JP2011149311A - Fuel injector for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that fuel spray of fuel injection valves 81 and 82 is entangled in the air flow flowing along a wall of an intake port 16, and fuel is adhered to the wall of the intake port 16. <P>SOLUTION: Intake valves 40 and 50 and the fuel injection valves 81 and 82 are provided in the intake port 16, and straight wall parts 181 and 191 of the intake port 16 are formed to be the straight shape parallel to intake valve center axes Pv1 and Pv2 when viewed from a cylinder center axis direction. Therefore, the air flow flowing in the intake port 16 is sucked into the intake valves 40 and 50 along the straight wall parts 181 and 191, and the adhesion amount of the fuel to the straight wall parts 181 and 191 of the intake port 16 and an inner peripheral wall 21 of a cylinder block 11 forming a cylinder 13 can be reduced. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a structure for mounting a fuel injection valve to an internal combustion engine and a fuel injection device for an internal combustion engine including the shape of an intake port of the internal combustion engine.

  As a conventional technique, in an internal combustion engine injection device in which one fuel injection valve is mounted in one cylinder, in order to divide the spray in two directions from one fuel injection valve, the upstream side of the intake port, that is, the fuel injection In the vicinity of the injection portion of the valve, the width of the intake port near the injection portion is generally narrower than the width of the intake port in the portion where the intake valve on the downstream side is provided. That is, the inner wall surface of the intake port is generally formed in a shape that widens from the upstream side to the downstream side and widens toward the end.

  However, in this case, since the fuel spray injected from the fuel injection valve spreads on the divergent airflow, the amount of fuel adhering to the inner wall surface of the intake port increases. As a result, the amount of fuel supplied into the cylinder is reduced, or the combustion efficiency in the cylinder is deteriorated, which causes a problem in improving fuel efficiency.

  In recent years, a direct-injection internal combustion engine that directly injects fuel into a cylinder is known as a technology for improving the fuel efficiency of an internal combustion engine for gasoline. This direct-injection internal combustion engine has a high system cost and a small displacement. It is not very popular in internal combustion engines.

  Therefore, in order to further improve fuel consumption, an invention in which one fuel injection valve is mounted on each intake valve is known from Patent Document 1. In Patent Document 1, in the intake port of a conventional internal combustion engine, in order to reduce the amount of fuel adhering to the inner wall surface of the intake port, the distance between the injection portions of each fuel injection valve is shortened, It is installed.

  That is, in Patent Document 1, the fuel spray is not caused to flow to the inner wall surface side by the airflow flowing at a high speed along the inner wall surface of the intake port so that the injection portion of the fuel injection valve is separated from the inner wall surface of the intake port. The fuel spray is directed toward the center of the intake valve.

JP 2007-309121 A

  In patent document 1, although the space | interval between the injection parts of a fuel injection valve is made small, when fuel injection valves are brought close enough, mounting of a fuel injection valve may be difficult. In particular, it is often more difficult if the fuel injection valve mounting interval and mounting direction are determined by the fuel rail. In addition, there is a similar problem when the fuel injection valve is mounted with a large inclination.

  The present invention has been made paying attention to such problems existing in the prior art, and an object of the present invention is to provide a sufficient space between the fuel injection valves and to ensure that the intake ports are not separated from each other. The fuel injection valve mounting structure and the intake port of the intake port can solve the problem that the fuel spray of the fuel injection valve is entrained in the airflow flowing at high speed along the wall surface and the fuel adheres to the inner wall of the intake port. An object of the present invention is to provide a fuel injection device for an internal combustion engine including a shape.

  The content of the patent document described as a prior art can be introduce | transduced thru | or incorporated by reference as description of the technical element described in this specification.

  In order to achieve the above object, the present invention employs the following technical means. That is, according to the first aspect of the present invention, in an internal combustion engine fuel injection device used in an internal combustion engine in which at least a pair of intake valves are juxtaposed to a cylinder, the intake port interior that guides the airflow that surrounds the intake valve and flows into the internal combustion engine. In addition, the fuel injection valves mounted corresponding to the respective intake valves are provided, and in the juxtaposition direction of the intake valves so as to define the linear shape of the inner wall of the intake port when viewed from the cylinder central axis direction. The present invention is characterized in that straight walls are formed of surfaces or lines of a predetermined length parallel to each other on the inner walls of the intake ports existing on both sides.

  According to the present invention, since the inner wall of the intake port has the straight wall portion that defines the linear shape of the inner wall of the intake port when viewed from the cylinder central axis direction, the airflow flowing in the intake port Flows along the straight wall. Therefore, even if the interval between the fuel injection valves is not extremely narrow or greatly inclined as in the prior art, the adhesion of fuel to the inner wall of the intake port and the inner peripheral wall of the cylinder block forming the cylinder is reduced. .

  In the invention according to claim 2, the intake port upstream width, which is the maximum width between the straight walls in the juxtaposed direction of the intake valves, is L1, and between the upstream ends of the valve seats with which the valve portions of the intake valves abut. When the maximum width is L2, the relationship of L1 ≧ L2 is established.

  According to the present invention, since the relationship of L1 ≧ L2 is established, the intake port does not have a divergent shape from upstream to downstream as in the prior art. The fuel adheres to the inner wall of the intake port and the inner peripheral wall of the cylinder block forming the cylinder.

  In the invention according to claim 3, the intake port includes a branch portion that is a starting point from which the airflow branches, and a pair of branch ports that branch from the branch portion, and each straight wall portion includes at least a branch portion. It is characterized in that it exists over an interval from the valve portion of the intake valve to the upstream end of the valve seat that abuts.

  According to the present invention, each straight wall portion exists at least in the interval from the branching portion to the upstream end of the valve seat with which the valve portion of the intake valve abuts. The flowing airflow also flows straight, and the adhesion of fuel to the inner wall of the intake port and the inner peripheral wall of the cylinder block forming the cylinder is reduced.

  The invention according to claim 4 is characterized in that each straight wall portion exists at least over the length of twice the interval.

  According to the present invention, each straight wall portion exists at least twice as long as the interval from the branch portion to the upstream end of the valve seat with which the valve portion of the intake valve abuts. Then, the airflow flowing in the intake port also flows more reliably in a straight line, and the adhesion of fuel to the inner wall of the intake port and the inner peripheral wall of the cylinder block forming the cylinder is reduced.

  In the invention according to claim 5, the branch ports are partitioned by the partition wall portion, and the portion of the partition wall portion facing each straight wall portion is also linear when viewed from the cylinder central axis direction. It is characterized by being formed so as to demarcate the shape.

  According to the present invention, the portion of the partition wall portion facing each straight wall portion is also formed so as to define a linear shape when viewed from the cylinder central axis direction. The airflow that flows in the intake port along the line also flows straight, and the adhesion of fuel to the wall surface of the partition wall portion, the inner wall surface of the intake port, and the inner peripheral wall of the cylinder block forming the cylinder is reduced.

  The invention according to claim 6 is characterized in that each straight wall portion is formed in parallel to the central axis of the intake valve when viewed from the central axis direction of the cylinder.

  According to the present invention, each straight wall portion is formed in parallel to the central axis of the intake valve when viewed from the central axis direction of the cylinder, and therefore flows in the intake port along each straight wall portion. The airflow flows straight, and the adhesion of fuel to the inner wall of the intake port and the inner peripheral wall of the cylinder block forming the cylinder is reduced.

  In the invention according to claim 7, each straight wall portion is formed in parallel to a virtual plane passing through the center between the pair of intake valves and the center axis of the cylinder when viewed from the direction of the center axis of the cylinder. It is characterized by being.

  According to the present invention, each straight wall portion is formed in parallel to a virtual plane passing through the center between the pair of intake valves and the center axis of the cylinder when viewed from the direction of the center axis of the cylinder. The airflow flowing in the intake port along each straight wall portion flows straight, and the adhesion of fuel to the inner wall of the intake port and the inner peripheral wall of the cylinder block forming the cylinder is reduced.

  In the invention according to claim 8, when viewed from the direction of the central axis of the cylinder, the plane including the central axis of the fuel injection valve and the plane including the central axis of the intake valve are installed in parallel to each other. It is a feature.

  According to this invention, both the intake valve and the fuel injection valve can be assembled from the same direction. Therefore, the assembly of the intake valve and the fuel injection valve can be facilitated, and the number of assembly steps can be reduced.

It is sectional drawing which shows the outline | summary of the internal combustion engine used for the fuel-injection apparatus for internal combustion engines in 1st Embodiment of this invention. FIG. 2 is a schematic external view of an intake port portion of a fuel injection device for an internal combustion engine as viewed from the direction of an arrow Y2 in FIG. It is an external view of the fuel injection valve mounted in the fuel-injection apparatus for internal combustion engines in the said embodiment. It is a model external view of the intake port part of the fuel-injection apparatus for internal combustion engines which shows 2nd Embodiment of this invention.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration.

  Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also a combination of the embodiments even if they are not clearly shown unless there is a problem with the combination. It is also possible.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view showing an outline of an internal combustion engine used in the fuel injection device for an internal combustion engine according to the first embodiment. FIG. 2 is a schematic external view of the intake port portion for explaining the positional relationship between the intake valve and the fuel injection valve, as viewed from the cylinder central axis direction of FIG.

  FIG. 3 is an external view of a fuel injection valve mounted on the fuel injection device for an internal combustion engine. In FIG. 1, an internal combustion engine 10 is a gasoline internal combustion engine using, for example, gasoline as fuel. The fuel is not limited to gasoline, but may be alcohol, for example.

  The internal combustion engine 10 includes a cylinder block 11 and a cylinder head 12 as a housing. The cylinder block 11 forms a cylindrical cylinder 13. The cylinder 13 accommodates the piston 14 on the inner side. The piston 14 is supported by the connecting rod 15 and reciprocates in the axial direction of the cylinder 13.

  The cylinder head 12 is disposed on one end side of the cylinder block 11. An intake port 16 and an exhaust port 17 are formed in the cylinder head 12. The intake port 16 branches into two branch ports 18 and 19 before being connected to the cylinder block 11 as shown in FIG.

  Further, as shown in FIG. 1, through the cylinder head 12, intake valves 40 and 50 for opening and closing the branch ports 18 and 19 (FIG. 2) and an exhaust valve 60 for opening and closing the exhaust port 17 are provided.

  As shown in FIG. 2, the intake valves 40 and 50 have shaft portions 41 and 51 and valve portions 42 and 52. The shaft portions 41 and 51 are slidably supported by the cylinder head 12 with the gasket 43 (FIG. 1) interposed therebetween.

  As for shaft parts 41 and 51, one end part of an axial direction is connected to valve parts 42 and 52, and the other end part is in contact with intake cam 44 across tappet 45, respectively, as shown in FIG. . A spring 46 as an elastic member is installed between the cylinder head 12 and the tappet 45 of each intake valve 40, 50. The spring 46 presses the tappet 45 in a direction away from the cylinder head 12. The tappet 45 moves integrally with the intake valves 40 and 50.

  The exhaust valve 60 penetrates the cylinder head 12. The exhaust valve 60 has a shaft portion 61 and a valve portion 62. The shaft portion 61 is movably supported in the cylinder head 12 with the gasket 63 (FIG. 1) interposed therebetween.

  As shown in FIG. 1, the shaft portion 61 of the exhaust valve 60 has one end portion in the axial direction connected to the valve portion 62 and the other end portion in contact with the exhaust cam 65 with the tappet 64 interposed therebetween. . A spring 66 as an elastic member is installed between the cylinder head 12 and the tappet 64. The spring 66 presses the tappet 64 in a direction away from the cylinder head 12. The tappet 64 moves integrally with the exhaust valve 60.

  The inner peripheral wall 21 of the cylinder block 11 forming the cylinder 13, the cylinder block 11 side surface of the cylinder head 12, the upper end surface of the piston 14 on the cylinder head 12 side, and the piston 14 side of the intake valves 40 and 50 on the piston 14 side. A space formed by the side end surface and the side end surface of the exhaust valve 60 on the piston 14 side is the combustion chamber 22.

  The combustion chamber 22 can communicate with the intake port 16 and the exhaust port 17. The intake port 16 communicates with an unillustrated surge tank at the end opposite to the combustion chamber 22. The end of the surge tank opposite to the intake port 16 communicates with an intake introduction portion (not shown). The air introduced from the intake air introduction portion flows into the intake port 16 via, for example, an air cleaner, a throttle, and the surge tank (not shown).

  In the cylinder head 12 of FIG. 1, an ignition device 70 is installed at a substantially central portion of the combustion chamber 22. The ignition device 70 is installed through the cylinder head 12. In the ignition device 70, an ignition coil and a spark plug (not shown) are integrally formed. The ignition device 70 has an end on the ignition plug side exposed to the combustion chamber 22.

  In the case of the first embodiment, the combustion chamber 22 communicates with two branch ports 18 and 19 branched from the intake port 16 as shown in FIG. An exhaust port 17 communicates with the combustion chamber 22. That is, the internal combustion engine 10 of the first embodiment is an internal combustion engine having four valves per cylinder.

  As shown in FIG. 2, the intake port 16 is branched into two branch ports 18 and 19 at a branch portion 23 provided between the surge tank and the combustion chamber 22. As a result, the intake air flowing from the surge tank to the intake port 16 is distributed from the branch portion 23 to the two branch ports 18 and 19. The branch port 18 and the branch port 19 are partitioned by a partition wall portion 24.

  Each of the branch ports 18 and 19 of the intake port 16 is provided with one fuel injection valve 81 and 82, respectively. In each of the fuel injection valves 81 and 82, one end in the axial direction is exposed to the branch ports 18 and 19, and the other end is connected to a fuel rail that stores fuel (not shown).

  FIG. 3 is a partial cross-sectional side view of the fuel injection valves 81 and 82. In the fuel injection valves 81 and 82, the end portions on the opposite side to the fuel rail are the end portions on the fuel injection side for injecting fuel. The fuel injection valves 81 and 82 have an injection hole 84 at the end on the fuel injection side. The fuel injection valves 81 and 82 inject fuel from the injection hole 84 to the intake air flowing through the branch ports 18 and 19, respectively.

  In the case of the first embodiment, the fuel injection valves 81 and 82 are each a kind of electromagnetic valve in which the needle 85 reciprocates in the axial direction by intermittently energizing a coil (not shown) inside the fuel injection valves 81 and 82.

  The needle 85 is intermittently injecting fuel from the injection hole 84 by being seated on or separated from the valve seat 87 formed in the body 86. The fuel injection valves 81 and 82 include an injection hole plate 88 that forms an injection hole 84 at the tip of the body 86.

  In the intake valve 40, the valve portions 42 and 52 abut against the valve seat provided at the end of the branch port 18 on the combustion chamber 22 (FIG. 1) side, or the valve portions 42 and 52 are separated from the valve seat. The outlets of the branch ports 18 and 19 are opened and closed. The intake valve 50 opens and closes the end of the branch port 19 on the combustion chamber 22 side. As shown in FIG. 2, the cylinder center axis Pc of the cylinder 13 passes through the center of the combustion chamber 22 in the direction perpendicular to the plane of FIG. The fuel injection valve 81 of the branch port 18 has a tip center C1 at the tip of the fuel injection side. The intake valve central axis Pv1 and the central axis Pi1 of the fuel injection valve 81 exist in a plane perpendicular to the paper surface of FIG.

  As shown in FIG. 3, the fuel injection valves 81 and 82 have fuel injection side tip centers C1 and C2 that are the fuel injection valve 81 and 82 injection hole plate 88 and the fuel injection valves 81 and 82, respectively. Is the position where the central axes Pi1 and Pi2 intersect. In FIG. 2, the separation distance between the fuel injection valve central axes Pi1 and Pi2 and the separation distance between the intake valve central axes Pv1 and Pv2 are made to coincide.

  As shown in FIG. 2, the intake air flowing through the intake port 16 flows separately into the branch port 18 and the branch port 19 in the branch portion 23. Therefore, the intake air flowing from the intake port 16 to the branch ports 18 and 19 in the radial direction of the cylinder 13 from the center side to the outer peripheral side of the intake port 16, that is, the cylinder block 11 forming the cylinder 13 in FIG. There is a tendency to flow to the peripheral wall 21 side.

  However, in the first embodiment, as shown in FIG. 2, when the straight wall portions 181 and 191 facing each other in the juxtaposition direction of the branch ports 18 and 19 are viewed from the cylinder central axis direction, the straight shape Is defined as a straight portion composed of surfaces or lines of a predetermined length parallel to each other along the intake valve central axes Pv1, Pv2.

  The intake port upstream width which is the maximum width between the straight walls 181 and 191 of the intake port 16 in the direction between the fuel injection valves 81 and 82 defining the upstream shape of the intake port 16 is L1, and the intake valve 40, When the intake port downstream width that is the width of each straight wall portion 181 and 191 of the intake port 16 near 50 (more precisely, the maximum width of the upstream end of the valve seat with which the valve portions 42 and 52 abut) is L2, The relationship L1 ≧ L2 is established.

  In the case of FIG. 2, the fuel injection valves 81 and 82 pass through the fuel injection valve central axes Pi1 and Pi2, and further pass through the valve center line Pv3 passing through the center between the intake valves 40 and 50 and the center of the exhaust valve 60. The straight wall portions 181 and 191 of the intake port are arranged in parallel to a plane perpendicular to the paper surface of FIG.

  In this way, the air flow flowing along the straight walls 181 and 191 that are straight and parallel to each other in the intake port 16 and the fuel spray injected from the fuel injection valves 81 and 82 are the intake valves 40 and 50. So as to flow into the combustion chamber 22 of the internal combustion engine 10.

  Further, the intake port 16 is formed so as to have a pair of branch ports 18 and 19 that are branched at the branch portion 23 on the upstream side where the airflow reaches the intake valves 40 and 50. That is, the branching portion is the most upstream end of the branching port provided at the portion where the airflow flowing in the intake port starts to branch right and left.

And each straight wall part 181 and 191 exists in the space | interval S1 from the branch part 23 to the upstream end of the valve seat which the valve parts 42 and 52 contact | abut. More preferably, the straight wall portions 181 and 191 exist at least over the interval S2 having a length twice as long as the interval S1.
(Operational effects of the first embodiment)
Hereinafter, the effect of 1st Embodiment which consists of the said structure is demonstrated. In the first embodiment, as described above, the straight wall portions 181 and 191 are formed straight. Therefore, since the airflow of the intake air flowing into the branch port from the upstream side of the intake port 16 flows straight along the straight wall portions 181 and 191 in the branch ports 18 and 19, at least the tips of the fuel injection valves 81 and 82. The flow of fuel spray injected from the centers C1 and C2 is also carried along this straight air flow and sucked into the intake valves 40 and 50.

  That is, since the straight wall portions 181 and 191 of the intake port 16 are formed straight, the fuel spray injected from the fuel injection valve 81 and the fuel injection valve 82 flows into the intake air flow indicated by the arrows F40 and F50. It is carried and flows into the combustion chamber 22 from the center of the branch ports 18 and 19, that is, the centers of the valve portions 42 and 52. Thus, since the fuel spray is carried not by the airflow that expands toward the downstream side as in the prior art, but by the airflow that flows straight, the inside of each of the straight wall portions 181 and 191 and the cylinder block 11 that forms the cylinder 13 The amount of fuel adhering to the peripheral wall 21 is reduced.

  Although the straight walls 181 and 191 of the intake ports 18 and 19 are straight, an inclined surface (not shown) on the further upstream side of the intake port 16 where the width of the intake port 16 gradually decreases toward the upstream side. Or a slope is formed. In other words, the straight state will not last forever. However, since the straight wall portions 181 and 191 of the intake port 16 are formed at least within the interval S1, the airflow flowing through the branch ports 18 and 19 is straight along the straight wall portions 181 and 191. It flows and is sucked into the valve portions 42 and 52 of the intake valves 40 and 50.

  In addition, since the range where each straight wall part 181 and 191 extends should be as long as possible, each straight wall part 181 and 191 should be formed over the length S2 at least twice the space S1. preferable.

  Further, as described above, the relationship between the intake port upstream width L1 and the intake port downstream width L2 in FIG. 2 is L1 ≧ L2. Thereby, the flow of the airflow which flows along each straight wall part 181 and 191 of the intake port 16 can be made more straight. Incidentally, in the case of the conventional patent document 1, the intake port upstream width L1 is configured to be smaller than the intake port downstream width L2.

  As described above, the amount of fuel that does not contribute to combustion is reduced by reducing the amount of fuel adhering to the branch ports 18 and 19 and the inner peripheral wall 21 of the cylinder block 11. Therefore, incomplete combustion of the fuel spray injected from the fuel injection valve 81 and the fuel injection valve 82 is reduced.

  As a result, the discharge of unburned fuel to the outside of the internal combustion engine 10 is reduced. Therefore, unburned hydrocarbons (HC) discharged from the internal combustion engine 10 can be reduced. Further, the fuel injected from the fuel injection valve 81 and the fuel injection valve 82 burns efficiently without becoming droplets. Therefore, when a predetermined output is requested from the internal combustion engine 10, the amount of fuel to be injected from the fuel injection valve 81 and the fuel injection valve 82 is reduced. Therefore, fuel consumption can be improved.

  2, when viewed from the direction of the central axis Pc of the cylinder 13, the central axis Pi1 of the fuel injection valve 81, the central axis Pv1 of the intake valve 40, the central axis Pi2 of the fuel injection valve 82, and the center of the intake valve 50 The direction of the axis Pv2 and the straight walls 181 and 191 extending in the straight direction are set parallel to each other.

  As a result, the intake valves 40 and 50 and the fuel injection valves 81 and 82 are all assembled from the same direction. Therefore, the assembly of the intake valves 40 and 50 and the fuel injection valves 81 and 82 can be facilitated, and the number of assembly steps can be reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following embodiments, the same components as those in the first embodiment described above are denoted by the same reference numerals, description thereof will be omitted, and different configurations and features will be described.

  FIG. 4 is a cross-sectional view showing an outline of the internal combustion engine showing the second embodiment. In the first embodiment, at least the straight wall portions 181 and 191 of the intake ports 18 and 19 facing the fuel injection valve are straight. However, the second embodiment is not limited to this, as shown in FIG. The portions 241 and 242 of the partition wall 24 of the intake ports 18 and 19 are also straight when viewed from the center axis direction of the cylinder.

  The partition wall portion 24 is a wall inside the branch ports 18 and 19 from the branch portion 23 to the upstream end of the valve seat with which the valve portions 42 and 52 come into contact, and with respect to the straight wall portions 181 and 191. This is a portion that opposes the juxtaposed direction of the branch ports 18 and 19.

  According to this, since the two branch ports 18 and 19 are separated from each other by the partition wall portion 24 and the portions 241 and 242 of the partition wall portion 24 are formed straight, the inside of the branch ports 18 and 19 While the air flow and fuel spray flow to the combustion chamber 22 in the internal combustion engine 10, the air flow and fuel spray flow to the wall portions 241 and 242 of the straight partition wall portion 24 of the branch ports 18 and 19 and this portion. It flows straight along the straight wall portions 181 and 191 opposite to each other. Therefore, the fuel spray injected from the fuel injection valves 81 and 82 is more reliably prevented from adhering to the portions 241 and 242 of the branch ports 18 and 19.

  Note that S1 and S2 in FIG. 4 are intervals between straight portions in the first embodiment. Thus, in this 2nd Embodiment, the length of the straight part is set longer than 1st Embodiment. However, as in the first embodiment, the length of the straight portion can be set short.

  Also in the second embodiment, the straight wall portions 181 and 191 formed straight reach at least the branch portion 23 to the upstream end of the valve seat with which the valve portions 42 and 52 of the intake valves 40 and 50 abut. Exists over the interval. In addition, it is more preferable if each straight wall part 181 and 191 formed in straight extends further to the upstream side, and exists over the length of 2 times the said space | interval.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows. For example, the branch ports 18 and 19 and the exhaust port 17 of the internal combustion engine 10 may be configured such that three or more each communicate with the combustion chamber 22 of one cylinder. Further, the number of branch ports and exhaust ports may be different as in a so-called one-cylinder five-valve internal combustion engine having two exhaust ports.

  Note that the fuel injection valves do not have to be parallel to each other, and may be inclined with respect to each other within an allowable range. Further, the fuel injection valve mounting interval may be made closer to each other within an allowable range to be smaller than the intake valve interval.

  In other words, even if each straight wall portion of the intake port is straight, there is an inclined portion or a slope portion on the further upstream side of this straight portion, so the flow in the intake port may not be completely straight, In this case as well, it is beneficial to make the interval between the fuel injection valves closer by utilizing the concept of Patent Document 1 or to incline the mounting angle of the fuel injection valves inward.

  In addition, when viewed from directly above the center axis Pc direction of the cylinder 13 as shown in FIG. 2, the shape of the intake ports 18 and 19 is symmetrical, but this objectivity may be lost. If the straight walls 181 and 191 of the intake ports 18 and 19 are made straight at least parallel to the central axes Pv1 and Pv2 of the intake valves 40 and 50, the airflow can be made closer to a straighter one. Because it is good, it does not have to be a complete object. Further, as the type of the fuel injection valve, as in Patent Document 1, fuel injection valves having various injection hole shapes can be employed.

  In FIG. 2, the interval between the fuel injection valve central axes Pi1 and Pi2 and the interval between the intake valve central axes Pv1 and Pv2 are made to coincide with each other. The fuel injection valve 81, 82 may be provided slightly closer to the center of the intake port by making the mutual interval between the fuel injection valve central axes Pi1, Pi2 smaller than the mutual interval between the central axes Pv1, Pv2.

  Further, the tip center C1 of the fuel injection valve 81 and the tip center C2 of the fuel injection valve 82 may be arranged closer to the center axis Pc side of the cylinder 13 than the intake valve center axis Pv1 or the intake valve center axis Pv2. However, this bias does not have to be arranged extremely on the center side as in the conventional patent document 1, and the fuel injection valves 81 and 82 can be sufficiently spaced apart from each other.

  Furthermore, as shown in FIG. 2, the relationship of L1 ≧ L2 is established, but the cross-sectional shape of the intake port for ensuring the above relationship is not circular when viewed from the direction of the arrow Y3 in FIG. Alternatively, it may be rectangular or elliptical.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 13 Cylinder 16 Intake port 18, 19 Branch port 23 Branch part 24 Partition wall part 40, 50 Intake valve 81, 82 Fuel injection valve 181, 191 Intake port straight wall part 241, 242 Partition wall surface L1 Each Inlet port upstream width, which is the maximum width between straight walls L2 Maximum width between upstream ends of the valve seat with which the valve portion of the intake valve abuts Pv1, Pv2 Central axis of the intake valve S1 Valve with which the valve portion abuts from the branch portion Spacing up to the upstream end of the seat S2 Double the spacing S1

Claims (8)

In a fuel injection device for an internal combustion engine used for an internal combustion engine in which at least a pair of intake valves are juxtaposed to a cylinder,
In the intake port that surrounds the intake valve and guides the airflow flowing into the internal combustion engine, a fuel injection valve mounted corresponding to each intake valve is provided,
Predetermined lengths parallel to each other on the inner walls of the intake ports existing on both sides in the juxtaposition direction of the intake valves so as to define a linear shape of the inner walls of the intake ports when viewed from the cylinder central axis direction A fuel injection device for an internal combustion engine, characterized by having a straight wall portion composed of a surface or a line.   The intake port upstream width, which is the maximum width between the straight wall portions in the juxtaposed direction of the intake valves, is L1, and the maximum width between the upstream ends of the valve seats with which the valve portions of the intake valves abut is L2. 2. The fuel injection device for an internal combustion engine according to claim 1, wherein a relationship of L1 ≧ L2 is established. The intake port includes a branch portion that is a starting point from which the airflow branches, and a pair of branch ports that branch from the branch portion.
3. The internal combustion engine according to claim 1, wherein each of the straight wall portions exists at least over an interval from the branch portion to an upstream end of a valve seat with which the valve portion of the intake valve abuts. Engine fuel injection device.   4. The fuel injection device for an internal combustion engine according to claim 3, wherein each of the straight wall portions exists at least over a length twice as long as the interval.   The branch ports are partitioned by partition walls, and the partition wall portions facing the straight walls also define a linear shape when viewed from the cylinder central axis direction. The fuel injection device for an internal combustion engine according to claim 3 or 4, wherein the fuel injection device is formed as described above.   Each said straight wall part is formed in parallel with the center axis | shaft of the said intake valve, when it sees from the said cylinder center axis direction, The Claim 1 thru | or 5 characterized by the above-mentioned. A fuel injection device for an internal combustion engine.   Each of the straight wall portions is formed in parallel to a virtual plane passing through the center between the pair of intake valves and the center axis of the cylinder when viewed from the cylinder center axis direction. The fuel injection device for an internal combustion engine according to any one of claims 1 to 6.   The plane including the central axis of the fuel injection valve and the plane including the central axis of the intake valve are installed in parallel to each other when viewed from the cylinder central axis direction. The fuel-injection apparatus for internal combustion engines as described in any one of them.

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