JP2002213300A - Engine cooling structure and method of manufacturing for cooling water passage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a cooling water passage through a small number of simple processes. SOLUTION: The cooling water passage 27 is manufactured by carrying out a casting process and a boring process in order. In the casting process, a protruding part 28 which protrudes into a water jacket 22 from the bottom of a cylinder head 14 is cast integrally with the cylinder head 14 having the water jacket 22. In the boring process, a hole 29 is bored from the bottom surface 14a of the cylinder head 14 to the tip of the protruding part 28, with the hole being biased with respect to the axis L1 of the protruding part 28 in the direction A of deviation of cooling water. This boring bores an inlet part 31 of the cooling water passage 27 through the bottom surface 14a and an outlet part 32 of the cooling water passage 27 through the outer peripheral surface 28a of the protruding part 28. In the cylinder head 14 having the cooling water passage 27, the cooling water flows out of the outlet part 32 in the direction different from the direction to flow into the inlet part 31, efficiently cooling high-temperature portions such as valve clearance portions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for an engine having a cooling water passage for forcibly changing a flow direction of cooling water, and a method for manufacturing the cooling water passage.

[0002]

2. Description of the Related Art At the bottom of a cylinder head of an engine, particularly, a portion surrounded by an intake port, an exhaust port and a combustion chamber is strongly affected by heat of exhaust gas. Therefore, various devices for locally cooling this portion have been proposed and put into practical use. One of them is Japanese Utility Model SHO 59-1945.
No. 24 discloses a cylinder head cooling device.

As shown in FIG. 8, a cooling water passage 52 is provided at the bottom of a cylinder head 51 at a portion (an inter-valve portion) between an intake valve and an exhaust valve. The cooling water passage 52 includes a horizontal hole 53, a plug 54, a vertical hole 55, a bias pipe (deflector) 56, and the like. One end of the lateral hole 53 opens to the side surface 51b of the cylinder head 51, and the other end thereof
It extends to a region 57 surrounded by the combustion chamber and the intake / exhaust ports, and opens into the water jacket 58 in this region 57. The plug 54 closes one end of the lateral hole 53.
The vertical hole 55 connects the horizontal hole 53 and the cooling water passage 60 of the cylinder block 59. The bias pipe 56 is a horizontal hole 53
Is mounted at the other end, and the front end enters the area 57. The lower half of the tip of the biasing pipe 56 is notched.

According to the cooling device, the cooling water flows in the order of the cooling water passage 60, the vertical hole 55, and the horizontal hole 53 as shown by the arrow in the figure. When the cooling water passes through the tip of the bias pipe 56, the flow of the cooling water is changed in a direction toward the bottom surface 51a of the cylinder head 51. Therefore, the bottom of the cylinder head 51 can be effectively cooled by the cooling water whose direction has been changed as described above.

[0005]

However, in the cooling device disclosed in the above publication, when the cooling water passage 52 is manufactured,
A step of forming a horizontal hole 53 and a vertical hole 55 in the cylinder head 51, a step of inserting a bias pipe 56 from an opening of one end of the horizontal hole 53, and pushing the tip until the tip reaches the region 57;
Many steps such as a step of closing one end of the lateral hole 53 with the stopper 54 are required. Further, in the step of pushing the bias pipe 56, the notch portion 56 a is located on the bottom surface 51 a side of the cylinder head 51, and the notch portion 56 a is located at a predetermined position of the region 57 in the circumferential direction. It is also necessary to perform axial positioning to ensure assembly accuracy.
Therefore, coupled with the large number of steps as described above, the manufacturing operation of the cooling water passage 52 becomes complicated. This contributes to an increase in the manufacturing cost of the cylinder head 51.

The present invention has been made in view of such circumstances, and has as its object to provide a cooling structure of an engine and a method of manufacturing a cooling water passage capable of manufacturing a cooling water passage with few and simple steps. Is to provide.

[0007]

The means for achieving the above object and the effects thereof will be described below. According to the first aspect of the present invention, a projection is provided together with the engine body having the water jacket by casting, and protrudes into the water jacket, and is decentered in a direction of deflecting the coolant with respect to a center axis of the projection. A cooling water passage formed by a hole extending toward the tip of the projection and having an outlet opening on the outer surface of the projection.

According to the third aspect of the present invention, a casting step of forming a projection projecting into the water jacket together with the engine body having the water jacket by casting, and cooling the center axis of the projection. A hole is formed in the outer surface of the projection by drilling a hole toward the tip of the projection in a state of being eccentric in the direction of deflection of water.

According to the first or third aspect of the present invention, in the casting step, a projection projecting into the water jacket is formed by casting together with the engine body having the water jacket. Thus, in the casting process originally performed for forming the engine main body, the projection is also formed together. Therefore, a dedicated process for forming the projection is not required.

Next, in the drilling step, a hole is drilled toward the tip of the projection while being decentered in the direction of deflecting the cooling water with respect to the center axis of the projection. The drilling process forms a cooling water passage, and the outlet of the passage opens to the outer surface of the projection. In this drilling step, it is only necessary to drill holes at predetermined positions, and no special processing is required. As described above, a desired cooling water passage can be manufactured by performing simple operations such as casting and drilling with a small number of steps such as a casting process and a drilling process.

In the engine having the cooling water passage, the cooling water flows in the cooling water passage, changes its flow direction when reaching the inner part thereof, and flows into the water jacket from an outlet opening on the outer surface of the projection. . The cooling water whose direction has been changed in this way cools a desired portion of the engine body.

According to a second aspect of the present invention, in the first aspect of the present invention, the engine body and the protrusion are formed by casting near the outlet, and are substantially in the direction of deflection of the cooling water. A deflecting wall extending along is provided.

According to the invention described in claim 4, in claim 3,
In the invention described above, at the time of performing the casting step, a deflecting wall extending along a substantially deflecting direction of the cooling water is formed near the protrusion by casting together with the engine main body and the protrusion.

According to the second or fourth aspect of the present invention, during the casting process, the deflection wall is formed together with the engine body and the projection. Therefore, a dedicated process for forming the deflection wall is not required. The deflecting wall thus formed extends in the vicinity of the protruding portion along a substantially deflecting direction of the coolant. The deflection wall regulates the flow of the cooling water flowing out of the outlet. The deflecting wall also prevents the cooling water from the outlet from being affected by the original flow of the cooling water in the water jacket. For this reason, the cooling water is allowed to flow to the location requiring cooling along the deflection direction, and the location can be efficiently cooled.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is embodied in an automobile gasoline engine (hereinafter simply referred to as an engine) will be described below with reference to FIGS.

As shown in FIG. 1, the engine body 11
Is provided with a cylinder block 13 having a plurality of cylinders (cylinders) 12, and a cylinder head 14 disposed thereon. A piston 15 is housed in each cylinder 12 so as to be able to reciprocate. A combustion chamber 16 is formed above each piston 15 between the cylinder block 13 and the cylinder head 14. Cylinder head 1
4 is provided with an intake port 17 and an exhaust port 18 communicating with each combustion chamber 16 respectively. In order to open and close these ports 17 and 18, an intake valve 24 and an exhaust valve 25 (see FIG. 3) are supported on the cylinder head 14 so as to be reciprocable.

Air outside the engine body 11 passes through the intake port 17 and is taken into the combustion chamber 16. The cylinder head 14 is provided with an injection valve mounting portion 19, and the fuel injection valve mounted here is provided with an intake port 17.
The fuel is injected toward the downstream side of. Then, a mixture of the fuel injected from each fuel injection valve and the intake air is introduced into each combustion chamber 16. Cylinder head 14
Is provided with a plug mounting portion 21. By the ignition of the spark plug mounted here, the air-fuel mixture introduced into the combustion chamber 16 is exploded and burned. The combustion gas generated in the combustion chamber 16 is discharged to the outside of the engine main body 11 through the exhaust port 18.

Water jackets 22 (cylinder blocks are not shown) are formed in each part of the cylinder block 13 and each part in the cylinder head 14, respectively. Is cooled. Some of the water jackets in the cylinder block 13 enter between the adjacent cylinders 12. To guide the cooling water in this water jacket to the cylinder head 14,
A cooling water passage 23 composed of a vertical hole is formed in the cylinder block 13.
Is provided. This cooling water passage 23 is open on the upper surface of the cylinder block 13.

As shown in FIG. 3, a part of the water jacket 22 in the cylinder head 14 is in a space between the intake port 17 and the exhaust port 18 near the combustion chamber 16. This part is the cylinder head 1
4, the space between the intake valve 24 and the exhaust valve 25 is also referred to as an inter-valve portion 26. Since the inter-valve portion 26 is close to the combustion chamber 16, the temperature tends to be higher than other portions.

A cooling water passage 27 is provided for efficiently cooling the valve section 26. Specifically, as shown in FIG. 2 and FIG. 4B, a columnar projection projecting into the water jacket 22 is provided at a position corresponding to the cooling water passage 23 of the cylinder block 13 at the bottom of the cylinder head 14. 28 are integrally formed. Cooling water passage 2
7 are projections 28 from the bottom surface 14a of the cylinder head 14.
Is formed by a hole 29 extending toward the front end of the hole. The center axis L2 of the hole 29 is eccentric in the deflection direction A of the cooling water with respect to the center axis L1 of the projection 28. One end of the cooling water passage 27 opens to the bottom surface 14a, and the cooling water inlet 3
1. The other end of the cooling water passage 27 opens to the outer peripheral surface 28a of the projection 28 to form a cooling water outlet 32.

The cooling water passage 27 is manufactured by sequentially performing a casting process and a drilling process. In the casting process, as shown in FIG.
And a projection 28 projecting into the water jacket 22 from the bottom of the cylinder head 14 by casting. in this way,
In the casting process originally performed for the production of the cylinder head 14, the projection 28 is also formed. Therefore, a dedicated process for forming the projection 28 is not required.

Next, in the drilling step, the bottom surface of the cylinder head 14 is cut by a cutting tool (perforator) 33 such as a drill while the cooling water is decentered in the deflection direction A with respect to the center axis L1 of the projection 28. A hole 29 is drilled from 14a toward the tip of the projection 28. As shown in FIG.
As shown in (b), a cooling water passage 27 having one end opened to the bottom surface 14a and the other end opened to the outer peripheral surface 28a is manufactured. In this drilling step, only holes 29 need to be drilled at predetermined locations, and no special processing is required.

In the cylinder head 14 having the cooling water passage 27, the relatively low-temperature cooling water that has passed through the cooling water passage 23 of the cylinder block 13 is deposited on the bottom surface 14a as shown by an arrow in FIG. Opening entrance 31
And flows through the cooling water passage 27. When the cooling water reaches the inner part (upper end in FIG. 4B) of the cooling water passage 27, the cooling water changes its flow direction and flows out into the water jacket 22 from the outlet part 32 opened on the outer peripheral surface 28a. The cooling water whose direction has been changed in this way flows along the bottom of the cylinder head 14 toward a desired position (in this case, the inter-valve portion 26) of the cylinder head 14, and cools the same. Thereafter, the cooling water flows together with the original cooling water in the water jacket 22.

According to the first embodiment described in detail above, the following effects can be obtained. (1) a step of forming a horizontal hole 53, a step of forming a vertical hole 55,
The required cooling water passage 27 can be manufactured with a small number of man-hours such as a casting process and a drilling process, as compared with the conventional technology requiring many man-hours such as a process of pushing the bias pipe 56 and a process of closing the lateral hole 53 with the plug 54. In particular, in the drilling step, only one hole is drilled, and the inlet 31 and the outlet 32
Can be manufactured at one time. Moreover, both the casting process and the drilling process do not require complicated operations. Therefore, the manufacturing cost of the cylinder head 14 can be reduced.

(2) Unlike the prior art in which it is necessary to position the biasing pipe 56 in the circumferential and axial directions after opening the horizontal hole 53, this embodiment does not require such complicated work. is there. In the present embodiment, in manufacturing the cooling water passage 27, in the drilling step, it is only necessary to adjust the drilling position (the amount of eccentricity of the central axis L2 from the central axis L1) and the depth to the design values.

(3) By changing the flow direction of the cooling water, it is possible to reliably supply the cooling water to a desired location (interval portion 26). Although the bottom surface 14a of the cylinder head 14 constituting the combustion chamber 16 becomes hot due to the combustion gas, the high temperature portion can be efficiently cooled.

(4) In the prior art, it is necessary to secure a linear space connecting the side surface 51b of the cylinder head 14 and the area 57 of the water jacket 58 in order to form the horizontal hole 53 and mount the offset pipe 56. In addition, the cooling water passage 52 can be set (arranged) only in a very limited portion of the cylinder head 51. In contrast, in the present embodiment,
It is only necessary to secure the space occupied by the projections 28. The cooling water passage 27 can be set at any location where drilling can be performed.

(5) For the hole 29, the opening area of the outlet 32 is changed by changing at least one of the eccentric amount (deviation amount) of the center axis L2 from the center axis L1 and the diameter of the hole 29. The flow rate of the cooling water can be adjusted. Even if the required flow rate of the cooling water differs for each type of engine, it can be easily dealt with.

(6) By changing the orientation of the center axis L2 with respect to the center axis L1, the position of the outlet 32 in the circumferential direction of the projection 28 can be changed, thereby changing the flow direction of the cooling water. For this reason, it is possible to easily cope with any of the deflection directions A of the cooling water. Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. The second embodiment is different from the first embodiment in that a deflection wall 34 is provided near the protrusion 28 in a casting process. Hereinafter, the description will be made focusing on this difference, but the same reference numerals will be given to the same members as those in the first embodiment, and description thereof will be omitted.

As shown in FIGS. 5 and 6, a pair of deflecting walls 34 extending along the deflecting direction A of the cooling water are provided near the projection 28 at the bottom of the cylinder head 14. These deflection walls 34 are connected to the protruding portions 28 in the vicinity of the side of the outlet portion 32. Both deflecting walls 34 have the same height as the projection 28, and both extend parallel to the deflecting direction A.

When manufacturing the cooling water passage 27, a casting step and a drilling step are performed as in the first embodiment. In the casting process, as shown in FIG. 7A, both the deflection walls 34 are integrally formed with the cylinder head 14 and the projections 28 by casting.

In the drilling step, the center axis L1
A hole 29 is drilled from the bottom surface 14a of the cylinder head 14 toward the tip of the projection 28 by a cutting tool 33 such as a drill while the cooling water is decentered in the deflection direction A of the cooling water. By this drilling, as shown in FIG.
The cooling water passage 27 having one end opened to the bottom surface 14a and the other end opened between the two deflection walls 34 and opened to the outer peripheral surface 28a of the projection 28 is manufactured. In this drilling step, only holes 29 need to be drilled at predetermined locations, and no special processing is required.

According to the present embodiment described in detail above, the following effects can be obtained in addition to the effects (1) to (6) of the first embodiment. (7) Even if the cooling water that has flowed out of the outlet portion 32 flows toward the side in the deflection direction A, it is regulated by the deflection wall 34. Further, the cooling water is hardly affected by the flow of the original cooling water in the water jacket 22 due to the deflection wall 34. For this reason, the cooling water from the outlet 32 flows in the deflection direction A substantially along the deflection wall 34 as shown by the arrow in FIG. By directing the flow of the cooling water to a location requiring cooling (the inter-valve portion 26), the location can be cooled more efficiently.

(8) Since the two deflection walls 34 are formed together with the projections 28 in the casting step, a new step for forming the deflection walls 34 is unnecessary. (9) The outlet 32 is opened between the two deflection walls 34.
By appropriately setting the diameter of the hole 29 and the amount of eccentricity of the central axis L1 from the central axis L1, the two deflecting walls 3 can be formed when drilling.
4 can be prevented from being cut off unnecessarily, and a decrease in strength can be prevented.

(10) The deflection wall 34 is mounted on the cylinder head 14
Since it is connected to the bottom and the projection 28, sufficient strength is exhibited. Note that the present invention can be embodied in another embodiment described below.

The present invention is applicable not only to the cylinder head 14 but also to the case where a cooling water passage in the cylinder block 13 is manufactured. -The deflection wall 34 does not necessarily need to be connected to the protrusion 28. That is, the deflection wall 34 may be slightly away from the projection 28 as long as the deflection wall 34 extends substantially along the deflection direction A of the cooling water.

The number of deflection walls 34 is not limited to two,
It can be changed to one or three or more. The deflecting wall 34 does not necessarily have to extend exactly along the deflecting direction A of the cooling water. For example, if the deflection wall 34 is 2
In the case where there are two deflecting walls 34, the deflecting walls 34 may be slightly inclined with respect to the deflecting direction A so that the distance between the deflecting walls 34 becomes smaller as the distance from the protruding portion 28 increases. Conversely, the deflecting walls 34 may be slightly inclined with respect to the deflecting direction A so that the distance between the deflecting walls 34 increases as the distance from the protrusion 28 increases.

The height of the deflection wall 34 may be different from the height of the projection 28. When the number of the deflecting walls 34 is plural, the height between the deflecting walls 34 may be different.
In this connection, the height may be different depending on the position of the deflection wall 34.

When there are a plurality of deflecting walls 34, the deflecting walls 3
The thickness may differ between the four. Further, the thickness may be different depending on the position of the deflection wall 34. .Protrusion 28
A shape other than a columnar shape, for example, an elliptical columnar shape, a polygonal columnar shape,
It can be changed to an appropriate shape.

The present invention is applicable to a direct injection spark ignition type gasoline engine. Further, the present invention is not limited to gasoline engines, but can be applied to other types of engines, for example, diesel engines.

In each of the above embodiments, the holes 29 are drilled in the drilling step so that the central axis L2 is parallel to the central axis L1, but the central axis L2 is slightly inclined with respect to the central axis L1. The hole 29 may be drilled with.

In the case of an engine provided with a plurality of exhaust valves 25 per cylinder, the intake valve 24 and the exhaust valve 25
Not only the inter-valve portion 26, but also the exhaust valve 25 and the inter-valve portion of the exhaust valve 25 are likely to be heated to a high temperature, so that the cooling water may flow toward this portion. The deflection direction A may be any direction as long as it is directed to a location where the temperature is particularly high at the bottom of the cylinder head 14, and is not limited to the inter-valve portion 26 described above.

In the second embodiment, the cooling water passage 27
May enter a part of the deflection wall 34. In this case, it is desirable to form the deflection wall 34 sufficiently thick in the casting process in order to ensure strength.

In addition, technical ideas that can be grasped from the above embodiments will be described together with their effects.
(A) A casting step of forming a projection projecting into the water jacket by casting at a position corresponding to a cooling water passage of a cylinder block in the cylinder head together with a cylinder head having a water jacket, and a center of the projection. A hole is formed from the bottom of the cylinder head toward the tip of the projection in a state where the cooling water is decentered in the direction of deflection of the cooling water with respect to the shaft, so that the inlet of the cooling water passage is opened on the bottom of the cylinder head. And forming a cooling water passage outlet on the outer surface of the projection.

According to the above construction, in addition to the same effect as the first aspect of the present invention, the relatively low-temperature cooling water flowing through the cooling water passage of the cylinder block is guided to the high-temperature portion at the bottom of the cylinder head. This part can be efficiently cooled.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the structure of a cylinder head according to a first embodiment of the present invention.

FIG. 2 is a partial perspective view of a cooling water passage provided in a cylinder head.

FIG. 3 is a schematic plan view showing a positional relationship between an inter-valve portion and a cooling water passage.

FIGS. 4A and 4B are partial cross-sectional views showing steps of manufacturing a cooling water passage.

FIG. 5 is a partial perspective view of a cooling water passage according to a second embodiment of the present invention.

FIG. 6 is a schematic plan view showing a positional relationship between an inter-valve portion and a cooling water passage.

FIGS. 7A and 7B are partial cross-sectional views illustrating a process of manufacturing a cooling water passage.

FIG. 8 is a partial sectional view showing a conventional engine cooling water passage.

[Explanation of symbols]

11: engine body, 14a: bottom, 22: water jacket, 27: cooling water passage, 28: projection, 28a
... outer peripheral surface, 29 ... hole, 31 ... inlet part, 32 ... outlet part, 3
4. Deflection wall, A: Deflection direction, L1, L2: Central axis.

Claims (4)

[Claims] 1. A protrusion provided by casting together with an engine body having a water jacket and projecting into the water jacket, wherein the protrusion is eccentric in a direction of deflecting the cooling water with respect to a center axis of the protrusion. A cooling structure for an engine, comprising: a cooling water passage formed by a hole extending toward a tip of the projection and having an outlet opening on an outer surface of the projection. 2. A deflecting wall is formed in the vicinity of the outlet portion by casting together with the engine body and the projection, and extends along a substantially deflecting direction of the cooling water. Engine cooling structure. 3. A casting step in which a projection projecting into the water jacket is formed by casting together with an engine body having a water jacket, and the cooling water is decentered in a direction of deflecting the coolant with respect to a center axis of the projection. Forming a hole in the outer surface of the projection by drilling a hole toward the tip of the projection in the state. 4. A deflecting wall extending along a substantially deflecting direction of the cooling water together with the engine main body and the protruding portion is formed near the protruding portion when the casting step is performed. A method for manufacturing an engine cooling water passage according to the above.