JP6388330B2 - Cylinder head of internal combustion engine - Google Patents

Description

  The present invention relates to a cylinder head that constitutes an internal combustion engine for a vehicle or the like, and is characterized by the form of an intake port.

  In an internal combustion engine, intake air is supplied to a cylinder (combustion chamber) from an intake port (intake passage) provided in a cylinder head. In a gasoline engine, fuel is often injected into an intake port by an injector. In order to improve intake performance, etc., it is common to provide two intake valves corresponding to one cylinder. However, there are two types of injectors: a single type provided with only one and a dual type provided with two. is there.

  When only one injector is provided as in the former case, for example, as disclosed in Patent Document 1, the intake port has an inlet portion as one collective flow path, and two branch flows in the middle from the middle. The fuel is divided into two branch channels by injecting the fuel toward the front end of the partition wall by positioning the nozzle of the injector in the middle of the collecting channel. Supply.

  On the other hand, when two injectors are provided as in the latter case, for example, as disclosed in Patent Document 2, an intake port corresponding to one cylinder is configured with two independent flow paths, On the other hand, fuel is injected from the injector.

JP-A-5-180049 JP 9-303199 A

  When two intake valves are provided corresponding to one cylinder, in order to improve the mixing of the fuel and the intake air, as in Patent Document 2, the fuel is supplied to the two branch passages by separate injectors. It is reasonable to inject.

  That is, as in Patent Document 1, when fuel is injected into two branch flow paths with one injector, the center of the fuel injection direction and the center of the branch flow path are greatly shifted. Although it is difficult to disperse evenly, if fuel is injected into the two branch channels with separate injectors, the fuel can be injected toward the center of the flow of intake air in the branch channel, so that the mixing of fuel into the intake air can be improved. .

  In addition, if there is only one injector, it is impossible to avoid the fuel adhering to the front end face of the partition wall. For this reason, there is a problem such as carbon deposition (especially when the EGR gas is refluxed). The solid component contained in the EGR gas easily adheres to the partition wall together with the fuel), and if an injector is provided for each branch channel, the problem of fuel adhesion can be solved or suppressed.

  On the other hand, if the entire intake port is separated into two branch flow paths, the volume of the partition wall increases, which increases the weight of the cylinder head and may lead to deterioration of fuel consumption. Furthermore, in order to improve the mixing property between the intake air and the EGR gas, it can be said that it is preferable to divide the intake port into branch channels as much as possible downstream. However, if the entire length of the intake port is divided into two branch channels, the intake air and the EGR gas There is also a concern that the mixing property with the lowering.

  The present invention has been made to improve the current situation.

The present invention relates to a cylinder head in which an intake port is formed.
“ One intake port that supplies intake air to one cylinder has an inlet formed in one collecting channel, and branched into two branch channels from the middle by a partition wall connected to the bottom surface and the ceiling surface And form.
While termination of the two branches passage Ru is opened and closed by an intake valve,
The nozzles of two injectors for individually injecting fuel into the two branch flow paths are respectively arranged at the locations of the collecting flow paths, and the fuel is injected by the injector without the fuel hitting the front end of the partition wall. `` It is done deeper than the front end of the partition so as to go to the branch channel. ''
It is the basic composition.

And in invention of Claim 1, in the said basic composition,
"On at least one of said current combined channel bottom and the ceiling surface, the extension building rectification promoting ribs toward the inlet continuously in front of the partition wall, the projection height from the bottom or the ceiling surface is substantially constant It is formed so as to become "
It is the composition.
When the rectification promoting rib is provided on the bottom surface of the collecting flow path, the front end portion of the rectifying promotion rib rises rapidly from the bottom surface, and when the rectification promoting rib is provided on the ceiling surface of the collecting flow path, It can be said that the front end often falls abruptly from the ceiling surface.

The present invention also includes the invention of claim 2. The present invention, in claim 1, the front end of the rectifier promoting Li blanking, rather than the inlet of the current combined channel located downstream 1

  In the present invention, since the fuel is injected into the two branch flow paths with separate injectors, the mixing property between the intake air and the fuel can be improved, and the adhesion of the fuel to the partition wall can be prevented or significantly suppressed. In addition, the cylinder head and the intake manifold can be easily transferred from the single injector type to the dual injector type without major design changes.

  Instead of providing the partition wall over the entire length of the intake port, the intake port also has a collecting flow path, so that the volume of the partition wall can be reduced as much as possible to prevent an increase in the weight of the cylinder head. For this reason, when applied to an internal combustion engine for a vehicle, it can contribute to an improvement in fuel consumption and is particularly beneficial.

  Moreover, since the rectification promoting ribs are provided in the collecting channel, the collecting channel is excellent in a branching function and a rectifying function in which intake air is divided into two branch channels, and the intake air amount in the two branch channels Can be equalized, and the directionality (straightness) of the intake air can be improved. For this reason, homogenization of the air-fuel mixture can be ensured while preventing an increase in the weight of the cylinder head. This is a great merit of the present invention.

  In the case of an internal combustion engine equipped with an EGR device, the presence of the collecting flow path increases the chance that the intake air will be mixed with the EGR gas before flowing into the branch flow path, so that the intake air and the EGR gas are mixed uniformly. It can be said that it can contribute to stabilization of combustion and improvement of exhaust gas.

  The cylinder head is usually cast using a metal such as aluminum, and in the casting mold, the portion corresponding to the branch channel is a core of sand. When the collecting flow path is provided in the intake port as described above, the cores of the adjacent branch flow paths are connected to each other, so that the core can be stabilized and contribute to the improvement of the efficiency of the casting process.

In the present invention, since the fuel does not hit the commutation promoting rib, problems such as generation of dust due to the fuel adhering to the commutation promoting rib can be accurately prevented. Further, when the second aspect is adopted, since the rectification promoting rib does not reach the inlet of the collecting flow path, the adjacent cores in the mold are also connected in front of the rectification promoting rib, thereby further stabilizing the core. It can be improved.

It is a longitudinal cross-sectional view of the principal part of embodiment, and is the II sectional view taken on the line of FIG. FIG. 2 is an external view of an intake port as viewed from the II-II viewing direction of FIG. 1. FIG. 3 is a perspective view of an intake port (a little different from FIG. 2). It is an enlarged view of the principal part of FIG. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 4. FIG. 6 is a sectional view taken along line VI-VI in FIGS. 4 and 5. It is a figure which shows other embodiment.

(1) Description of Structure Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to an internal combustion engine for a vehicle, and the internal combustion engine has a cylinder block 1 and a cylinder head 2 fixed to the upper surface thereof as main components of the engine body. A plurality of cylinders (cylinder bores) 3 are formed in the cylinder block 1, and pistons 4 are slidably fitted into the respective cylinders. The cylinder head 2 is formed with a trapezoidal recess 5 that opens toward the cylinder 3.

  An intake port 6 and an exhaust port 7 are formed corresponding to each cylinder 3 at portions on both sides of the cylinder head 2 across the crank axis. The intake port 6 includes a collective flow path 10 opened on one side surface (intake side face) 9 of the cylinder head 2 and two branch flow paths 11 branched from the collective flow path 10. 11 are arranged in the crank axis direction. Accordingly, a pair of adjacent branch channels 11 are separated by a partition wall 14 connected to the bottom surface 12 and the ceiling surface 13.

  The collecting channel 10 has a shape that is long in the crank axis direction when viewed from the flow direction of the intake air. In FIG. 2, the left and right side portions (front and rear side portions when viewed from the crank axis direction) are formed in an arc shape. Therefore, the collecting channel 10 has an oval shape. On the other hand, in FIG. 3, the left and right side portions of the collecting channel 10 are formed flat. Either form can be adopted.

  An outlet 11 a of the branch channel 11 opens from the inclined surface of the recess 5 in the cylinder head 2 toward the cylinder 3, and each outlet 11 a is opened and closed by an intake valve 15. The intake valve 15 is slidably mounted on the cylinder head 2 via a sleeve 16 and is urged in the closing direction by a spring 16a. A valve seat is fitted in the recess 5.

An intake manifold 17 (or spacer) is fixed to one side 9 of the cylinder head 2. A branch passage 18 of the intake manifold 17 communicates with the collective flow path 10 of the intake port 6. Therefore, the terminal end of the branch passage 11 and the inlet 19 of the collecting channel 10 are basically in the same form. Further, as shown in FIG. 5, the collective flow channel 10 and the branch flow channel 11 extend toward the recess 5 while expanding in the crank axis direction toward the downstream side.

  An injector 21 corresponding to each branch channel 11 is attached to the intake manifold 17. That is, a pair of injectors 21 for injecting fuel toward the branch flow path 11 of the intake port 6 are mounted side by side in the crank axis direction at each branch passage 18 in the intake manifold 17. Although not shown, each injector 21 is connected to a distribution pipe (delivery pipe) that is long in the crank axis direction, and fuel is supplied to the end of the distribution pipe. In the case of three cylinders, six injectors 21 are provided.

  The injector 21 has a main body portion 21a attached to the distribution pipe, a small diameter nozzle 21b exposed to the collecting flow path 10, and a stepped portion 21c positioned between the two. It is held in the mounting hole 23 of the intake manifold 17 via the ring 22. The above-described distribution pipe is fixed to the intake manifold 17 with bolts. The injection control device is connected to the main body 21a.

  The nozzle 21 b of the injector 21 is disposed on the upper part of the collective flow path 10. For this reason, the injector 21 is inclined so as to become lower toward the tip as viewed from the crank axis direction. Therefore, the axial center of the injector 21 and the axial center of the branch flow passage 11 cross each other when viewed from the crank axis direction. Further, a concave groove 24 is formed in the upper part of the collective flow path 10 to bring the nozzle 21b as far as possible.

As described above, the two branch channels 11 are in a non-parallel posture in a plan view so that the distance increases as the distance from the collective channel 10 increases. On the other hand, each injector 21 is in a parallel posture. Therefore, for example, as can be understood from FIG. 5, the injector 21 is arranged in the collecting flow path 10 so as to be slightly shifted toward the front and rear outside in the crank axis direction. Thereby, it can prevent that a fuel adheres to the partition 14. Therefore, the fuel does not hit the front end of the partition wall 14.

  As clearly shown in FIG. 4, the collective flow path 10 and the branch flow path 11 are formed in a tapered shape in which the vertical width H <b> 1 decreases from upstream to downstream as viewed from the crank axis direction. The collecting channel 10 and the bottom surface 12 of the branch channel 11 extend substantially linearly, and the ceiling surface 13 of the branch channel 11 also extends linearly. On the other hand, as shown in FIG. 5, the width dimension in the crank axis direction of the branch channel 11 is substantially constant in a plan view. Therefore, the cross-sectional area of the branch channel 11 decreases from the upstream toward the downstream, and as a result, the flow rate of the intake air increases as it goes downstream.

  On the bottom surface 12 of the collecting channel 10, a lower rectification promoting rib 25 is formed integrally with the front end of the partition wall 14 and extends toward the inlet 19. The tip 25a of the lower rectification promoting rib 25 rises abruptly from the bottom surface 12, and the height H2 from the bottom surface 12 is slightly smaller toward the downstream side, but is approximately the same. The tip 25a of the lower rectification promoting rib 25 may be inclined as shown by a one-dot chain line in FIG. Further, the lower rectification promoting rib 25 may make the height H2 completely constant, or may slightly increase the height H toward the downstream side.

  When viewed from the direction of intake air flow, the lower rectification promoting rib 25 has a plate shape as shown in FIG. 6, but may have a trapezoidal shape or a mountain shape (in FIG. 2, it is displayed in a trapezoidal shape). .) The height H2 of the lower rectification promoting rib 25 is about 寸 法 of the height of the collecting flow path 10, but the height H2 can be set arbitrarily.

  Further, the tip 25 a of the lower rectification promoting rib 25 is located downstream of the inlet 19. That is, the lower rectification promoting rib 25 does not exist in the front portion of the collecting channel 10. Among the molds for casting the cylinder head 2, the cores forming the adjacent branch flow paths 11 are integrally connected at the location of the collective flow path 10, and particularly correspond to the front portion of the collective flow path 10. The part has a sturdy structure.

  An upper rib 26 that is continuous with the front end of the partition wall 14 is also integrally formed on the ceiling surface 13 of the collecting channel 10. Accordingly, when the upper and lower ribs 26 and 25 are viewed as a part of the partition wall 14, the partition wall 14 is wound in a forward concave shape when viewed from the crank axis direction.

The upper rib 26 has a lower height toward the tip, and is lower than the lower rectification promoting rib 25. Therefore, the upper rib 26 is not the rectification promoting rib described in the claims (not that the upper rib 26 does not have a diversion / rectification action, but that the degree is not strong). The tip of the upper rib 26 is also located downstream from the inlet 19.

When the lower rectification promoting rib 25 is viewed in relation to the spread area of the fuel injected from the injector 21, as shown by the dotted line in FIG. 4, most of the lower rectification promoting rib 25 is viewed from the crank axis direction. It is located outside the spreading area (inner area surrounded by dotted lines). Further, as shown in FIG. 5, the lower rectification promoting rib 25 is located outside the fuel spreading area even in a plan view. Therefore, the fuel does not hit the lower rectification promoting rib 25 and the fuel does not hit the front end of the partition wall 14. That is, the fuel injection by the injector 21 is performed deeper than the front end of the partition wall 14 so that the fuel does not hit the front end of the partition wall 14.

  The exhaust port 7 has two exhaust ports for one cylinder 3, and each exhaust port is opened and closed by an exhaust valve 27. Each exhaust port is assembled into one.

(2) Summary In this embodiment, since fuel is injected from the individual injectors 21 into the two branch flow paths 11, the mixing property between the intake air and the fuel can be improved, and the fuel adheres to the partition wall 14. Is not generated at all or hardly. In particular, in this embodiment, since the cross-sectional area of the branch channel 11 becomes smaller toward the downstream side, the flow velocity of the intake air becomes faster toward the downstream side. It is guided to the cylinder 3 by the intake flow without adhering to the cylinder.

  Moreover, since the partition wall 14 is in a state of being cut off at the location of the collecting flow path 10, it is particularly useful because the cylinder head 2 can be reduced in weight and contribute to improvement in fuel consumption. In addition, since the parallel flow-shaped lower rectification promoting ribs 25 are provided in the collective flow path 10, as shown by arrows in FIG. As a result, it is possible to equalize the flow rates flowing through the two branch flow paths 11 and improve straightness, and to ensure homogenization of the air-fuel mixture in the cylinder.

  Now, the speed of the fuel injected from the injector 21 decreases in proportion to the distance. That is, the linearity is high near the nozzle 21b, but the linearity decreases as the distance from the nozzle 21b increases, making it easier to get in the intake air. Therefore, as in the embodiment, the front end of the partition wall 14 is moved away from the nozzle 21b as much as possible, and the branch channel 11 is formed in a taper shape to increase the flow velocity of the intake air toward the downstream side, so that the fuel can be It is possible to prevent the fuel from adhering to the ribs 25 and 26 and to put the fuel on the intake air.

  Although the cylinder head 2 is an aluminum casting product, the core forming the branch channel 11 of the mold is integrally connected at the location of the collecting channel 10, so that the core is stabilized and the efficiency of the casting process is improved. Can also contribute. In particular, when the tip of the lower rectification promoting rib 25 is shifted downstream from the inlet 19 as in the embodiment, the volume of the portion connecting adjacent cores increases, so that the stability of the core can be further improved.

  As in the embodiment, when the concave groove 24 for allowing the injector 21 to escape upward is formed in the upper part of the collective flow path 10, the tip of the injector 21 is prevented from entering the collective flow path 10 as much as possible. Since the nozzle 21b of the injector 21 can enter the downstream side of the collecting flow path 10 as much as possible, fuel can be injected toward each branch flow path 11 while reducing the flow resistance of the intake air as much as possible (the fuel is Adhering to the lower rectification promoting rib 25 can be accurately prevented.)

  Further, when the bottom surface 12 and the ceiling surface 13 of the branch flow path 11 are formed in a straight line shape (straight shape) as in the embodiment, the flow resistance of the intake air can be reduced and the straightness of the intake air can be improved, so that the cylinder 3 There is an advantage that the function of forming a tumble flow or swirl flow inside can be promoted.

  In the embodiment shown in FIG. 7, the lower rectification promoting ribs 25 are formed on the bottom surface 12 of the collecting flow path 10, and the upper rectification promoting ribs 28 are also formed on the ceiling surface 13. The height of the upper rectification promoting rib 28 is twice or more than the height of the lower rectification promoting rib 25. Further, the front ends of the vertical rectification promoting ribs 28 and 25 are located at positions that are substantially shifted from the inlet 19 by the same amount downstream. The basic structure of the intake port 6 is the same as in the previous embodiment.

  Although the tip of the injector 21 is arranged at the upper part of the collective flow path 10, there is a possibility that the flow of the intake air is disturbed at the upper part of the collective flow path 10, but the height of the ceiling surface 13 is large as in this embodiment. If the rectification promoting rib 28 is provided, it can be said that the intake air can be evenly divided into the two branch channels 11 even if the intake air is disturbed. Further, since the lower rectification promoting rib 25 is also provided on the bottom surface 12, it is excellent in intake air diversion performance. Furthermore, since the heights of the rectification promoting ribs 25 and 28 are made different from each other while being different from each other, an increase in intake flow resistance can be prevented.

  The present invention can be embodied in various ways other than the above-described embodiment. For example, the rectification promoting ribs can be formed only on the ceiling surface, or the rectification promoting ribs having the same height can be formed on both the bottom surface and the ceiling surface. When the rectification promoting ribs are formed on both the bottom surface and the ceiling surface, the position of the front end can be shifted in the flow direction of the intake air.

  The present invention can be embodied in a cylinder head of an internal combustion engine for a vehicle or the like. Therefore, it can be used industrially.

2 Cylinder head 3 Cylinder 5 Recess (combustion chamber)
6 Intake port 7 Exhaust port 9 One side of cylinder head 10 Collecting flow path 11 Branch flow path 12 Bottom surface 13 Ceiling surface 14 Bulkhead 15 Intake valve 17 Intake manifold 19 Inlet of collecting flow path 21 Injector 21c Nozzle 25 Lower rectification promoting rib 26 Rib 28 Upper rectification promotion rib

Claims (2)

One intake port for supplying intake air to one cylinder, the inlet portion is formed in one collective flow path, and is branched into two branch flow paths by a partition wall connected to the bottom surface and the ceiling surface from the middle And
While termination of the two branches passage Ru is opened and closed by an intake valve,
The nozzles of two injectors for individually injecting fuel into the two branch flow paths are respectively arranged at the locations of the collecting flow paths, and the fuel is injected by the injector without the fuel hitting the front end of the partition wall. It is a configuration that is performed toward the back rather than the front end of the partition so as to go to the branch channel ,
On at least one of the bottom surface and the ceiling surface of the current combined channel, the extension building rectification promoting ribs toward the inlet continuously in front of the partition wall, a substantially constant projecting height from the bottom or the ceiling surface Formed to be,
Cylinder head of internal combustion engine. The front end of the rectifying promoting Li blanking, rather than the inlet of the current combined channel is located downstream,
The cylinder head of the internal combustion engine according to claim 1.

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