JP5330088B2 - Cylinder head water jacket structure - Google Patents

Description

  The present invention relates to a water jacket structure for a cylinder head in which a cooling water passage for cooling the periphery of a plurality of combustion chambers is formed inside a cylinder head of a multi-cylinder engine.

  A pair of water jackets surrounding the periphery of two exhaust valves and a water jacket surrounding the periphery of one spark plug are formed on the upper wall of the combustion chamber of the cylinder head of the engine. Japanese Patent Application Laid-Open Publication No. 2004-228707 discloses a water jacket that is connected to a water jacket that surrounds a spark plug.

Special Table 2007-530851

  By the way, a water jacket that cools the high-temperature portion around the combustion chamber of the cylinder head includes two main cooling water passages through which cooling water flows in the same direction, and one communication water passage that connects these main cooling water passages to each other. When the shape of the two main cooling water passages and one communication water passage are symmetrical with respect to the center line, and the flow rate of the cooling water flowing through the two main cooling water passages is the same , The pressure of the opening communicating with the main cooling water passage is antagonized, and the cooling water in the communication water passage becomes stagnant and does not flow smoothly, and the communication water passage is sufficient for cooling the high temperature part around the combustion chamber. There is a problem of not contributing.

  The present invention has been made in view of the above-described circumstances. When the two main cooling water passages of the water jacket that cools the high-temperature portion around the combustion chamber of the cylinder head are connected by one communication water passage, The purpose is to eliminate the stagnation of cooling water.

In order to achieve the above object, according to the first aspect of the present invention, a combustion chamber that divides the combustion chamber into a cylinder head of a multi-cylinder engine in which a plurality of combustion chambers are arranged in a cylinder row direction. And a cooling water passage for flowing cooling water from the intake side to the exhaust side or from the exhaust side to the intake side to cool the vicinity of the upper wall of the combustion chamber. Are an upstream valve hole located upstream in the flow direction of cooling water, a downstream valve hole located downstream in the flow direction of cooling water, and a spark plug and a fuel injection valve at a position sandwiched between the valve holes. A cooling member insertion hole into which at least one of the cooling member passage is inserted, and the cooling water passage includes a wall portion in which the upstream valve hole is formed, a wall portion in which the cooling member insertion hole is formed, In the intake and exhaust direction through the wall portion where the downstream valve hole is formed And a pair of cooling water passages adjacent to each other in the cylinder row direction are connected between the wall portion where the upstream valve hole is formed and the wall portion where the member insertion hole is formed. A water jacket structure of a cylinder head in which a communication water passage is formed in a wall portion where the upstream valve hole is formed in the vicinity of one opening portion where the communication water passage opens into the pair of cooling water passages. A water jacket structure for a cylinder head is proposed in which a protrusion is provided that protrudes toward the downstream side of the cooling water passage in the cooling water flow direction.

  According to the invention described in claim 2, in addition to the configuration of claim 1, the protruding portion is provided on the wall portion of the pair of cooling water passages on the side where the flow rate of cooling water is low. A water jacket structure of a cylinder head characterized by the above is proposed.

  The intake valve hole 14 of the embodiment corresponds to the upstream valve hole of the present invention, the exhaust valve hole 15 of the embodiment corresponds to the downstream valve hole of the present invention, and the spark plug insertion hole of the embodiment. 16 corresponds to the member to be cooled insertion hole of the present invention, and the main cooling water passage 20a of the embodiment corresponds to the cooling water passage of the present invention.

According to the configuration of the first aspect of the present invention, on the upper wall of the combustion chamber of the cylinder head of the multi-cylinder engine, in the intake and exhaust direction , the cooling water passage for flowing the cooling water from the intake side to the exhaust side or from the exhaust side to the intake side , The side valve hole, the downstream side valve hole, and the cooled member insertion hole are formed, and the cooling water passage passes through the wall portion where the upstream side valve hole, the cooled member insertion hole and the downstream side valve hole are formed. A pair of cooling water passages adjacent to each other in the cylinder row direction are connected between the wall portion in the intake / exhaust direction and the wall portion in which the upstream valve hole is formed and the wall portion in which the member insertion hole is formed. Since the communication water passage is formed, the wall portion in which the upstream valve hole, the member insertion hole to be cooled and the downstream valve hole are formed can be cooled by the cooling water flowing through the pair of cooling water passages, and the flow through the communication water passage Cooling the wall portion in which the upstream valve hole and the member insertion hole to be cooled are formed with cooling water Door can be. At this time, if the flow rate of the cooling water flowing through the pair of cooling water passages is antagonized, the cooling water in the communication water channel connecting them stagnate and does not contribute to cooling, but the communication water channel opens to the pair of cooling water passages In the vicinity of the one opening portion, the wall portion where the upstream valve hole is formed is provided with a protruding portion protruding toward the downstream side in the cooling water flow direction of the cooling water passage. The flow of the cooling water in the pair of cooling water passages becomes unbalanced, and the stagnation of the cooling water in the communication water channel is eliminated, and the cooling effect is enhanced.

  According to the second aspect of the present invention, since the protrusion is provided on the wall portion of the pair of cooling water passages where the flow rate of the cooling water is low, the passage of the cooling water passage where the flow rate of the cooling water is low is interrupted. By narrowing the area by the protruding portion of the wall portion and increasing the flow velocity, the flow velocity of the cooling water in the pair of cooling water passages can be made uniform to effectively cool the upper wall of the combustion chamber.

Sectional drawing of the direction orthogonal to the cylinder axis line of the cylinder head of an in-line four cylinder engine. FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. The top view of the core which shape | molds the water jacket of a cylinder head. The bottom view of the core which shape | molds the water jacket of a cylinder head. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view of a cylinder head 11 of an in-line four-cylinder engine cut along a plane parallel to a coupling surface with a cylinder block, as viewed from above (head cover side). The upper side is the exhaust side. Four combustion chambers 12 are arranged along the cylinder line L1 on the lower surface (the back side of the paper surface) of the cylinder head 11, and two intake valve holes are formed in the combustion chamber upper wall 13 shown in cross section. 14, two exhaust valve holes 15, 15 and a spark plug insertion hole 16 surrounded by them are formed.

  Inside the cylinder head 11, a water jacket J surrounded by an intake side wall 11a, a timing chain chamber side wall 11b, an exhaust side wall 11c and a transmission side wall 11d is shown in white. 6 and 7 show the shape of the core 17 used when casting the cylinder head 11, and the shape of the core 17 is the same as the shape of the water jacket J. FIG. Hereinafter, the structure of the water jacket J will be described with reference to FIGS. 1, 6, and 7.

  The water jacket J connects the intake side gallery 18 along the intake side side wall 11 a of the cylinder head 11, the exhaust side gallery 19 along the exhaust side side wall 11 c of the cylinder head 11, and the intake side gallery 18 and the exhaust side gallery 19. Individual passage expansion portions 20... The three passage expansion portions 20 are arranged on the cylinder row line L1 and at positions sandwiched between the four combustion chambers 12. The intake side gallery 18 and the exhaust side gallery 19 at the lower position of the cylinder head 11 are indicated by solid lines in FIG. 1, but the three passage expansion portions 20 are higher than the intake side gallery 18 and the exhaust side gallery 19. Because of its position, it is shown in phantom in FIG.

  A cooling water inlet 18a to which cooling water is supplied from a cooling water pump provided in the cylinder block is provided on the lower surface of the intake side gallery 18, and the four cylinder axes L2,. Four first cooling water passages 18b extend from the cooling water inlet 18a toward the position a. From the four a positions, each of the two second cooling water passages 18c extends toward the cylinder row line L1, and the three to six second cooling water passages 18c that gather together are The three passage positions 20 between the four combustion chambers 12 communicate with the three passage extensions 20.

  A total of eight second cooling water passages 18c are formed with communication holes 18d communicating with the water jacket on the cylinder block side, and a part of the cooling water flowing through the intake side gallery 18 is formed with the communication holes 18d. Is distributed to the water jacket on the cylinder block side. Further, the exhaust side gallery 19 is formed with four communication holes 19a at positions shifted from the four cylinder axis lines L2 to the exhaust side, and a part of the cooling water flowing through the exhaust side gallery 19 is in communication. It passes through the holes 19a and is distributed to the water jacket on the cylinder block side. Two cooling water outlets 19b and 19b are formed at a position near the transmission side wall 11d of the exhaust side gallery 19, and the cooling water that has flowed through the water jacket J to the end passes through the cooling water outlets 19b and 19b to form a cylinder. Returned to the water jacket on the block side.

  Next, the structure of the channel | path extension part 20 is demonstrated based on FIGS.

  Since the three passage expansion portions 20 at positions sandwiched by the four combustion chambers 12 on the cylinder line L1 have substantially the same structure, the one passage expansion portion 20 will be described below. .

  The passage expanding portion 20 communicates the intake side gallery 18 and the exhaust side gallery 19, and by forming a rib 21 in the vertical direction at the center thereof, the cooling water can be moved in the left and right direction (two Two main cooling water passages 20a, 20a are formed for diversion in the direction of the two combustion chambers 12, 12. Accordingly, the cooling water flowing through the passage expanding portion 20 branches to the two main cooling water passages 20a and 20a that bypass the rib 21 at the b position on the intake side, and then merges again at the c position on the exhaust side to form the exhaust side gallery. 19 flows into.

  That is, as is apparent from FIG. 8, the cooling water flowing into the passage expanding portion 20 at the position b is blocked by the rib 21 and branches into the left and right main cooling water passages 20a and 20a, and the intake valve holes 14 and 14 are formed. After cooling the wall portions 11e and 11e, the wall portion 11f in which the spark plug insertion hole 16 is formed, and the wall portions 11g and 11g in which the exhaust valve holes 15 and 15 are formed, at the position c on the exhaust side. It merges again and flows into the exhaust side gallery 19.

  Two main cooling water passages 20a, 20a opposite to each other of two passage expansion portions 20, 20 adjacent to each other in the direction of the cylinder line L1 are provided with wall portions 11e, 11e in which intake valve holes 14, 14 are formed, and ignition. It is connected by a communication water passage 20b disposed between the wall portion 11f in which the plug insertion hole 11f is formed, and the wall portions 11e and 11e of the intake valve holes 14 and 14 and the ignition by the cooling water flowing through the communication water passage 20b. The wall portion 11f of the plug insertion hole 16 is further cooled.

  In FIG. 8, the flow rate of the cooling water (see arrow A1) flowing through the main cooling water passage 20a of the left passage expansion portion 20 and the cooling water flowing through the main cooling water passage 20a of the right passage expansion portion 20 (see arrow A2). If the flow rate of the refrigerant is antagonized, the cooling water stays in the communication water passage 20b that allows the two main cooling water passages 20a and 20a to communicate with each other, and the wall portions 11e of the intake valve holes 14 and 14 that the communication water passage 20b faces. 11e and the cooling effect of the wall portion 11f of the spark plug insertion hole 16 are reduced.

  In order to solve this problem, in the present embodiment, one of the wall portions 11e and 11e of the left and right intake valve holes 14 and 14 facing the opening portions at both ends of the communication water channel 20b (in the embodiment, on the right side of FIG. 8). A protruding portion 11h that protrudes from the intake side toward the exhaust side is formed in the wall portion 11e) of the intake valve hole 14.

  By forming this protrusion 11h, the cooling water (see arrow A2) flowing through the main cooling water passage 20a on the right side in the figure is directed to the exhaust side and hardly flows into the right end opening of the communication water passage 20b. On the other hand, the cooling water (see arrow A1) flowing through the main cooling water passage 20a on the left side in the figure is likely to flow into the left end opening of the communication water passage 20b because there is no protrusion 11h, and the communication is lost due to the loss of the balance. The flow of the cooling water from the left to the right indicated by the arrow A3 is generated in the water channel 20b, and the cooling effect of the wall portions 11e, 11e of the intake valve holes 14, 14 and the wall portion 11f of the spark plug insertion hole 16 can be enhanced. .

  In addition, it is desirable to provide the side where the protrusion 11h is provided on the side of the left and right main cooling water passages 20a, 20a where the flow rate of cooling water is low. The reason is that by providing the protrusion 11h, the main cooling water passage 20a is throttled and the flow velocity increases, so the flow velocity of the cooling water flowing in the left and right main cooling water passages 20a, 20a is made uniform, and the cooling effect is made uniform. Because it can be done.

  Next, the structure of the rib 21 provided in the center of the channel | path expansion part 20 is demonstrated based on FIGS. 2-5 and FIG.

  The rib 21 erected at the center of the passage expanding portion 20 is formed in a substantially columnar shape, and both ends of the through water passage 20c formed in the direction of the cylinder row line L1 are left and right main cooling water passages 20a and 20a. Open to. A branch water channel 20 d extends from the central portion of the through water channel 20 c toward the exhaust side, and an outlet end thereof opens at a point c of the exhaust side gallery 19. The through water channel 20c and the branch water channel 20d are formed in a substantially T shape in the horizontal cross section (see FIGS. 4 and 8), and the rib 21 is formed by one semicircular portion and two fan-shaped portions in the horizontal cross section. To separate. Accordingly, a part of the cooling water flowing through the left and right main cooling water passages 20a, 20a flows in from both ends of the through water channel 20c and flows toward the center, then flows into the branch water channel 20d and flows out to the exhaust side gallery 19. To do.

  In the upper half of the rib 21, a pin hole 21 a that extends upward from the intersection of the through water channel 20 c and the branch water channel 20 d and penetrates to the upper surface of the cylinder head 11 is formed. The bottom of the pin hole 21a, that is, the upper side of the intersecting portion of the through water channel 20c and the branch water channel 20d is closed by the press-fitting of the cap 22, thereby preventing the cooling water from leaking from the pin hole 21a.

  When the cylinder head 11 is cast, the core 17 (see FIGS. 6 and 7) for forming the water jacket J is supported in the cavity of the mold via a plurality of core pins. The lower end of the core pin 23 (see FIGS. 2 and 5) of the book is applied to the center portion of the rib 21, more specifically to the portion where the penetrating water channel 20c and the branch water channel 20d of the core 17 are intersected. By contact, the core 17 is held in the mold.

  3 and 4, reference numeral 24... Is an intake port connected to the intake valve hole 14..., And 25 is an exhaust port connected to the exhaust valve hole 15.

  As described above, the core pin 23 is inserted into the central portion of the rib 21 to form the pin hole 21a, and therefore the weight of the cylinder head 11 is reduced by reducing the thickness of the rib 21 by the amount of the pin hole 21a. Can do. Further, it is difficult to secure the arrangement space for arranging the core pin 23 while avoiding the position of the rib 21, or it becomes difficult to arrange the core pin 23 at an appropriate position, thereby strengthening the core 17. Although it cannot be supported, according to the present embodiment, the above problem can be solved.

  Further, since the through water channel 20c and the branch water channel 20d are formed inside the rib 21, it is possible to further reduce the weight of the cylinder head 11 by reducing the thickness of the rib 21, and to effectively cool the rib 21. be able to.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the water jacket J of the embodiment, the cooling water flows from the intake side to the exhaust side of the cylinder head 11, but the cooling water may flow from the exhaust side to the intake side.

  The member to be cooled inserted into the member to be cooled insertion hole of the present invention is a spark plug, but the member to be cooled may be a fuel injection valve.

  In the embodiment, three of the four communication channels 20b are provided with projections 11h in three communication channels 20b (see FIG. 6 and FIG. 7), but at least one communication channel 20b is provided with at least one communication channel 20b. The protrusion part 11h should just be provided.

11 Cylinder head 11e Wall part 11f in which upstream valve hole is formed Wall part 11g in which cooled member insertion hole is formed Wall part 11h in which downstream valve hole is formed Projection part 12 Combustion chamber 13 Combustion chamber upper wall 14 Intake Valve hole (upstream valve hole)
15 Exhaust valve hole (downstream valve hole)
16 Spark plug insertion hole (cooled member insertion hole)
20a Main cooling water passage (cooling water passage)
20b Communication channel L1 Cylinder row line

Claims (2)

A combustion chamber upper wall (13) that partitions the combustion chamber (12) into a cylinder head (11) of a multi-cylinder engine in which a plurality of combustion chambers (12) are arranged in a cylinder row line (L1) direction, and the combustion A cooling water passage (20a) is provided in the intake / exhaust direction to cool the vicinity of the chamber upper wall (13) and allows cooling water to flow from the intake side to the exhaust side or from the exhaust side to the intake side ,
The combustion chamber upper wall (13) has an upstream valve hole (14) positioned upstream in the flow direction of cooling water, a downstream valve hole (15) positioned downstream in the flow direction of cooling water, A cooled member insertion hole (16) into which at least one of the spark plug and the fuel injection valve is inserted is formed at a position sandwiched between both valve holes (14, 15),
The cooling water passage (20a) includes a wall (11e) in which the upstream valve hole (14) is formed, a wall ( 11f ) in which the member insertion hole (16) is formed, and the downstream The wall portion (11e) in which the side valve hole (15) is formed and extending in the intake / exhaust direction through the wall portion (11g) is formed, and the cooled member is inserted into the wall portion (11e) in which the upstream valve hole (14) is formed. A communication water passage (20b) is formed between the wall portion (11f) where the hole (16) is formed so as to connect the pair of cooling water passages (20a) adjacent in the direction of the cylinder row (L1). The water jacket structure of the cylinder head
In the vicinity of one opening where the communication water channel (20b) opens to the pair of cooling water channels (20a), the cooling water channel (11e) is formed in the wall (11e) where the upstream valve hole (14) is formed. A water jacket structure for a cylinder head, which is provided with a protrusion (11h) protruding toward the downstream side in the flow direction of the cooling water 20a).   The cylinder head according to claim 1, wherein the protrusion (11h) is provided on the wall (11e) on the side of the pair of cooling water passages (20a) on which the flow rate of cooling water is low. Water jacket structure.

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