JP2014062495A - Fuel injection device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suck a fuel into a combustion chamber from a side far from a curvature center of a curved portion and a side close to the same with good balance, in a port-injection type internal combustion engine including an intake port provided with the curved portion between a fuel injection valve and an intake valve.SOLUTION: A fuel injection valve 21 injects first fuel spray FS1 directing to a wall surface 15a2 at a side close to a curvature center of a curved portion 15a, and second fuel spray FS2 directing to a side far from the curvature center of the curved portion 15a with respect to the first fuel spray FS1. A penetrating force of the first fuel spray FS1 is determined to be higher than that of the second fuel spray FS2. Thus the first fuel spray FS1 attaches to a wall surface 15a2 at the side close to the curvature center of the curved portion 15a, and vaporized fuel flows into a combustion chamber 13 to the side close to the curvature center of the curved portion 15a from the side close thereto. On the other hand, the second fuel spray FS2 flows into the combustion chamber 13 from the side far from the curvature center of the curved portion 15a accompanying intake air floating in an intake port 15 and flowing while deviating to the side far from the curvature center of the curved portion 15a.

Description

  The present invention relates to a fuel injection device for an internal combustion engine in which a curved portion is formed in an intake port between an intake valve and a fuel injection device, and fuel is injected into the intake port.

  Patent Document 1 has a fuel injection valve capable of injecting two fuel sprays extending toward both sides of the spark plug so that the fuel spray does not spray on the spark plug facing the cylinder, and the fuel injection valve An in-cylinder injection internal combustion engine is disclosed in which the penetrating force of one of the two fuel sprays injected at is lower than the penetrating force of the other.

JP 2006-299888 A

In a port injection type internal combustion engine in which a curved portion is formed in an intake port between an intake valve and a fuel injection device and fuel is injected into the intake port, a wall surface (inside of the curve) on the side close to the curved center C of the curved portion. The wall surface becomes an obstacle, and fuel may not be able to be injected directly at the peripheral portion of the intake valve on the side close to the bending center C of the bending portion.
In such a case, if the penetration force of the fuel spray injected into the intake port is weak, the fuel spray rides on the flow of the intake air, so that it is on the side far from the curve center C of the curved portion (the wall surface on the outside of the curve). If the fuel spray is biased while the penetration force of the fuel spray is strong, a large amount of fuel adheres to the wall surface of the curved portion near the curved center C.
For this reason, in the method of adjusting the penetration force of one fuel spray, it is difficult to suck the fuel into the combustion chamber in a well-balanced manner from the side far from the curved center C of the curved portion, and the mixture in the combustion chamber. There is a problem that the homogeneity of the fuel consumption decreases and the fuel efficiency decreases.

  The present invention has been made in view of the above problems, and in a port injection type internal combustion engine in which a curved portion is formed in an intake port between an intake valve and a fuel injection device and fuel is injected into the intake port, the intake port An object of the present invention is to provide a fuel injection device capable of sucking fuel into a combustion chamber in a well-balanced manner from the side far from the bending center C of the curved portion of the curved portion.

  Therefore, in the fuel injection device according to the present invention, the first fuel spray directed to the wall surface near the curve center C of the curved portion of the intake port, and the wall surface closer to the wall farther from the curve center C than the first fuel spray. And the penetration force of the first fuel spray is set higher than the penetration force of the second fuel spray.

  According to the above-described invention, fuel is sucked into the combustion chamber in a well-balanced manner from the side far from the curved center C of the curved portion of the intake port and the side close to the first fuel spray and the second fuel spray having different directivity directions and penetrating forces. Can improve fuel efficiency.

1 is a system configuration diagram of an internal combustion engine in an embodiment. It is sectional drawing which shows the nozzle hole part of the fuel injection valve in embodiment. It is a figure which shows the combination pattern of 1st fuel spray FS1 and 2nd fuel spray FS2 in embodiment. It is a figure which shows the combination pattern of 1st fuel spray FS1 and 2nd fuel spray FS2 in embodiment. It is a figure which shows the combination pattern of 1st fuel spray FS1 and 2nd fuel spray FS2 in embodiment. It is a figure which shows the combination pattern of 1st fuel spray FS1 and 2nd fuel spray FS2 in embodiment. 1 is a system configuration diagram of an internal combustion engine in an embodiment. It is a figure which shows the setting of the spraying direction in embodiment.

Embodiments of the present invention will be described below.
FIG. 1 shows an internal combustion engine equipped with a fuel injection device according to the present invention.
The cylinder head 12 of the internal combustion engine 11 shown in FIG. 1 opens to the upper part of the combustion chamber 13 of each cylinder (in other words, the surface facing the top surface of the piston 14), and intake air that is opened and closed by an intake valve 16. A port 15 is formed.

A curved portion 15 a is formed in the intake port 15 between the intake valve 16 and a fuel injection valve 21 (fuel injection device) that injects fuel into the intake port 15.
The intake port 15 extends from the outside of the cylinder head 12 to the vicinity of the combustion chamber 13 along the radial direction of the cylinder 17 when the cylinder head 12 is viewed from the axial direction of the cylinder 17. Then, the curved portion 15 a of the intake port 15 is bent with the center of the piston 14 closer to the piston 14 than the axis of the intake port 15 in the axial direction of the cylinder 17, and is connected to the combustion chamber 13.
1 is described assuming that the radius of curvature of the intake port 15 is constant in order to simplify the illustration, but the intake port 15 in which the radius of curvature changes is illustrated. Even when there are a plurality of bending centers, the bending center C is specified as the set, and the bending center C indicates the inner side of the bending portion 15a.

An ignition plug 18 is disposed near the center of the cylinder head 12 forming the combustion chamber 13, and an intake valve 16 and an exhaust valve 19 are provided across the ignition plug 18. Opened and closed.
A fuel injection valve 21 is provided in the upstream portion of the wall surface 15a1 far from the bending center C of the curved portion 15a of the intake port 15 as a fuel injection device that injects fuel into the intake port 15 of each cylinder. That is, the internal combustion engine 11 includes one fuel injection valve for each cylinder.

The fuel injection valve 21 is an electromagnetically driven injection valve that opens the valve body with electromagnetic force generated by a solenoid, and injects fuel in an amount proportional to the valve opening time.
An engine control unit (ECU) 30 that is a control device that includes a microcomputer and controls the internal combustion engine 11 outputs an injection pulse signal that controls energization of the solenoid of the fuel injection valve 21.

The ECU 30 inputs output signals from various sensors that detect the operating state of the internal combustion engine 11. As the various sensors, an airflow sensor 31 that detects the intake air flow rate QA of the internal combustion engine 11, a crank angle sensor 32 that outputs a pulse signal POS in synchronization with the rotation of the crankshaft of the internal combustion engine 11, and cooling water for the internal combustion engine 11 A water temperature sensor 33 for detecting the temperature TW is provided.
The ECU 30 calculates an injection pulse width TI for adjusting the valve opening time (fuel injection amount) of the fuel injection valve 21 based on signals (engine operating state) from various sensors, and injection of the injection pulse width TI is performed. The pulse signal is output to the fuel injection valve 21 of the cylinder at the injection timing in accordance with the cycle of each cylinder. That is, the fuel injection control of the present embodiment is of a control method called so-called sequential injection control.

The fuel injection valve 21 constituting the fuel injection device injects two fuel sprays having different spray characteristics and directing directions as fuel sprays that pass through one intake valve 16 and are sucked into the combustion chamber 13.
The first fuel spray FS1 injected by the fuel injection valve 21 is downstream of the portion where the fuel injection valve 21 is disposed, and is closer to the curved center C of the curved portion 15a (wall surface 15a2 on the inner side of the curved surface). ). Further, the second fuel spray FS2 injected by the fuel injection valve 21 is closer to the wall surface 15a1 (the wall surface on the outside of the curve) on the side farther from the curve center C of the curved portion 15a than the first fuel spray FS1. The 16 umbrella portions 16a are substantially oriented.

Further, the spray characteristics of the fuel injection valve 21 are set so that the penetration force (flow velocity) of the first fuel spray FS1 is higher (faster) than the penetration force (flow velocity) of the second fuel spray FS2. More specifically, the second fuel spray FS2 whose penetration force is weaker than that of the first fuel spray FS1 floats in the intake port 15 without almost reaching the wall surface of the intake port 15, and the penetration force is the second fuel spray. The first fuel spray FS1 stronger than FS2 penetrates the fuel sprays FS1 and FS2 so as to reach and adhere to the wall surface of the opposed intake port 15 (the wall surface 15a2 on the side close to the bending center C of the bending portion 15a). The power is set.
In addition, the directivity direction of the second fuel spray FS2 whose penetration force is weaker than that of the first fuel spray FS1 can suppress interference with the first fuel spray FS1, and the outer peripheral side of the curved portion 15a of the intake port 15 What is necessary is just to set in the range which can fully suppress adhesion of the fuel with respect to a wall surface etc., and it is not limited to the setting which orient | assigns the umbrella part 16a of the intake valve 16. FIG.

FIG. 2 is a partially enlarged sectional view showing an example of the injection hole structure of the fuel injection valve 21.
In the fuel injection valve 21 shown in FIG. 2, a spherical valve body 211 is seated on a valve seat 212 formed in a funnel shape, and the valve body 211 is lifted by a magnetic attractive force of an electromagnetic coil (not shown). When the valve seat 212 is separated, the valve is opened. When the valve body 211 of the fuel injection valve 21 is lifted and opened, the fuel passes through the gap between the valve body 211 and the valve seat 212, and the nozzle plate 214 in which the valve body 211 and the nozzle hole 213 are formed. And then injected into the fuel reservoir 215 sandwiched between the nozzle holes 213.

Here, the injection hole 213 includes a first injection hole group 213a including at least one injection hole for injecting the first fuel spray FS1, and at least one injection hole for injecting the second fuel spray FS2. 2nd nozzle hole group 213b.
The fuel injection valve 21 is attached to the intake port 15 so that the umbrella portion 16a of the intake valve 16 is substantially positioned on an extension line of the central axis H of the cylindrical main body.

The first injection hole group 213a is directed so that the first fuel spray FS1 injected from the first injection hole group 213a is directed to the wall surface 15a2 on the side close to the bending center C of the bending portion 15a of the intake port 15. Formed with an inclination angle such that the axis of the injection hole gradually moves away from the central axis H toward the downstream side with respect to the injection hole plate 214 near the wall surface 15a2 near the bending center C of the bending portion 15a. Has been.
On the other hand, the second injection hole group 213b is far from the bending center C of the bending portion 15a so that the second fuel spray FS2 injected from the second injection hole group 213b is substantially directed to the umbrella portion 16a of the intake valve 16. The nozzle hole axis 214 is formed so that the axis of the nozzle hole is substantially parallel to the central axis H with respect to the nozzle hole plate 214 on the side close to the side wall surface 15a1.

As a result, the angle formed by the directing direction of the first fuel spray FS1 and the central axis H of the fuel injection valve 21 is θ1, and the angle formed by the directing direction of the second fuel spray FS2 and the central axis H of the fuel injection valve 21 is set. When θ2, θ1> θ2 is set.
The fuel injection valve 21 can be attached to the intake port 15 so that the central axis H of the fuel injection valve 21 faces the wall surface 15a2 on the side close to the bending center C of the bending portion 15a. Even when the first fuel spray FS1 is set, the first fuel spray FS1 is directed to the wall surface 15a2 closer to the curved center C of the curved portion 15a of the intake port 15, and the second fuel spray FS2 is directed to the intake port 15 than the first fuel spray FS1. The first nozzle hole group 213a and the second nozzle hole group 213b are set so as to be directed toward the wall surface 15a1 on the side farther from the bending center C.

  When each cylinder has two intake valves 16 and two intake ports opened and closed by each intake valve 16 merge on the upstream side, one fuel injection valve 21 on the upstream side of the merging portion. Place. The fuel injection valve 21 performs a total of four sprays, two first fuel sprays FS1 directed to the two intake ports and two second fuel sprays FS2 directed to the two intake ports, respectively. Set to spray.

On the other hand, the difference in penetration force between the first fuel spray FS1 and the second fuel spray FS2 is set by the turning force applied to the spray injected from the nozzle hole, the spray angle, the presence or absence of the collision of the spray, the particle size of the spray, and the like. The
3 to 6 show examples of combination patterns of the spray characteristics of the first fuel spray FS1 and the second fuel spray FS2, and show the spray shape in the cross section of the intake port 15. FIG.

In the example shown in FIG. 3, a plurality of sprays injected from a plurality of nozzle holes constituting the second nozzle hole group 213b collide with each other to form one second fuel spray FS2 (impact spray). On the other hand, the spray injected from the nozzle holes constituting the first nozzle hole group 213a forms the first fuel spray FS1 (non-impact spray) without colliding with each other.
In this case, the second fuel spray FS2 has a wider angle than the first fuel spray FS1 due to the collision of the spray, the flow velocity becomes weaker, the fuel particle size becomes smaller, and the first fuel spray does not collide with the spray. The spray is weaker in penetration than FS1.

In FIG. 3, the plurality of nozzle holes constituting the second nozzle hole group 213b are arranged at intervals along the radius of curvature of the curved portion 15a, and the sprays injected from these nozzle holes are mutually connected. , The second fuel spray FS2 that is long in the direction perpendicular to the direction in which the nozzle holes are arranged (the curvature radius direction of the curved portion 15a) and has an elliptical cross section is formed.
On the other hand, the substantially conical first fuel spray FS1 having a spray angle narrower than the spray angle in the longitudinal direction in the cross section of the second fuel spray FS2 is injected from the nozzle holes constituting the first nozzle hole group 213a. .

  The second nozzle hole group 213b for injecting the second fuel spray FS2 as the collision spray can be composed of two or more injection holes, and injects the first fuel spray FS1 as the non-impact spray. Therefore, the first nozzle hole group 213a can be composed of one or more nozzle holes. When the first nozzle hole group 213a includes a plurality of nozzle holes, the first fuel spray FS1 is formed as a set of a plurality of sprays that are prevented from colliding with each other.

In the example shown in FIG. 4, the first fuel spray FS <b> 1 is a non-collision spray as in FIG. 3, while the nozzle holes constituting the second nozzle hole group 213 b for injecting the second fuel spray FS <b> 2 are formed in the fuel. The fuel is injected through a swirl chamber that imparts a swirl (swirl force), and the second fuel spray FS2 is a spray imparted with a swirl (swirl spray).
In addition, as a structure of the swirl chamber for forming a swirl spray, and a nozzle hole, a well-known structure as disclosed by Unexamined-Japanese-Patent No. 2012-077664 etc. is applicable, for example. Also, the swirl spray can be formed as a collection of a plurality of swirl sprays.
Even in the combination of the first fuel spray FS1 that is a non-impact spray as described above and the second fuel spray FS2 that is a swirl spray, swirl is imparted to the second fuel spray FS2, so that the second fuel spray FS2 The penetration force is weaker than that of the first fuel spray FS1 to which no swirl is applied.

Further, in the example shown in FIG. 5, the first fuel spray FS1 that is a collision spray and the second fuel spray FS2 that is a swirl spray are combined. Also in this case, the penetration force of the second fuel spray FS2 can be set weaker than that of the first fuel spray FS1.
In other words, although the collision spray has a lower penetration force than the non-impact spray, the penetration force of the swirl spray can be further weakened than that of the collision spray. If collision spray is used as the first fuel spray FS1, since the spray angle of the collision spray becomes wide, the fuel is thinly adhered to a wide range of the wall surface 15a2 on the side near the curved center C of the curved portion 15a. , Vaporization from the attached fuel can be promoted.

In the example shown in FIG. 6, the first fuel spray FS1 and the second fuel spray FS2 are both swirl sprays, while the spray angle of the first fuel spray FS1 is smaller than the spray angle of the second fuel spray FS2. By doing so, the penetration force of the second fuel spray FS2 (wide angle swirl spray) is set weaker than that of the first fuel spray FS1 (narrow angle swirl spray).
In addition, the particle size of the injected fuel becomes smaller as the diameter of the injection hole becomes smaller and the penetration force becomes weaker. The first fuel spray FS1 and the first fuel spray FS1 can be appropriately combined with known means (injection hole specifications) for adjusting the penetrating force. It is possible to inject the second fuel spray FS2 having a lower penetration force.

As described above, the first fuel spray FS1 has a penetration force (flow velocity) higher (faster) than the second fuel spray FS2 and the wall surface 15a2 on the side close to the curve center C of the curved portion 15a of the intake port 15. Since it is injected so as to be directed, it adheres in a liquid state and forms a liquid film on the wall surface 15a2 on the side near the bending center C of the bending portion 15a of the intake port 15.
The liquid fuel film generated on the wall surface 15a2 on the side of the curved portion 15a near the curve center C is vaporized by the heat of the wall surface of the intake port 15 (heat of the internal combustion engine 11), and the vaporized fuel is contained in the intake port 15. It rides on the flow of intake air and passes through the intake valve 16 from the side near the bending center C of the bending portion 15 a and flows into the combustion chamber 13.

On the other hand, the second fuel spray FS2 has a lower penetration force than the first fuel spray FS1, and is closer to the wall surface 15a1 farther from the curve center C of the curved portion 15a of the intake port 15 than the first fuel spray FS1. Since the head portion 16a of the intake valve 16 is substantially directed, adhesion to the inner wall of the intake port 15 is suppressed, and the intake port 15 floats in the intake port 15. The fuel spray that floats in the intake port 15 rides on the intake air that flows biased away from the curved center C of the curved portion 15a and passes through the intake valve 16 while biased toward the far side from the curved center C of the curved portion 15a. And flows into the combustion chamber 13.
That is, by injecting the first fuel spray FS1 and the second fuel spray FS2, the fuel flows into the combustion chamber 13 from both the side far from the curved center C of the curved portion 15a and the side near the curved center C. As a result, the homogeneity of the fuel in the combustion chamber 13 is improved and the combustibility is improved, so that the fuel efficiency can be improved.

One fuel spray is injected from the fuel injection valve 21 toward one intake valve 16, and fuel is injected into the combustion chamber 13 from both the side far from the bending center C of the bending portion 15a and the side close to the bending center C. In order to make it flow in, it will be requested | required to make a spray collide uniformly to the whole region of the umbrella part 16a.
However, when the intake port 15 has a curved portion 15a, when the intake valve 16 is viewed from the injection hole side of the fuel injection valve 21, the wall surface on the side where a part of the intake valve 16 is close to the curved center C of the curved portion 15a. It may become a shadow of 15a2. In such a case, if the penetration force of the fuel spray injected into the intake port is weak, the fuel spray rides on the flow of the intake air, so that it is on the side far from the curve center C of the curved portion (the wall surface on the outside of the curve). If the fuel spray is biased while the penetration force of the fuel spray is strong, a large amount of fuel adheres to the wall surface of the curved portion near the curved center C.

For this reason, if the penetration force of the fuel spray is high, a large amount of fuel adheres to the wall surface 15a2 on the side close to the bending center C of the bending portion 15a, and the inside of the combustion chamber 13 from the side far from the bending center C of the bending portion 15a. The amount of fuel flowing into the tank will be too small. On the other hand, if the penetration force of the fuel spray is weakened so that the fuel spray floats in the intake port 15, the adhesion of fuel to the wall surface 15a2 on the side close to the bending center C of the bending portion 15a is suppressed, but the bending portion The floating fuel rides on the flow of intake air that flows biased away from the curved center C of 15a, so that the amount of fuel flowing into the combustion chamber 13 from the side near the curved center C of the curved portion 15a becomes too small.
Therefore, when a single fuel spray injected from the fuel injection valve 21 (with a constant spray characteristic) is sucked through the single intake valve 16, the side far from the curved center C of the curved portion 15a is closer to the side. Therefore, it is difficult to cause the fuel to flow into the combustion chamber 13 at an appropriate ratio, and it is difficult to sufficiently increase the homogeneity of the fuel in the cylinder.

In contrast, the fuel injection valve 21 injects two fuel sprays FS1 and FS2 having different spray directing directions and penetrating forces, the penetrating force (flow velocity) is relatively high (fast), and the intake port 15 The first fuel spray FS1 directed to the wall surface 15a2 near the bending center C of the bending portion 15a adheres to the wall surface 15a2 near the bending center C of the bending portion 15a, and the fuel vaporized from the liquid film is bent. From the side of the portion 15 a close to the center of curvature C, it passes through the intake valve 16 and flows into the combustion chamber 13.
Further, the second fuel spray FS2 having a relatively low (slow) penetration force (flow velocity) floats in the intake port 15 and rides on the flow of the intake air flowing away from the bending center C of the bending portion 15a. Then, it passes through the intake valve 16 from the side far from the bending center C of the bending portion 15 a and flows into the combustion chamber 13.
For this reason, in the internal combustion engine 11 provided with the fuel injection valve 21 (fuel injection device), the fuel can flow into the combustion chamber 13 at an appropriate ratio from both the side far from the bending center C of the bending portion 15a and the side closer to the bending center 15a. It is possible to improve the fuel efficiency by sufficiently increasing the homogeneity of the fuel in the combustion chamber 13.

Here, the injection timing by the fuel injection valve 21 is that the start of injection is in the exhaust stroke (during the closing period of the intake valve 16, that is, before the intake valve 16 is opened), and the end of injection is in the intake stroke. The injection timing is such that the intake valve 16 is opened (that is, after the intake valve 16 is opened).
The first fuel spray FS1 is injected so that fuel adheres to the wall surface 15a2 on the side close to the bending center C of the bending portion 15a, but during the intake stroke in which the flow of intake air occurs in the intake port 15, the first fuel spray FS1. The amount of fuel flowing into the combustion chamber 13 from the side close to the bending center C of the bending portion 15a is reduced when the FS1 is caused to flow by the intake air. For this reason, the amount of fuel flowing into the combustion chamber 13 from the side far from the bending center C of the bending portion 15a becomes excessive, and the homogeneity of the fuel in the combustion chamber 13 decreases.

Therefore, in order to secure the amount of fuel flowing into the combustion chamber 13 through the intake valve 16 from the side near the bending center C of the bending portion 15a, fuel is injected during the exhaust stroke (while the intake valve 16 is closed). It is necessary to cause the fuel to adhere to the wall surface 15a2 on the side close to the bending center C of the bending portion 15a by the first fuel spray FS1.
However, since the first fuel spray FS1 and the second fuel spray FS2 are injected at the same time, if the fuel injection is finished during the exhaust stroke, the second fuel spray FS2 is also injected into the intake port 15 where there is no intake flow. Will be done. For this reason, the second fuel spray FS2 diffuses excessively and adheres to the wall surface of the intake port 15, so that the amount of fuel flowing into the combustion chamber 13 from the side far from the bending center C of the bending portion 15a decreases. .

Therefore, in order to secure the amount of fuel flowing into the combustion chamber 13 from the side far from the bending center C of the bending portion 15a, the fuel is injected during the intake stroke (while the intake valve 16 is opened), and the second fuel spray is performed. It is desirable to place FS2 on the flow of intake air.
Therefore, in the fuel injection valve 21 in which the first fuel spray FS1 and the second fuel spray FS2 are simultaneously injected only during the same period, the injection of the first fuel spray FS1 and the intake air during the exhaust stroke (while the intake valve 16 is closed) In order to perform the injection of the second fuel spray FS2 during the stroke (while the intake valve 16 is open), the injection timing is set so that the fuel is injected from the exhaust stroke to the intake stroke.

As a result, the amount of fuel flowing into the combustion chamber 13 from the side far from the bending center C of the curved portion 15a and the amount of fuel flowing into the combustion chamber 13 from the near side are set as appropriate ratios so that the fuel in the combustion chamber 13 is homogeneous. Try to increase the degree.
Further, in the fuel injection valve 21, when the fuel amount injected as the first fuel spray FS1 and the fuel amount injected as the second fuel spray FS2 are set to be the same, that is, the share ratio of the injection amount is 50%. When set to 50%, the amount of fuel vaporized from the liquid film on the wall surface 15a2 near the bending center C of the bending portion 15a is insufficient, and flows into the combustion chamber 13 from the side near the bending center C of the bending portion 15a. The amount of fuel may become too small.

Therefore, the share ratio of the injection amount by the first fuel spray FS1 is set so that the fuel amount injected as the first fuel spray FS1 is larger than the fuel amount injected as the second fuel spray FS2. It is made to become larger than the share ratio of the injection amount by FS2. The setting of the sharing ratio can be realized by making the number and diameter of the nozzle holes different between the first nozzle hole group 213a and the second nozzle hole group 213b.
Thereby, it is possible to secure a sufficient amount of fuel to be vaporized from the liquid film on the wall surface 15a2 on the side close to the bending center C of the bending portion 15a, and the fuel flowing into the combustion chamber 13 from the side far from the bending center C of the bending portion 15a. The homogeneity of the fuel in the combustion chamber 13 can be increased by setting the amount and the amount of fuel flowing into the combustion chamber 13 from the near side to an appropriate ratio.

Incidentally, the fuel injection device shown in FIG. 1 injects the first fuel spray FS1 and the second fuel spray FS2 from one fuel injection valve 21, but as shown in FIG. 7, the first fuel spray FS1 is injected. It can be set as a fuel injection device provided with the 1st fuel injection valve 21a which injects, and the 2nd fuel injection valve 21b which injects the 2nd fuel spray FS2.
In the fuel injection device shown in FIG. 7, the first fuel injection valve 21 a and the second fuel injection valve 21 b are provided in the upstream portion of the wall surface 15 a 1 far from the bending center C of the bending portion 15 a of the intake port 15, and the first A second fuel injection valve 21b is disposed downstream of the one fuel injection valve 21a.

The first fuel injection valve 21a injects the first fuel spray FS1 directed to the wall surface 15a2 on the side close to the bending center C of the bending portion 15a, and the first fuel spray FS1 is injected by the second fuel injection valve 21b. The penetration force is set to be stronger than that of the second fuel spray FS2.
On the other hand, the directing direction of the second fuel spray FS2 by the second fuel injection valve 21a is directed toward the wall surface 15a1 farther from the bending center C of the bending portion 15a than the first fuel spray injected by the first fuel injection valve 21a. To do. More specifically, the directing direction of the second fuel spray FS2 by the second fuel injection valve 21a can sufficiently suppress the second fuel spray FS2 from interfering with the first fuel spray FS1, and the intake port It is set within a range in which the adhesion of fuel to the wall surface 15a1 on the side far from the bending center C of the 15 bending portions 15a can be sufficiently suppressed.

Further, as shown in FIG. 8, two cylinders are provided with two intake valves 16a and 16b, and two intake ports 151 and 152 that are opened and closed by these intake valves 16a and 16b are provided in each cylinder. When the first intake port 15 branches to the two intake ports 151, 152 from the middle, the first fuel injection valve 21a and the second fuel injection valve 21b are arranged upstream of the branching portion.
The first fuel injection valve 21a injects the first fuel spray FS1 in two directions toward the intake ports 151 and 152, and the second fuel injection valve 21b in two directions toward the intake ports 151 and 152, respectively. To inject the second fuel spray FS2.

As described above, when the first fuel injection valve 21a for injecting the first fuel spray FS1 and the second fuel injection valve 21b for injecting the second fuel spray FS2 are provided separately, the two fuel injection valves 21a and 21b are provided. The injection timing and the injection pulse width in can be individually set.
Therefore, the injection start timing of the second fuel injection valve 21b can be delayed from the injection start timing of the first fuel injection valve 21a. For example, the injection start timing of the first fuel injection valve 21a is set during the exhaust stroke (intake air). On the other hand, the injection start timing of the second fuel injection valve 21b can be set during the intake stroke (when the intake valve 16 is opened or after the valve is opened).

Further, the amount of fuel injected as the first fuel spray FS1 and the amount of fuel injected as the second fuel spray FS2 can be arbitrarily set by setting the pulse width of the injection pulse signal output to each fuel injection valve 21a, 21b. By setting the injection pulse width, the amount of fuel injected as the first fuel spray FS1 can be made larger than the amount of fuel injected as the second fuel spray FS2.
The amount of fuel injected when the first fuel injection valve 21a is opened for a unit time is set to be larger than the amount of fuel injected when the second fuel injection valve 21a is opened for a unit time. While the injection pulse signal having the same injection pulse width is output to each fuel injection valve 21a, 21b, the amount of fuel injected from each fuel injection valve 21a, 21b can be made different.

Further, the amount of fuel injected when the first fuel injection valve 21a is opened for a unit time is set to be larger than the amount of fuel injected when the second fuel injection valve 21a is opened for a unit time. In addition, the injection pulse width of the first fuel injection valve 21a is made longer than the injection pulse width of the second fuel injection valve 21a, and the amount of fuel injected as the first fuel spray FS1 is changed to the second fuel spray FS2. The amount of fuel injected can be increased.
In other words, the fuel injection device shown in FIG. 7 includes two fuel injection valves 21a and 21b for each cylinder, so that the fuel injection device includes one fuel injection valve 21 for each cylinder shown in FIG. The degree of freedom in setting the injection timing and the injection amount of the first fuel spray FS1 and the second fuel spray FS2 is high, and the homogeneity of the fuel in the combustion chamber 13 can be further improved.
On the other hand, if the fuel injection device shown in FIG. 1 is provided with one fuel injection valve 21 for each cylinder, the number of fuel injection valves used can be reduced, so that the cost of the fuel injection device can be suppressed and combustion can be performed. The homogeneity of the fuel in the chamber 13 can be sufficiently increased.

Although the preferred embodiments have been specifically described above, it is obvious that those skilled in the art can take various modifications.
For example, in both of the fuel injection devices shown in FIGS. 1 and 7, the injection timing depends on the operating conditions such as the engine temperature (the wall surface temperature of the intake port 15), the engine load, the engine rotational speed (intake flow velocity), and the fuel properties. Can be changed.
Further, in the fuel injection device provided with two fuel injection valves 21a and 21b for each cylinder shown in FIG. 7, the engine temperature (the wall surface temperature of the intake port 15), the engine load, the engine rotation speed (intake flow velocity), The share ratio of the fuel injection amount in the two injection valves (the first fuel spray FS1 and the second fuel spray FS2) can be changed according to the operating conditions such as the fuel properties.

Here, technical ideas other than the claims that can be grasped from the above embodiment will be described together with effects.
(A) A fuel injection valve for injecting fuel into an intake port of an internal combustion engine,
The angle formed between the axis of the fuel injection valve and the directing direction of the fuel spray is θ1, and the angle formed between the axis of the fuel injection valve and the directing direction of the fuel spray is smaller than the angle θ1. A fuel injection valve in which the second fuel spray is injected and the penetration force of the first fuel spray is set higher than the penetration force of the second fuel spray.
According to the above invention, the first fuel spray that adheres to the wall surface of the curved portion near the curve center C and the second fuel spray that floats in the intake port can be injected. The fuel can be sucked into the combustion chamber in the flow, and the fuel vaporized from the liquid film on the wall surface of the curved portion near the curved center C can be sucked into the combustion chamber.

(B) The fuel injection device for an internal combustion engine according to claim 1, wherein the second fuel spray is a collision spray formed by a collision of a plurality of fuel sprays, and the first fuel spray is a non-collision spray.
According to the above invention, by causing a plurality of fuel sprays to collide with each other, the penetrating force becomes weaker than when not colliding, and the first fuel spray having a penetrating force stronger than the second fuel spray that is a colliding spray can be injected. it can.

(C) The fuel injection device for an internal combustion engine according to claim 1, wherein the second fuel spray is a swirl spray obtained by imparting a swirl to the fuel spray.
According to the said invention, it can be set as the 2nd fuel spray with a weak penetration force by giving a swirl to fuel spray.

  DESCRIPTION OF SYMBOLS 11 ... Internal combustion engine (engine), 12 ... Cylinder head, 13 ... Combustion chamber, 14 ... Piston, 15 ... Intake port, 15a ... Curved part, 16 ... Intake valve, 17 ... Cylinder, 18 ... Spark plug, 19 ... Exhaust valve 20 ... exhaust port, 21 ... fuel injection valve, 30 ... engine control unit, 31 ... air flow sensor, 32 ... crank angle sensor, 33 ... water temperature sensor

Claims (3)

A fuel injection device for an internal combustion engine in which a curved portion is formed in an intake port between an intake valve and a fuel injection device, and fuel is injected into the intake port,
Injecting a first fuel spray directed to a wall surface closer to the curve center of the curved portion of the intake port, and a second fuel spray directed to a wall surface farther from the curve center than the first fuel spray; And the fuel-injection apparatus of an internal combustion engine by which the penetration force of the said 1st fuel spray is set higher than the penetration force of the said 2nd fuel spray.   A fuel injection valve having an injection hole for injecting the first fuel spray and an injection hole for injecting the second fuel spray, or a first fuel injection valve and the second fuel spray for injecting the first fuel spray. The fuel injection device for an internal combustion engine according to claim 1, further comprising a second fuel injection valve that injects fuel.   The fuel injection device for an internal combustion engine according to claim 1, wherein a fuel injection amount by the first fuel spray is set to be larger than a fuel injection amount by the second fuel spray.