JP2008038815A - Fuel injection system and internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection system and an internal combustion engine which can improve combustion stability by forming an optimal fuel spray form in accordance with operating conditions of the internal combustion engine. <P>SOLUTION: A fuel passage 53 is provided in a housing 41, and a suck part 44 and three injection ports 45, 46, 47, all of which are connected to the fuel passage 53, are formed at the tip of the housing 41. Then a needle valve 48 is movably supported by the housing 41, so that opening and closing of the fuel passage 53 is made possible. The three injection ports 45, 46, 47 are formed in a fan-like shape with a wide angle in the up-and-down directions, and are formed side by side in the right-and-left directions. The fuel spraying contraction rate of the second injection port 46 located in the center is set larger than that of the first and the third injection ports 45, 47 which are located on both sides. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injection device capable of injecting a predetermined amount of fuel into a combustion chamber, and an internal combustion engine equipped with the fuel injection device.

  2. Description of the Related Art Conventionally, a direct injection internal combustion engine that directly injects fuel into a combustion chamber instead of an intake port is known. In this direct injection internal combustion engine, when the intake valve is opened, air is sucked into the combustion chamber from the intake port, and during this intake stroke or during the compression stroke in which the piston rises to compress the intake air, the fuel injection valve burns. Inject fuel directly into the chamber. Then, high-pressure air and mist-like fuel are mixed in the combustion chamber, and the spark plug ignites and explodes with respect to this air-fuel mixture, and the exhaust gas is discharged from the intake port when the exhaust valve is opened.

  In this direct injection internal combustion engine, fuel can be injected into the combustion chamber during the compression stroke to perform stratified combustion at a lean air-fuel ratio, and fuel can be injected into the combustion chamber during the intake stroke to achieve uniform mixing. Homogeneous combustion that forms gas can be realized. That is, in the low load operation region of the internal combustion engine, when the intake valve is opened in the intake stroke of the piston, the air in the intake port is sucked into the combustion chamber, and the intake air is compressed during the compression stroke. Are injected and mixed, and this air-fuel mixture is led to a spark plug and ignites and burns. On the other hand, in the medium / high load operation region of the internal combustion engine, when the intake valve is opened in the intake stroke of the piston, air in the intake port is sucked into the combustion chamber and fuel is injected into the intake air to An air-fuel mixture dispersed in the combustion chamber is formed, and the dispersed air-fuel mixture is ignited by a spark plug. In other words, when the internal combustion engine is at a low load, fuel is injected during the compression stroke to perform stratified combustion, and at a middle or high load, the fuel is injected during the intake stroke to perform homogeneous combustion.

  The fuel injection device applied to the in-cylinder internal combustion engine is energized so that the needle valve is movable and the fuel passage is closed in a housing having a sac portion and an injection port at the tip. The injection port is a so-called slit injection port formed in a fan shape with a wide angle on the left and right. Accordingly, when this needle valve is moved at a predetermined timing to open the fuel passage, the fuel in the fuel passage is injected from the injection port toward the combustion chamber via the sac portion.

  As described above, in a direct injection internal combustion engine, fuel is injected into the combustion chamber during the compression stroke to execute stratified combustion at a lean air-fuel ratio, and fuel is injected into the combustion chamber during the intake stroke. Homogeneous combustion that forms a homogeneous air-fuel mixture. In the fuel injection device having the slit injection port formed in a fan shape with a wide angle to the left and right as described above, when fuel is injected into the combustion chamber during the compression stroke, the fuel spray is guided to the spark plug by the piston cavity. By igniting the air-fuel mixture containing this fuel spray, proper stratified combustion can be realized. However, when fuel is injected into the combustion chamber during the intake stroke, the fuel spray is in the form of a horizontal fan, so that it is difficult to disperse throughout the combustion chamber and the formation of a uniform air-fuel mixture becomes insufficient, thus achieving proper homogeneous combustion. It becomes difficult.

  On the other hand, there is a fuel injection device in which slit injection ports formed in a fan shape with wide angles up and down are arranged side by side. In this fuel injection device, when fuel is injected into the combustion chamber during the intake stroke, the fuel spray has two vertical fan shapes, so that it can be easily dispersed throughout the combustion chamber to form a uniform mixture. Homogeneous combustion can be realized. However, when fuel is injected into the combustion chamber during the compression stroke, the fuel spray is dispersed in the vertical direction, and the air-fuel mixture cannot be guided to the spark plug by the piston cavity, thereby realizing proper stratified combustion. It becomes difficult.

  In addition, there exists what was described in the following patent document 1 as a fuel injection valve which made the spray form change according to an engine operating state. The fuel injection valve described in Patent Document 1 forms two slit-shaped injection holes having different injection angles, and changes the fuel pressure depending on the engine operating state, so that the spray shape is adapted to the engine operating state. A dispersion type spray or a concentrated type spray can be formed.

JP-A-11-082244

  However, in the conventional fuel injection valve described in Patent Document 1 described above, by changing the fuel pressure, it is possible to form a wide dispersion type spray or a concentrated type spray, and the engine operation. The fuel pressure control according to the state is required and the fuel injection control becomes troublesome, and when the fuel pressure is lowered, atomization of the fuel spray becomes a problem and the combustion may be deteriorated. . Moreover, in this conventional fuel injection valve, although the spray shape is changed according to the engine operating state, it is not optimal for realizing stratified combustion and homogeneous combustion, and a stable combustion state is obtained. There is a risk that it will not be possible.

  The present invention is intended to solve such a problem, and provides a fuel injection device and an internal combustion engine that are capable of forming an optimal fuel spray form in accordance with the operating state of the internal combustion engine to improve combustion stability. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a fuel injection device of the present invention includes a housing having a fuel passage and a sac portion and an injection port that communicate with the fuel passage at a tip portion, and the housing moves to the housing. In a fuel injection device comprising an injection valve that is freely supported and capable of intermittently connecting and disconnecting the fuel passage, the injection port is formed in a fan shape with a wide angle in the vertical direction, and the first and second 2. The fuel spray contraction rate of the second injection port that has the third injection port and is located at the center is set to be larger than the fuel spray contraction rate of the first and third injection ports that are located on both sides. It is a feature.

  In the fuel injection device of the present invention, the fuel spray separation angle of the second injection port is set to be larger than the fuel spray separation angles of the first and third injection ports.

  In the fuel injection device of the present invention, the fuel spray angles of the first, second, and third injection ports are set to the same angle.

  An internal combustion engine of the present invention is provided with the fuel injection device according to any one of claims 1 to 3 at an intake port side and inclined downward by a predetermined angle, and combusts toward an exhaust port side. The fuel can be directly injected into the chamber.

  According to the fuel injection device of the present invention, the first, second, and third injection ports that are formed in a fan shape with a wide angle in the vertical direction and are arranged in the left-right direction are provided, and the fuel in the second injection port located in the center Since the spray contraction rate is set to be larger than the fuel spray contraction rates of the first and third injection ports located on both sides, when fuel is injected into the combustion chamber during the intake stroke, the fuel forms three vertical fan shapes. It becomes spray and can be dispersed throughout the combustion chamber to form a uniform air-fuel mixture, achieving proper homogeneous combustion. On the other hand, when fuel is injected into the combustion chamber during the compression stroke, the second injection Since the fuel spray shrinkage rate of the mouth is large, this fuel spray does not diffuse in the vertical direction and merges by interfering with the fuel spray from the first and third injection ports on both sides, and the combined fuel spray is caused by the piston cavity. It will be led to the spark plug, and proper stratified combustion will be realized. It can be. As a result, by achieving both homogeneous combustion and stratified combustion, an optimal fuel spray form can be formed according to the operating state of the internal combustion engine, and combustion stability can be improved.

  Further, according to the internal combustion engine of the present invention, the above-described fuel injection device is provided on the intake port side and inclined downward by a predetermined angle so that fuel can be directly injected into the combustion chamber toward the exhaust port side. Therefore, when fuel is injected from the intake port side during the intake stroke, three vertical fan-shaped fuel sprays can be dispersed throughout the combustion chamber to form a uniform mixture, and during the compression stroke When fuel is injected from the intake port side, the fuel spray from the second injection port does not diffuse vertically but merges with the fuel spray from the first and third injection ports, and the combined fuel spray is a piston. This leads to the spark plug through the cavity, and by achieving both homogeneous combustion and stratified combustion, an optimal fuel spray form can be formed according to the operating state of the internal combustion engine, and combustion stability can be improved. .

  Embodiments of a fuel injection device and an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

  1 is a longitudinal sectional view of a main part showing a fuel injection device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line I-II in FIG. 1, and FIG. 3 is a sectional view taken along line I-III in FIG. 4 is a graph showing the contraction rate with respect to the distance B in the injector, FIG. 5-1 is a schematic diagram showing fuel spray from the first and third injection ports during the intake stroke, and FIG. 5-2 is during the intake stroke. Schematic showing fuel spray from the second injection port, FIG. 5-3 is a schematic diagram showing fuel spray from all the injection ports during the intake stroke, and FIG. 6 is an intake stroke by the fuel injection device of this embodiment. Fig. 7-1 is a schematic diagram showing injection, Fig. 7-1 is a schematic diagram showing fuel spray from the first and third injection ports during the compression stroke, and Fig. 7-2 is fuel spray from the second injection port during the compression stroke. FIG. 7-3 is a schematic diagram showing fuel spray from all injection ports during the compression stroke, and FIG. FIG. 9 is a schematic diagram showing compression stroke injection by the fuel injection device of this embodiment, and FIG. 9 is a schematic configuration diagram of an internal combustion engine to which the fuel injection device of this embodiment is applied.

  In the internal combustion engine to which the fuel injection device of this embodiment is applied, as shown in FIG. 9, the engine 10 is an in-cylinder injection spark ignition engine. In this engine 10, a cylinder head 12 is fastened on a cylinder block 11, and pistons 14 are fitted to a plurality of cylinder bores 13 formed in the cylinder block 11 so as to freely move up and down. A crankshaft 15 is rotatably supported at the lower portion of the cylinder block 11, and the pistons 14 are connected to the crankshaft 15 via connecting rods 16, respectively.

  The combustion chamber 17 is composed of a cylinder block 11, a cylinder head 12, and a piston 14. The combustion chamber 17 has a pent roof shape that is inclined so that the central portion of the upper portion (the lower surface of the cylinder head 12) is raised. Yes. An intake port 18 and an exhaust port 19 are formed on the upper portion of the combustion chamber 17, that is, the lower surface of the cylinder head 12, and the intake valve 20 and the exhaust valve 19 are opposed to the intake port 18 and the exhaust port 19. The lower end portions of 21 are located respectively. Accordingly, when the intake valve 20 and the exhaust valve 21 move up and down at a predetermined timing, the intake port 18 and the exhaust port 19 are opened and closed, and the intake port 18 and the combustion chamber 17, and the combustion chamber 17 and the exhaust port 19 are respectively connected. You can communicate.

  A surge tank 23 is connected to the intake port 18 via an intake manifold 22, and an intake pipe 24 is connected to the surge tank 23, and an air cleaner 25 is attached to an air intake port of the intake pipe 24. Yes. An electronic throttle device 26 having a throttle valve is provided on the downstream side of the air cleaner 25. Further, the cylinder head 12 is provided with an injector (fuel injection device) 27 for directly injecting fuel into the combustion chamber 17, and this injector 27 is located on the intake port 18 side, and its tip portion is downwardly inclined at a predetermined angle. It is inclined and can inject fuel toward the exhaust port 19 side. Further, the cylinder head 12 is provided with a spark plug 28 that is located above the combustion chamber 17 and ignites the air-fuel mixture.

  On the other hand, an exhaust pipe 30 is connected to the exhaust port 19 via an exhaust manifold 29. The exhaust pipe 30 is a catalyst device that purifies harmful substances such as HC, CO, and NOx contained in the exhaust gas. 31 and 32 are mounted. Further, an exhaust gas recirculation passage (EGR passage) 33 is provided between the downstream side of the surge tank 23 in the intake pipe 24 and between the catalyst devices 31 and 32 in the exhaust pipe 30. Is provided with an EGR valve 34.

  In addition, an electronic control unit (ECU) 35 is mounted on the vehicle, and the ECU 35 can control the injector 27, the spark plug 28, the EGR valve 34, and the like. That is, an air flow sensor 36 is mounted on the upstream side of the intake pipe 24, and an intake negative pressure sensor 37 is mounted on the surge tank 23, and the measured intake air amount and intake negative pressure are output to the ECU 35. Further, the electronic throttle device 26 outputs the current throttle opening degree to the ECU 35, and the engine speed sensor 38 outputs the detected engine speed to the ECU 35. Therefore, the ECU 35 determines the fuel injection amount, the injection timing, the ignition timing, the EGR valve opening, based on the detected engine operation state such as the intake air amount, intake negative pressure, throttle opening (or accelerator opening), and engine speed. The degree is determined.

  In the injector 27 mounted on the engine 10 configured as described above, as shown in FIGS. 1 to 3, the housing 41 has a hollow cylindrical shape, and the distal end portion 43 has a small diameter with respect to the main body portion 42. A sack portion 44 having a spherical shape is formed at the distal end portion 43, and three injection ports 45, 46, and 47 that are open to the outside are formed. A needle valve 48 as an injection valve is configured such that a valve body 50 having a columnar shape integrally extends downward from a flange portion 49 having a disk shape, and an outer peripheral surface of the flange portion 49 is an inner side of the main body portion 42 in the housing 41. It is fitted to the peripheral surface and supported so as to be movable along the axial direction (vertical direction in FIG. 1). Further, the needle valve 48 has the outer peripheral surface of the valve body 50 inserted into the inner peripheral surface of the tip portion 43 of the housing 41 with a predetermined gap, and the tip surface 51 having a conical shape contacts the inclined surface 52 of the tip portion 43. Here, a seal portion is formed.

  Accordingly, the fuel passage 53 is formed between the housing 41 and the needle valve 48, and the lower end side of the fuel passage 53 can communicate with the injection ports 45, 46, 47 via the sack portion 44. Yes. The fuel passage 53 can be blocked by the tip surface 51 of the needle valve 48 coming into contact with the inclined surface 52 of the housing 41, while the fuel passage 53 is opened when the tip surface 51 moves away from the inclined surface 52. The fuel in the fuel passage 53 can be injected to the outside (combustion chamber 17) from the injection ports 45, 46, 47 via the sac portion 44.

  A support plate 55 is fixed in the housing 41 via a support ring 54, and a coil spring 56 is interposed between the support plate 55 and the needle valve 48 in a compressed state. Accordingly, the needle valve 48 is biased in a direction in which the tip surface 51 is in close contact with the inclined surface 52 of the housing 41 by the biasing force of the coil spring 56 and blocks the fuel passage 53. On the other hand, a solenoid 57 is built in the wall of the housing 41 so as to face the flange portion 49 of the needle valve 48 and be positioned slightly above. Therefore, when the solenoid 57 is energized, a suction force is generated, and the needle valve 48 is moved upward against the biasing force of the coil spring 56, so that the fuel passage 53 can be opened.

  A fuel pump, a fuel tank, and the like are connected to the base end portion of the injector 27 via a delivery pipe (not shown), and fuel of a predetermined pressure is supplied to the upstream side of the fuel passage 53 through the housing 41. .

  By the way, in the injector 27 of the present embodiment, the fuel spray contraction rate injected from the second injection port 46 located in the center is injected from the first injection port 45 and the third injection port 47 located on both sides thereof. It is set larger than the fuel spray shrinkage rate.

That is, the second injection port 46 is formed along the axis L ₂ of the injector 27, and the axis L having a predetermined injection angle α with respect to the axis L ₂ on both sides in the horizontal direction of the second injection port 46. _By forming the first injection port 45 and the third injection port 47 along ₁ and L ₂ , the three injection ports 45, 46 and 47 are arranged with the injection angle α in the left-right direction. . Further, each of the injection ports 45, 46, 47 is formed in a fan shape with a wide angle up and down so that the fuel spray to be injected diffuses up and down, and the spray angle β is set. , 47 are set to the same angle. Therefore, each injection port 45, 46, 47 is a cross-sectional passage having a rectangular shape.

By the way, as shown in FIGS. 2 and 3, each of the injection ports 45, 46, 47 is formed by inserting a fan-shaped electrode from the front end side of the housing 41 and performing electric discharge machining, and the electrode to the housing 41 is formed. The width of the injection ports 45, 46, 47 is set according to the amount of insertion. In this case, in fan-shaped injection opening 45, 46 and 47 formed by the electric discharge machining, the distance along the axis L ₂ of the injector 27 of the sack center O ₂ of the processing center O ₁ and the sack portion 44 Assuming B, in this embodiment, the distance B _{2 at} the second injection port 46 is shorter than the distances B ₁ and B _{3 at} the first and third injection ports 45 and 47. By setting the distances B ₁ and B ₂ in this way, the fuel spray separation angle θ ₂ of the second injection port 46 is determined from the fuel spray separation angles θ ₁ and θ _{3 of} the first and third injection ports 45 and 47. It will be set large.

Here, the fuel spray contraction rate is the ratio of the deviation between the actual spray spread angle β ₁ injected from the injector 27 into the atmospheric pressure field and the actual spray spread β ₂ injected into the pressurized field (β ₁ −β ₂ ) / β ₁ . The fuel spray shrinkage ratio (β ₁ −β ₂ ) / β ₁ and the fuel spray peeling angles θ ₁ , θ ₂ , θ _{3 at the} injection ports 45, 46, 47 are the distances B ₁ , B ₂ , B _3. It will be set according to. That is, as shown in FIG. 4, it is known that the fuel spray shrinkage ratio β ₂ / β ₁ tends to decrease as the distance B in the injector 27 increases. That is, since the fuel spray contraction rate is small at the first and third injection ports 45 and 47 where the distances B ₁ and B ₃ in the injector 27 are large, the actual spray angle β ₁ injected into the atmospheric pressure field and the pressure field The actual spray angle β ₂ injected into the nozzle is almost the same. On the other hand, since the fuel spray contraction rate β ₂ / β ₁ is large at the second injection port 46 where the distance B ₂ in the injector 27 is small, the pressure is applied to the actual spray angle β ₁ injected into the atmospheric pressure field. The actual spray angle β ₂ to be injected is small.

Further, as the distances B ₁ , B ₂ , and B ₃ in the injector 27 increase, the fuel spray separation angles θ ₁ , θ ₂ , and θ ₃ become smaller. This is because when the fuel spray separation angles θ ₁ , θ ₂ , and θ ₃ are increased when fuel is injected from the sack portion 44 through the injection ports 45, 46, and 47 into the combustion chamber 17, the injection ports 45, 46, and 47 It is considered that the fuel easily peels from the wall surface and concentrates in the central portion without spreading according to the spray angle β.

  Accordingly, as shown in FIGS. 1 to 3, when the solenoid valve 57 is energized from the state where the needle valve 48 closes the fuel passage 53 by the biasing force of the coil spring 56 in the injector 27, the needle valve 48 is coiled. The fuel passage 53 is opened by moving upward against the urging force of the spring 56, and the fuel in the fuel passage 53 is supplied to the sac portion 44, and burns through the injection ports 45, 46, 47 from the sac portion 44. It is injected into the chamber 17. When the predetermined period has elapsed, the energization of the solenoid 57 is stopped, and the needle valve 48 is moved downward by the urging force of the coil spring 56 to close the fuel passage 53, and from the fuel passage 53 to the sack portion 44. The fuel supply is stopped, and fuel injection from the injection ports 45, 46, 47 is completed.

  At this time, if fuel is injected from the injector 27 into the combustion chamber 17 during the intake stroke of the engine 10, the combustion chamber 17 is in the atmospheric pressure field, so that each injection is performed as shown in FIGS. The fuel sprays injected from the ports 45, 46, and 47 have substantially the same fan shape, and as shown in FIGS. 5-3 and 6, three fuels spread in a fan shape along the vertical direction of the combustion chamber 17. The spray is aligned in the left-right direction of the combustion chamber 17. Therefore, the fuel spray injected from the injection ports 45, 46, 47 can be dispersed throughout the combustion chamber 17 to form a uniform air-fuel mixture, and the dispersed air-fuel mixture is ignited by the spark plug 28. The ignition mixture becomes a fire type and the mixture dispersed throughout the combustion chamber 17 is combusted, so that proper homogeneous combustion can be realized.

  On the other hand, when fuel is injected from the injector 27 into the combustion chamber 17 in the compression stroke of the engine 10, the combustion chamber 17 is in a pressurized pressure field, so that the fuel spray contraction rate is small as shown in FIG. The fuel sprays injected from the first and third injection ports 45 and 47, which are set to have a small spray peeling angle, have substantially the same fan shape, and as shown in FIGS. The two fuel sprays spreading in a fan shape along the vertical direction are aligned in the left-right direction of the combustion chamber 17. Further, as shown in FIG. 7-2, the fuel spray injected from the second injection port 46 set to have a large fuel spray shrinkage rate (a large fuel spray peeling angle) is shown in FIGS. 7-3 and FIG. Thus, it does not spread in the vertical direction of the combustion chamber 17 but is positioned in a rod shape between the two fuel sprays injected from the first and third injection ports 45 and 47.

  The fuel spray injected from the second injection port 46 spreads in the left-right direction due to the Coanda effect of the two fuel sprays injected from the first and third injection ports 45 and 47 on both sides of the fuel spray and merges. The combined fuel spray forms a wall guide directed upward by the cavity 14 a of the piston 14. The air-fuel mixture traveling upward from the cavity 14a of the piston 14 is efficiently guided to the spark plug 28, and appropriate stratified combustion can be realized.

  As described above, in the fuel injection device and the internal combustion engine of the present embodiment, the fuel passage 53 is provided in the housing 41, and the sac portion 44 and the three injection ports 45 and 46 communicating with the fuel passage 53 are provided at the front end portion. 47, and the needle valve 48 is movably supported in the housing 41 so that the fuel passage 53 can be opened and closed, and the three injection ports 45, 46, 47 are formed in a fan shape with wide angles up and down. The fuel spray contraction rates of the second injection ports 46 formed side by side in the left and right direction are set to be larger than the fuel spray contraction rates of the first and third injection ports 45 and 47 positioned on both sides. .

  Therefore, when fuel is injected from the injection ports 45, 46, 47 of the injector 27 into the combustion chamber 17 during the intake stroke, three fuel sprays having a substantially vertical fan shape are formed side by side in the left-right direction. The fuel spray is dispersed throughout the combustion chamber 17 to form a uniform air-fuel mixture, and appropriate homogeneous combustion can be realized. On the other hand, when fuel is injected from the injection ports 45, 46, 47 of the injector 27 into the combustion chamber 17 during the compression stroke, the fuel in the second injection port 46 with respect to the first and third injection ports 45, 47. Since the spray shrinkage rate is large, the fuel spray from the first and third injection ports 45 and 47 forms a substantially vertical fan shape, but the fuel spray from the second injection port 46 does not diffuse in the vertical direction. The fuel spray from the first and third injection ports interferes and merges, and the merged fuel spray travels toward the cavity 14a of the piston 14 and is guided to the spark plug 28 by the cavity 14a, thereby realizing proper stratified combustion. can do. As a result, by achieving both homogeneous combustion and stratified combustion, an optimal fuel spray form can be formed according to the operating state of the engine 10, and combustion stability can be improved.

  Further, in the fuel injection device and the internal combustion engine of the present embodiment, the fuel spray separation angle of the second injection port 46 in the injector 27 is set larger than the fuel spray separation angles of the first and third injection ports 45 and 47. . Accordingly, since the fuel spray separation angle of the second injection port 46 is larger than that of the first and third injection ports 45 and 47, the fuel spray from the second injection port 46 does not diffuse and the first and third injections are not diffused. The fuel spray from the mouth and the Coanda effect will be combined well, and the combined fuel spray will be directed to the cavity 14a of the piston 14 and guided to the spark plug 28. Stratified combustion can be realized.

  In the fuel injection device and the internal combustion engine of the present embodiment, the fuel spray angles of the first, second, and third injection ports 45, 46, and 47 are set to the same angle. Accordingly, by setting the fuel spray angle of each of the injection ports 45, 46, 47 to the same angle, and setting the fuel spray shrinkage rate of the second injection port 46 at the center large, it is possible during the intake stroke or the compression stroke. Even if it exists, a spray form can be formed in an optimal shape and combustion stability can be improved.

  In the fuel injection device and the internal combustion engine of the present embodiment, the injector 27 is located on the intake port 18 side and is inclined downward by a predetermined angle so that fuel can be directly injected into the combustion chamber 17 toward the exhaust port 19 side. It is said. Accordingly, proper homogeneous combustion can be realized in the intake stroke injection, and proper stratified combustion can be realized in the compression stroke.

  In the above-described embodiment, the first, second, and third injection ports 45, 46, and 47 are each formed in a fan shape that is wide-angled up and down so that the injected fuel spray spreads up and down. Although the angle β is set to the same angle, the spray angle β may be made different or the spray center may be shifted up and down depending on the shape of the cavity 14a in the combustion chamber 17 and the piston 14.

  In the above-described embodiment, the injector 27 is disposed on the intake port 18 side, and the tip end portion is inclined downward by a predetermined angle so that fuel can be injected toward the exhaust port 19 side. However, the present invention is limited to this configuration. It is not a thing. That is, the injector 27 may be disposed on the exhaust port 19 side, the tip end may be inclined downward by a predetermined angle, and fuel may be injected toward the intake port 18 side. Further, the injector 27 may be disposed between the intake port 18 and the exhaust port 19, that is, at the center upper portion of the combustion chamber 17, so that fuel can be injected into the cavity 14 a of the piston 14 with the tip portion directed downward. .

  As described above, the fuel injection device according to the present invention is capable of forming an optimal fuel spray form in accordance with the operating state of the internal combustion engine so as to improve combustion stability, and is used for any type of internal combustion engine. Is also suitable.

It is a principal part longitudinal cross-sectional view showing the fuel-injection apparatus which concerns on one Example of this invention. It is I-II sectional drawing of FIG. It is I-III sectional drawing of FIG. It is a graph showing the shrinkage | contraction rate with respect to the distance B in an injector. It is the schematic showing the fuel spray from the 1st, 3rd injection port at the time of an intake stroke. It is the schematic showing the fuel spray from the 2nd injection port at the time of an intake stroke. It is the schematic showing the fuel spray from all the injection openings at the time of an intake stroke. It is the schematic showing the intake stroke injection by the fuel-injection apparatus of a present Example. It is the schematic showing the fuel spray from the 1st, 3rd injection port at the time of a compression stroke. It is the schematic showing the fuel spray from the 2nd injection port at the time of a compression stroke. It is the schematic showing the fuel spray from all the injection openings at the time of a compression stroke. It is the schematic showing the compression stroke injection by the fuel-injection apparatus of a present Example. 1 is a schematic configuration diagram of an internal combustion engine to which a fuel injection device according to an embodiment is applied.

Explanation of symbols

10 Engine (Internal combustion engine)
17 Combustion chamber 27 Injector (fuel injection device)
28 Spark plug 35 Electronic control unit (ECU)
41 Housing 44 Suck Part 45 First Injection Port 46 Second Injection Port 47 Third Injection Port 48 Needle Valve (Injection Valve)
53 Fuel Passage

Claims (4)

  A fuel injection apparatus comprising: a housing having a fuel passage and a sac portion and an injection port communicating with the fuel passage at the tip; and an injection valve movably supported by the housing and capable of intermittently connecting the fuel passage The fuel injection nozzle has a first, a second and a third injection ports which are formed in a fan shape with a wide angle in the vertical direction and are arranged in the left-right direction, and the fuel spray of the second injection port located in the center. A fuel injection device, wherein the shrinkage rate is set to be larger than the fuel spray shrinkage rates of the first and third injection ports located on both sides.   2. The fuel injection device according to claim 1, wherein a fuel spray separation angle of the second injection port is set larger than a fuel spray separation angle of the first and third injection ports.   3. The fuel injection device according to claim 1, wherein fuel spray angles of the first, second, and third injection ports are set to the same angle.   The fuel injection device according to any one of claims 1 to 3 is provided on the intake port side and inclined downward by a predetermined angle so that fuel can be directly injected into the combustion chamber toward the exhaust port side. An internal combustion engine characterized by that.

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