JP4011078B2 - Fuel injection valve and fuel injection valve mounting structure - Google Patents

Description

  The present invention relates to an in-cylinder injection fuel injection valve attached to a cylinder head for injecting fuel directly into a cylinder of an internal combustion engine and a structure for attaching the fuel injection valve to the cylinder head.

Conventionally, in fuel injection valves for internal combustion engines, particularly in-cylinder injection fuel injection valves that inject fuel directly into a cylinder of a gasoline engine, the portion facing the cylinder of the fuel injection valve is exposed to the combustion gas of the cylinder and becomes high temperature, The fuel remaining in the fuel injection hole is carbonized and adheres to the fuel injection hole, causing a change in the fuel injection amount or non-uniformity of the fuel spray, and so-called carbon deposit which impairs the reliability of the fuel injection valve. .
As an example of a solution to this problem, the cylinder side surface of the nozzle body and the low temperature side of the nozzle body are brought into thermal contact with each other for the purpose of suppressing deposit generation by keeping the fuel injection hole at a low temperature. It has been shown that a heat conduction protector having an injection window that can be formed is provided (for example, Patent Document 1).

  In addition, even when fuel is injected from the nozzle hole of the nozzle hole plate, if the intake air flow rate generated according to the operating state of the engine is high, the intake air flow partially inhibits the spread of the spray formed by the fuel injection. In order to prevent a part of the hindered spray from adhering to and remaining on the tip of the fuel injection valve, a protruding member having eight convex portions is attached to the tip of the fuel injection valve. It is shown that it is provided on the extension, and this adhering fuel joins the injected fuel and is injected again (for example, Patent Document 2).

JP 09-2222057 A (FIG. 1) JP 2003-322070 A (FIG. 54, column 0270)

However, the one disclosed in Patent Document 1 can suppress deposit adhesion to the fuel injection hole, but it does not describe anything about the deposit prevention to the portion other than the fuel injection hole, particularly the injection window. Not done.
In addition, since the positional relationship between the eight protrusions provided on the projecting member and the fuel injection hole is not clearly shown in the above-mentioned Patent Document 2, the fuel spray from the fuel injection hole is not shown. There is a portion that does not become a passage, and there is a problem that the deposit washing effect by fuel spray cannot be expected in this portion, and the deposit grows remarkably.

  Thus, in an engine that does not sufficiently suppress deposit generation, the deposited deposit and fuel spray interfere with each other, causing a change in the spray shape. As a result, the spray characteristics that have changed due to the deposit growth change abruptly. For example, when learning control of the engine control device is performed, the spray characteristics change rapidly, so the control parameters change, and the combustion stability of the engine deteriorates. There is a problem of significant damage.

  The present invention is for solving the above-described problems, and is provided with a rectifying plate having an opening for rectifying fuel spray provided in contact with a nozzle plate having a fuel injection hole. The generation of deposit is suppressed by appropriately selecting the plane and cross-sectional shape of the portion with respect to the fuel injection hole.

A nozzle plate provided with a plurality of injection holes for injecting fuel toward the cylinder at the tip of a valve body of a fuel injection valve mounted on a cylinder head of the internal combustion engine, and a cylinder side in contact with the nozzle plate And a rectifying plate having a predetermined plate thickness having an opening for rectifying the fuel spray injected from the injection hole of the nozzle plate is provided integrally with the valve body,
The center line of the injection hole toward the cylinder of the nozzle plate is set with a predetermined angle away from the center line of the fuel injection valve,
The plate shape direction cross-sectional shape of the rectifying plate opening has a wall surface that widens toward the cylinder side from the side in contact with the nozzle plate, and the planar profile of the rectifying plate opening is the most of the plurality of fuel injection holes. A plurality of injection holes having the same number as that of the injection holes arranged on the outside are formed so as to form recesses by connecting circles having a predetermined distance from the edges of the injection holes so as to face the injection holes.

The fuel injection valve of the present invention is provided with a rectifying plate having an opening for rectifying fuel spray injected from a plurality of injection holes of a nozzle plate, and the center line of the injection hole toward the cylinder of the nozzle plate is a fuel It is set with a predetermined angle away from the center line of the injection valve, and the cross-sectional shape in the thickness direction of the rectifying plate opening has a wall surface that widens toward the cylinder side from the side in contact with the nozzle plate, and is flat. Since the profile is formed so as to form a recess by connecting a plurality of the same number of outermost injection holes and a circle having a predetermined distance from the edge of the injection hole to the injection hole. In this case, the portion where the fuel spray is stagnated is reduced, and as a result, the deposit can be suppressed.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is an enlarged cross-sectional view of a main part of a fuel injection valve 100 for an internal combustion engine. The fuel injection valve 100 includes a valve body 1, a plunger 2 that serves as a valve, a valve seat 3, a nozzle plate 5 having a plurality of fuel injection holes 4, and fuel spray injected from the fuel injection holes 4. It is comprised with the rectifying plate 7 which has the predetermined plate | board thickness provided with the opening part 6 which lets it pass through without stagnation.
The component parts other than the plunger 2 have a structure integrated by, for example, welding. The fuel injection valve 100 having such a configuration is fixed to, for example, a cylinder head 20 of a gasoline engine by a fixing mechanism (not shown), and the spring washer 8 prevents the combustion gas burned in the cylinder 21 from leaking out of the cylinder 21. The seal is done. The cross-sectional shape in the plate thickness direction of the opening 6 of the rectifying plate 7 has a wall surface 9 that widens toward the cylinder 21 from the side where the rectifying plate 7 is in contact with the nozzle plate 5. The center line of the fuel injection hole 4 of the nozzle plate 5 is set with a predetermined angle so as to be away from the center line of the fuel injection valve. Details of the shapes of the opening 6 and the injection hole 4 will be described later.

2 is a perspective view of the nozzle plate 5 and the rectifying plate 7 of the fuel injection valve 100 shown in FIG. 1 as viewed from the cylinder 21 side. The opening 6 provided in the rectifying plate 7 and the nozzle plate 5 are provided. A plurality of fuel injection holes 4 are shown. Here, ten examples of the plurality of fuel injection holes 4 are shown. The plane profile in the direction orthogonal to the plate thickness of the opening 6 of the rectifying plate 7 is the same as the number of the fuel injection holes 4 a arranged on the outermost side among the plurality of fuel injection holes 4 provided in the nozzle plate 5. Then, six recesses 10 are formed to face the fuel injection holes 4. Further, the cross-sectional shape in the plate thickness direction of the opening 6 of the rectifying plate 7 forms a wall surface 9 that widens toward the cylinder 21 from the side in contact with the nozzle plate 5 shown in FIG.
3A and 3B show an embodiment of the recess 10 provided in the rectifying plate 7. The concave portion 10 of the rectifying plate 7 in the front view seen from the cylinder side shown in FIG. 3A is formed so as to face the fuel injection holes 4 a arranged on the outermost side of the nozzle plate 5. The recess 10a in FIG. 3 (a) is a recess profile on the side in contact with the nozzle plate 5 shown in FIG. 3 (b). Similarly, the recess 10b in FIG. 3 (a) is on the cylinder 21 side shown in FIG. 3 (b). A concave profile is shown, during which the diverging wall surface 9 is formed. The arc 10c connecting the plurality of recesses 10a is a part of a circle that includes at least the outermost injection hole 4a.

As shown in FIG. 3, since the recess 10 is formed such that the distance L between the edge of the fuel injection hole 4a provided on the outermost side provided in the nozzle plate 5 and the recess 10a is constant, conventional injection is performed. Since the distance from the hole edge is not constant, deposits are attached to a far site due to the difference in distance from the injection holes. In the first embodiment, the generation of deposits is suppressed and the fuel spray injected from the fuel injection holes 4a. Is introduced into the cylinder 21 without stagnation.
The distance L is set so that the fuel spray injected from the outermost fuel injection hole 4a does not interfere with the fuel spray and does not form a stagnation portion too far from the fuel spray. The position and angle of the hole 4 and the distance L of the concave portion of the rectifying plate 7 are used as parameters, and are determined by simulation, experiment, and the like.
In place of the profile of the recess 10 shown in FIG. 3A, a plurality of recesses are separated from the center of the injection hole 4a by a distance Lc as shown in FIG. A profile formed by connecting circles having Further, it may be oval so as to have an equal distance L from the edge of the outermost fuel injection hole.

Next, FIG. 5 is an enlarged sectional view of the fuel injection valve 100 including a plurality of outermost fuel injection holes 4 a provided in the nozzle plate 5 and the opening 6 of the rectifying plate 7. The relationship between the line 100a, the center line 4b of the outermost fuel injection hole 4a, and the wall surface 9 of the opening 6 in the plate thickness direction of the rectifying plate 7 is shown. Here, the center line 4b of the fuel injection hole 4a is set to have a predetermined angle θ with respect to the center line 100a of the fuel injection valve 100 so as to be separated outward.
The distance between the center line 4b and the wall 9 of the fuel injection hole 4a wherein arranged at the furthest outside, the distance L ₁ side is in contact nozzle plate 5 of the vanes 7 in the thickness direction front end position of the vanes 7 and the relationship between the distance _{L 2} is set _L 2> _{L 1} and becomes like.
The reason why the distance between the wall surface 9 of the recess 10 of the rectifying plate 7 and the fuel injection hole center line 4b is L ₂ > L ₁ is that the fuel spray injected from the fuel injection hole 4a is the outlet of the fuel injection hole 4a. The flow path expands as the distance from the surface increases, but the end wall surface 9 satisfies L ₂ > L ₁ in accordance with the expansion. Therefore, there is little interference between the fuel flow path and the wall surface 9.

As described above, in the first embodiment, by configuring the distance L from the edge of the fuel injection hole 4a to the wall surface of the recess 10 to be constant, the distance between the fuel spray and the wall surface 9 becomes constant, and a specific distance is obtained. Accumulation or growth of deposits in the part is suppressed. Further, as the distance L is reduced, the distance between the fuel spray and the wall surface 9 is reduced, and the deposit adhesion suppressing effect is enhanced.
Furthermore, the distance between the center line 4b of the fuel injection hole 4a and the wall surface 9 is configured to be widened from the outlet of the fuel injection hole 4 toward the tip of the rectifying plate 7, thereby suppressing interference between the wall surface 9 and the spray. and, Ru effect of suppressing there a deposit adhering to the wall 9.

Embodiment 2. FIG.
Next, the second embodiment will be described with reference to FIG.
FIG. 6 is a diagram showing the rectifying plate 7 viewed from the cylinder 21 side of the fuel injection valve 100 according to the second embodiment. In the second embodiment, the rectifying plate 7 is provided with two openings 6a. is there. The multi-hole fuel injection valve 100 having a plurality of injection holes 4 has a feature that the arrangement and number of the fuel injection holes 4 can be freely set. In the example of FIG. 6, the six fuel injection holes 4 are equally spaced. Rather, they are arranged in two groups. Since there is a distance between the groups of the two fuel injection holes 4, the opening 6 a of the rectifying plate 7 is provided for each group, and a total of two openings 6 a are provided, but this number is limited. The number may be selected as appropriate depending on the arrangement of the fuel injection holes 4.
In the second embodiment, the reason why the fuel injection holes 4 are divided into two groups is that, for example, one side is directed to the spark plug direction and the other is directed to the center of the cylinder to improve engine combustibility. Is to be divided into two.
Since each spray is injected so as not to cross each other, a large stagnation portion is generated between the fuel injection holes 4. Therefore, an opening 6a is provided for each group of fuel injection holes 4 in order to reduce the stagnation portion. At this time, the concave portion 10 of the opening 6a may be provided on the outer peripheral portion of the entire fuel injection hole 4, or may be provided opposite to the injection hole arranged on the outermost side. This can suppress deposit adhesion.
In this way, by providing a plurality of openings 6a according to the arrangement and number of fuel injection holes 4, regardless of the arrangement and number of fuel injection holes 4, the stagnation portion where deposits are likely to adhere can be reduced, and the opening 6a. As compared with the first embodiment in which there is one, there is an effect of enhancing the effect of suppressing deposit adhesion to the wall surface 9 of the opening 6a.

Embodiment 3 FIG.
FIG. 7 shows a cross-sectional shape of a main part of the fuel injection valve 100a according to the third embodiment. In this third embodiment, the rectifying plate 7a having the opening 6 is configured separately from the fuel injection valve 100a. . The rectifying plate 7a having the opening 6 that is separately configured is connected to the cylinder head 20 and the fuel injection valve 100a so that the positional relationship between the recess 10 of the opening 6 and the fuel injection hole 4 is the same as in the first embodiment. The fuel injection valve 100a is inserted between the cylinder head 20 and fixed. By configuring in this way and optimizing the material and shape of the current plate 7a, it is possible to add a function of sealing the combustion gas.
As shown in FIG. 7 of the third embodiment, the rectifying plate 7a having the opening 6 is configured separately from the fuel injection valve 100a, thereby providing the same effects as those of the first embodiment and rectifying. By making the plate 7a seal the combustion gas, the spring washer 8 for sealing the combustion gas shown in FIG. 1 can be omitted, and the number of parts can be reduced.

Embodiment 4 FIG.
FIG. 8 shows a cross-sectional shape of a main part of the fuel injection valve 100b according to the fourth embodiment. In the fourth embodiment, the cylinder head 20 is provided with a rectifying unit 20a. The positional relationship between the recess 10 of the opening 6 of the rectifying unit 20a and the fuel injection hole 4 of the nozzle plate 5 is the same as that of the first embodiment. By adopting a structure in which the fuel injection valve 100b having such a structure is attached to the cylinder head 20, the wall surface 9 of the opening 6 of the cylinder head 20 has a cooling function that efficiently removes the heat received from the combustion chamber. The cylinder head 20 can escape.
As described above, in the fourth embodiment, by configuring the rectifying unit 20a in the cylinder head 20, the same effect as in the first embodiment can be obtained, the number of parts can be reduced, and the temperature of the wall surface 9 of the opening 6 can be reduced. It has the effect of suppressing the rise and enhancing the effect of suppressing deposit adhesion to the wall surface 9.

Embodiment 5 FIG.
FIG. 9 is a cross-sectional shape of a main part of the fuel injection valve 100c according to the fifth embodiment. In the fifth embodiment, the nozzle plate 5 and the rectifying plate 7 of the fuel injection valve 100 according to the first embodiment are arranged. A heat insulating layer 15 formed of a material having a lower thermal conductivity than a metal material such as a ceramic or an air layer is provided. The heat insulating layer 15 may be provided, for example, such that a ceramic plate is entirely interposed between the nozzle plate 5 and the rectifying plate 7, and the ceramic plate is partially disposed between the nozzle plate 5 and the rectifying plate 7. An air layer may be formed by providing the air layer. This configuration has the same effect as that of the first embodiment, prevents the nozzle plate 5 from being exposed to heat from the cylinder 21 due to engine operation, and prevents the nozzle plate 5 from becoming high temperature. It also has the effect of enhancing the adhesion suppression effect.

Embodiment 6 FIG.
FIG. 10 shows a cross-sectional shape of a main part of the fuel injection valve 100d according to the sixth embodiment. In this sixth embodiment, heat is generated from an electric heater or the like on the back surface of the wall surface 9 of the opening 6 provided in the rectifying plate 7b. A body 16 is provided, and the wall surface 9 of the opening 6 is heated to a certain temperature by the heating element 16.
In a normal operation state, the wall surface 9 of the opening 6 is exposed to the combustion gas and is at a high temperature. Therefore, the fuel that is to adhere to the wall surface 9 is difficult to adhere due to evaporation. On the other hand, at the time of cold start of the engine, the fuel injection valve 100d and the cylinder head 20 are about the engine ambient temperature close to the outside air temperature. When the engine is started in this state, part of the fuel does not evaporate and adheres to the wall surface 9. In this state, the wall surface 9 is heated by the combustion gas, and the adhered fuel becomes a deposit. Further, a part of the fuel adhering to the wall surface 9 is not combusted and is discharged from the cylinder 21 as an HC component (unburned fuel) during the exhaust stroke of the engine, which causes air pollution. In order not to be in such a state, the heating element 16 is energized within a predetermined time by a separately prepared controller before the cold start to maintain the wall surface 9 at a high temperature in advance, and the fuel adhering to the wall surface 9 is evaporated at the start. .
This configuration has the same effect as that of the first embodiment, and also has the effect of suppressing deposit adhesion to the wall surface 9 of the opening 6 and the amount of HC emission during cold start.

  Embodiments 1 to 6 of the present invention can be used for an in-cylinder fuel injection valve used in an internal combustion engine.

It is a principal part enlarged view of the fuel injection valve of Embodiment 1 of this invention. It is the perspective view seen from the cylinder side of the fuel injection valve of Embodiment 1 of this invention. It is a front view which shows the recessed part seen from the cylinder side of the baffle plate of Embodiment 1 of this invention. It is a front view which shows the other Example of the recessed part seen from the cylinder side of the baffle plate of Embodiment 1 of this invention. It is an expanded sectional view which shows the baffle plate and nozzle plate of Embodiment 1 of this invention. It is a front view of the baffle plate of Embodiment 2 of this invention. It is principal part sectional drawing of the fuel injection valve of Embodiment 3 of this invention. It is principal part sectional drawing of the fuel injection valve of Embodiment 4 of this invention. It is principal part sectional drawing of the fuel injection valve of Embodiment 5 of this invention. It is principal part sectional drawing of the fuel injection valve of Embodiment 6 of this invention.

Explanation of symbols

1 valve body, 4, 4a fuel injection hole, 5 nozzle plate, 6, 6a opening,
7, 7a, 7b Current plate, 9 wall surface, 10 recess, 16 heating element,
20 cylinder head, 20a rectifier, 21 cylinder,
100, 100a, 100b, 100c, 100d Fuel injection valve.

Claims (13)

A fuel injection valve mounted on a cylinder head of an internal combustion engine, and a nozzle plate in which a plurality of injection holes for injecting fuel toward the cylinder are disposed at a valve body tip of the fuel injection valve; A rectifying plate having a predetermined thickness provided on the cylinder side in contact with the nozzle plate and having an opening for rectifying fuel spray injected from an injection hole of the nozzle plate is integrated with the valve body. Is provided,
The center line of the injection hole toward the cylinder of the nozzle plate is set with a predetermined angle away from the center line of the fuel injection valve,
The cross-sectional shape in the plate thickness direction of the rectifying plate opening has a wall surface that widens from the side in contact with the nozzle plate toward the cylinder, and the planar profile of the rectifying plate opening has the plurality of fuel injections A plurality of holes, the same number as the outermost injection holes, are formed so as to form recesses by connecting circles having a predetermined distance from the edges of the injection holes so as to face the injection holes. The fuel injection valve characterized by the above-mentioned. The recess of the current plate opening, the fuel injection valve according to claim 1, characterized in that it is formed so as to connect the elliptical that have a predetermined distance from the edge of the fuel injection hole. 2. The fuel injection valve according to claim 1, wherein the recess of the rectifying plate opening is formed so as to connect concentric circles having a predetermined distance from the center of the fuel injection hole. The wall surface shape that widens toward the end of the opening of the current plate includes a distance L ₁ to the wall surface at a position in contact with the center line of the fuel injection hole and the nozzle plate in the thickness direction of the current plate, and the plate thickness. _2. The fuel injection valve according to claim 1, wherein the distance L ₂ to the wall surface at the tip position in the direction is set to have a relationship of L ₂ > L ₁ . 2. The fuel injection valve according to claim 1, wherein a plurality of the rectifying plate openings are provided corresponding to the arrangement of the plurality of fuel injection holes provided in the nozzle plate. The fuel injection valve according to claim 1, wherein the rectifying plate is separable from the valve body. The fuel injection valve according to claim 1, wherein a heat insulating layer is provided between the nozzle plate and the rectifying plate. 2. The fuel injection valve according to claim 1, wherein a heating element is provided on a rear surface of the wall surface of the rectifying plate opening, and the wall surface is heated by the heating element within a predetermined time when starting the internal combustion engine. A fuel injection valve mounting structure mounted on a cylinder head of an internal combustion engine, wherein a plurality of injection holes for injecting fuel toward a cylinder are disposed at a tip of a valve body of the fuel injection valve A nozzle plate is provided, and the cylinder head is provided with a rectifying unit having a predetermined thickness having an opening, and the fuel injection valve nozzle plate is disposed in contact with the rectifying unit,
The center line of the injection hole toward the cylinder of the nozzle plate is set with a predetermined angle away from the center line of the fuel injection valve,
A cross-sectional shape in the thickness direction of the rectifying opening has a wall surface that widens toward the cylinder side from the side in contact with the nozzle plate, and the planar profile of the opening is the inner surface of the plurality of fuel injection holes. A plurality of the same number as the outermost injection holes, and formed so as to form a recess by connecting a circle having a predetermined distance from the edge of the injection hole so as to face the injection hole, An attachment structure of a fuel injection valve, wherein the fuel injection valve is attached to the cylinder head so that fuel spray injected from an injection hole of a nozzle plate of the injection valve is rectified by the rectification unit. The recess of the rectification section opening, the mounting structure of a fuel injection valve according to claim 9, characterized in that it is formed so as to connect the elliptical that have a predetermined distance from the edge of the fuel injection hole. 10. The fuel injection valve mounting structure according to claim 9 , wherein the recess of the rectifying unit opening is formed to connect concentric circles having a predetermined distance from the center of the fuel injection hole. The shape of the wall surface that widens toward the end of the opening of the rectifying unit includes: a distance L ₁ to the wall surface at a position in contact with the center line of the fuel injection hole and the nozzle plate in the thickness direction of the rectifying unit; The fuel injection valve mounting structure according to claim 9 , wherein a distance L ₂ to the wall surface at a distal end position in a direction is set to have a relationship of L ₂ > L ₁ . The fuel injection valve mounting structure according to claim 9 , wherein a plurality of the rectifying unit openings are provided in correspondence with the arrangement of the plurality of fuel injection holes provided in the nozzle plate.

Images