the operation of a needle valve 73 described later.

  A plunger 72 is slidably provided in the passage 71. A needle valve 73 is formed at the tip of the plunger 72. The needle valve 73 is biased by the coil spring 74 in the tip direction of the fuel injection valve 7 (downward in FIG. 2). An annular solenoid coil 75 is provided in the body 78 so as to surround the plunger 72. When the solenoid coil 75 is excited, a suction force is exerted on the plunger 72, and the plunger 72 is moved in a direction opposite to the tip direction of the fuel injection valve 7 against the biasing force of the coil spring 74 (upward direction in FIG. 2). ) Can be displaced. In the fuel injection valve 7, the suction force acting on the plunger 72 is controlled by adjusting the amount of current supplied to the solenoid coil 75.

  A seat portion 79 is formed in the vicinity of the front end portion in the body 78. When the needle valve 73 is seated on the seat portion 79 by the biasing force of the coil spring 74, the supply of fuel from the passage 71 to the nozzle hole 76 is shut off. That is, the fuel injection valve 7 is closed, and fuel injection is stopped. On the other hand, when the solenoid coil 75 is excited, a suction force is generated with respect to the plunger 72, whereby the needle valve 73 is lifted upward (upward in FIG. 2), and the needle valve 73 is separated from the seat portion 79. Then, fuel is supplied from the passage 71 to the nozzle hole 76. That is, the fuel injection valve 7 is opened and fuel is injected. Control of the lift amount from the seat 79 of the needle valve 73 during fuel injection will be described later.

  In the fuel injection valve 7 according to the present embodiment, six nozzle holes are arranged side by side on the circumference at the tip of the body 78. Each injection hole 76 is formed so as to incline in the tip direction of fuel injection valve 7 (downward in FIG. 2) from the inner side to the outer side with respect to the axis of body 78. That is, the six injection holes 76 are formed so as to expand from the inner side to the outer side toward the distal end direction of the fuel injection valve 7. With such a configuration, the spray of fuel injected from the fuel injection valve 7 spreads conically from the tip of the fuel injection valve 7. Note that the number of nozzle holes is not necessarily six, and a plurality of nozzle holes may be arranged side by side on the circumference.

  Further, in the fuel injection valve 7 according to the present embodiment, each nozzle hole 76 has a plane formed by the inlet side opening of the nozzle hole 76 with the axis of the nozzle hole 76 directed from the inner side to the outer side. It is formed so as to be inclined outward from the vertical direction. That is, the angle of the axis of the injection hole 76 on the outside of the fuel injection valve 7 and the axis of the fuel injection valve 7 with respect to the plane formed by the inlet side opening of the injection hole 76 (θt in FIG. 3A: hereinafter, deflection) Is called 90 °). The effect of such a configuration will be described later.

[Lift control]
Next, needle valve lift control during fuel injection according to this embodiment will be described with reference to FIGS. FIG. 4 is a diagram showing the lift position of the needle valve during fuel injection. FIG. 5 is a view showing a state of spraying fuel injected from the fuel injection valve.

  As described above, when fuel is injected from the fuel injection valve 7, the needle valve 73 is lifted upward so that when the needle valve 73 is separated from the seat portion 79, the passage 71 leads to the injection hole 76. Fuel is supplied and fuel is injected from the nozzle hole 76. And in the fuel injection valve 7 which concerns on a present Example, the attraction force which acts on the plunger 72 is controlled by adjusting the amount of electric current supplied to the solenoid coil 75, Thereby, the lift of the needle valve 73 at the time of fuel injection The amount can be variably controlled. Here, the lift amount of the needle valve 73 is a period from when the needle valve 73 is separated from the seat portion 79 until it is next seated on the seat portion 79 (that is, a period during which one fuel injection is performed). The lift amount when the position of the needle valve 73 is farthest from the seat portion 79.

  FIG. 4A shows the lift position of the needle valve 73 when the lift amount of the needle valve 73 at the time of fuel injection is controlled to an arbitrary intermediate lift amount smaller than the maximum lift amount. FIG. 4B shows the lift position when the lift amount of the needle valve 73 during fuel injection is controlled to the maximum lift amount. 4 (a) and 4 (b), arrows indicate the flow of fuel. FIG. 5A shows the state of fuel spray when the lift amount of the needle valve 73 during fuel injection is controlled to an intermediate lift amount. FIG. 5B shows the state of fuel spray when the lift amount of the needle valve 73 during fuel injection is controlled to the maximum lift amount. The maximum lift amount is a maximum value of the lift amount of the needle valve 73 determined due to the configuration of the fuel injection valve 7.

  When the lift amount of the needle valve 73 is controlled to an intermediate lift amount, the distance between the needle valve 73 and the seat portion 79 of the body 78 is smaller than when the lift amount of the needle valve 73 is controlled to the maximum lift amount. Then, when the fuel flows into the nozzle hole 76, the magnitude of the component of the pressure acting on the fuel in the vertical direction (the axial direction of the fuel injection valve 7) is reduced. Therefore, the fuel that has flowed into the nozzle hole 76 is less likely to flow in the axial direction of the fuel injection valve 7, and easily flows in the axial direction of the nozzle hole 76. As a result, when the lift amount of the needle valve 73 is controlled to the intermediate lift amount, the central angle (spreading angle) θc of the fuel spray 10 is larger than when the lift amount of the needle valve 73 is controlled to the maximum lift amount. Become. Further, in this case, the penetrating force of the fuel spray 10 is smaller than when the lift amount of the needle valve 73 is controlled to the maximum lift amount. In other words, the distance from the tip of the fuel injection valve 7 at the position where the fuel spray reaches is shortened.

  Here, in the internal combustion engine 1 according to the present embodiment, when performing homogeneous combustion, as described above, fuel injection from the fuel injection valve 7 is performed a plurality of times during the intake stroke. In such a case, it is necessary to perform fuel injection even in the initial stage of the intake stroke. However, in the initial stage of the intake stroke, the piston 9 is located above the cylinder 8. Therefore, the fuel spray injected from the fuel injection valve 7 is likely to interfere with the top surface of the piston 9.

Therefore, in the present embodiment, at the time of fuel injection at the initial stage of the intake stroke, the needle valve 73 is used.
The lift amount is controlled to an intermediate lift amount. Thereby, since the penetration force of the fuel spray can be reduced, it is possible to suppress the fuel spray from interfering with the top surface of the piston 9.

  On the other hand, since the intake valve 4 is open during the intake stroke, the fuel spray injected from the fuel injection valve 7 may interfere with the intake valve 4. Therefore, in this embodiment, the lift amount of the needle valve 73 is controlled to the maximum lift amount at the time of fuel injection at a time after the initial stage of the intake stroke.

  FIG. 6 is a diagram showing the positional relationship between the fuel spray injected from the fuel injection valve and the intake valve during the intake stroke. In FIG. 6, 10a represents fuel spray when the lift amount of the needle valve 73 is controlled to an intermediate lift amount, and 10b represents the amount of fuel when the lift amount of the needle valve 73 is controlled to the maximum lift amount. Represents spraying. When the lift amount of the needle valve 73 is controlled to the maximum lift amount, the spread angle of the fuel spray can be reduced. Therefore, as shown in FIG. 6, as shown in FIG. It can suppress that it interferes with.

  As described above, according to the lift control of the needle valve at the time of fuel injection according to the present embodiment, in order to perform homogeneous combustion in the internal combustion engine 1, when performing fuel injection a plurality of times during the intake stroke, the intake stroke initial stage , The fuel spray interference with the top surface of the piston 9 can be suppressed, and the fuel spray interference with the intake valve 4 can be suppressed at a time later than the initial stage in the intake stroke. Therefore, it is possible to suppress the fuel from adhering to the top surface of the piston 9 and the intake valve 4. As a result, it is possible to suppress an increase in the amount of unburned fuel components and particulate matter due to fuel adhering to them.

[Intermediate lift injection execution timing and intermediate lift amount]
Hereinafter, fuel injection performed by controlling the lift amount of the needle valve 73 to the intermediate lift amount is referred to as “intermediate lift injection”. The fuel injection performed by controlling the lift amount of the needle valve 73 to the maximum lift amount is referred to as “full lift injection”.

  FIG. 7 is a diagram illustrating the execution timing of the intermediate lift injection and the execution timing of the full lift injection in the intake stroke. In FIG. 7, the horizontal axis represents the crank angle (BTDC) of the internal combustion engine 1, the upper vertical axis represents the lift amount of the intake valve 4, and the lower vertical axis represents the position of the piston 9 in the cylinder 8. Represents. As shown in FIG. 7, the execution timing of the intermediate lift injection and the execution timing of the full lift injection in the intake stroke are defined based on the relationship between the lift amount of the intake valve 4 and the position of the piston 9 in the cylinder 8. The

  FIG. 8 shows the lift amount of the needle valve, the spread angle of the fuel spray, the metering ratio (the area between the needle valve and the seat portion when the needle valve is lifted / the cross-sectional area of the nozzle hole), and the fuel It is a figure which shows the relationship with the particle size of spray. In FIG. 8, the horizontal axis represents the lift amount of the needle valve 73, the upper vertical axis represents the fuel spray spread angle, the middle vertical axis represents the metering ratio, and the lower vertical axis. The axis represents the particle size of the fuel spray. As shown in FIG. 8, the intermediate lift amount during the intermediate lift injection is set based on the relationship between the fuel spray spread angle, the metering ratio, and the fuel spray particle size.

  Here, if the lift amount of the needle valve 73 is controlled to an amount where the metering ratio is smaller than 1, a throttle larger than the throttle due to the injection hole 76 is generated in the seat portion 79 in the body 78. . Therefore, the intermediate lift amount at the time of intermediate lift injection is set in a range where the metering ratio is larger than 1, as shown in FIG.

[Flow of fuel injection control]
Hereinafter, the flow of the fuel injection control according to the present embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing a flow of fuel injection control according to the present embodiment. This flow is stored in advance in the ECU 30, and is repeatedly executed by the ECU 30.

  In this flow, in step S101, the temperature To of the lubricating oil of the internal combustion engine 1 detected by the oil temperature sensor 34 is higher than the predetermined temperature, and the temperature Tw of the cooling water of the internal combustion engine 1 detected by the water temperature sensor 33 is the predetermined temperature. It is determined whether or not it is higher. Here, the predetermined temperature is determined as to whether or not there is a high possibility of excessive dilution of the lubricating oil or increase in the discharge amount of particulate matter due to fuel adhering to the top surface of the piston 9 or the intake valve 4. This is a temperature that becomes a threshold value. This predetermined temperature is determined in advance based on experiments and the like, and is stored in the ECU 30.

  If an affirmative determination is made in step S101, it can be determined that there is a low possibility that a problem will occur even if, for example, full lift injection is performed at the beginning of the intake stroke to perform homogeneous combustion. Therefore, in this case, next, in step S105, full lift injection is executed.

  On the other hand, if a negative determination is made in step S101, the process of step S102 is executed next. In step S102, it is determined whether or not the operating state of the internal combustion engine 1 belongs to the stratified combustion region. If an affirmative determination is made in step S102, stratified combustion is selected as the combustion mode of the internal combustion engine 1, so fuel injection in the intake stroke is not performed. Therefore, in this case, next, in step S105, full lift injection is executed.

  On the other hand, if a negative determination is made in step S102, homogeneous combustion is selected as the combustion mode of the internal combustion engine 1. In this case, the process of step S103 is performed next. In step S103, it is determined whether or not the timing of fuel injection during the intake stroke belongs to the execution timing of intermediate lift injection as shown in FIG. If an affirmative determination is made in step S103, then intermediate lift injection is executed in step S104. On the other hand, if a negative determination is made in step S103, it can be determined that the fuel injection timing during the intake stroke belongs to the execution timing of full lift injection as shown in FIG. Therefore, in this case, next, in step S105, full lift injection is executed.

  According to the flow as described above, fuel injection is performed during the intake stroke to perform homogeneous combustion in the internal combustion engine 1 under the condition that the temperature To of the lubricating oil of the internal combustion engine 1 or the temperature Tw of the cooling water is equal to or lower than the predetermined temperature T0. When executed, the intermediate lift injection is executed at the injection timing at the initial stage of the intake stroke, and the full lift injection is executed at the injection timing after the initial stage of the intake stroke.

[Effects of the structure of the nozzle hole according to this embodiment]
In the fuel injection valve 7 according to the present embodiment, as described above, the deflection angle of the injection hole 76 is larger than 90 °. According to such a configuration, the plurality of injection holes 76 are formed so as to expand from the inner side toward the outer side toward the distal end direction of the fuel injection valve 7. Therefore, the spread angle of the fuel spray is further increased and the penetration force of the fuel spray is further reduced as compared with the case where the deflection angle of the nozzle hole 76 is 90 ° or less. In particular, at the time of intermediate lift injection, since the fuel that has flowed into the nozzle hole 76 tends to flow in the axial direction of the nozzle hole 76, such an effect becomes more remarkable.

  Therefore, by making the deflection angle of the injection hole 76 larger than 90 °, it becomes possible to further suppress the interference of fuel spray on the top surface of the piston 9.

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Intake port 4 ... Intake valve 6 ... Spark plug 7 ... Fuel injection valve 71 ... Passage 72 ... Plunger 73 ... Needle valve 74 ... Coil spring 75 · · Solenoid coil 76 · · Injection hole 77 · · Inlet 78 · · Injection valve body (body)
79 ·· Seat 8 · · · Cylinder 9 · · · Piston 30 · · ECU

Claims (2)

A fuel injection valve for directly injecting fuel into a cylinder of an internal combustion engine,
A valve body that can be displaced in the axial direction is provided in the injection valve body,
A plurality of nozzle holes are arranged circumferentially at the tip of the injection valve body facing the top surface in the cylinder, and each nozzle hole faces from the inner side to the outer side with respect to the axis of the injection valve body. And inclined toward the tip of the fuel injection valve,
When the valve element is separated from the valve seat formed inside the injection valve body, the fuel is supplied to the nozzle hole, and when the valve element is seated on the valve seat, the fuel supply to the nozzle hole is shut off. A fuel injection valve that is closed; and
When fuel is injected from the fuel injection valve during the intake stroke, the lift amount from the valve seat portion of the valve body is controlled to an arbitrary intermediate lift amount smaller than the maximum lift amount at the time of fuel injection at the initial stage of the intake stroke, At the time of fuel injection at a time after the initial stage of the intake stroke, a lift control unit that controls the lift amount from the valve seat portion of the valve body to the maximum lift amount;
A fuel injection system for an internal combustion engine.   Each nozzle hole of the injection valve main body is inclined outwardly from the direction perpendicular to the plane formed by the inlet side opening of the nozzle hole, with the axis of the nozzle hole being directed from the inside to the outside. 2. The fuel injection system for an internal combustion engine according to claim 1, which is formed as described above.

Images